FCC ID: NX5XDD-1000C C-BAND DOPPLER WEATHER RADAR

 

Technical Manual C-Band 1 MW Transmitter Pulse Systems Part Number TR-1038 Magnetron SFD 313A August 22, 2003 Prepared By:

Pulse Systems Inc. 222 Bolivar Street Canton, MA 02021 Prepared For Barron Services 4930 Research Drive Huntsville, AL 35805 TABLE OF CONTENTS GENERAL DESCRIPTION..................................................................... 2 Introduction.................................................................................. 2 System Specifications .................................................................... 2 General Technical Discussion.......................................................... 2 Mechanical................................................................................... 4 POWER SUPPLY SECTION .................................................................. 6 Technical Approach ....................................................................... 6 Schematic Diagram........................................................................ 6 Mechanical Considerations.............................................................. 8 Interface ...................................................................................... 8 MODULATOR SECTION....................................................................... 9 Technical Approach ....................................................................... 9 Schematic diagram ........................................................................ 9 Mechanical Considerations............................................................ 10 Interface .................................................................................... 11 MAGNETRON HEATER POWER SUPPLY .............................................. 12 Technical Discussion ................................................................... 12 OPERATING INSTRUCTIONS.............................................................. 13 Procedure For Setting All System Parameters ................................... 13 MAINTENANCE................................................................................ 15 Introduction................................................................................ 15 The Power Supply Section............................................................. 15 The Modulator Section.................................................................. 15 APPENDIX...................................................................................... 16 Magnetron Specifications.............................................................. 17 Figures...................................................................................... 35 GENERAL DESCRIPTION Introduction The system described in this manual consists of four main parts:

A:

B. C. D. The Main High Voltage Power Supply The Modulator System The Corner Cutter Filament Power Supply In order to achieve the design objectives of this contract, our design approach has to follow state-of-the-art technology in solid-state design. The evolution of third generation IGBT technology and the various power supply topologies makes it a challenge to make the right choice for our present application. The design objective calls for generating narrow pulses of various pulse-widths under single pulsing conditions. The cathode pulses will drive a CPI Magnetron operating in the C-Band frequency with minimum peak output power 1.0 Mw. The power supply section is self-contained in an enclosure as shown in Figure 1.0. Our design is based on series resonance topology driving a full bridge circuit. The modulator is a hard-tube type, utilizing IGBT technology, and is under oil environment. The mechanical enclosure for the modulator is shown on Figure 2.0 System Specifications The specifications for the systems are outlined in the Appendix along with the magnetron specifications. General Technical Discussion As previously mentioned, the whole system consists of the high-voltage power supply and the solid-state hard tube modulator. The solid-state power supply contains the following sections:

A. B. C. D. E. Off-Line Rectifiers, Filters, and Controls Series Resonance Full Bridge Inverter Series Resonance Frequency Modulation Control High Voltage Output Section Low Voltage Power Supplies F. G. Hard Tube Modulator Control Solid-State Filament Power Supply The Modulator section contains the following sections:

A. B. C. D. Switch Driver Assy PRF Driver High Power Switch Section Magnetron Peak Current Detector The input voltage for the system is 220 VAC single phase and it enters the system via a connector located in the rear lower panel of the cabinet. The input line voltage enters the system via a circuit breaker located on the control panel. The control panel is located on the front upper section of the main cabinet. Figure 3.0 shows the mechanical configuration of the system. The front view of cabinet shows the control panel located on the upper section. The main electrical system diagram is shown on figure 4.0. The main power is switched on by the circuit breaker on the control panel and is further fused before entering the power supply section. It enters the front end of the power supply and is applied to the power factor correction section. The Power Factor Correction Module performs the rectification, in-rush current limiting and preregulation of the input line voltage. The power factor module provides a preregulated DC Voltage level of 360 VDC. The above 360 VDC is applied to the input of the series resonance converter which, in turn, provides a final adjustable level of 0-900 VDC available at the modulator section. The above DC output is sent to the modulator section through three of wires leaving the back of the power supply section. The input PRF, which is TTL level, enters the control panel and is further processed by the Modulator control circuit. It enters the Modulator Control Circuit, which transforms this input signal to a selectable pulse-width level proper for triggering the modulator section of the system. The modulator control circuit performs additional functions, as will be discussed later under the Power Supply section. Figure 5.0 shows the complete power supply section of the system. The power supply also provides the low voltage bias levels required by the modulator. The modulator section receives the trigger input from the modulator control circuit located in the power supply. The function of the modulator is to receive the input signal and provide a high-power pulse of 36-38 KV at the cathode of the magnetron, thus causing the magnetron to oscillate at C-Band frequency under the selected pulse width set by the modulator control circuit. The maximum cathode peak current under the above conditions is 60 Amperes peak. The above voltage and current levels result in a peak output power of 1.0 MW. In the meantime, the filament power supply requires programming according to the magnetron specifications. For the stand-by condition, the filament voltage is set to 5.0 VDC at 18-22 Amps and is reduced to 2.0 VDC at the maximum duty cycle of

.001. The cathode voltage is fed to the magnetron via the high voltage bushing located on top of the modulator. The magnetron peak current is being monitored via a wide band current transformer under the magnetron and over the modulator section. The sensitivity of the current transformer is set to 0.1v/ amp. For example, if we are looking at the scope displaying the current monitor output, a 6.0 volt peak pulse level will indicate 60 Amps peak magnetron current. Next to the modulator high voltage output terminal is a spark gap, which prevents the magnetron from reaching much higher than normal pulse voltage levels. The voltage of the spark gap is set to 45 KVPK. When the magnetron misfires the pulse output voltage could theoretically reach a maximum pulse voltage level of 76 KV. The spark gap limits this level to a maximum of 45 KV pulse thus reducing the voltage stress level of the system to a more reasonable level. Mechanical As previously mentioned, the mechanical outline drawings of both the power supply and modulator are shown in Figures 1.0 and 2.0. Figure 3.0 shows the mechanical outline of the whole system The power supply is of dry construction and is mounted on rails at the lower section of the equipment cabinet. It can be removed by first removing the rear connections at the rear section of the unit and then slide the whole assembly out of the cabinet. The modulator on the other hand is contained in an oil-filled container for insulating and cooling reasons. The modulator is mounted above the power supply on its own compartment. Next to the modulator, the corner cutter assembly is mounted and its output is connected to the cathode terminal of the modulator. The magnetron is mounted above the modulator shelf and the high voltage bushing projects into the modulator compartment through a hole located on the magnetron shelf. Under this hole, the wide band current transformer is mounted and its output is terminated to a BNC connector located on the control panel. The magnetron compartment provides the space for the assembly of all the microwave components required by the system. POWER SUPPLY SECTION Technical Approach In order to meet our design objectives of reliability, efficiency, simplicity and cost, our approach for the system is derived from our past experience. For the power supply, we feel that the series resonance converter topology is the best choice. First the efficiency of the system is greatly optimized under this topology and both the RFI and EMI levels are kept at a minimum. In contrast with PWM systems, the series resonance converter operates smoothly with sine wave currents, rather than square wave excitation. Efficiency levels of 95% are easily attained under the chosen power supply topology with proper design techniques. For the modulator section of the system, the approach is a hard tube modulator topology using solid-state technology switching. Schematic Diagram Figure 5.0 shows the complete schematic of the power supply. The main sections of the power supply are as follows:

The input power enters the power supply at the command of the 24-VDC-control voltage. Relay K2 receives the +24vdc level and allows the main power to enter the power supply. The control transformer T-1 when energized provides four regulated output voltage levels:

Input relay section Power factor section Full bridge inverter section High voltage output section SRI control circuit Heater PWM & Metering circuit Magnetron heater section

+24 VDC

+28 VDC

+15 VDC A:

B:

C:

D:

E:

F:

G:

A;

B:

C:

D:

-12 VDC The above voltage levels are regulated via linear series regulator circuits with associated filter networks. The input line voltage enters next the Power Factor Correction Circuit. The power factor modules (three) rectify the input line voltage, regulate it, and limit the input inrush current to a reasonable level. The final level of 360 VDC is applied to a capacitive input filter properly sized for the full power of the system and, finally, is applied to the full bridge circuit shown next to the power factor circuit. The full bridge circuit is driven by the SRI Control circuit, which generates, regulates and provides protection for the whole power supply system. The SRI control circuit sends two drive pulses, noted as Drive A and Drive B. Both pulses are identical in amplitude and pulse-width but they are frequency modulated, depending on the power demand of the system. This is the way the power supply regulates. When the load demands more power, the frequency of the drive pulses is raised to a higher level and when the load demand diminishes, the frequency slows down to the point that the system meets its regulating requirements. The two drive pulses are applied to the bridge circuit of the main inverter and they drive the main switches into full conduction during their on state and off during their off state. Turn-on and turn-off occur at zero current switching conditions. This alternating voltage waveform is impressed across the primary winding of the inverter transformer, with the proper turns ratio, the output is rectified and filtered to a maximum level of 900 VDC. The output voltage of the power supply is controlled by a potentiometer located at the front control panel. The top arm of the potentiometer is connected to +10 VDC and the wiper is connected to one terminal of an operational amplifier. The other input terminal of the operational amplifier is connected to the feedback terminal of the output section of the power supply. The design objective is to keep the two input terminals of the operational amplifier to an equal level. If the arm of the potentiometer is set to a higher voltage level, thus demanding higher output voltage from the power supply, the feedback signal is raised to the same corresponding level as the arm of the potentiometer. This is the way the system regulates against input and load variations. Metering circuits are provided for the output voltage of the power supply, the output current, the filament voltage, the magnetron average current and the system voltage. The return section of the power supply goes through a sensing resistor whose level is detected and processed for over-current protection. Mechanical Considerations Figure 1.0 shows the mechanical configuration of the power supply. The enclosure is made of chemically treated aluminum alloy and is cooled with fans located inside the power supply frame. The power level of the power supply system is set to a maximum of 5.0. KW. The maximum temperature rise of the power supply is 25 degrees Centigrade over the ambient temperature. The system operating at maximum duty cycle of .001 requires a power level of 36,000 x 60 x .001 = 2,160 watts. If we assume a system efficiency including both the power supply and modulator of 75%, the power level of the power supply becomes 2,880 watts, which is lower than the maximum power supply limit of 5000 watts. Interface The power supply is controlled by the front panel controls of the main cabinet of the system. The local control in the front panel of the power supply adjusts the output level of the power supply and performs also the resetting action against various system faults. The radiate command and pulse width selection is done also via the front panel controls. All controls and monitors are located in the front control panel. The power supply communicates with the modulator and monitors fault conditions relating to the magnetron misfiring, over-current and over-duty conditions. Figure 4.0 is a functional diagram showing the power supply and modulator interconnected with the control panel. MODULATOR SECTION Technical Approach Several solid-state modulator systems have been designed, built, and delivered by Pulse Systems. All designs feature the Mosfet or IGBT technology. Our design approach for reliable operation has been to limit the switching voltage level within the solid-state switch capability and to avoid stacking switches in series configuration. The design approach is shown in Figure 6.0 Schematic diagram For the discussion, which follows, we make reference to Figure 6.0 The whole system is enclosed in oil environment for insulating and cooling reasons. Figure 6.0 shows the main sections that are contained in the modulator system. The PRF driver is set at the front section of the system. It receives its signal from the modulator control, designed to be slaved to an external PRF generator. The only control that the external generator has over the modulator control is the frequency count. The rest of the pulse width processing and control is governed by the modulator control circuit. The complete modulator system consists off three drive circuits, a supervisory control circuit governing the operating conditions of the drive circuits and the output section. The output section consists of a solid state switch assembly, three high voltage step-

up pulse transformers, and a pulse shaping network. In order to generate the narrow pulses with proper rise and fall time, the pulse transformer design demands special consideration in selecting the proper magnetic material and proper winding configuration. This information is proprietary to Pulse Systems Inc. The magnetron tube also requires proper rate of rise of the cathode voltage. This level has to be kept between 90 and 110 kV/sec in order to avoid magnetron moding. In order to achieve this low rate of rise of voltage, a corner cutter is added to the system to prepare the tube before conduction. The schematic diagram of the corner cutter is shown in figure 6 next to the modulator circuit diagram. The solid state switch assembly is turned on during the positive portion of the drive pulse and kept off when the drive pulse goes to a negative bias level. The output pulse-width of the system bears a close relationship to the drive pulse of the switch driver. The pulse current is monitored via a wide-band current transformer and fed back to the peak over current detector, which removes the drive pulse from the switch driver circuit if the magnetron pulse current is out of specification. The modulator control circuit has a provision and allows a number of peak over-

current conditions within the time frame of one minute. This number is selectable via a switch assembly located in the modulator control circuit. Missing magnetron pulses and magnetron misfiring occurs quite often and the above-mentioned quality of the modulator control circuit is essential to allow the system to run and overcome the magnetron temporary miss occurrences. If the abnormalities associated with magnetron continue on beyond the set limits, the system latches to the stand-by condition and a manual reset is required. The magnetron average current level is also detected in the same way and controlled. Figure 6 shows also the schematic of the corner cutter. Diodes D1-D40 are isolating special high voltage diodes and they isolate the corner cutter from the secondary high voltage pulse up to the threshold point set by the string of the zener diodes. What the corner cutter really does is to allow the cathode voltage to reach 75% of its full voltage at a very fast rate and when conduction begins the corner cutter capacitor is connected to the output pulse loading down its rate of rise. The value of the corner cutter capacitor and the resistor in series determine the rate of rise of voltage during conduction of the magnetron tube. The mechanical outline drawing of the corner cutter is shown in figure 7.0. Mechanical Considerations The modulator outline drawing is shown in Figure 2.0. The modulator top section contains all the necessary terminals for the proper operation of the system. Terminals E7, E8, and E9 are connected to the high voltage section of the power supply and provide high voltage to the four modulator channels. Terminals E4 and E5 are connected to the primary winding of the heater power supply inverter transformer. There is a BNC connector located along the same line with the above terminals dedicated for the input drive pulses from the modulator control circuit. All the terminals located above the BNC connector are the control and feedback voltages to and from the modulator. Directly across the input heater terminals we see a high-voltage bushing dedicated for the cathode and heater of the magnetron tube. The cathode terminal is connected to a high voltage spark gap located next to the high voltage bushing. Interface The modulator connections to the power supply and to the rest of the system are shown in Figure 4.0. MAGNETRON HEATER POWER SUPPLY Technical Discussion The magnetron heater power supply consists off three parts:

A. B. C. Heater meter control card High voltage inverter transformer Filter section The control card for the heater power supply is shown in figure 8.0. The control circuit generates a PWM signal to drive a discontinuous mode power supply. The high voltage section of the power supply is inside the modulator including the filter section and feedback. The feedback signal returns to the control circuit and regulates the heater voltage for both stand by and full duty cycle conditions. The feedback signal is fed back through the bifilar winding of the pulse transformer. The control card provides the metering circuit for the filament voltage. OPERATING INSTRUCTIONS Procedure For Setting All System Parameters After the system has been received and inspected a cable should be prepared for the outside power connection to the 220 VAC 50/60 Hz. The external source should be capable of providing 220 VAC 50/60 Hz at a minimum current of 25 amps. Before we apply power to the system, we make sure that the high voltage adjust potentiometer is set all the way counter clockwise. This ensures that when the power supply turns on, it will start at almost zero volts DC. This is only essential when we first set the system up and after we have completed all the steps, the system can return to its previous settings without further adjustments. We now turn the power supply on by turning on the main circuit breaker on and the power on switch. We notice at this point that the +24VDC and the warm up light indicators are turned on. We have to wait five minutes approximately for the heater to come up to the right temperature before being able to radiate power. Also, we notice that the monitor indicating the heater voltage is up to the proper voltage level of 5.0 VDC. We monitor through an external oscilloscope the peak magnetron current. When the ready light turns on (after five minutes) we turn the radiate switch on and proceed turning the RF control potentiometer clockwise raising the modulator power to the point where a rectangular current pulse is being displayed on the oscilloscope. The sensitivity of the scope should be set to 1.0 per division indicating 10 amps/division and the total current display should be six divisions high, thus indicating 60 amps, which is the maximum magnetron current for 1.0 MW power output level. The system has to operate within the specified conditions. The modulator will power the magnetron smoothly under all pulsing conditions. Because the power supply and modulator are quite adjustable in terms of voltage amplitude and pulse width, the output system performance could easily get out of specification and either the duty cycle or the peak cathode current of the magnetron can be exceeded. The two most important things to remember are the 60 Amperes of peak cathode current and the 0.001 duty cycle. The peak cathode current is easily observed on the screen of the oscilloscope. In the case of the duty cycle, each pulse condition has to be evaluated to ensure compliance with the magnetron specification. Since the product of the pulse width in usec and the pulse repetition rate in cycles gives directly the value of the duty cycle, we have to mathematically evaluate it before proceeding with any pulse condition. The pulse shape has to meet the specifications in terms of rise and fall time. Also an important parameter is the rate of rise of the cathode voltage. This parameter has been set by the manufacturer as the time of the steepest tangent, between the 70%

point of the cathode voltage crossing the zero axis. MAINTENANCE Introduction This sections covers information regarding the maintenance of the system. In general, the incorporation of solid-state devices makes the system an easier system to care for as time goes on. There is basically no component in the system that has a time limit or exhibits performance degradation as a function of time. The Power Supply Section The power supply section is cooled by forced air-cooling fans located in the rear section. The reliability of the selected fans is quite high and, so far, we have not encountered any problem in this area. Periodic examination to ensure that no build up of any foreign material is accumulating in any area near the cooling fans is essential. Removing the power supply top cover for a quick examination is recommended every year to ensure that the air flow passages are clean, that no evidence of overheated parts is present, and that all other components are in normal operating condition. The Modulator Section The modulator, in contrast to the power supply, is inside an oil environment and a slight air movement inside the cabinet is sufficient to keep it cool. There should be no need ever to replace the oil of the modulator.

 

 

FasTrac Millennium Users Guide FasTrac Millennium Users Guide May 2003 FasTrac Millennium, FasTrac, NexTrac, VIPIR, City Streets, StormScan, Storm Spotter, Neighborhood Weather Net and Street Spotter are registered trademarks of Baron Services, Inc. FutureScan, PasTrac and Severe Weather Module are trademarks of Baron Services, Inc. The products, systems, and/or methods described or otherwise mentioned herein are covered by one or more of the following U.S. Patents: 5,717,589; 5,940,776; 6,018,699;

6,125,328; 6,163,756; 6,188,960; 6,266,063; 6,272,433; 6,275,744; and 6,278,947. 2001 Geographic Data Technology, Inc. This document contains images with proprietary and confidential property of Geographic Data Technology, Inc. Unauthorized use, including copying for other than testing and standard backup procedures, of this product are expressly prohibited. Microsoft Windows products are registered trademarks of Microsoft Corporation. The trademarks of other companies used in this manual are the respective property of those companies. All efforts were taken to ensure the accuracy of this document. However, this information is subject to change without notice. Copyright 1994-2003. Baron Services, Inc. 4930 Research Drive Huntsville, Alabama 35805-5906 ii FasTrac Millennium Users Guide May 2003 2.1 2.2 2.2.1 2.2.2 2.2.3 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Table of Contents Table of Contents___________________________________________________________iii Preface_____________________________________________________________________ vii 1. Overview ________________________________________________________________ 1 Databases ___________________________________________________________ 1 File Structure ________________________________________________________ 1 Protecting Your Data _________________________________________________ 2 NetRad____________________________________________________________ 3 Starting Your FasTrac Millennium ______________________________________ 4 System Commands Not Meant for Client Use______________________________ 7 Points to Remember __________________________________________________ 8 2. Setting Up Your System ______________________________________________________ 9 Setting Up Map Layers _______________________________________________ 10 Setting Up Display Levels (for clients without .psf mapping data)____________ 10 Editing Display Levels for Roads ____________________________________ 11 Editing Display Levels for Bodies of Water ____________________________ 12 Setting the Enable Range for City Streets ______________________________ 13 Adding Water-Fill Points (for clients without .psf mapping data) ____________ 13 Fixing Floods with Anti-Fill Points (for clients without .psf mapping data) ____ 16 Editing the Places Database ___________________________________________ 16 Adjusting the Color Palette____________________________________________ 20 Using the Baron Chart _______________________________________________ 21 Editing Colors for 256-Color Palettes ___________________________________ 22 Creating Gradients ________________________________________________ 23 Duplicating Palettes _______________________________________________ 23 2.9 Customizing Font Displays ____________________________________________ 24 2.10 Manipulating the Automatic Legend ____________________________________ 25 2.11 Using Overlays ______________________________________________________ 26 2.11.1 Creating new Overlays ____________________________________________ 26 2.11.2 Adding an Overlay to a View _______________________________________ 26 2.11.3 Removing Overlays _______________________________________________ 28 Setting Overlays for Data Products ___________________________________ 28 2.11.4 2.11.5 Setting the FutureScan Product Overlay _______________________________ 29 2.12 Setting Up Icons _____________________________________________________ 29 2.13 Points to Remember _________________________________________________ 31 2.3 2.4 2.5 2.6 2.7 2.8 2.8.1 2.8.2 iii FasTrac Millennium Users Guide May 2003 3.5 3.4.1 3.4.2 3.1 3.2 3.3 3.4 3. Adjusting Views__________________________________________________________ 33 Using the View Main Panel____________________________________________ 34 Setting Map Parameters ______________________________________________ 35 Editing Topographical Data ___________________________________________ 36 Saving and Organizing Views__________________________________________ 37 Saving Views____________________________________________________ 37 Organizing Your Views____________________________________________ 38 Using the View Options_______________________________________________ 39 Adding Text to a View ____________________________________________ 39 3.5.1 Zooming In and Out From a View____________________________________ 39 3.5.2 Pointing to Features on a View ______________________________________ 39 3.5.3 Panning on a View________________________________________________ 39 3.5.4 Labeling Streets with Street Spotter __________________________________ 40 3.5.5 Controlling Display of Radar Data ___________________________________ 42 3.5.6 Utilizing TeleTrac ________________________________________________ 42 3.5.7 Displaying Lightning Strikes on a View _______________________________ 43 3.5.8 Displaying Storm Spotter Van data _________________________________ 44 3.5.9 3.5.10 Toggling High-Definition Data Processing _____________________________ 45 3.5.11 Displaying NEXRAD forecast data___________________________________ 45 3.5.12 Displaying Neighborhood Weather Net Sensor Data____________________ 46 3.5.13 Zooming to a Specific City _________________________________________ 48 3.5.14 Adding Fronts and Pressure Markers__________________________________ 48 3.5.15 Creating Temporary Pixel Query Points _______________________________ 49 3.5.16 Creating Fixed Pixel Query Points ___________________________________ 49 3.5.17 Displaying Precipitation Type Maps __________________________________ 50 Saving the Current View as a Bitmap _________________________________ 51 3.5.18 3.5.19 Printing the Current View __________________________________________ 51 3.5.20 Highlighting Your Spotter Network On-Air ____________________________ 52 3.5.21 Displaying National Weather Service Warnings_________________________ 53 3.5.22 Displaying Wind Speed and Direction ________________________________ 54 Points to Remember _________________________________________________ 56 Managing Storm Tracks_________________________________________________ 57 Setting Defaults for Storm Tracks ______________________________________ 58 Creating Storm Tracks _______________________________________________ 59 Creating Fan Projections ___________________________________________ 59 Creating Circle Projections _________________________________________ 60 Creating Squall Projections _________________________________________ 61 Deleting Storm Tracks_____________________________________________ 63 Editing Storm Tracks ________________________________________________ 63 Editing the Storm Marquee ___________________________________________ 65 4.4.1 Selecting Communities for Your Storm Track ETA Box __________________ 65 4.4.2 Moving the Storm Track Marquee____________________________________ 65 4.2.1 4.2.2 4.2.3 4.2.4 4.3 4.4 4.1 4.2 3.6 4. iv FasTrac Millennium Users Guide May 2003 5.2 5.1 4.5 4.6 4.7 4.8 4.5.1 4.5.2 5.2.1 5.2.2 4.6.1 4.6.2 4.6.3 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 Using PasTrac ______________________________________________________ 66 Auto-Tracking Real-Time Radar Data ________________________________ 66 Auto-Tracking NEXRAD Data ______________________________________ 66 Identifying Storms with StormScan_____________________________________ 67 Setting Up StormScan _____________________________________________ 68 Using Storm Marquees ____________________________________________ 69 Using the Storm Table _____________________________________________ 70 Creating Automatic Storm Sequences ___________________________________ 71 Points to Remember _________________________________________________ 72 5. Using SEQUENCER _____________________________________________________ 73 Starting SEQUENCER _______________________________________________ 74 Creating a New Sequence __________________________________________ 74 Inserting New Events______________________________________________ 75 Deleting Events from Sequences _____________________________________ 75 Deleting Sequences _______________________________________________ 75 Starting and Playing a Sequence _____________________________________ 75 Exiting SEQUENCER_____________________________________________ 76 Using SEQUENCER with Zooms and Pans ______________________________ 76 Creating Zooms and Pans __________________________________________ 77 Previewing Your Zoom Event _______________________________________ 77 5.3 Working with Time-Lapse Events ______________________________________ 78 Creating Real-Time Radar Time-Lapses _______________________________ 79 Creating NEXRAD Time-Lapses ____________________________________ 80 Previewing Your Time Lapse _______________________________________ 81 Editing Time-Lapse Frames ________________________________________ 81 Combining Time-Lapse and Zoom Events _______________________________ 81 Repainting to a Sequence _____________________________________________ 82 Adding a Radar Lapse to a Sequence ___________________________________ 82 Inserting NEXRAD Data in a Sequence _________________________________ 82 Points to Remember _________________________________________________ 83 6. Controlling Your Radar ___________________________________________________ 85 Controlling Your Non-Baron Radar ____________________________________ 86 6.1 6.2 Controlling Your Baron Radar ________________________________________ 86 6.3 Manipulating NEXRAD Data__________________________________________ 89 Using the NEXRAD Main Panel_____________________________________ 89 Adjusting Shear Marker Settings_____________________________________ 95 Using the Advanced Baron Chart ____________________________________ 96 Customizing Product and Time Marquees______________________________ 97 5.4 5.5 5.6 5.7 5.8 6.3.1 6.3.2 6.3.3 6.3.4 5.3.1 5.3.2 5.3.3 5.3.4 v FasTrac Millennium Users Guide May 2003 6.4 6.4.1 6.4.2 Utilizing Multiple Real-Time Radars Via Network ________________________ 98 Using Network America ___________________________________________ 98 Changing the Width of the Radar Sweep Cursor_________________________ 98 Comparing Base Reflectivity and Composite Reflectivity ___________________ 99 Points to Remember ________________________________________________ 101 Glossary_____________________________________________________________________ 1 6.5 6.6 vi Preface This manual describes the operating procedures for Baron Services FasTrac Millennium software, the industry standard for display and storm tracking. You can use these products to present critical weather data that will provide customized weather displays. Document Organization The information in this manual is organized as follows:

Chapter 1 is a general overview of the system and provides the information needed to start the program.

Chapter 2 describes the operations needed to set up your system.

Chapter 3 describes how to manipulate your views (screen displays).

Chapter 4 describes how to create and manage storm tracks.

Chapter 5 describes how to use SEQUENCER

Chapter 6 describes how to control both non-Baron radars and Baron radars. Before using FasTrac Millennium, you should have a working knowledge of Microsoft Windows. Support Information The Baron Services support team is available to answer questions about technical-support issues and to assist you with operations and procedures. You can reach the support team by calling

(256) 881-8811. You will need the following information when you call:

Product name and version.

Station name, your name and your job title.

Number of a telephone close to your workstation. Do not give a fax number.

Brief description of your problem. You can also access troubleshooting documentation from the Baron Services Tech Support website. You will need your username and password to enter the site. The site URL is:

http://techpage.baronservices.com To learn about our about Baron Services' products, the newest enhancements and additions to our product lines, and the latest in news and weather events, go to our primary website at:

http://www.baronservices.com vii Preface Type Faces Italic Bold Courier Symbols FasTrac Millennium Users Guide May 2003 Indicates a document title, the first occurrence of a new term, a directory or file name, or a system response that explains what the system is doing. For example: Open the example cities.bmp file in your C:\fastrac\places directory. Indicates an item in the graphical interface, such as the OK button or a command button. Indicates information you type. For example, Set the signal processor parameters by typing SOPRM. The following document conventions are used throughout this manual:

Information that is not critical to system operation but describes useful procedures or information that will optimize system operation. Very important information about a command or a procedure. Critical instructions that must be followed to prevent loss of data. Keyboard Conventions ALT CTRL DEL ENTER ESC SHIFT TAB Alternate key. Control key. Delete key. Return/enter key. Escape key. Shift key. Tab key viii FasTrac Millennium Users Guide May 2003 Preface Terminology Click Double click To position the pointer on the screen, and then to press and quickly release the left mouse button. To quickly press and release a mouse button twice without moving the mouse. This action is used as a shortcut for common actions, such as activating an icon, opening a file, or selecting a word or graphic element. Click and drag To click and hold a mouse button while moving the mouse. This action is used to identify a range of objects, to move objects, or to resize objects. To input information by typing or by using the mouse. To locate an element on the screen either by clicking it or by typing the name. Enter Identify Click and hold To press and hold down a mouse button to perform an action, such as Scroll Select Type resizing a window. To move through text or graphics. To click a button, a text box, an item in a list, or some other item on a menu or window. To key in data. To complete this action, you may also need to click OK, press ENTER, or press TAB. What to Expect from This Document This document describes how to start, set-up, and run FasTrac Millennium. All of the menus and procedures you will use while working with the program are fully explained in this guide. After reading this manual, you should be able to:

Start FasTrac Millennium.

Customize the weather displays to fit your needs.

Use storm tracks and sequences to quickly and effectively inform viewers about pertinent weather information.

Understand the capabilities of every feature you have on your system. ix 1. Overview This manual describes the FasTrac Millennium product. FasTrac Millennium is the industry standard for providing real-time, local weather information to your users, allowing you to analyze real-time radar and to translate it into meaningful predictions of potentially harmful weather phenomena for your community. It also provides NEXRAD data, combining exceptional resolution, topography, and street-level mapping with Barons unique, intuitive user interface. Most users use the program both for NEXRAD sites and their own, real-time radar. This chapter introduces the main system components, including the databases, the file structure and the main FasTrac Millennium display. 1.1 Databases Two databases, known as Places and Maps, provide the mapping information underlying the functions. When Baron Services introduced these databases to the meteorological world, they were referred to as liquid databases because the user could smoothly change the map display and effortlessly zoom into and out from points of interest rather than using the static one or two radar displays that were then the norm. When Baron Services installs your system, the databases are populated and ready for use. However, as discussed in Chapter 2, you can specify which communities are displayed (referred to as prioritizing places) and add important features, such as schools, malls, and parks, to the Places database. Thus, you easily can customize your display to fit your needs. 1.2 File Structure All the Baron files are in the C:\fastrac directory or one of its subdirectories. While there are many files and subdirectories in the \fastrac directory, the following table lists the ones that you must have to run your system properly. File or Directory Name Basepal.bmp file Fast95.exe file Lapses directory Logs directory Maps directory Nexrad directory Description The color palette bitmap that defines the colors for all data displays. An executable file that activates the main program. The directory that contains time-lapse files created through SEQUENCER (see Chapter 5, Using SEQUENCER). The directory that contains archived radar data (in the \Radar subdirectory) and archived lightning strike data (in the \Strikes subdirectory). The directory that contains the files for the map databases, including roads, rivers, and state lines. The default directory for storing NEXRAD files. 1 Overview FasTrac Millennium Users Guide May 2003 File or Directory Name Omninet.ini file Overlays directory Places directory Views.ini file Zooms directory Description The main configuration file. The directory that contains bitmap files that can be placed on the screen. The directory that contains the data files for all the communities in the Places database. The View configuration file that contains parameters for every saved view. The directory that contains all files for zooms created with SEQUENCER. Do not adjust the .ini files or the Basepal.bmp file unless you receive directions from a Baron Services representative. We preset all settings and software in your system according to your specific needs. Tinkering with Windows or any program outside your FasTrac Millennium is potentially dangerous. If you are not sure about what you are doing, please call our Client Services Department at (256) 881-8811. 1.3 Protecting Your Data You may back up your system by whatever normal backup procedures your business uses to protect important software. A CD R/W drive is provided with all new systems, letting you perform backup operations. When your system is delivered, we strongly recommend that you back up your \fastrac directory to a CD. Alternatively, you can back up the system on your hard drive using the Backup command:

1. Open FasTrac Millennium. 2. Select File > Backup to open the Backup menu. 3. The menu to the right will appear, asking you to designate a directory in which to create the backup. You must have C:\FasTrac as a parent directory. 4. Click Backup to automatically copy system files to the designated directory. This will take several minutes. 5. When a message indicating that backup is complete appears in the text box, click Cancel to exit the menu. Our system offers unique customization opportunities. You may want to back up individual files to protect your customized set-up. If possible, shut down Windows before restarting your computer. Shutting down a computer before exiting Windows may create hardware complications. Experienced Windows operators will often have FasTrac Millennium operating simultaneously with other programs. If FasTrac Millennium is operating and you return to the desktop before 2 FasTrac Millennium Users Guide May 2003 Overview exiting the program, you may not return to it by clicking on the icon. You must click on the minimized icon on the task bar to return to the program. This safety feature is designed to prevent multiple copies of FasTrac Millennium from running at the same time. 1.4 NetRad The NetRad module lets you specify which radar sites provide NEXRAD data to your system. You must enable it before starting FasTrac Millennium, as described in this section. 1. Double-click on your NetRad desktop icon or double click on the netrad.exe filename to open NetRad. 2. Select Connect > Disconnect, and then select Setup > Main Setup to open the NetRad Setup menu. 3. Use the Add Site and Remove Site commands to select the sites you wish to display. The FutureScan products option on the NetRad Setup menu is available only if you own the FutureScan module. Be sure that the Data Compression box is checked, as this reduces the load on the NetRad server. 4. Set the Folder pathname to reflect the directory that will contain the NEXRAD product files, and click OK to return to the NetRad main menu. 5. Select Connect > Connect to reconnect to the NEXRAD server. If you have modified your NEXRAD sources, go to the folder to which NetRad delivers files (the folder defined in the Folder field in the NetRad Setup dialog box) and delete all of the files in the folder. You may now view NEXRAD products in FasTrac using the NEXRAD panel, as described in section 6.3.1. 3 Overview FasTrac Millennium Users Guide May 2003 1.5 Starting Your FasTrac Millennium FasTrac Millennium automatically starts up when you boot up the computer. To manually start, double-click on the FasTrac desktop icon (shown on the right). Either method displays the following main FasTrac screen:

To exit the program, select File > Exit or click the Close (X) button in the upper-right corner of the screen. Subsequent paragraphs describe each screen component. Program Name and Release Date technical support. The release date is very important in determining which version of software you are using. The title bar at the top-left of the FasTrac Millennium screen display is information you will need when calling in for Main Menu Bar This tool bar provides access to the main pull-down lists, referred to as Main Menus in this manual, which allow you to access advanced functions of your system. Clicking on a menu title at the top of the screen opens a pull-down list. To activate a particular function, hold down the mouse button, place the cursor over your choice on the menu, and release the mouse button. Hot Buttons Hot buttons appear just under the Main Menus. There are two rows of ten symbols each. You can use these buttons for simple, one-click execution of system functions. Left-clicking activates the main function of the button. Some buttons have dual functions, activated by right-clicking the mouse button. 4 FasTrac Millennium Users Guide May 2003 Overview Temporary Text opens the Temporary Text dialog box, which lets you key in text that displays when you click OK and click on the text location. Lightning replays the lightning in the past hour. Right-click on this hot button to disable Lightning. Note that the button changes to the button shown on the right. This button blinks when the connection to the TCP/IP lightning server is down. Sweep displays real-time radar data. Left-click on the Sweep hot button to display intensity, and right-click on it to display velocity. If you are viewing NEXRAD data, left-

clicking on the icon refreshes the display with the current NEXRAD product. (This icon blinks when the RDAC connection is inoperable.) Storm Spotter Van displays the current location of your Storm Spotter Van. The button blinks when Van data is being received. See Section 3.5.8 for more information. Radar Lapse lets you display time-lapse frames. If you have real-time radar, seven minutes of radar data displays. If you have NEXRAD data, the number of frames specified for the Lapse parameter on the NEXRAD Main panel displays. Weather Wire Data lets you set up and edit Weather Wire warning features. This icon blinks when the National Weather Service data feed is not operational. See section 3.5.20 for more information. Telestrator lets you do free-form drawing on your weather display. Right-click on this icon to open the Telestrator Pen Information menu, which lets you specify the width, color, and type of drawing. Zoom closes in on the area defined by your cursor. Right-clicking on this icon zooms out to double the current range. NEXRAD activates the NEXRAD Main Panel on the left side of the FasTrac display. This icon blinks when the NEXRAD connection is not operational. Show View displays the saved view corresponding to the number on the hot button. Fronts/Hi/Low lets you draw weather fronts with the cursor, as well as create high and low pressure markers. See section 3.5.13 for details. Map Pointer activates the Map Pointer. When you select this hot button, Telestrator drawings disappear. Left-clicking on a road causes its name to appear in the Cursor Status Area. Right-click on this button to enter Pixel Query mode, which indicates the radar data

(this works for all data products) and level at your cursor position. Map Pan enables Pan mode, letting you set a different center point for the current view. Neighborhood Weather Net lets you edit and manipulate live weather data that can then be displayed on map views. See Section 3.5.11 for more information. 5 Overview FasTrac Millennium Users Guide May 2003 StormScan activates the Arrow Filter panel on the left side of the FasTrac display. See Section 4.6, StormScan, for more details. Street Spotter allows you to find and label the streets in your database. See Section 3.5.4 for details. SpotterNet lets you display a network of eyewitnesses for weather activity. See Section 3.5.19 for details. Main Status Area The Main Status Area is the area in white, just to the right of the hot buttons. This area displays the following:

Latitude and longitude of the map pointer. Azimuth and range of the current pointer from its last selected position (reset this by right-clicking on the view). Current system time in local time and in Greenwich Mean Time (ZULU). We equip our systems with time keeping software to ensure that the system time remains accurate, but you may use a different time keeping program if you wish. Azimuth and elevation of the live radar. Azimuth, range, and height of the your radars beam center at the cursor position. Cursor Status Area The gray bar located under the main status area is the Cursor Status Area. This bar is dual-purpose. First, it displays information about your last selected command. For instance, if you place the cursor over the Lightning hot button, the words replay last hours lightning appear. Secondly, this area displays various status messages relating to system activity. Select Panel The Select Panel options, described below, occupy the left column of your screen. Description Opens the View Main panel, which displays map radius, map center, and map name. This is the default panel and displays upon system startup. Opens the Storm Track panel, which lets you control storm track settings. STORMS SEQUENCES Opens the SEQUENCER panel. NEXRAD Opens the NEXRAD Main panel, which lets you display NEXRAD products. Option VIEWS 6 FasTrac Millennium Users Guide May 2003 Overview More Settings The More Settings area, which appears at the bottom of the left column when the View panels are active, lets you display the following panels:

Option Description Controls street, road, water, and county line displays for the current view. MAP DATA Controls appearance of radar and lightning data on the current view. The Radar Control option lets you control the real-time radar. TOPO Controls the topography display, and specifies the textured background bitmap. MISC Controls radar cursor appearance, radar range height indicator (RHI) mode, and overlays. 1.6 System Commands Not Meant for Client Use In the Setup and Misc Main Menus, there are several commands that are intended for use by Baron Services personnel for the purpose of system maintenance and troubleshooting. You should not use any of these commands without the assistance of a Baron Services representative. The commands are as follows:

Setup > Map > Advanced > Map Window Setup > Miscellaneous Setup > Data > NexRad Status > Debug Window Status > Advanced > System Report Status > Advanced > Memory Check Status > Advanced > Toggle Debug 7 Overview 1.7 Points to Remember FasTrac Millennium Users Guide May 2003

When you start your system, you automatically enter the FasTrac environment. If you have exited FasTrac, you can double-click on the FasTrac icon on your desktop to manually initialize FasTrac.

Perform back-up operations often, to protect your data and setup configurations.

All of the operations that you may use are covered in this manual. If you find something that is not discussed, it is best not to tamper with it. Again, if you have questions, feel free to call the Client Services Department at (256) 881-8811. This chapter merely provides an overview of FasTrac Millenniums capabilities. The other chapters describe the five primary areas of program functionality. Description Chapter Setting Up Your System Chapter 2 View Manipulation Chapter 3 Storm Tracking Sequencing Radar Control Chapter 4 Chapter 5 Chapter 6 8 2. Setting Up Your System This chapter describes how to prepare your system for displaying crucial weather data in meaningful formats for your users. While you can readily perform most of the Setup commands, some operations are not so apparent. Before you start setting up, you should back up the delivered \fastrac directory as explained in section 1.3, Protecting Your Data. This chapter addresses the functions described in the following list:

Setting Up Map Layers

Setting Up Display Levels

Editing the Places Database

Prioritizing the Places Database

Adjusting the Color Palette

Using the Baron Chart

Customizing Font Displays

Manipulating the Automatic Legend

Using Overlays

Setting Up Icons 9 Setting Up Your System FasTrac Millennium Users Guide May 2003 2.1 Setting Up Map Layers The Map layer editor menu, which you can access with the Setup > Map > Map Layers command, allows you to edit the appearance and viewing range of all the water and road types in your map database, as well as county and state lines. Clients without .psf mapping data should use the Display Levels commands detailed in Section 2.2 to adjust the appearance of roads and water. The pull-down list lets you select which map feature type you wish to modify (for example, Lakes, Rivers, County Lines, State Lines and Roads). Two Color specifies that two colors define the selected map feature and is available only for county lines, state lines, and various types of roads. Inner Line defines the color of one-color features, and the inside color of two-color features. Outer Line is enabled only if you select the Two Color option. This option defines the outside color of two-color features. Min Range defines the minimum range at which you can see the selected feature. You will not see the feature when your views range is less than the specified Min Range. Max Range defines the maximum range at which you can see the selected feature. You will not see the feature when your views range is greater than the specified Max Range. Preview displays the selected feature type and the one or two specified colors for that feature. 2.2 Setting Up Display Levels (for clients without .psf mapping data) For clients without .psf map data, the Setup > Map > Advanced > Display Levels commands control what roads and bodies of water are displayed within your map at a particular range. This system utilizes both the 1:2,000,000 database and the City Streets database. See Section 2.2.3 for information on how to set the range at which the display switches between the two databases. The Display Levels commands only appear for clients that do not use

.psf data for mapping. Clients with .psf data should use the Setup >

Map > Map Layers command detailed in Section 2.1 to edit the appearance of roads and water. 10 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2.2.1 Editing Display Levels for Roads (for clients without .psf mapping data) Select the Setup > Map > Advanced >

Display Levels > 1:2,000,000 Roads command to open the 1:2,000,000 Road Display Levels menu. This menu has nine categories reflecting different levels, or subsets, of roads. The Cutoff Range area lets you activate the databases at different ranges so that an appropriate amount of detail appears, regardless of range. For example, interstates are appropriate at any range, so they receive a high value, like 999. Residential roads, on the other hand, are only appropriate when you zoom in close, so they receive a low value, like 10. This configuration results in interstates appearing on any map with a range of less than 999 miles - in effect, on every map. Residential roads only appear when your map range is less than 10 miles - a more appropriate activation range. These ranges are adjustable to suit your needs. Select the Setup > Map > Advanced >

Display Levels > City Streets Roads command to open the City Street Display Levels menu. Although City Streets Roads is a separate menu with six levels, levels 1 through 4 (Interstates, Divided Highways, Highways, and Roads) are roughly comparable to the 1:2,000,000 database. Streets and Minor Streets occupy levels 5 and 6 and use the City Streets database. This prevents the database from placing much detail at longer ranges. too 11 Setting Up Your System FasTrac Millennium Users Guide May 2003 The Display Style area lets you adjust the graphic look of the roads in your system. There are six graphic styles:

Road Style Type Example Smallest Single Line Small Single Line Medium Double Line Major Double Line Divided Triple Line Two Color Triple Line Triple-line styles are usually assigned to interstates, and divided highways and double-line styles are usually assigned to state and county highways. Single-line styles work best when assigned to the smallest roads. Use the Setup > Colors command to adjust the road colors. 2.2.2 Editing Display Levels for Bodies of Water (for clients without .psf mapping data) The Setup > Map > Advanced > Display Levels > 1:2,000,000 Water and Setup > Map >

Advanced > Display Levels > City Streets Water menus operate exactly the same way as their respective Roads menus, except that you do not need to assign different looks. Water is usually blue (unless you would like to select a different color). Again, you use this command to set ranges for the different levels where you want the water database to appear. If you want to display more water bodies at a certain range, see what the current level is and raise the cutoff range value. 12 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2.2.3 Setting the Enable Range for City Streets (for clients without

.psf mapping data) Select the Setup > Map > Advanced > Display Levels > City Streets Range command to open the City Street Maximum Enable Range menu. This menu lets you set the range threshold at which the system will move between the 1:2,000,000 database and the City Streets database. If you specify 20, for example, the system will use the 1:2,000,000 database at ranges greater than 20 miles. At ranges less than 20 miles, it will use the City Streets database. Setting this value too high can result in excessive clutter and slower processing times. The City Streets database is very large and is usually too great for any computer to handle at ranges above 20 miles. You can override the range by selecting the City Streets Use control and its associated Lock control on the View Map Features panel. 2.3 Adding Water-Fill Points (for clients without .psf mapping data) The main water database contains only the outlines of bodies of water. While water bodies normally appear as solid, blue shapes, you may have to use the Setup > Map > Advanced >

Water Fill command to fill in a water shape. The Water Fill command only appears for clients that do not use .psf data for mapping. Clients with .psf data should use the Setup > Map > Map Layers command detailed in Section 2.1 to edit the appearance of water. 1. Use the Setup > Colors command to verify that the water color is correct. Adjust as required. 2. Use the Zoom Out option to display the body of water in question. Note in the following example how the river body, bounded by the dark, bolded lines, is empty. 13 Setting Up Your System FasTrac Millennium Users Guide May 2003 3. Select the Setup > Map > Advanced > Water Fill command to display the Setup Water Fill panel on the left side of the screen.

Zoom Out automatically zooms out the map display to 50% of the current range. You can continue to issue this command until you have the appropriate view.

Add Line opens the Add Water Fill Line dialog box. This dialog box lets you fix the display of two separate bodies of water. If there is a gap between such features, the water fill could extend beyond the intended boundaries (referred to as a flood). You can use Add Line to connect the two bodies for a water-

fill operation. You then could select During Fill Only to display the line only during a water-fill operation.

Refresh Map updates the map display.

Auto Refresh automatically updates the map display when you add a line or point.

City Street displays the city str optional City Streets module.) eets. (This option is available only if you have the City Street Lock prevents the street levels that you specified with the Setup > Display Levels > City Streets Roads command from changing when you zoom in and out o f the view. (This option is available only if you have the optional City Streets module.)

Water Level +/- lets you move to different levels on the map.

Water Level Lock prevents the water level that you specified with the Setup > Display

> 1:2,000,000 Water command from changing when you zoom in and out of the Levels view.

Map Cursor Normal places your map cursor in pointer mode.

Map Cur display. sor Pan places your map cursor in pan mode, letting you move around the map

Map Cursor Zoom places of points of interest. your map cursor in zoom mode, letting you get closer views 4. Right-click your mouse button on the body of water in question to add a water-fill point. 14 FasTrac Millennium Users Guide May 2003 Setting Up Your System 5. Verify that the water body is filled with the water color. The following example depicts the water fill. Note that the water-fill point appears as a small white square on the map For best results, click near the center of the water body, away from the boundary lines. 6. Zoom out to ensure that the entire body of water is filled in correctly, as shown in the following example. Notice that multiple water-fill points have been added. To edit an existing water fill point, click on it to open a dialog box that has places to enter the fill points ID and to enable or disable it. There are also boxes that specify the display level, the minimum a ude of the point. To change the latitude and nd maximum ranges, and the latitude and longit tion. longitude, click on the map at the new loca A water-fill point must be visible on the screen before it will fill water bodies with color. 15 Setting Up Your System FasTrac Millennium Users Guide May 2003 2.4 Fixing Floods with Anti-Fill Points (for clients without .psf mapping data) etimes when filling a large body of water with water-fill points, you may accidentally place a Som point that makes the land area fill with the blue color. This is referred to as a flood. Since it can be difficult to find the particular fill point that is causing the flood, the Baron program allows you to u d to fix the problem. se Anti-Fill comman 1. Select the Setup > Map > Advanced > Anti-Fill command to display the Anti-Fill Control dialog box on the left side of the display. 2. Select Add, and click on the map somewhere in the flo that a small, green-filled point appears. oded area. Notice 3. To remove a point, select Remove and click on the point you want to rem ve. o 4. Click OK, and s elect the Setup > Map > Advanced > Water Fill e command to op n the Setup Water Fill panel on the left side of the screen. 5. Select Refresh M ap to see your adjustments. g the Places Database 2.5 Editin As part of your system, we include every populated community in every state. When you a re tracking severe weather, you do not want to miss the small communities that could be affected the most. The Setup > Map >

Places Database command lets you determ ine the priority level (in miles) of every populated community in your area. In this manner, you determine ar on the map and when they are e at what range various communities app listed in the St uees, such as the one displayed on the left. You can also use the Places Database command to add or delete orm Track ETA Marq ommunity names from the database. c he following steps describe how to customize your database:

T 1. Select the Setup > Map > Places Database command to open the Select State menu. 16 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2. Click on a state name, and click OK to open the Place List for the selected state. Note that all the populated communities in the selected state alphabetically. are listed 3. Click Add to create a new place, or click an existing place name and click Edit to modify it. The Add Place and Edit Place menus have identical features, although a place you edit already have informati on filled in. will You can also select an existing place by clicking on the community name then pressing the ENTER key, or double-clicking on the community name. 4. Enter the desired parameters on the Add Place or Edit Place menu. The following paragraphs describe each par ameter:

Name Defines the full place name.

Abbreviation Defines an abbreviation that can be displayed instead of the full place name.

County Specifies the county in which the place is located.

Population Defines the known population, in thousands.

Altitude Defines the altitude, in feet, if known.

Latitude and Longitude Specifies the geographical coordinates. You can automatically assign coordinates to the place by left clicking on the desired spot in your view.

Use abbreviation on map Displays the abbreviated name, rather than the full place name, on views.

Use abbreviation on Storm Track Displays the abbreviated name on storm tracks. This is a useful tool for managing the size of storm track boxes. For example, abbreviating Mahan Center Cross Roads to Mahan. Cen. results in a much smaller box.

Allow automatic scale adjust Automatically adjusts the storm marquee to fit the displayed places. 17 Setting Up Your System FasTrac Millennium Users Guide May 2003

Show Range Defines the range, in miles, at which the place will display. For example, a place with a Show Range parameter of 1 will not display until your view range is one mile or less.

Show on maps Displays the place name on views when it is in range.

Show on Storm Tracks Displays the place name on Storm Track ETA displays.

Original Data Reserved for future use. When adding places, do not start them with a number (e.g., 1st Street). The system functions best with all letters in the name, rather than numbers. Spell out the number if you want to use it. While your Places database contains thousands of place names, you need not adjust them all. The program defaults all of its communities to a Show Range of 1, which means that a community will never appear on a map unless your map range is one mile or less. By default, all communities appear in storm tracks, which is where community names are most powerful. The only thing you need to do in the Setup Places operation is to raise the Show Range value for the appropriate communities in your viewing area, as explained in the following subsection. This allows communities to appear in your maps when you are creating saved views or when you are moving around the map in a real-time situation. Changing the Show Range Parameter This function is one of the most powerful operations you will perform with your system. This subsection describes how to easily and efficiently prioritize the places that are already present on your system. The Places database includes every populated community in range of your radar, for approximately a 300-mile radius from your location. Use your discretion when you prioritize the database to meet the needs of your users. 1. Select the Map Pan hot button and click on the major city in your viewing area to center the map on it. 2. Select Views to activate the View Main panel, key in 250 in the Radius text box, and click the Update button to show a 250-mile view of the city. 3. Decide which cities you want to appear at this range. 4. Select Setup > Map > Places Database to open the Select State menu, select the state, and click OK to open the Place List for the selected state. 5. Select a city, and click Edit to open the Edit Place menu. 6. Key in 250 in the Show Range text box, make any other relevant changes, select the Show on Maps and Show on Storm Tracks options, and click OK. 7. Repeat steps 5 through 7 for each city that you wish to display at the 250-mile range. 8. Click Update on the View Main panel to refresh the map, and verify that the cities you want appear. You may end up repeating this process several times. 18 FasTrac Millennium Users Guide May 2003 Setting Up Your System 9. Repeat steps 2 through 8 to set up map displays for 200-, 150-, 100-, 75-, 50-, 25-, 10-, 5-, and 3-mile ranges. 10. Repeat steps 1 through 9 for each important city in your viewing area. 11. Verify that you have a good coverage of the cities you want to see by zooming in and out on relevant areas of your viewing area. Customizing the Places Database Many of our clients have gone beyond editing to customizing their Places Database. An example of this customization process is identifying important intersections. At times, some locations should be emphasized to stress the importance and location of weather phenomenon to your users. The Baron database is completely client-customizable. You can take advantage of the opportunity by creating identifiers for local features like schools, malls, churches, parks, and stadiums. To add places for this purpose, follow these steps:

1. Select Setup > Map > Places Database to open the Select State menu, select the state, and click OK to open the Place List for the selected state. 2. Click Add to open the Add Place menu. 3. Click on the appropriate location on your map display to have the longitude and latitude coordinates automatically generated, or key in the longitude and latitude coordinates. 4. Key in the text (for example, enter an intersection name) in the Name box, type in the range at which you want the place to display in the Show Range Text box, select the Show on Maps options, and click OK to return to the Place List. 5. Click Done. You will be asked if you want to save the new name to a file. Click OK. 6. Go to the Views panel on the left side of the display. Verify that the view is in the range specified in step 4, and click Update. Make sure that the new text is displayed. To further emphasize a customized place, you can use the Street Spotter feature to import an icon for it. See Section 3.5.5 for details. 19 Setting Up Your System FasTrac Millennium Users Guide May 2003 2.6 Adjusting the Color Palette The Setup > Colors command lets you adjust the color palette used by FasTrac Millennium. If you have access to the Advanced Baron Chart (via the Setup > Data > Baron Chart command, see section 6.3.3), you should use it rather than the Setup Colors menu to adjust radar colors. Also, you should use the Setup > Map > Map Layers command discussed in section 2.1 to adjust mapping colors. The following steps describe how to use this particular function:

1. Select Setup > Colors to open the Setup Colors menu. Note that a color value is assigned to each listed element. 2. Select an element, and click Edit to open the Choose Color menu. 3. Adjust the color, which changes as you edit the values. There are six options: Hue, Saturation, Lightness, Red, Green, and Blue. Enter a number from 0 through 255 in each of these spaces to specify the amount of that component to include. You can also move the sliding pointer below the rainbow colored bar to raise and lower the hue value. You can click anywhere on the large colored box to the left of the number boxes to automatically change the values of that color (this method affects every value except the hue). As you change the numbers, the rectangle below the number spaces indicates the color. Press ENTER or click OK when you have adjusted the color to the way you want. You can exit without making any changes by pressing the escape key (ESC) or by clicking Cancel. 20 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2.7 Using the Baron Chart The Baron Chart lets you specify the colors used for the various NEXRAD products and your real-time radar data. All of these use the Baron Chart. To display it, select Setup > Colors to open the Setup Colors menu, and select Baron Chart. The square on the right shows all 256 colors in the color palette. When you move the mouse cursor over these colors, the text box lists the index number of the color to which the mouse cursor is pointing and specifies the color title. If appropriate, the text box describes the red, green, and blue values that define the color and the general classification, which is described in the following list:

MODIFIABLE indicates that the color is available for use in any product, and you can change its RGB components by double-clicking on it to open the Edit Color menu.

UNSTABLE indicates that the color is available for use in any product, but you cannot change it from this menu. We do not recommend that you use these colors since other features use them and they are subject to change.

FIXED indicates that you cannot change this color, but it is safe to use in your products since it will not change.

RESERVED indicates that you cannot use or change this color. Palette entries surrounded by white squares are the safest to use with Baron Chart, since they were originally reserved for radar. The left portion of the Baron Chart contains colors for the different NEXRAD product types. The numbers in the Reflectivity column indicate dBZ values, while the other columns indicate the levels (1 - 15). As you move the mouse cursor over these, the rectangle above the palette box 21 Setting Up Your System FasTrac Millennium Users Guide May 2003 displays text that identifies the colors used. The following steps describe how to change a particular level in a product:

1. Select a color for a particular level from the palette by clicking on a color on the Baron Chart. 2. Click on the level that you want to change (for example, level 7 of VIL). 3. Click OK to save your edit and to return to the Setup Colors menu. You can change any MODIFIABLE color on the palette. To do so, double-click on the color to open the Color Edit menu, which is described in section 2.5, Adjusting the Color Palette. Changing a color in the palette will affect everything that uses that color. Clicking OK saves any changes you have made. You must, however, select OK Save on the Setup Colors menu to effect the changes. For example, if you click OK on the Baron Chart menu and then click Cancel on the Setup Colors menu, you cancel the changes to the palette. The changes to the color representations of product levels stay the same. To avoid confusion, it is best either to click OK in both places or to click Cancel in both places. 2.8 Editing Colors for 256-Color Palettes There are several new data products that utilize a 256-color palette rather than the normal 16 colors. These products can be edited with a separate menu called the Edit full color radar palette menu. To access this menu, select Setup > Data >

BaronChart256. The box in the upper left corner displays the names and product codes of the currently existing 256-color palettes. The product highlighted in this box displays its palette in the center area. The box to the right of the box containing the product names and codes displays the level number and RGB values of the palette entry over which your cursor is currently positioned. For reflectivity palettes, the dBZ value corresponding to that level also appears. The Edit Color button below the palette area allows you to edit the colors for the palette entries. See section 2.5, Adjusting the Color Palette, for information on using the Choose color menu. The Add button lets you create a new 256-color palette. The palette will be black by default. 256-color palettes will not display properly if a precipitation type map is currently displaying (see section 3.5.17, Displaying Precipitation Type Maps). 22 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2.8.1 Creating Gradients The Normal Gradient and HSL Gradient buttons let you automatically create a smooth scale of colors between two entries on a palette. 1. Manually edit the colors of the palette entries that you wish to be the starting and ending points of the gradient, using the Edit Color button. 2. Select the range of palette entries for the gradient by left-clicking on the starting entry and dragging the mouse to the ending entry. The entries in between the two entries will be highlighted, as shown in the example to the right. 3. Click either the Normal Gradient or HSL Gradient button to create the gradient. You should experiment with both options to find which one you prefer. 2.8.2 Duplicating Palettes You can use the Duplicate button to apply the color scheme of an existing weather product to the currently selected product. This process is intended to replace the colors of the currently selected palette with the colors of another palette, not to create a copy of a palette. If you wish to create a palette with the same color scheme as an existing palette, you should first create a blank palette with the Add button, then use the Duplicate button to copy the colors of the original palette into the blank palette. When you click the Duplicate button, the Duplicate product palette menu appears. The pull-down list labeled Source product indicates the product whose color palette you wish to duplicate. Product names with an asterisk at the beginning are 16-

color palettes. The area labeled Destination product indicates the product to which you are copying colors. If this is not the palette you wish to change, click Cancel to exit the menu. 23 Setting Up Your System FasTrac Millennium Users Guide May 2003 You only need to use the Level mapping area if the palette you are duplicating is a 16-color palette. In the text boxes, type the number in the 256-color range that you wish each of the 16-

level colors to appear. The Use reflectivity mapping button automatically assigns reflectivity values and colors to the target palette. To assign the new color scheme, click OK. To exit without changing the palette, click Cancel. 2.9 Customizing Font Displays The Setup > Fonts command lets you customize the font displays for Places, Storm ETA displays, Storm Marquees, Temporary Text, Street Names, NexRad products, Pixel Query Point text and Metar data. All of the menus opened by the Setup > Fonts command have the same components, which are described in the following list:

The Font pull-down list lets you choose any font installed in Windows. The listed fonts are true type fonts that are available in the

\Windows\Fonts directory. You can add new font s or delete existing fonts in this directory. The Fon then be updated. t list will The Effects area lets you define, in pixels, the size of the letters, the extrusion or degree of shadowing, and the width of the outline. The Bold option doubles the width of the font. The Italic option angles the font forward. The Anti-Alias option eliminates the blocky e Round Outlines appearance of computer fonts. Th option gives anti-aliasing to the font outlines.

The Colors area lets you define color values for both the font and the shadow. We suggest n that black outlines have an RGB value of at least 12 - 12 - 12. True black, 0 - 0 - 0, is ofte lor. You may select any color you wish by varying the amounts of red, the default key co green, and blue.

Extrude Direction specifies the direction of your drop shadow.

Preview displays the changes you have made and have not yet saved. Click OK t changes you made, or click Cancel to discard your changes and close the menu. o save the When you change fonts, they change only for that time forward. The new fonts not affect saved views. When changing fonts for Storm Track ETA boxes, you must select Update at the bottom of the storm track panel to enact your changes. do 24 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2.10 Manipulating the Automatic Legend Use the options under the Legend menu to control the automatic legend, shown below.

DISPLAY lets you toggle the automatic legend on and off. When the legend is on, a check appears next to this option.

RAIN MODES lets you display rain, snow, and mixed weather in the legend.

RESIZABLE BORDER lets you adjust the size of the legend for the best fit on maps. When selected, a Windows-style resizable frame appears around the legend. Use normal Windows techniques to resize the legend.

OPTIONS opens the Legend Options menu, which lets you change the configuration and location of the legend display. Radar Levels specifies the levels for your radar products. The legend will not display color bars for the higher levels that do not apply to your radar. It can take some trial and error to get the results you want with this setting, so it will help to test it before using it in a real-time situation. This option does not affect the NEXRAD display mode. The colors on the legend automatically change when you display a different type of radar product. If you are in velocity mode, the legend says TOWARD on one side and AWAY on the other; for intensity modes, it says LIGHT on one side and HEAVY on the other. One interesting thing to note about the automatic legend is that any level with a color set to transparent in the Baron Chart does not appear in the legend. The other bars expand to fill the gap. This is possibly a more flexible technique than the Radar Levels command in the Legend Options menu. The legend is actually a separate window, and is always on top of everything else in the display. You can move the legend to any position on the screen while it is active by left-clicking and dragging it. You may want to adjust the legends size off air, and then turn off the RESIZABLE BORDER option before going on air. This prevents you from accidentally resizing the legend while trying to move it. 25 Setting Up Your System FasTrac Millennium Users Guide May 2003 2.11 Using Overlays The Tools-1 > Overlay > Add Overlay and Tools-1 > Overlay > DragDrop Overlay commands let you bring logos, customized legends, or other kinds of pictures into your system, and then place them on your map at a specific pixel location. Overlays retain their screen position, no matter how you switch your views. 2.11.1 Creating new Overlays 1. The Setup > Overlays/Icons > Overlays command lets you associate a bitmap in your /fastrac/Overlays subdirectory with a meaningful mnemonic. Select the command to open the Overlay List menu. 2. Select the Add option to create a new overlay, or select Edit to modify an existing overlay. Either way, a menu labeled Overlay appears. 3. In the text box labeled Name, type the name you want to appear in the Overlay List. 4. In the Filename textbox, enter the filename of the picture you wish to use for your overlay (or click the Browse button to select it from a menu). 5. Click the Preview button to verify that you have selected the picture you want. 6. Press ENTER or click OK to save the overlay and return to the Overlay List. To permanently remove an overlay name from the Overlay List, left-click on its name, then click the Delete button. When you are finished working with overlays, click Done. 2.11.2 Adding an Overlay to a View There are two methods for adding an overlay, using the commands Tools-1 > Overlay > Add Overlay and Tools-1 > Overlay > DragDrop Overlay, respectively. Add Overlay allows you to apply the overlay to a fixed screen position with a single click. DragDrop Overlay lets you add the overlay, then move it by clicking and dragging before fixing its position. 26 FasTrac Millennium Users Guide May 2003 Setting Up Your System For the Add Overlay procedure, follow these steps:

1. Select the Tools-1 > Overlay > Add Overlay command to open the OVERLAY LIST. 2. Select the overlay you want to place on screen from the list by left-clicking it. 3. In the text box labeled Transparency, select the amount that you want the overlay to move behind other screen elements (0 is least and 100 is most). 4. Press ENTER or click OK to close the menu. 5. Move the cursor to the point on t to appear. he view where you want the upper-left corner of the overlay 6. Left-click to add the overlay to the screen. For the DragDrop Overlay procedure, follow these steps:

1. Select the Tools-1 >

OVERLAY LIST. Overlay > DragDrop Overlay command to open the 2. Select the overlay you want to place on screen from the list by left-clicking it. 3. 4. In the text box labeled Transparency, select the amount that you want the overlay to move behind other screen elements (0 is least and 100 is most). Press ENTER or click OK to clo upper-left corner of the screen. se the menu. The overlay will appear in the 5. To move the overlay, left-click and drag it with the mouse. 6. When the overlay is in the position you want, right-click it to fix it in place. Use the View > Save As command to permanently associate an overlay with a view. 27 Setting Up Your System 2.11.3 Removing Overlays FasTrac Millennium Users Guide May 2003 When you wish to remove a fixed overlay from the screen, follow these steps:

1. Select the Tools-1 > Overlay > Remove Overlay command to open the Remove Overlay menu. 2. Left-click on the overlay you wish to remove. 3. Press ENTER or click OK to close the menu. The overlay will then disappear. You cannot remove an overlay that you add using the DragDrop Overlay command until you fix its position by right-clicking it. 2.11.4 Setting Overlays for Data Products With the Setup > Overlays/Icons > Product Overlays command, you can assign an overlay to appear whenever you display a data product. Select this command to open the Setup Product Overlay menu.

The Display product overlays checkbox toggles the display of overlays for all products.

The pull-down list labeled Product Information lets you select the data product that you want to associate with an overlay. When you select a product, the Product Number area changes to reflect the new product.

In the list under Overlay Information, select the overlay you wish to associate with the data product.

In the text box labeled Transparency, select the a mount that you want the overlay to move behind other screen elements (0 is least and 100 is most).

The Upper Left X textbox determines how far to the right from the upper left corner (in pixels) that the overlay will appear, while the Upper Left Y textbox determines how far below the upper left corner (in pixels) that the overlay will appear.

The Preview Overlay button allows you to look at the overlay you selected, to ensure that it is the one you want. Click OK to save your changes and exit the menu, or Cancel to exit without saving changes. 28 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2.11.5 Setting the FutureScan Product Overlay For clients with the FutureScan module (see section 3.5.11), the FutureScan product is automatically associated with a bitmap labeled futurescan.bmp. You should therefore check to ensure that this bitmap is in your fastrac/overlays folder. You can control the appearance of the FutureScan overlay through the FutureScan Overlay menu. Select Setup > Overlays/Icons >

FutureScan Overlay to open this menu.

The area at the top of the menu should display the message Logo Detected if the FutureScan overlay is in the proper place.

The checkbox labeled Logo Enabled allows you to toggle whether the overlay appears when FutureScan is active.

The X and Y textboxes allow you to control how far to the right and down, respectively, the overlay will appear from the upper left corner of the screen (in pixels). 2.12 Setting Up Icons Icons are similar to overlays, with the exceptions that they are attached to specific geographical coordinates and are permanently displayed once you create them. This section discusses how to set up your icons for display. 1. Select Setup > Overlays/Icons > Icons to open a menu that prompts you for a keyword. 2. If you wish to find a specific icon, type in all or part of the icons name and click the Use Keyword button. Otherwise, hit ENTER or click the All Icons button to display the entire Icon List. 3. The Icon List menu is similar to the Overlay List menu. Click the Add button to create a new icon, or click the Edit button to change an existing icon. 29 Setting Up Your System FasTrac Millennium Users Guide May 2003 4. Either way, a menu labeled Icon appears. Enter the name you wish to associate with the icon in the Name text box. 5. Enter the filename for the picture you wish to use for the icon, or click the Browse button to select it from a menu. 6. Click the Preview Bitmap button to verify that you have selected the picture you wanted for the icon. 7. In the Transparency text box, enter the degree to which you want the icon to move behind other screen elements (0 is lowest, 100 is highest). 8. Check the box labeled Above radar if you wish the icon to display over radar data. 9. If you know the latitude and longitude of the location where you want to display the icon, key in the coordinates in the Lat and Lon text boxes. Alternatively, you can click on the desired map location, and then click Map Edit. 10. In the Start Range text box, type in the maximum range (in miles) at which the icon displays. 11. In the End Range text box, type in the minimum range (in miles) at which the icon displays. Upon completion, select OK to return to the Icon List. You will need to change or refresh the view before the icons display. To permanently remove an icon name from the Icon List, left-click on its name, then click the Delete button. When you are finished working with icons, click Done in the Icon List menu. If you set an icon to appear at both long and short ranges, you may run into problems due to the latitude and longitude data not always matching up at different ranges. If this happens, try adding additional screen coordinates for the icon to appear for multiple subsets of the desired total range. 30 FasTrac Millennium Users Guide May 2003 Setting Up Your System 2.13 Points to Remember

Before you make any major changes, back up your \fastrac directory and subdirectories.

One of the most important commands is the Setup > Map > Map Layers command, which controls the roads and bodies of water that appear on your map display.

For systems without .psf mapping data, the Display Levels, Water Fill, and Anti-Fill commands control the appearance of roads and water.

Use the Setup > Map > Places Database command to specify which locations

(places) display on your map.

Use the Setup > Colors command to adjust the colors on your views.

Use the Legend commands to control the automatic legend.

Use the Setup > Fonts command to customize the display of various font types.

You can insert bitmap images into your system as overlays and icons, then display them on views. 31 3. Adjusting Views This chapter describes how to control the display of your weather map displays, or views. Views control how your weather data is presented. This chapter addresses such functions as:

Using the View Main Panel

Setting Map Parameters

Editing Topographical Data

Saving and Organizing Views

Using the View Options 33 Adjusting Views FasTrac Millennium Users Guide May 2003 3.1 Using the View Main Panel The View Main window is the first panel available upon opening the program. (The name of the current view window is always at the top of the window.) Buttons for the four other windows appear in the More Settings area at the bottom of the panel. If you are currently viewing another panel, the Views button is always availabl e in the Select Panel area. The following paragraphs describe all the controls available on the View Main panel:

Saved Views identifies all views that you have saved. Click on the down arrow to display available views and click on a name to open that view. Note that there are two temporary views, Temporary 1 and Temporary 2, which are the last two updates you have made.

Previous recalls the view that was active before you switched to the current one. This option lets you toggle back and forth between two views. You can use this option to recover from mistakes.

Radius is the vertical distance, in miles, between the center of the screen and the top of the screen.

Lat-Lon are the center coordinates for the map display.

Quick Settings allows you to toggle the display of Radar, Lightning, and Topography data, as well as whether the lightning data icons Blink.

Smooth Transitions lets you perform dynamically smooth pans and zooms when you zero in on areas of interest. Checking Active activates the feature, while checking Include radar causes radar data to smoothly transition as well.

More Settings lets you activate the other panels.

Update renews the map display after you have changed display parameters.

Undo returns the view parameters to those existing when Update was last selected. You will use the View Main commands often to adjust your display. For example, if you want to change the size of your viewing area, key in the new range in the Radius text box and click Update. The Previous command is particularly helpful in moving rapidly from one storm to the next while maintaining your bearings, as shown in the following scenario:

1. Show the base view that has all the storms of interest. 2. Give your users an overview of the current weather situation. 3. Select the Zoom hot button to display your area of concern. 34 FasTrac Millennium Users Guide May 2003 Adjusting Views 4. Click the Previous button on the Main View panel to return to your base view, and then zoom in to the next area of interest. Once you are comfortable with using this sequence to present storm views, you will want to use it often. Many broadcast clients use the Previous button as a quick map switch, as shown in the following example. Assume that you are doing a short cut-in before going on the air. 1. Zoom into the area of concern, then click the Previous button to return to the overview so that you are ready for your cut-in. 2. When your cut-in starts, show the overview, and then say something similar to, Lets zoom into the area of concern. 3. Select Previous to have the system instantly zoom into that location. You can now discuss the situation and even place a storm track. 3.2 Setting Map Parameters The View Map Features panel controls the map display. To activate it, click on the Map button in the More Settings area at the bottom of the panel. After you save all parameters for a view, any other manipulation of that view keeps those same parameters. Topographical and texture mapping is also saved as a parameter. This lets you have specialty backgrounds for instantly displaying news graphics. Your most often used parameters should be on your default view. (You can activate Views 1 through 4 by using the hot buttons at the top of the screen.) The system will use those parameters when the view is activated. The following paragraphs describe each option on the panel.

Boundaries lets you turn both state and county lines on or off individually.

Roads lets you display roads at the specified level. Show controls whether any roads appear. Lock sets the display of roads at the specified level. (The higher the level, the more roads will be posted.)

Waters/Rivers functions are similar to the Roads functions. Show lets you turn on and turn off displays of rivers and other bodies of water. Lock sets the display of bodies of water and rivers at the specified level. If rivers are turned off when you update the view, subsequent zoom or pan operations result in a view with no river features. Fill automatically fills in empty water features. When selected, Fill bolds the river water lines. Thus, if a river is narrow enough, it will be filled.

Bold Map Lines doubles the size of all map lines. While it usually is inappropriate at large distances, this option can be quite useful at close ranges. 35 Adjusting Views FasTrac Millennium Users Guide May 2003

Places controls the display of city names. Show turns on and turns off the display of community names. Normally, the system uses the default settings you established with the Setup > Map > Places Database command (see section 2.4, Editing the Places Database). To override the default settings, key in a new level in the Level text box, and click Update. Click Lock to set the specified priority level for future pans and zooms.

More is reserved for future enhancements.

Undo returns all parameters to their previous settings following the last Update command. While you can select Update after changing each map feature, we designed the system so that you can change as many mapping parameters as you like and then click Update one time to effect all of your desired changes. 3.3 Editing Topographical Data Click on the Topo button under the More Settings panel area to activate the View Topo panel. While all Millennium systems have actual topographical capability out to a specific distance, you can supplement displays by using texture maps. If the topographical data is inappropriate for any reason, the system reverts to a backup, generalized texture bitmap that approximates topographical features. Background Bitmap lets you display a single background that is loaded from a graphic file. Although the display of roads and rivers changes when zooming or panning the map, the bitmap will not change in perspective. The background bitmap may also be a customized 640 x 480 pixel-sized file developed specifically for your weather presentation.

Enable displays the background graphic supplied by the specified file. If you do not select Enable, the background is a solid gray.

Keep on Move lets you keep the bitmap displayed as you zoom or pan around the map. Select this option unless you want a gray background.

Filename specifies the bitmap. You can use any bitmap as a background. It must be 24-bit (full color) file. The mandatory bitmap size is 640 x 480. The bitmap displays only when the topography is o of range. ut Topo Data allows you to toggle your real topographical data on and off with the Enable checkbox. In addition, you can set the range in miles at which the topographical data will appear with the Min Range and Max Range textboxes. When zooming in to a very close range, the real topographical data can cease to appear properly, at which point it would b a good idea to switch over to the background texture map. You should experiment at different ranges to find the appropriate range at which to set this threshold. e 36 FasTrac Millennium Users Guide May 2003 Adjusting Views 3.4 Saving and Organizing Views This section describes how to save and organize your views. 3.4.1 Saving Views Once you have all the parameters defined for a given view, you will want to save it. When saving a view, you have the option of just saving the view or of saving the view as a bitmap file. For most purposes, the liquid databases are such powerful tools that there is little need to save a large number of views. The first four views you create correspond to the four numbered hot buttons. Traditionally, the first view is your overview map; the other four views are those that you use the most. Therefore, you should try to only save views that you know you will use many times. You may also save views specifically for SEQUENCER use. 1. Select the View > Save As command to open the Save View As menu, which has a pull-down list labeled View Name. 2. Select a view from the pull-down list, or key in a new name. If you use an existing view name, the old view will be overwritten. Use descriptive names that will help you identify them later. 3. Click the Use Bitmap button to save the view to the bitmap file specified in the Bitmap Filename text box, as described below. The bitmap name should be eight or less letters, followed by the .bmp extension. If you do not add an extension, the system automatically adds the .bmp extension. If you save the view as a bitmap, you save everything except the background and logos as a .bmp file. Your system stores views as full color images; therefore, the number of actual colors used is quite small. One advantage is that recall may be somewhat faster for bitmap views saved with this approach, depending upon your hardware configuration. In addition, you can export a views bitmap to a paint program. You can then add features, and return the finished product to the system. The only restrictions pertain to the set of colors used by map features. If you choose not to save the view without using a bitmap, you store the data with the saved view, but not as part of it. In other words, the system knows which background to put with a foreground but does not save both as a single view. It can also save all the mapping parameters, such as rivers and roads, as a data file. The result is that when you call up a view, the system first opens the background map and then draws all the rivers, roads, communities, radar, and lightning

(if available), as required. It then displays the finished map. There are three advantages to this approach. First, it uses less room on the hard drive because it stores fewer bitmaps. Second, if you choose to change fonts or backgrounds at some point, it will use the latest choice in putting your view together. Finally, the system does not have to create a foreground bitmap. 37 FasTrac Millennium Users Guide May 2003 Adjusting Views Whenever you are saving views, it is very important to use a consistent naming convention. We recommend the name (or abbreviation) of the community closest to the center of the view and the range of the view. For example, you could save a 150-mile view that is centered over Huntsville, Alabama as HSV 150. This naming convention makes it easy to identify what the saved views represent.

Save All Graphics saves the current view with the current data, such as radar sweep, lightning, and storm tracks. (This is particularly useful in creating a static view of a severe-

weather event. Later, you could use the saved image for such events as promotions.) New radar data will not paint over a view saved with all graphics, and the system warns you if you select a saved view that includes graphics. 3.4.2 Organizing Your Views Several commands are available for you to arrange your views: Arrange View, Delete View, and Export View. If you are creating numerous views to cover every region, county, and city in your area, it is important to use a structure that facilitates the easy access to them. One method is to start with a view of the region. Under that region, you should place every associated county and, under each county, place every associated city. This lets you easily find important locations quickly. Some clients have arranged all of their views first alphabetically and then by range. Following this method, every view of the city appearing first alphabetically from 200 miles to 3 miles would be grouped together, from the farthest to the closest, followed by all other cities in alphabetical order.

View > Arrange lets you move views to the desired location in your Recall List. When selected, the Arrange Views menu opens, listing the saved views. To move views, scroll through the saved views until you find the view you wish. Click on the view, and press the Move Up or Move Down buttons until the view is where you want it. When you finish arranging, select OK. To cancel your changes, select Cancel. The first four views in the Recall List correspond to the hot buttons labeled 1 though 4 across the top of the screen.

View > Delete lets you remove the current view. When you select the command, a small warning appears in the left corner of the control screen, telling you which view you will delete. To delete, click OK. 38 FasTrac Millennium Users Guide May 2003 Adjusting Views

View > Export saves the current view to a floppy disk or your hard drive. You may then transfer the view to your IRIS computer and post the view on the Internet. When you select this option, the menu to the right appears, which contains instructions on preparing views for exporting. Follow these instructions, then select the number of views you wish to export and the destination folder for the view files (either a floppy disk or a specified folder on your hard drive). When these parameters are set, click OK to export the views. 3.5 Using the View Options This section covers other features used in connection with views. All of these involve manipulating the current view. 3.5.1 Adding Text to a View The Temporary Text hot button lets you quickly add additional text of user-specified size and color to a view. Some example messages are "Tornado Warning until 6:00 p.m.,"

or "Ferry Capsized Here." Click the Temporary Text hot button, key in the text on the menu that appears, and then click on the map where you want the text to appear (it will be centered around the cursor). Left-clicking on the Temporary Text button adds text and right-

clicking on it removes text. See section 2.8, Customizing Font Displays, to adjust the font. 3.5.2 Zooming In and Out From a View 1. Click on the Zoom hot button, and then move the Zoom tool (the magnifying glass) over the area of interest. If you have any Telestrator graphics, they disappear. 2. Click and hold on the center point of the desired new view. As you move the Zoom tool, a red rectangular box that delineates the boundaries of your zoom appears. The zoom range in miles appears in the Cursor Status Area. 3. Release the mouse button at the desired range. The system automatically redraws the view to your specifications. Right-click on the Zoom hot button to zoom out to double the current range. 3.5.3 Pointing to Features on a View Use the Map Pointer hot button when you do not wish to make any changes to the map but want to point out a feature. You can activate Pixel Query Mode, which is described in section 3.5.15, by right clicking on this hot button. 3.5.4 Panning on a View The Map Pan hot button lets you maintain the same radius while moving your map to the right, left, up, or down. Select the Map Pan button, move your cursor around the map, 39 Adjusting Views FasTrac Millennium Users Guide May 2003 and click on the new center. 3.5.5 Labeling Streets with Street Spotter The Street Spotter feature allows you to locate and label important streets and landmarks. Basic Operation 1. To activate Street Spotter, click on the Street Spotter hot button. The cursor icon will then change to a small arrow above a two-lane street. You will use this cursor to perform Street Spotter operations. 2. Right-click on the desired street and its name should appear in the Cursor Status Area. 3. Label the street by left-clicking on it, dragging the line in the direction that you want your text to appear, and releasing the mouse button where you want the line to end. 4. Repeat steps 2 and 3 for every street you want to label. 5. Erase all the Street Spotter labels by right clicking on the Street Spotter hot button. Editing Street Spotter Text Displays Select Setup > Street Spotter to open the Street Spotter menu, which lets you adju appearance of Street Spotter text. st the

The options in the upper-left area control text color. These buttons have no effect if you select the Anti-Alias option; in that case, you must the select the color using the Setup > Fonts > Street Spotter command.

Anti-aliased fonts eliminate the blocky appearance of computer fonts.

Dynamic sizing changes the size of Street Spotter text proportionally to the views range when you zoom. This option works for both anti-aliased and non-anti-aliased fonts. If you do not select Dynamic Sizing, you must select the font size to use. For anti-aliased text, you must use the Setup > Fonts > Street Spotter command to change the font size. For non-anti-aliased text, you can change the text size by clicking the up and down arrows just below the Dynamic Sizing checkbox, and view the result in the adjacent sample text viewer.

Text to display lets you enter a message to display instead of a street name. If you select a street, its name will appear in this textbox when you open the Street Spotter menu. 40 FasTrac Millennium Users Guide May 2003 Adjusting Views

Undo last removes the most recently placed Street Spotter text. You can use this option as many times as there are blocks of text, even if you change the view after placing text.

Clear all removes all Street Spotter text from the view.

Find opens the Locate Street or Intersection menu, as explained in the next section.

OK saves changes and closes the menu.

Cancel closes the menu without saving changes. Locating Streets or Intersections The Locate Street or Intersection menu helps you find a street or intersection that appears in your database. 1. Set up your view to include the streets or intersections that you wish to find. 2. Select Setup > Street Spotter to open the Street Spotter menu. 3. Click Find to open the Locate Street or Intersection menu. 4. Select Strict and/or Bound w/view to facilitate finding the desired street(s). Bound w/view causes only the streets appearing in the current view to appear in the list. Strict causes the extensions of streets (St., Rd., etc.) to appear, making it easier determine the right street if there are multiple streets with similar names. to 5. Enter the zoom range in the Zoom range text box. 6. Set Color 1 and Color 2 to the desired color for your streets. Color 1 is used for the street selected from the left box, and Color 2 is used for the street selected from the right box. 7. From the list of letters below each box, click the first letter of the name of both streets (or the same letter for both boxes if you are looking for a single street) to list all the streets that begin with that letter. 8. If you are looking for an intersection, select one of the intersecting streets from the left list box and the other street from the right list box. If you are looking for a single street, select it in both boxes. 41 Adjusting Views FasTrac Millennium Users Guide May 2003 9. Click OK when you have made your selections. After a few seconds, a new view at the specified zoom range will appear, centered either on the intersection or on some point on the street. The streets will be shown in the colors that you selected for them. 3.5.6 Controlling Display of Radar Data There are several commands located in the Radar Main Menu that allow you to control the appearance of live radar data on a view, as well as replay recorded data from past weather patterns. The Radar > Radar Levels command opens the Levels menu, which lets you toggle the real-time radar display levels on and off. For instance, should you decide not to show radar data for the lowest level of intensity, open the Levels menu and click the square labeled "1" to remove the selection. Drop specific levels deletes the selected radar levels from your real-time radar. Cut off reflectivity levels below DBZ value specified displays only levels that are above the specified dBZ value. This option is useful for dropping data from both real-time and NEXRAD radars. It also automatically removes the dropped colors from the on-screen legend. The Radar > NEXRAD Levels command works similarly to the Radar >

Radar Levels command except that the command controls the display levels of your NEXRAD products and is product-specific. The Radar > Log to File command records real-time radar data to a log file in the C:\fastrac\Logs\Radar directory. The file then can be used to display for use in time-lapse sequences. The radar log files are purged every 24 hours. By default, this command is selected. The Radar > Play File and Radar > NEXRAD File commands allow you to display stored real-time radar and NEXRAD radar data, respectively. These commands are mostly used for troubleshooting. For real-time data, the system will also ask you to specify the number of radar sweeps to display, as well as whether to show wind velocity and intensity data, if applicable. 3.5.7 Utilizing TeleTrac The TeleTrac feature lets you draw freehand lines on your view with a graphics tablet and pen. These lines are used mostly to emphasize data currently on the screen. To begin drawing TeleTrac lines, left click the TeleTrac hot button. The cursor will change to a marker-like icon and the Cursor Status Menu will indicate with which color you are drawing. To draw a line, left click on the view where you wish to start the line, 42 FasTrac Millennium Users Guide May 2003 Adjusting Views hold down the button on the pen, and drag the cursor to where you want the line to end. To change line colors quickly, click the right mouse button. The colors appear in the order: red, blue, green, yellow, white, black, purple, cyan, and gray. You can change additional settings with the Telestrator Pen Information menu, w hich you can open by right clicking on the TeleTrac hot button. You can change the Width of the Telestrator lines to any value from 0 to 99. If you select the Transparent option, the Telestrator lines you draw will chan ge appearance so that you can see the map graphics under the line. The last option in this menu i s to ge select the line color. The currently selected color has a dot in the center of its circle. To chan colors, click on another color. To rem ove Telestrator lines from the screen, click either the Map Pointer or Zoom hot button. 3.5.8 Displaying Lightning Strikes on a View Select the Lightning hot button to display a lapse of the lightning strikes that have occurred over the past hour. Right-click on the button to deactivate lightning. You may also turn off lightning through the View Main panel, b Settings area. y deselecting the Lightning and Blink options under the Quick Both Lightning displays and Lightning time-lapses can be inserted as eve a Sequence (see Chapter 5, Using SEQUENCER, for more information). nts into Editing Lightning Displays In the View Data panel, you can select from several options.

Show turns on the lightning display.

Blink causes lightning strikes to flash.

Bold doubles the thickness of the displayed strikes.

Cursor causes the latest lightning bolt to appea continually jumps to the newest lightning strike. r as a larger icon, which Specifying Lightning Colors There are six colors in the Setup > Colors menu associated with Lightning: L

(Hot, Warm and Cold), and Lightning Negative (Hot, Warm, and Cold). ightning Positive 43 Adjusting Views FasTrac Millennium Users Guide May 2003

Positive refers to the cloud-to-ground movement of lightning.

Negative refers to the ground-to-cloud movement of lightning.

Hot refers to a strike that occurred less than five minutes previously. *

Warm indicates a strike that hit between five and ten minutes previously. *

Cold refers to a strike that occurred between ten and fifteen minutes previously. *

*The fade times for these attributes are user-definable in the omninet.ini file. See section 2.7, Adjusting the Color Palette, for instructions on editing these colors. 3.5.9 Displaying Storm Spotter Van data The Storm Spotter Van feature lets you track the position of, and receive data from, a Baron Storm Spotter vehicle. The connection between the Storm Spotter Van and FasTrac is made possible by a cellular telephone that is linked to FasTrac and is available in the van. Configuring the Van Marquee Right-click on the Storm Spotter Van hot button or select Tools-3 > Vehicle Info to open the Van Settings menu. Caption contains the words that appear at the top of the Van Marquee. Show displays the associated attribute on the marquee. Lock secures the associated parameter as the stated value. The value will not change when new data is available. Latitude and Longitude define the location of the van icon. Select Lock to keep the icons location at the specified coordinates. Displaying the Van Icon and Marquee Left-click on the Storm Spotter Van hot button to open the Vehicle Quick Settings menu. To remove either the icon or marquee, uncheck the associated option. Sometimes the Storm Spotter Van icon will not appear even when if Show van icon is selected. If this occurs, try locking the latitude and longitude on the Van Settings menu. 44 FasTrac Millennium Users Guide May 2003 Adjusting Views 3.5.10 Toggling High-Definition Data Processing The High Definition Data Processing (HDDP) feature creates clearer NEXRAD displays than those available with the normal pixilated display. The HDDP display is generated in real time without loss of accuracy as shown in the following comparison:

Normal, Pixilated Display HDDP Display To enable high-definition processing, select Radar > High Definition. A check mark next to High Definition option means that the HDDP feature is active. To enable dithering of high definition radar colors, select Radar > Dither. A check mark next to Dither means that the Dither feature is active. It is best to have HDDP enabled at all times. Disable it only if you wish to look at unprocessed radar data. 3.5.11 Displaying NEXRAD forecast data The optional FutureScan module forecasts and displays up to thirty minutes of projected NEXRAD radar data. Although very complicated processes and calculations are involved in producing a forecast, it is all done for you. All you must do is select a compatible site and product and then use the FutureScan menu to create your forecast. FutureScan is inoperable when the radar is in Clear Air mode. Using FutureScan 1. Open the NEXRAD Main panel. 2. 3. 4. 5. Select a site to display. Select Max Reflectivity. Select Tools-2 > FutureScan to open the FutureScan menu. Specify the Span number. FutureScan creates one frame for each 5-minute span into the future. Span should be a multiple of 5 and not exceed 30. Click the FutureScan button, and frames will appear on the screen. Use the forward (>) button to scroll forward through the sequence, and the back (<) button to scroll backward. 45 Adjusting Views FasTrac Millennium Users Guide May 2003 3.5.12 Displaying Neighborhood Weather Net Sensor Data You can use the Neighborhood Weather Net (NWN) interface to show NWN sensor data on your maps. NWN provides non-storm related data, such as temperature, humidity, wind speed, wind direction, and barometric pressure. Setting Up Locations to Receive Data 1. Select Setup > Data > Advanced > NWN Interface to open the NWN Locations menu. All of the values in the upper section (except for User Defined Text) are updated automatically if you have a NWN system. Otherwise, you must change them manually.

The Pull-down list contains all of the locations you have already set up. Select Delete Place to remove the displayed location from the list. Select Add Place to add a new location.

Temperature displays the latest recorded temperature, in degrees Fahrenheit.

Wind displays the wind direction and force, in miles per hour.

Pressure displays the amount of barometric pressure, measured in millibars.

Humidity, which is measured in percentages, displays the amount of moisture that the air contains compared to how much it could hold at a given temperature. A figure of 100%

means that the air has become saturated.

Daily Rainfall displays the amount of rainfall within the last 24 hours. The daily rainfall sensor is zeroed every day at midnight.

Solar Radiation displays the total electromagnetic radiation emitted by the sun.

User Defined Text is the user-specified text that appears at the specified latitude and longitude coordinates.

Sensor ID must correspond to the number used in the NWN program.

Show Level indicates the maximum range at which the sensor data appears on the map.

Latitude and Longitude specify where the text will appear. It will always appear at these coordinates regardless of where you go on your maps.

Add Place lets you create a new location.

Delete Place removes the currently displayed location. 46 FasTrac Millennium Users Guide May 2003 Adjusting Views 2. When you have completed editing locations, click Done. 3. Select Setup > Fonts > Temp Text to specify the font size, type, and color. Setting Data Thresholds You can set the minimum and maximum values that will display for an NWN data item with the Sensor Thresholds menu. Open this menu by selecting the Setup > Data > Advanced > NWN Thresholds command. There are two additional data types for which you can set thresholds. Both are derived from other data:

Temperature and Humidity are used to calculate the Heat Index.

Wind Chill is calculated from an equation involving Temperature and Wind Speed. Displaying Sensor Data Now that your places are set up, you must either use another menu or SEQUENCER to display the data. Set the map view within the range of the location that you specified in the previous section. 1. Click on the Sensor Data menu. hot button to open the Sensor Data 2. In the Mode area, you can select the current days lowest or highest value. If you are manually inputting values, you can only show the current value. 3. Select the desired data type Text type area. 4. You may specify the Y Pixel Offset to indicate the location of the data. ted The data will appear the specified number of pixels below the selec geographic coordinates. This lets you prevent conflicts with places shown on the map at certain ranges. 5. Select Update to display the appropriate data at the latitude and longitude you specified in the NWN Locations menu. You must be within the cutoff range to see the data. 47 Adjusting Views FasTrac Millennium Users Guide May 2003 3.5.13 Zooming to a Specific City The Find City feature allows you to automatically zoom to any city in your database at a selected range. 1. Select Tools-1 > Find City to open the Find City menu. 2. In the text box labeled Community Name, type in the name of the community you wish to focus on. 3. Click Search, and the system will display a list of all of the communities that start with the letters you typed (capitalization is ignored for this process). 4. Select the desired community by clicking on it. 5. In the text box labeled Scale, enter the range, in miles, at which you wish to view the selected city. 6. Click OK to zoom to the selected city. Note that the menu remains on the screen, so that you may select another city to focus on using the same process. If you do not wish to find any more cities, click Off to remove the menu. 3.5.14 Adding Fronts and Pressure Markers Using the Fronts Hot Button, you can add graphics that represent fronts and pressure markers to a view. To begin drawing cold and warm fronts, left-click on the Fronts Hot Button. You may then draw cold fronts by clicking and dragging with the left mouse button, and draw warm fronts by clicking and dragging with the right mouse button. Clicking and dragging in a clockwise direction will cause the front arrows to appear on the outside of the curve. Clicking and dragging in a counterclockwise direction causes the front arrows to appear on the inside of the curve. To begin adding low and high-pressure markers, right click on the Fronts Hot Button. The Front Drawing menu will appear, which allows you to choose between adding fronts and adding pressure markers. Click the Letters circle to select pressure markers, then left-click to add low-pressure markers and right-

click to add high-pressure markers. Overlays labeled HighPressureSystem and LowPressureSystem must be present in your system for pressure markers to appear. To remove front and pressure markers from the screen, right-click on the Temporary Text hot button. 48 FasTrac Millennium Users Guide May 2003 Adjusting Views 3.5.15 Creating Temporary Pixel Query Points Using the Map Pointer hot button, you can create text messages that indicate the severity of various types of radar data such as reflectivity. These messages are known as pixel query points. To begin the process of adding pixel query points, right-click on the Map Pointer hot button to enter pixel query mode. You will notice that when you move the cursor over radar data while in this mode, the text associated with the level of severity of the data appears in the Cursor Status Area. To add a pixel query point, left-click on the view at the desired spot. A text message will appear indicating the weather type (for example, 5 dBZ for reflectivity). You can remove pixel query points by refreshing or adjusting your view. You can change the appearance of pixel query point text with the Setup >

Fonts > Pixel Query Mode command. To change the text used for pixel query point messages based on real-time data, open the Level Descriptions menu using the Setup > Data >

Descriptions command and edit the textboxes corresponding to reflectivity or wind velocity. To edit the pixel query text for NEXRAD data types, use the Advanced Baron Chart (see section 6.3.3). 3.5.16 Creating Fixed Pixel Query Points An added feature of FasTrac Millennium is the ability to create pixel query points that will remain where you set them regardless of how your view changes. Use the following procedure to add these points:

You must have radar data present on your view to add pixel query points. 1. Select the Setup > Map > Pixel Query Points command to open the Query Points menu. 2. Click the Add button to set your cursor for adding pixel query points. 3. In the text box labeled Name of point, enter a name for the point you wish to place. 4. Enter the maximum range at which you want the point to appear in the View range text box, or click the button labeled Set to current range to automatically enter the current view range. 5. Click on the desired spot on your view to add the point. 6. Repeat steps 3 through 5 to add more points. You will notice that you can pan and zoom around your view without removing the pixel query points, as long as they are within the view range. 49 Adjusting Views FasTrac Millennium Users Guide May 2003 To temporarily hide your fixed pixel query points, uncheck the box at the top of the Query Points menu labeled Display points. To permanently remove a fixed pixel query point, select it from the list in the Query Points menu and click Remove. 3.5.17 Displaying Precipitation Type Maps Select Tools-2 > Precip Type Map to open the Precip Type panel, which allows you to download a 461 x 461 pixel (kilometer) map from Baron Services Snow Machine server. You can then modify the grid, which is overlaid on the current view, to reflect the current situation in your area.

Enabled forces a new grid to be downloaded each time one is created. You must have both Enabled and Autoload grids selected to automatically download grids from Baron Services.

Autoload grids downloads a new grid from the Snow Machine server every time a new one is created. The only reason to not select this option is when you want to keep the manual map for display purposes.

Fill Type lets you create a Rain, Freezing, or Snow area. When you select this option, the mouse cursor turns into a pencil and you can then define the weather line by clicking and dragging.

Undo Fill clears the last area that was manually filled.

Clear Lines erases all the lines you have drawn.

Clear All erases everything off the screen and returns to the display shown before you downloaded the grid.

Outside Area changes the area outside of the grid to rain, freezing, or snow.

Load allows you to manually load a previously downloaded grid file. To clear the Precip Map from your viewing area and close the Precip Type menu, click OK. 50 FasTrac Millennium Users Guide May 2003 Adjusting Views Setting Up the Precip Type Background While your precipitation type map is set up for you upon delivery, you may have to adjust it during troubleshooting procedures. To open the Precip Type Setup menu, select Setup > Data > Precip Type Map. The only items you should change are the Line Width and Fill Colors settings. The Line Width text box lets you set the width (in pixels) of the boundary lines you draw between precipitation types. The Fill Colors commands open the Edit Color menu, which lets you set the fill colors for rain, freezing rain, and snow. Click OK to save the color setting and to return to the Precip Type Setup menu. Upon completion, click OK to save your changes and to close the Precip Type Setup menu. 3.5.18 Saving the Current View as a Bitmap A fast way to save the current view along with its weather and other data as a bitmap is to use the Screen Grab Utility. The process for saving a bitmap in this manner is as follows:

1. Select Tools-2 > Screen Grab Utility to open the Screen Grab Utility menu. 2. Specify the filename path in which the screen grab will reside in the Destination path textbox. 3. Choose a filename for the bitmap in the Base filename textbox. 4. Verify that the Counter Value textbox contains a 1 if you are using a new filename for these bitmaps, or that it is at the desired number if you are using the same filename as you previously have used. The Full Filename box should now list the path you want for the bitmap. 5. Click Grab to save the bitmap. The counter value will increment by one. Exit closes the screen grab utility. 3.5.19 Printing the Current View To quickly print out the currently displayed view, select the File > Print command. The view will print to the designated printer for your FasTrac Millennium computer, and a message will appear indicating a successful print operation. 51 Adjusting Views FasTrac Millennium Users Guide May 2003 3.5.20 Highlighting Your Spotter Network On-Air The SpotterNet feature, which Millennium users can access through the SpotterNet hot button, gives you the opportunity to show the positions of your storm spotters in the field to your viewers. Setting Up Your SpotterNet Database 1. Right-click the SpotterNet hot button to open the SpotterNet Database menu. 2. The existing list of spotters appears in the pull-down list at the top of the menu. To add a new spotter, click Add Spotter. 3. Type in identification data for the spotter in the Name, Location, Phone Number, and Comment textboxes. 4. Enter the maximum range at which the spotter icon should appear in the Show range

(miles) textbox. 5. Enter the geographic coordinates at which you want the icon to appear in the Latitude and Longitude textboxes, or click on the desired spot on the view with the map pointer and then click the Lat/Lon Map Edit button to automatically set coordinates. 6. Click Show on Map to set the spotters icon to appear when your view is in range and SpotterNet is toggled on. Checking Trained Spotter causes the system to identify the spotter as trained when you click on his or her icon. Blink me makes the spotters icon appear to blink on the view, making it easier to identify. The Delete Spotter button lets you remove the spotter whose data currently appears on the menu. Using SpotterNet On-Air Once your SpotterNet database is set up, using it during a broadcast is a matter of left-clicking on the SpotterNet hot button to toggle on the icons you want to display. You can then indicate one of the icons near the weather pattern while mentioning to your viewers that you are receiving a live report from the spotter at that location. You can also left-click on the icon to open a small menu providing some of the data you entered about the spotter, to facilitate correct identification. 52 FasTrac Millennium Users Guide May 2003 Adjusting Views 3.5.21 Displaying National Weather Service Warnings Using the Weather Wire Data hot button, you can control the display of National Weather Service warnings for counties in your viewing area. Left clicking the button opens the Warnings Display panel, which shows the current alerts that are in effect, which counties are involved and when the alerts expire.

To view the full text of a warning, click on a line of the warning in the Warnings Display text box and click View Msg.

To close the Warnings Display menu, click Hide. Right clicking the button opens the NWS Setup menu, which allows you to toggle settings for display of NWS warnings.

Fill counties toggles whether counties that are under a warning are filled with the appropriate color. The fill color will replace your topo image.

Border points toggles the display of points indicating the boundary lines for a county. This feature is intended for troubleshooting and should n be used on-air. ot

Border numbers toggles the display of numbers indicating the boundary lines for a county. This feature is intended for troubleshooting and should not be used on-air.

The Fill Color Settings allow you to set the colors for Tornado (TOR), Severe Thunderstorm (SVR), Flood (FLW), and Flash Flood (FFW) warnings. See section 2.6 for information on adjusting colors.

County Setup is an advanced feature used for testing purposes. You should not use this feature without the assistance of a Baron Services representative.

Reload Warnings lets you reload warnings that the system parsed during the previous FasTrac session, in the event that you are forced to close and restart FasTrac. To save your changes and close the menu, click OK. To exit without saving changes, click Cancel. 53 Adjusting Views FasTrac Millennium Users Guide May 2003 3.5.22 Displaying Wind Speed and Direction The Wind Display feature allows you to quickly show the speed and direction of winds at various elevations over your broadcast area. The Rapid Update Cycle Model (RUC) provides wind data. The RUC is an operational atmospheric prediction system comprising primarily of a numerical forecast model and an analysis system to initialize that model. It serves users needing short-range weather forecasts, including those in the U.S. aviation community. Wind data will appear over any other data that you display and remains on screen until you uncheck the Active button, even if you close the menu. Therefore, always remember to uncheck Active before exiting the menu. To begin using this feature, select Tools-3 > Wind display to open the Wind display menu. Active toggles the display of wind data. Wind markers such as the one on the right appear, showing wind speed in the area they appear over, at the height selected. A triangle indicates 50 knots, a long line indicates 10 knots, and a short line indicates 5 knots. Adding up all of the lines on a marker gives the wind speed. (The marker in the example indicates 65 knots total.) Show legend toggles a legend depicting colors for different levels of wind speed. This legend is used in conjunction with the Streamlines option, which is described below. You can change the colors for the legend with the Advanced Baron Chart (see section 6.3.3). The Thin lines option, when checked, removes the black line from around the wind markers (or streamlines if they are activated). This makes the data update faster, but can make the markers harder to see. Streamlines changes the display to show the direction of the winds as well as their speed. As shown in the example on the right, the arrows indicate the direction in which wind is traveling along the lines. The wind speed is indicated by the variations in color along the lines, with the color values appearing in the legend. Rows and Columns affect the number of wind markers and streamlines that appear on the screen. For example, if your Rows and Columns boxes both have 10 entered, there will be 10 rows and 10 columns of wind markers. Similarly, if Streamlines is activated with 10 entered for both Rows and Columns, there will be 100 total streamlines on the screen (10x10). 54 FasTrac Millennium Users Guide May 2003 Adjusting Views Step (knots) changes the number by which the levels of wind speed increment when you are in streamlines mode. For example, if you have 10 entered in the Step box, the legend will change to increments of 10 knots each, up to 140 knots. Entering 12 will produce increments of 12 and a maxiumum of 168 knots. The Height area contains a slider bar that allows you to change the height at which winds are being measured. The range is from winds along the surface to a maximum of 42,000 feet, in increments of 3,000 feet. Sliding the bar up or down will cause the system to automatically display the winds for the new height. The Surface level in the Height bar measures wind speed along the land or water surface regardless of height above sea level; therefore, data will always be present. However, with the other heights data will not appear if the land surface is higher in elevation than the height selected. Close closes the Wind Display menu, allowing you to use other menus while viewing wind data. 55 Adjusting Views 3.6 Points to Remember FasTrac Millennium Users Guide May 2003

The panels shown on the left side of the display can be used to change commands that were specified by the Setup commands. Changing parameters through these panels is often a faster and more efficient way to control your display.

Use the Radius setting on the Main View panel to specify your map range.

Use the View Map Features panel to control map features, such as roads and rivers.

Use the View Topo panel to display a topographical background.

Use the hot buttons to zoom in, zoom out, and re-center your map.

Remember to save your views for later recall. 56 4. Managing Storm Tracks We designed the new series of FasTrac, as its name implies, to provide you with the fastest, most detailed tracking of storms. You will find storm tracking an easy, instantaneous process with some truly inventive features. This chapter describes the processes for designing your storm presentations, such as:

Setting Defaults for Storm Tracks

Creating Storm Tracks

Editing Storm Tracks

Editing the Storm Marquee

Using PasTrac

Using StormScan 57 Managing Storm Tracks FasTrac Millennium Users Guide May 2003 4.1 Setting Defaults for Storm Tracks The Setup > Storm > Storm Track command, which opens the Storm Track Setup menu, lets you establish default settings for storm tracking. In essence, you determine the original settings (defaults) for each storm track and then individually adjust parameters to meet your needs.

INITIAL TRACK DURATION specifies the length, in minutes, of the tracking period. When you create your storm track, this number specifies the amount of time in which the storm will travel the distance of the red line you create. For example, if you create a 15-mile storm track with Initial Track Duration of 15 minutes, the computer will calculate a speed of 60 miles per hour. If you change your Initial Track Duration to 60 minutes, the speed then will be 15 miles per hour.

DEFAULT FAN WIDTH refers to the width of the base of a fan-projection of a storm track. You can either set the default fan width value on the Storm Track Setup menu or enter a specific Width value on the Storm Track panel. Typically, the Default Fan Width value is between 2 and 5 miles.

MINIMUM SHOW SIZE specifies, in pixels, the minimum size of the storm track. Use this variable to prevent storm tracks from appearing in long-range maps (e.g., a 150-mile map). Minimum Show Size specifies how large the track graphic should be before the storm track can be seen. This prevents storm tracks intended for close ranges from cluttering up long-range map displays. Thus, you can use long-range maps to show your audience where the storm is located. You can then zoom in to show a small storm track at close range.

MINIMUM AMOUNT ON SCREEN specifies the smallest amount of the storm projection that appears on the map display. This lets you prevent a small portion of a large storm track from appearing on your map display. When only part of the storm-track area (the area defined by the yellow storm track box) is on screen, it can be confusing. Just as Minimum Show Size prevents small storm tracks from cluttering long-range maps, Minimum Amount on Screen prevents pieces of long-range storm tracks from appearing on close-range maps. The usual setting for Minimum Amount on Screen is 65. When Minimum Amount on Screen is set to 65, you must display 65% of the storm track area for the storm track to appear. Displaying anything less makes the storm track disappear until you select an appropriate range and center for your map display.

ETA BOX LEFT OFFSET defines the number of pixels from the left of the screen at which the Storm Track ETA Box will appear. You may then drag-and-drop the Storm Track ETA box anywhere on the screen.

ETA BOX TOP OFFSET defines the number of pixels from the top of the screen at which the Storm Track ETA Box will appear. 58 FasTrac Millennium Users Guide May 2003 Managing Storm Tracks

ETA BOX NUMBER OF LINES specifies the size, in lines, of the ETA box graphics. For example, to display eight communities, enter 8.

PLACES SHOW RANGE ZERO CUTOFF specifies at which range every community appears. For example, if you create a storm projection based on a 60-mile view and have all the communities posted, your projection would be crowded by locations. To alleviate this problem, we have created an option that tells the computer the range at which you want each community to show. Typically, that value is between 25 and 75 miles. At distances greater than specified value, the system will post every community, prioritized at half the map range. For instance, if you set Places Show Range Zero Cutoff to 50 and you have a 60-mile radius map and do a storm projection, the system will post all communities with priorities 30 miles or above. Once the radius is within the zero cutoff zone, it will post all communities. Clients who prioritize their Places database usually set a low value (between 25 and 50 miles) for the Places Show Range Zero Cutoff variable. The earlier prioritization of cities at different miles means that cities will appear in a storm track displayed above the specified range. Clients who have done relatively little Places prioritization should set Places Show Range Zero Cutoff to a relatively high value (between 50 and 75 miles). Of course, even after you set this parameter, you should test storm tracks a few times to verify that the desired number of cities appears in the storm track. If not, set the Places Show Range Zero Cutoff value higher to display more cities; set the value lower to display fewer cities.

STORM TRACK MAX SHOW RANGE specifies the maximum range, in miles, at which storm track graphics (the storm track and the Storm ETA box) begin to appear. 4.2 Creating Storm Tracks The Storm > Add command contains options for creating three kinds of storm projections: Fan, Circle, and Squall. The following subsections describe each type of projection. 4.2.1 Creating Fan Projections Fan projections indicate a fan-shaped area, which depicts storm tracks that are close to the leading edge of the storm. 1. Select Storm > Add > Fan, and move your cursor to the location of the storm. You will see a small storm projection icon with a small crosshairs (+) above it. The crosshairs represent the center point. 2. Place the storm project icon the leading edge of the storm you wish to track, and then press and hold down the left mouse button. Note that a red elastic band forms, rooted from the point of your initial click to where your mouse is now. 3. Move the red rubber band in the direction of storm movement, and note that the status bar indicates your azimuth (direction in degrees), speed, and range. The speed is based on the Initial Track Duration parameter you set in the Initial Track Setup menu (see section 4.1, Setting Defaults for Storm Tracks). 59 Managing Storm Tracks FasTrac Millennium Users Guide May 2003 4. When the direction and speed displayed in the status area match the known storm conditions, release the mouse button to display the storm projection. The marquee will appear at the position defined by the ETA BOX LEFT OFFSET and ETA BOX TOP OFFSET variables on the Storm Track Setup menu (see section 4.1). 4.2.2 Creating Circle Projections Circle projections show where the cities and communities are in relation to a storm in a circle-

shaped area. 1. Select Storm > Add > Circle, and move your cursor to the storm location. Unlike the fan projection, you use the normal default cursor when you define a circle projection 2. Place the tip of this arrow cursor over the storm you wish to track, and then press-and-hold the left mouse button. Note that a red elastic band forms, rooted from the point of your initial left-click to where your mouse is now. Notice that the azimuth, speed, and range that are displayed in the status bar change as you move the red rubber band. 3. Release the left mouse button when range matches the distance from the center of the storm to the edge, or when the red band reaches the edge of the area affected by the storm. Note that the special circle projection marquee indicates the communities that are inside the circle projection, as well as their distance and direction with respect to the storm. This marquee appears at the position defined by the ETA BOX LEFT OFFSET and ETA BOX TOP OFFSET variables on the Storm Track Setup menu

(see section 4.1). 60 FasTrac Millennium Users Guide May 2003 Managing Storm Tracks 4.2.3 Creating Squall Projections Squall projections track the progress of a line of storms. 1. Zoom in on the storm that is to be tracked, as shown in the following example:

2. Select Storm > Add > Squall from the Storm menu to add the squall projection. 61 Managing Storm Tracks FasTrac Millennium Users Guide May 2003 3. Click and drag your mouse to define the height of the storm and the two points that define the northernmost and southernmost edges of the storm. If the storm is moving north or south, define the width of the storm and the easternmost and westernmost points. In both cases, you will define a line that is perpendicular to the storms movement (shown in the following figure as line 1-2). 4. Click and drag the mouse to define the leading edge of the storm, the squall amount, the speed, and the direction. The four points (including the two points defined in step 3 and the two points defined in this step (Line 3-4) are used to calculate the squall. 62 FasTrac Millennium Users Guide May 2003 Managing Storm Tracks 5. Release the mouse to display the squall projection, as shown in the following example. If the projection is smaller than your default criteria for posting, you will see nothing, but the parameters will display in the track area box. If you choose a closer view and the storm projection is within it, the projection will be posted. 4.2.4 Deleting Storm Tracks To remove the currently selected storm track, select Storm > Delete. To remove all existing storm tracks, select Storm > Delete All. 4.3 Editing Storm Tracks Once you create a storm track, you can edit the storm track and the places that appear in the storm marquee box. You can do this with the Storm Track panel as described below, or with the Storm Track Places panel (described in section 4.4). Modifying Storm Tracks Select the Storms option in the upper part of the panel to display the Storm Track panel.

Storm Name identifies the current storm track (in this example, it is Storm 1). Select a storm from the pull-down list. You can key in another storm name (for example, Athens Storm 1 or Possible Tornado). In either case, click Update at the bottom of the window. You should retain the number identification in the heading and on the storm projection itself in case you post more than one projection.

Type identifies the type of the current storm projection. 63 Managing Storm Tracks FasTrac Millennium Users Guide May 2003

Enable displays the current storm projection. It is possible, and in many cases preferable, to create a storm projection but not display it. In this manner, you can track a storm that has severe weather potential. Regardless, by deselecting Enable, you maintain the storm track in memory without actually posting it.

Start Time refers to the time you made the storm projection. Make sure the computer time is accurate. To change the time, go to the Windows desktop. Select Start Settings Control Panel to open the Control Panel menu. Double-click on the Date/Time option to open the Date/Time Properties menu, and make your changes.

ID refers to the storm reference number noted at the time you made the projection. You may delete earlier projections at times. For example, if the current storm track is the third projection you have made, ID will be 3. The ID number resets when you use the Storm >

Delete All command.

AutoTrac invokes the AutoTrac function, which creates a new projection based on your real-time radar or NEXRAD data. Wait at least five minutes after tracking a storm before selecting AutoTrac. This gives the system enough time to make accurate updates. Select AutoTrac, and click on the storms leading edge. The system computes the storms direction and speed since the last update and plots a new projection. AutoTrac is more accurate at closer viewing ranges because fewer pixels represent each mile on the screen. See Section 4.5, Using PasTrac, for more information. (PasTrac lets you track a storms progress by comparing older radar data to the storms current position.)

Track Area parameters describe the storm. You can change any one or more of these parameters and click Update to renew the storm track display. Some parameters are not applicable to all storm track types. You can also click on Trac Edit, and then click on the new storms leading edge to update to the new storm track. Trac Edit maintains the same direction and speed. This helps when you are tracking multiple storms associated with a storm front. Instead of dragging for direction and speed for each storm, click Trac Edit and you can move from storm to storm, all the way down a line of storms. This lets you focus on each storm and clearly identify which communities will be affected by that storm instead of displaying multiple storm tracks on the same screen. 64 FasTrac Millennium Users Guide May 2003 Managing Storm Tracks 4.4 Editing the Storm Marquee While the Storm Track panel is displayed, select the Places button to display the Storm Track Places panel.

Place Box Visible lets you keep a storm projection but not post the storm marquee. Deselect Place Box Visible, and then click Update to hide the marquee.

Max # of Lines lets you change the number of communities listed in the Storm ETA box, overriding the default number of lines defined by the ETA Box Number Lines variable in your Storm Track Setup menu. This allows you to quickly change the Storm ETA box.

Show Range lets you change the priority setting for communities posted. For example, a Show Range of 0 will show all communities and a value of 15 will show all communities normally displayed at a 15-mile range. You must click on Update to effect the change.

Place List shows all communities at risk according to the given storm projection. Note that all the items in the list include the time and name. Communities that have a hyphen (-) sign in front of them means they are not listed (for example, the Cavalry Hill listing in our example Storm Track Places illustration). Surrounding parentheses means that the item is hidden, such as -(Chelsea). 4.4.1 Selecting Communities for Your Storm Track ETA Box The First and Hide buttons on the Storm Track Places panel control how communities appear on the Storm Marquee. Use the First button to assign a community to the first place in a track. In this example, assume that a storm has passed the first three communities in your storm track. Go to the fourth; then click First. Note that the communities instantly update. Repeat the procedure with any other community to have it be the first displayed. The communities that are located before the one you select as the first automatically assume a hyphen (-) sign to show that they no longer appear. Use the Hide button to temporarily remove a community from the marquee. Select the community, and click Hide. A set of parentheses appears around the community. Repeat the procedure to hide other communities. To return a community to the display, highlight the hidden community and click Hide. The system automatically hides places that have ETAs that are older than the current system time. 4.4.2 Moving the Storm Track Marquee If you would like to change the position of the storm track marquee, click on the Marquee option under the More Settings area on the Storm Track Places panel. Move your cursor to the map. You will see a miniature marquee on the screen. Click at whatever point you would like the upper-left corner of the marquee to be displayed. The marquee will move to its new location, 65 Managing Storm Tracks FasTrac Millennium Users Guide May 2003 staying there through any map change until you move it again or delete it. You can also move the storm track marquee around by clicking on it, holding down the mouse button, and dragging it to the new location. The system holds in memory as many storm projections as you will ever use in one severe-weather event. 4.5 Using PasTrac The PasTrac feature lets you easily track the progress of a storm by comparing its current position to its position in recent data. You can use PasTrac to automatically track either real-time radar data or NEXRAD data, but the process is slightly different. 4.5.1 Auto-Tracking Real-Time Radar Data Use the Radar > Log to File command to log your incoming data. You need to log radar data at least five minutes before you can use PasTrac. Your radar should be in reflectivity mode five minutes in advance. (This option should be active, by default.) 1. Zoom in for a close view of the storm (less than 25 miles). This will let you accurately depict the storm. 2. Make sure you are in conventional mode (i.e., no NEXRAD product is in use). 3. Select Storm > Add Fan from the menu bar. 4. Display the Storm Track panel. 5. Click AutoTrac. The status panel on the upper-left portion of the display will indicate Replaying archived data for AutoTrac. After a short period, the status panel indicates Finished replay. 6. Carefully click on the storms position (where the storm was several minutes ago). Only click once. 7. The status panel will indicate Resweeping current radar for AutoTrac. Upon completion, carefully click only once on the storms new position for an instant auto-track. 4.5.2 Auto-Tracking NEXRAD Data 1. Show the product that you want to use (with the proper site selected) by using the NEXRAD Main panel. 2. Zoom in to a close view of the storm (25 miles or less). This will let you accurately depict the storm. 3. Select the Storm > Add > Fan command. 4. Invoke the Storm Track panel (if it is not already on screen). 66 FasTrac Millennium Users Guide May 2003 Managing Storm Tracks 5. Select the AutoTrac button. The status panel will indicate, Replaying archived data for AutoTrac. After a short pause, it will read, Finished replay. Left-click on storms position. 6. Carefully click the position of the storm during this archived sweep. Click only once. 7. After the system finishes the NEXRAD replay, carefully click on the new position for an instant auto-track. Identifying Storms with StormScan 4.6 StormScan displays cell-by-cell characteristics of a storm system, letting you easily view and summarize the characteristics of a storm, including the presence of hail, hail size, storm top height, storm speed, and the direction in which the storm is traveling. You may also access tornado signatures, max dBZ, and circulation through StormScan. You can easily review current and past storm parameters by comparing two consecutive NEXRAD sweeps. In short, StormScan displays the complete attributes of the storm system, as shown in the following example:

The following tables describe the default color codes used to describe weather characteristics. The five SCITs in the first table are derived from National Weather Service data:

Description Color Storms with Tornado Vortex Signature (TVS) LIGHT RED DARK RED Storms with mesocyclonic activity DARK BLUE Storms with a chance of severe hail LIGHT BLUE HailAttributeColor=0,0,255 Storms with a chance of hail GREEN Normal thunderstorms StormAttributeColor=0,128,0 Code and RGB Value TVSAttributeColor=255,0,0 MesoAttributeColor=128,0,0 SevHailAttributeColor=0,0,128 67 Managing Storm Tracks FasTrac Millennium Users Guide May 2003 The SCITs in the second table are derived from data provided by Baron Services algorithms:

Description Storms with heavy rain, lightning, and hail Storms with wind shear 4.6.1 Setting Up StormScan Color PINK ORANGE Code and RGB Value SevStormAttributeColor=255,0,255 ShearAttributeColor=255,153,0 1) Open the NEXRAD Main panel, select Reflectivity or Composite and select Auto Update on the NEXRAD More panel (NEXRAD page 2). 2) Select Setup > Storm > StormScan or click on the Scan hot button to open the Arrow Filter panel.

Show SCITs displays storm arrows.

Auto Scan uses the most recent product for storm arrows.

Use Alert Sound issues an audible beep when a new product updates attribute data.

Use Alert Message displays a small message box in an off-air area of the screen to notify you of attribute updates.

Show Storm IDs displays the ID given to each storm by the National Weather Service on the SCIT arrow.

SWP in Markers shows Severe Weather Probability on the SCIT arrow.

Visible SCITs lets you toggle the display of SCIT arrows with certain types of storms. For example, if you unselect the Thunder Storm option, no green storm arrows will appear.

Site to Scan indicates the site that is currently using its composite reflectivity products to provide storm attribute data. You cannot change this attribute from the Arrow Filter panel; the currently active NEXRAD site controls this display.

Reset Defaults resets the selections to the default selections.

Marquee Options opens the StormScan Marquee Setup menu (see section 4.6.2).

Table Options opens the StormScan Table Setup menu (see section 4.6.3). You can left click on the base of one these arrows to make a regular storm track that matches this storms criteria. The header of the storm track ETA box indicates the storms contents. Other than the header, this storm acts just like any other storm track. 68 FasTrac Millennium Users Guide May 2003 Managing Storm Tracks 4.6.2 Using Storm Marquees Right-clicking on the base of the storm arrow displays the marquee for the storm. The marquee is similar in style to the storm ETA box, but it gives information about the storm. This information includes storm direction, speed, max dBZ level, height, VIL level, top altitude, probability of hail, hail size, and whether it exhibits Tornado Vortex Signature (TVS) or mesocyclonic activity. You can control which of these attributes to display by selecting Marquee Options in the Arrow Filter panel and opening the StormScan Marquee Setup menu. Be careful. This menu appears in the on-air portion of the screen. To toggle display of a particular attribute, click the option in the Marquee Preferences area. VIL Density and SWP displays are reserved for COBRA Storm Tracking. The top-half of the StormScan Marquee Setup menu has two other areas. Be careful: these options can be confusing. The Storm Filters area lets you set the minimum values for speed and dBZ. Storm arrows will not appear for any storm whose speed or dBZ falls below the minimum specified value. The maximum attributes work differently. Storms with values higher than the specified maximums do not filter from display. Instead, the marquee shows the maximum speed or dBZ instead of the storms real values, and storm arrows shorten to reflect the maximum speed rather than the storms speed. This can be useful because the National Weather Service sometimes sends values that are excessively high. This ceiling feature prevents your viewers from seeing these anomalies. To understand the Max Number of Storms Arrows to Display option, you must understand how the system decides which storms to display. You also should know the storm priority formula. According to the current formula, the first attribute by which the system sorts storms is the presence of a TVS. The next attribute that has priority is mesocyclonic activity, followed by severe hail, normal hail, hail size, dBZ, and storm speed. The formula sorts storms with TVS and mesocyclonic activities matched by the probability of severe hail. The process continues until it sorts all of the storms. After sorting the list, the system takes the maximum number of storms from the list. The second part of the StormScan Marquee Setup menu is Hail Filters. This part does not filter storm arrows from display. It merely flags the system that the marquee for that storm should not display the value in question if the probability of hail or severe hail for any storm is below a certain level. For instance, you might set the Min Probability for Severe Hail Storm to 50%. If you then activate the marquee for a storm whose severe hail probability is less than 50%, the marquee will not have a line that indicates the storms probability of severe hail. Furthermore, the storm will not be dark blue, which normally indicates hail presence. 69 Managing Storm Tracks FasTrac Millennium Users Guide May 2003 Display Delta Values controls the feature that shows how much an attribute has changed for a particular storm since the previous sweep. Display NWS ID causes the marquee header to show the storms designation used by the National Weather Service. 4.6.3 Using the Storm Table Another useful feature of StormScan is the Storm Table, which is opened by right clicking on the Scan hot button. The Storm Table appears in the on-air portion of the screen and displays the highest priority storms. You can click on an item in this list to activate the marquee for a storm. The system will zoom in on that storm arrow, post the storm marquee, and eliminate the other storm arrows. You can then left-click on the storm arrow to display an automatic storm track based on the National Weather Service data. Right-click anywhere on the view to restore the other arrows. The StormScan Table Setup menu, which is opened by the Table Options command in the Arrow Filters panel, controls the Storm Table.

Max Number of Storms/Rows in Table specifies the maximum number of storms that will display in the Storm Table. If there are more storms than the specified value, the system uses the storms with the highest priority calculated by the formula.

Display NWS IDs identifies the storm according to the National Weather Service.

Display Storm Rank identifies the storm according to the rank calculated by the storm priority formula. Selecting Display NWS ID or Display Storm Rank does not change the order in which storms are displayed. They are sorted by rank, regardless of the selection. The Table Contents Preferences area lets you select which attributes are displayed in the Storm Table. Be careful. If you select too many of these items, the table may not fit in the on-air portion of the screen. Experiment before you present the Storm Table to your users. The font that is used is controlled by the Setup > Fonts > Storm ETA Boxes command. 70 FasTrac Millennium Users Guide May 2003 Managing Storm Tracks 4.7 Creating Automatic Storm Sequences The Storm Sequence Main Menu has only one control: Go!. The area is restricted by the parameters you specify in the Setup > Storm > Storm Sequence command. When you select Go, the program locates the most dangerous storm within the current range, generates an ETA box that lists the communities that lie in the path of the storm and the time at which the storm is predicted to arrive at each community, generates the SCITs for the storm in question, and displays the storm track. When you select Go again, the program repeats the same process for the next most dangerous storm. We recommend that you limit the number of storms to four. Setting up Storm Sequences When you select Setup > Storm > Storm Sequence, the Storm Sequence Setup menu opens. Region of Interest defines the boundaries of your sequence by the specified coordinates. Set to current view changes the sequence boundaries to match the currently displayed view. Clear (allow all storms) displays all storms regardless of geographical location. Pan out to overview map between sides displays the overview map between lapses in your sequence. Number of storms to view in sequence specifies the maximum number of storms you can track (we recommend 4). Minimum view range when zoom in to storm specifies the minimum zoom range, in miles, when you zoom in on a sequence. The zoom range is based on storm speed. This prevents the system from zooming in too closely. 71 Managing Storm Tracks 4.8 Points to Remember FasTrac Millennium Users Guide May 2003

Before you begin to project storm tracks, use the Setup > Storm Track command to set up the default parameters.

Determine what type of storm track will best depict the storm: fan, circle, or squall.

Change your storm track display quickly through the Storm Track panel. Always select the Update option to put your changes into effect.

Use the Storm Track Places panel to change the storm track marquee listings and the marquees position. You can always move the storm track marquee by clicking on it and dragging it to a new location.

Use the AutoTrac command to have your system use real-time radar data or NEXRAD data to create your storm track based on the actual movement of the storm over a period of time.

Trac Edit moves storm tracks to a new position but does not change direction or speed. 72 5. Using SEQUENCER The Storm Tracking system has a variety of functions that you may automate by using SEQUENCER capabilities. SEQUENCER lets you perform various operations, such as displaying various maps, repainting radar sweeps, zooming and panning from one map to another, and creating time lapses of radar and lightning data. When you group these functions in a sequence, they become events. You may permanently save sequences of zoom, pan, and time-

lapse events on the system for later use. SEQUENCER loads your events into RAM memory. This can take anywhere from a few seconds to a minute to load the first time. On subsequent playbacks, the load takes only a few seconds. It is best to preview your sequence before going on the air. This maximizes the performance of your system. This chapter describes the steps you need to execute to create an event, as described in the following list:

Starting SEQUENCER

Creating and Manipulating Sequences

Creating and Using Zooms and Pans

Working with Time-Lapse Events

Combining Time-Lapse and Zoom Events

Repainting a Time-Lapse Event

Inserting NEXRAD Data in a Sequence 73 Using SEQUENCER FasTrac Millennium Users Guide May 2003 5.1 Starting SEQUENCER To invoke SEQUENCER, click the Sequences button on the Select Panel at the left side of your display. The SEQUENCER panel then opens. While this panel is open, most non-sequence functions are inoperable. To exit the SEQUENCER panel, click EXIT. The SEQUENCER text box specifies the current sequence. To choose a different sequence, open the pull-down list and select another sequence. If this section is empty, it indicates that the system currently has no sequences. The second part of the panel lists the current sequence's events. This list appears directly beneath the name of the current sequence. Some of the events have user-defined names. For example, you may call a zoom Zoom to L or name a time lapse Texas. If an event consists of a slide (view), the event name is identical to the name of the view. Other events, such as radar-sweep repaints, do not have user-defined names. To view details about a particul ar event, highlight the event to display a menu that describes the event in detail. For example, slide events indicate the views name, range and mapping d etails

(such as the level of roads and water bodies). Other events, of course, have different characteristics. The extended menu that describes zoom events indicates the starting view, the ending view, and the number of frames in the zoom. You can characterize time-lapse events by their base view, beginning time, ending time

, iterations (the number of times that the full lapse repeats), and number of frames. ouisville The third part of the Sequence Control Panel is the section of buttons at the bottom of the panel:

Up, Down, New Seq, Ins Evt, Start Seq, Del Seq, Del Evt, and Exit. Use the Up and Down buttons to move events around in the sequence. The remaining buttons provide functionalities that are essential to the creation and manipulation of sequences and events. The following subsections describe the use and functionality of each of these buttons. 5.1.1 Creating a New Sequence Click New Seq to invoke a small menu that asks you for a sequence name. Choose the name carefully because once you enter a sequence name you may never change it. You may, however, delete the sequence. 1. Key in the name of the new sequence, and press ENTER or click OK to create the sequence. 2. When you create a sequence, the name automatically appears in the SEQUENCER panel. The list of events (the second part of the SEQUENCER panel) is always empty when you create a sequence. To fill the sequence with events you must use the Ins Evt command. 74 FasTrac Millennium Users Guide May 2003 Using SEQUENCER 5.1.2 Inserting New Events 1. If you have existing events and want to insert a new event, select the event under which you want to place the new event. 2. Click Ins Evt button to open a selection menu. You can use this command to create new events or to add existing events (such as zooms or time lapses created for other sequences). 3. Review the menu that appears, including such items as SLIDE, ZOOM, TIME LAPSE, RADAR, LIGHTNING, and NWN. The list of events depends on the configuration of your system. For example, NWN events are restricted to users who also have the optional Neighborhood Weather Net system and LIGHTNING events are restricted to users with integrated lightning detection. You may use the Ins Evt function to insert an event in a particular location (such as between two existing events in the list). 4. Double-click on the event you want to insert, and verify that the selected event displays in the sequence list. 5.1.3 Deleting Events from Sequences 1. Select the event you wish to delete. 2. Click Del Evt. A confirmation menu will ask you to verify the deletion. 3. Click Yes to remove the event. The Del Evt command does not permanently delete events from your system. For example, if you delete a zoom called Zoom to Huntsville from a particular sequence, it may still exist as an event in other sequences. It will still be available as a choice when you select INS EVT and select a zoom event. To permanently delete a zoom or time-lapse from the system you actually have to use the insert event feature. When the menu offers a particular event name, you may highlight it and hit the delete button. 5.1.4 Deleting Sequences Select Del Seq to delete the current sequence. The current sequences name and events appear on the SEQUENCER panel. When you delete a sequence, its events are not deleted from your system. Instead, zooms or time lapses that are part of the system are still available as choices when you use the Insert Event option. 5.1.5 Starting and Playing a Sequence The Start Seq command displays all events in the current sequence. 1. Select Start Seq. SEQUENCER scans the sequence for zooms and time lapses. If SEQUENCER locates such events, the Loading Frames message displays and you cannot select any SEQUENCER command. SEQUENCER then loads the frames of the first zoom or 75 Using SEQUENCER FasTrac Millennium Users Guide May 2003 time lapse to electronic memory. This allows the system to display these frames at a higher speed upon recall. This operation may take several seconds. 2. SEQUENCER displays a window that describes the first event. This window also has three command buttons: Next, NonStop, and Abort.

Next displays the next event. During the sequence, the machine will pause before each zoom or time lapse to load the event's frames. SEQUENCER displays the Loading Frames message each time that this occurs.

NonStop displays the ensuing events without pausing. You may select NonStop button at any time during the sequence execution to display the remainder of the sequence without pausing.

Abort exits from the sequence review function. 5.1.6 Exiting SEQUENCER EXIT simply exits SEQUENCER. This command removes the SEQUENCER panel and enables the functions that are not sequence related. You may use the EXIT command any time that it is visible. Your sequence and event data are saved. If SEQUENCER is busy, such as when creating a zoom or prompting the operator for input, EXIT will have no effect. 5.2 Using SEQUENCER with Zooms and Pans Zooms and pans are special groups of .bmp picture files that you use to create a zoom or pan effect. In the case of zooms, the map's center remains the same, while the range decreases to create a zooming-in effect. (The range may increase instead of decreasing when you zoom outward.) In the case of pans, the map's range stays the same but the center point changes to create a panning effect. You may also combine the zoom and pan effects by allowing the maps center and range to change at the same time to create a simultaneous zooming and panning effect. Frequently, we refer to zooms and pans separately, but a pan is merely a zoom with a center point that changes considerably more than its range. You can create the same effect for non-SEQUENCER zooms and pans by using the Smooth Transitions feature, found on the View Main panel. The following conditions must exist before you start this operation:

You must have already created the view at which you want to start and the view at which you want to end. You cannot create views from inside the zoom function: you can select only from pre-saved views. See Section 3.4.1 for information on creating views.

It is important to use a meaningful naming convention when you create your zooms, so that you can recognize and use them in the future. We highly recommend descriptive names. Assume that you might have a start with a 150-mile map centered over Huntsville, Alabama, and name it HSV 150. You then zoom in to a 5-mile map 76 FasTrac Millennium Users Guide May 2003 Using SEQUENCER centered over Athens, Alabama, and name it Athens 5. One suggested name of this zoom is HSV 150 to Athens 5. This naming convention makes it very easy to return to SEQUENCER, identify the pans and zooms you have created, and retrieve them for immediate use.

The system uses the starting view parameters to determine the parameters of the other views. This means, for example, that if the map lines are bold for the starting view, they will be bold for all the views in between. Creating Zooms and Pans 5.2.1 The following operation is the same used to create pan events. If the starting and ending views have the same approximate center point but have considerably different ranges, the event will be a zoom. If the views have completely different center points and equal ranges, the event will be a pan. The system does not differentiate between a zoom and a pan. It just creates the intermediate frames based on the specified starting and ending views. Zooms and pans are both in the zoom category. 1. Open SEQUENCER, and click Ins Evt to open the selection menu. 2. Double-click on the ZOOM listing to open the Event List menu. This menu lists the available zooms and includes the Create New, Delete, and Cancel commands. If no zooms or pans are in the system, the list of available zooms will be blank (the maximum allowed at one time is 19). 3. Click Create New to open the Zoom menu, which lets you to define the new zoom parameters. 4. Key in the new zoom name in the Name text box. 5. Specify the starting and ending views from the pull-

down lists. You must create your views before you create a zoom event. 6. Specify the number of frames that that will be in the zoom event. (You can display 2 to 40 frames.) 7. Click Create. The Creating Frames message displays. SEQUENCER will post the starting view, the ending view, and each intermediate frame and then play the new zoom event. The intermediate frames and the zoom name are saved on the hard drive. This data will remain on your system until you choose to delete it. 5.2.2 Previewing Your Zoom Event After you create a zoom or pan, the event appears on the event list beneath the current sequence name. Click on the event name to open a menu that describes the zoom. This menu indicates the name of the zoom or pan, the number of frames, the starting view's name, 77 Using SEQUENCER FasTrac Millennium Users Guide May 2003 and the ending view's name. It also contains the Preview, Edit Frames, and Del From Seq commands. 1. 2. Click Preview. As your system loads the zoom frames, the Loading Frames message ap and remains during frame loading and the preview of the zoom frames. Unless you are previewing an event, this message does not appear on the screen during sequence play. pears Click Edit Frames to display the event frame-by-frame. The Loading Frame message appears. After loading, th e first frame displays and the Frame Editor menu open s, asking if you want to delete the frame. This process continues through the frame-by-frame display until select CANCEL or until the preview is complete. you 3. Click Del from Seq to delete the zoom from the sequence. You may also use the Del command at the bottom of the SEQUENCER panel to perform this same operation. Evt 5.3 Working with Time-Lapse Events There are several important points to remember when creating a time-lapse event:

You must create the view you wish to show before you create the time-lapse event. You erely pick from pre-

cannot create views from inside the time-lapse function. You can m saved views. See Section 3.4.1 for information on creating views.

It is very important to use a meaningful naming convention when creating time lapses, so that you can recognize and use them in the future. We recommend that you use the date

, time frame, and map of the time lapse. For example, 2-26 4-6pm HSV 25 could be the name for a time lapse on February 26, from 4 to 6 p.m., on a Huntsville map with a ran n you look at this time lapse, you will be able to identify it for of 25 miles. Later, whe future use or deletion. ge

Before you can create a real-time time lapse, you must use the Radar > Log to Fil at the lapse will cover. (The Log to File command to log data during the period th command should be active, by default.) e

You can create a NEXRAD time-lapse that always displays the latest data NEXRAD product with more than one frame. See Section 5.6 for details. by inserting a 78 FasTrac Millennium Users Guide May 2003 Using SEQUENCER 5.3.1 Creating Real-Time Radar Time-Lapses 1. Open SEQUENCER, and click Ins Evt to open the selection menu. 2. Double-click on the TIME LAPSE listing to open the Event List, which lists the available time lapses. If no time lapses are in the system, the list will be blank. 3. Click Create New to open the Radar Type menu. 4. Select REALTIME RADAR to open the Radar menu, which lets you define the radar parameters for a time lapse. In the Event Type area, click Time Lapse. 5. Key in the time-lapse name in the Name text box. 6. Select the base view that the time lapse will use. To keep the current view, do not change Base View. 7. Set the Beginning Time and Ending Time parameters to fit your needs. The default times create a lapse for the last hour according to the system clock. These times are in military time. To change them, click in the appropriate time text box and key in the ne w time. 8. Change the following parameters to fit your needs:

Iterations specifies the number of times that the entire time lapse will appear when viewing the lapse event.

Pause specifies the time, in milliseconds, between time-lapse frames. 1000 milliseconds=1 second.

Interval specifies the number of sweeps composed in each frame. For example, an interval of 1 (the default value) records a frame after each sweep. An interval of 2 records a frame every other sweep. 9. Click Add to Seq. The system will then create the time lapse and insert it into the current sequence. This data will remain on your system until you choose to delete it. 79 Using SEQUENCER FasTrac Millennium Users Guide May 2003 5.3.2 Creating NEXRAD Time-Lapses 1. Configure your ingestor program (such as NetRad or WSIrad) to delete NEXRAD files that are older than four hours. (This will retain the setting and only needs to be set once.) The procedure is different for different programs. 2. Open SEQUENCER, and highlight the sequence's event after which you want to insert the time lapse. (If no events exist in this sequence, the new time lapse will become the first event.) 3. Click Ins Evt to open the selection menu. 4. Double-click on the TIME LAPSE listing to open the Event List, which lists the available time lapses. If no lapses are in the system, the list of available lapses will be blank. 5. Click Create New to open the Radar Type menu. 6. Select the radar type that describes your needs:

Baron/Unisys/WSI NexRad or WxCentral NexRad. 7. Select the Name text box, and type in a unique name (the system will warn you if you pick an existing name). Select the NEXRAD site from the Site pull-down list. The system will only let you choose sites from which your system has products. The product pull-down list, however, lists all possible products, not just the ones available. 8. Specify the number of iterations and the pause between frames, in milliseconds. (See step 8 in section 5.3.1 for explanations of the terms.) 9. Click Lapse up to 24 hours to list all the available NEXRAD files for the specified site and product from the last 24 hours, or click Lapse up to 30 days to list all files from the past 30 days. 10. Select individual products to use in the time lapse by clicking on the first file you want, and then holding down the CTRL key while you select subsequent files, or select a range by clicking on the first file you want and then holding down the SHIFT key while you select the last product. 11. When you have highlighted all the products you want in the lapse, click Create Lapse. If you have done everything correctly, the system will use the selected products to create a time lapse. You can play back and edit this time-lapse event like any other time-lapse event. 80 FasTrac Millennium Users Guide May 2003 Using SEQUENCER 5.3.3 Previewing Your Time Lapse After you create a time-lapse event, SEQUENCER adds the new event to the list on the SEQUENCER panel, which you can them preview. 1. Open the SEQUENCER panel. 2. Click the event name to open the menu that describes the lapse. This menu indicates all of the information that you entered for the lapse. 3. Click Preview. As the your system loads the lapse frames, a message displays Loading Frames. This message remains on the screen during frame loading and during the preview of the time lapse. 4. To delete the time lapse from the sequence, select Del From Seq or select Del Evt at the bottom of the SEQUENCER panel. To exit from the process without making chang SEQUENCER panel or select Exit from the bottom of the another event from the SEQUENCER panel. es, select 5.3.4 Editing Time-Lapse Frames If you do not like delete the frame:

a particular frame in a time-lapse event, use the following steps to permanently 1. Open the SEQUENCER panel. 2. 3. Click the event name to open the menu that describes the lapse. This menu indicate entered for the time lapse. s all of the information that you have Click Edit Frames to display the time-lapse one frame at a time. When you se delete the frame. lect Edit Frames, the first frame displays and you are asked if you want to 4. Click Yes to delete the frame, or click No to advance to the next frame. 5. Click Cancel to end the frame editing and to quickly display the remaining frames. 5.4 Combining Time-Lapse and Zoom Events One dramatic and effec in the following steps:

tive operation is to combine the time-lapse and zoom events, as described 1. Create a sequence with an overview slide. (A slide is just a static map view.) 2. Add a time lapse of the past several hours. 81 Using SEQUENCER FasTrac Millennium Users Guide May 2003 3. Zoom in to the location where the heaviest rain occurred. 4. Do another time lapse over that location. This provides both the overview and the local weather information, which makes a difference to your viewers. 5.5 Repainting to a Sequence 1. Open SEQUENCER, and click Ins Evt to open the event types menu. 2. Double-click CONVENTIONAL RADAR. This will open the menu that we used earlier to create a time lapse. 3. Select Repaint, and click Add to Seq. In SEQUENCER, the system usually paints (displays radar sweeps) views in the sequence. Repainting is still useful, however, for switching from NEXRAD mode to real-time radar mode in the middle of a sequence. 5.6 Adding a Radar Lapse to a Sequence This function allows you to add a real-time radar lapse into a sequence. 1. Open SEQUENCER, and click Ins Evt to open the event types menu. 2. Double-click CONVENTIONAL RADAR. This will open the menu that we used earlier to create a time lapse. 3. Select Replay, specify the lapse time and whether you want Doppler or Intensity data, and click Add to Seq. Inserting NEXRAD Data in a Sequence 5.7 1. Open SEQUENCER. 2. Select Ins Evt, and double-click NEXRAD PRODUCT to open the NEXRAD Product Setup menu. 3. Click the Lapse radio button to activate the Lapse Settings area. 4. Under Lapse Settings, enter the number of Iterations (times the lapse is shown), the time in minutes for the entire lapse and the time allocated to each frame (the total time divided by the time per frame equals the number of frames that will be created). 5. Select the site and the product, and click OK. 82 FasTrac Millennium Users Guide May 2003 Using SEQUENCER You should insert this event after a slide/view event. The system will continue to be in NEXRAD mode until you activate a repaint event. Specifying a number of frames greater than 1 allows you to create a NEXRAD time-lapse that is always up to date. 5.8 Points to Remember

Use SEQUENCER to display saved mapping scenarios, such as zooming into areas with critical weather and time lapses of radar and lightning data.

Before you create zoom and time-lapse events, you must create the starting and ending views.

Name your events so that you easily can recognize them when you need to replay them.

Use Preview to review your zoom and time-lapse events before you play them for your viewers.

Use the Repaint and Replay options under the Conventional radar menu to add real-time radar sweeps and time-lapses, respectively. 83 6. Controlling Your Radar This chapter describes how to control both Baron and non-Baron radars. Non-Baron radars are controlled through the Radar Control panel and Baron radars are controlled through the Radar Data Acquisition and Control System (RDACS). The operations described in the following subsections include:

Controlling Your Non-Baron Radar

Controlling Your Baron Radar

Using NEXRAD Data

Comparing Base Reflectivity and Composite Reflectivity 85 Controlling Your Radar FasTrac Millennium Users Guide May 2003 6.1 Controlling Your Non-Baron Radar If you have a Baron Radar Processor, you can use the procedures described in this section to control your radars range and operating mode. 1. Click the Views button on the Select Panel, then click the Data button on the More Settings panel. 2. Click the Radar Control button to open the Radar Control panel.

Range specifies the radars range. You can either enter a number or select a choice from the pull-down list.

Elevation specifies the radars elevation. You can either enter a number or select a choice from the pull-down list.

Log Intensity selects the long-lapse log mode, which extends 300 miles.

Doppler Intensity selects the 75-mile Doppler mode.

Velocity Single selects the single-PRF mode, which extends 75 miles and has a +/- signal of 16 miles per hour.

Velocity Dual selects the dual-PRF mode, which extends 75 miles per hour and has a +/- signal of 37 miles per hour.

Clutter Cancel negates the clutter filter. There are two types of clutter filters: Mask and Doppler. The system automatically determines which one applies, based on the current mode of operation.

Snow opens the Snow Machine panel, which allows you to select from several products created by the Snow Machine. Refer to section 6.3.1 for product descriptions.

Commands lists the radar command that fits the requested adjustment. This area merely lists the commands, which are not sent until you select Update. If you select Exit, the commands are not sent and you exit from the Radar Control process. 3. Make the required selections, and review the Commands area. To remove a command, drag the mouse across the command text, and press Delete. To add a command, click after the last command and key in the command. If there are more commands than can be listed, use the scrollbar on the right side of the box to review them. 4. Click Update. 6.2 Controlling Your Baron Radar If you have RDACS, you can use the procedures described in this section to control your radars range and operating mode. 86 FasTrac Millennium Users Guide May 2003 Controlling Your Radar The Status > Rdac status command allows you to quickly ensure that your radar is connected and functioning properly. Click the Views button on the Select Panel, then click the Data button on the More Settings panel. Click the Radar Control button to open the RDACS Control panel.

Range sets the range, in miles. In Doppler mode, the maximum range is usually 75 miles; in log mode, the range is usually 300 miles. The radars configuration, however, may affect the maximum. For better resolution of closer targets, set the range less than the maximum range. If you apply a range greater than the maximum allowed for the radar mode, RDACS will use the maximum valid range and will display the corrected value.

Skip specifies the range, in miles, from which acquisition begins. For example, a value of 1 means that data sampling will begin one mile from the radar. Use Skip to remove the display of the strong signal received just after the radar pulse. (A typical value to use for Skip is 0.5 to 5.0 miles.) The Radar Paint Skip Zone setting in the Omninet.ini file controls what appears in the skip zone. A value of 1 means that no radar data appears in the skip zone. A value of 0 means that a new sweep does not clear any previously displayed data in the skip zone. 87 Controlling Your Radar FasTrac Millennium Users Guide May 2003

Mode specifies the radar mode. While not all modes are valid for all radar types and may not appear in the pull-down list, the following list describes the possible modes:

Mode Description Powerdown Radar electronics are off. Standby Long Log+Turb Single PRF Dual PRF VHD Radar electronics are on, but the transmitter is off. Long pulse, no velocity, and range up to 300 miles. Log mode plus detection and display of turbulence in return data. Single-pulse Doppler mode, range 75 miles, +/- 16 m/s. Dual-pulse Doppler mode, range 75 miles, +/- 32 m/s. Very High Definition (dual-pulse) Doppler mode, range 49 miles, +/- 48 m/s. When you select a mode, the typical values for range and velocity appear. When you select Powerdown, it may take several minutes before the radar shuts down (cools off). When the radar powers up, it will take several minutes before radiation is possible. You can observe the status at the RDACS computer or view the H250C.EXE or config.exe programs.

Scan specifies one of the antenna modes described in the following list. Select PPI for constant rotation in azimuth with a fixed elevation. Use Sector to scan a sector in azimuth. Use RHI to scan in elevation with a vertical cross-section. Use Stop to point the antenna to a target. The following table shows which fields work in each antenna mode:

Mode Stop PPI Sector RHI Azimuth X X X Span X Elevation X X X X Upper X Azimuth sets the antenna azimuth, in degrees. Span sets the antenna angle, in degrees, traversed in Sector mode. Elevation sets the lower scan limit for antenna elevation, in degrees, in RHI mode. Upper sets the upper elevation limit, in degrees, in RHI mode. 88 FasTrac Millennium Users Guide May 2003 Controlling Your Radar

Linear Intensities controls which format of reflectivity data the radar uses when it is in one of the Doppler modes. Typically, early RDACS controllers leave it off and later controllers leave it on. On the early RDACS controllers (HDDS.EXE), both linear and log reflectivity data are available and the log data is usually of higher quality, so leave the Linear Intensities option unselected. On the newer RDACS controllers (H250S.EXE), only linear data is available during Doppler modes, so you must select Linear Intensities. The Linear Intensities option is set in later versions. Once activated, it will remain set, even if you exit and reload the program.

Load Settings loads a saved RDACS configuration. You can create and save up to 10 configurations (labeled 0 to 9) using the RDACS control program, the H250C.EXE or HDDC.EXE file. Configuration 0 is the loaded whenever you restart RDACS. The other configurations can be whatever you desire. For example, Configuration 1 could use a different color level table to implement a clear air mode. By convention, Configurations 8 and 9 are temporary "saves" of test configuration. Load Settings opens up a menu that lets you select the numbered configuration to load. 6.3 Manipulating NEXRAD Data The systems functionality allows direct manipulation of NEXRAD radar data. 6.3.1 Using the NEXRAD Main Panel Click the NexRad button on the Select Panel to open the NEXRAD Main panel. You can use this panel to display any NEXRAD product (such as a reflectivity or velocity sweep) on any view. You may also show several products at the touch of a button to create a time-lapse effect. The Status > Nip status command allows you to quickly ensure that your NEXRAD data is arriving properly. Site lists the current NEXRAD site that you are monitoring. One to four sites are available to the typical NEXRAD client. Lapse lets you view a specified number of frames when viewing products. You can create a continuous Lapse of current radar data by toggling the Tools-3 > Nexrad Loop active command. When this feature is checked, the system will automatically create Lapses of the specified product, with a 10-second delay between each lapse. You can edit the length in seconds between lapses by adding the following line into your omninet.ini file:

RadarLoopPeriodInSeconds=(desired #) 89 Controlling Your Radar FasTrac Millennium Users Guide May 2003 Shear Markers displays two types of rings that represent the presence of significant shear. A yellow ring indicates that the shear is in level 2 or above, while a red ring indicates a Low Level Lock at level 1. Upper level shear markers appear when the wind shear reaches 50 knots. Low Level Lock appears when the wind shear reaches 50 knots at level 1 and 30 knots at level 2. Arrows displays NWS and Baron Services SCITs. A more detailed description of storm arrows is in section 4.6, Storm Scan. Lvl determines the sweeps elevation level (1, 2, 3, or 4) for a product. Any product described as using a certain number of scans uses this button to switch between levels. The Product pull-down list lets you choose from any available NEXRAD product. The menu will always show All Products even after you choose a single one, but the radar image will show only the product that you selected. You may program the buttons above the product menu to display your products in any configuration you wish. To change a button product, right click on the button to open the Configure Panel Button menu, shown to the right. The text box at the top of the menu allows you to assign the text to display on the button. The second text box lets you enter the product code and modifiers. The syntax for the code entry text box is as follows:

<product code> <lapse duration> <frame update> <options>

You can either type in the product code or select it from the menu below the text box.

<lapse duration> is the total lapse time in minutes, while <frame update> is the interval between lapse frames in minutes. For example you could enter 13E 1440 5 to have the product give a 24-hour lapse of reflectivity with a frame interval of 5 minutes (for a total of 288 frames). There are two values you can enter in the options field:

Site=xxx overrides the site list box and specifies a single site for the button. Lapse=n overrides the lapse checkbox and count. Continuing the previous example, you could enter 13E 1440 5 site=C04 lapse=12 to have the button give a 24 hour lapse of reflectivity with a frame interval of 5 minutes from site C04 that repeats 12 times. 90 FasTrac Millennium Users Guide May 2003 Controlling Your Radar The following table lists the code for each product. Baron Level III Data Product Name Free Text Radar Site Information Base Reflectivity (4 tilts) Corrected (De-Alaised) Mean Base Velocity (4 Tilts) Mean Base Velocity (4 Tilts) Echo Tops (4km) Corrected (De-Alaised) Storm Relative Velocity (2 Tilts) Storm Relative Velocity (2 Tilts) VIL (Vertical Integrated Liquid) (4 km) 1 hour Accumulation 3 hour Accumulation Storm Total Accumulation Base 300 mile reflectivity Composite Reflectivity (4k) Millennium:

Product Name Baron Shear and Severe Storm Arrows (SCITS) 4 EMWIN Warnings (Tornado, Severe Thunderstorm, Flood, and Flash Flood) METARs Severe Weather Module:

Product Name Max Reflectivity (1km) Baron Button (1 km) [Heavy Rain/Shear Hail]

Max Composite Gate-to-Gate Shear (1 km) VIL Density (1 km) Storm Relative Velocity Shear (1 km) Storm Relative Velocity Shear Markers Mean Base Velocity Shear (1 km) Mean Base Velocity Shear Markers Hydro Module:

Product Name Precipitation Rate 1 Hourly Total Precipitation Accumulation 3 Hourly Total Precipitation Accumulation 12 Hourly Total Precipitation Accumulation 24 Hourly Total Precipitation Accumulation Heavy Rain/Flood Product Code (0x) 4B 13E 31BE 1BE 29 31CE 38E 39 4E 4F 50 14 26 Location Netrad Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Code (0x) 62 EMWIN Server Connection 883 Code (0x) 226 265 25F 160 161E 64 15FE 63 Code (0x) 266 270 271 272 27C 290 Location See Section 4.6 See Section 3.5.20 Panel Button Location Panel Button Panel Button Panel Button Panel Button Panel Button See Section 6.3.2 Panel Button See Section 6.3.2 Location Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button 91 Controlling Your Radar FasTrac Millennium Users Guide May 2003 Snow Machine:

Product Name Snow Machine (1 km) [Precipitation Type/Rate]

4 km Precipitation Type Mask 1 Hourly Snow Accumulation 1 Hourly Mixed Accumulation 3 Hourly Snow Accumulation 3 Hourly Mixed Accumulation 12 Hourly Snow Accumulation 12 Hourly Mixed Accumulation 24 Hourly Snow Accumulation 24 Hourly Mixed Accumulation Heavy Snow (1 km) 1 Hourly Winter Precipitation 3 Hourly Winter Precipitation 12 Hourly Winter Precipitation Whole US Snow Machine Mask Site R01 FutureScan:

Product Name FutureScan 5 minutes into future FutureScan 10 minutes into future FutureScan 15 minutes into future FutureScan 20 minutes into future FutureScan 25 minutes into future FutureScan 30 minutes into future National Composites Product Name Hybrid Maximum Reflectivity Composite (1km) 24 Hour Precipitation Composite (1km) VIL Density Composite (1km) Echo Tops (1km) Whole US Baron SCITS (1km) RUC Model Product Name Winds data from (Surface to 42,000 ft) FasTrac Level II Data Product Name 256 Color Intensity (4 Tilts) 256 Color Velocity (4 Tilts) 92 Code (0x) 268 401 279 276 27A 277 27B 278 27F 27E 291 292 293 294 1001 Location Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Panel Button Code (0x) 326 326 326 326 326 326 Location See Section 3.5.11 See Section 3.5.11 See Section 3.5.11 See Section 3.5.11 See Section 3.5.11 See Section 3.5.11 Code (0x) CO4 302 C04 30D C04 310 C04 311 C04 62 Location Panel Button Panel Button Panel Button Panel Button Panel Button Code (0x) X01 49 Location See Section 3.5.22 Code (0x) 66 68 Location Panel Button Panel Button FasTrac Millennium Users Guide May 2003 Controlling Your Radar The following paragraphs describe most of the possible products:

Base Reflectivity displays the 150-mile reflectivity sweep of the site. This product is available only for the first four scans of the volume. Composite Reflectivity shows the greatest reflectivity at a location, regardless of height. Base Velocity displays wind speed and direction in reference to the radar beam. It is available only for the first four scans of the volume. Storm Relative Velocity displays Storm Relative Velocity (SRV), which indicates wind speed and direction relative to storm movement. SRV is available only for the first two scans of the volume. Shear products, such as SRV Shear (Storm Relative Velocity Shear) and BV Shear (Base Velocity) are the respective velocity products, showing the amount of gate-to-gate shear on adjacent radials. SRV Shear is available for the first two scans of the volume. RV Shear is available for the first four scans of the volume. Composite Shear is derived from both Storm Relative and Radial shears, showing the greatest shear, regardless of the storms velocity or height. Baron Button enables the system to display a special product designed to provide an overall assessment of a storm in one display. It incorporates Rain Rate, VIL Density, and Composite Shear parameters into one product. Vertically Integrated Liquid (VIL) uses the water content feature to estimate the amount of water in kilograms per meter squared (kg/m2). Its primary use is for hail detection. VIL Density uses the NEXRAD VIL and Echo Tops products to determine the amount of water in kilograms per meter cubed (kg/m3). This gives a more accurate reflectivity reading of surface hail that meets or exceeds 18.5 dBZ. Echo Tops indicates the highest altitude that the radar senses. Storm Total graphically represents the total rain in an area after the radar mode changes from Clear Air Mode to Precipitation Mode. Rate shows the amount of rainfall, in inches per hour, for a given time period. C01 indicates that no recent data has been received from the site. C02 indicates that the radar is in Clear Air Mode. R01 displays the precipitation type forecast grid for the eastern U.S. The 1 hr and 3 hr buttons show the estimated rain accumulations over one-hour and three-hour periods. 93 Controlling Your Radar FasTrac Millennium Users Guide May 2003 Pick lets you select a single frame from a list of archived frames. After you select a frame, use the < and > buttons to move the radar sweep forward or back one frame. Use this option to review data that is not current. R/T switches the radar to real time to show new frames as they appear. Off puts the system back into real-time radar mode (that is, your own radars sweeps start to display again and NEXRAD is deactivated). At the bottom of the panel is a row of buttons labeled 1 through 6. The 1 button opens the NEXRAD Main panel. The 2 button opens a panel with additional settings that are described below. The 3 and 4 buttons open panels intended for Snow Machine products. The 5 and 6 buttons open panels that are identical to the NEXRAD Main panel, allowing you to configure buttons for additional products if there was not room for them on the main panel. The 2 button opens the NEXRAD More panel, shown on the right.

Auto Update makes the system update automatically when a new product is ingested.

1K Raster Products can show a higher resolution (1 km x 1 km) of all products. The 1K Raster products are derived by using the 4-km products and the 1-km radial from NEXRA D.

Fast Load decreases the loading time when switching between products. This box should always be checked.

Master Enable controls the display of all shear markers. Uncheck this box to turn all shear markers of f.

All sites turns shear markers on or off for all sites. We recommend that you leave all sites on until some display shear markers. Once markers appear, you can turn off sites you do not ne ed.

Velocity Level 1 shows shear markers from the lowest level radial velocity.

Velocity Level 2 shows shear markers from the second lowest level radial velocity.

Vel Level >2 shows the shear markers from the third and fourth levels of radial velocity.

SRV Level 1 shows the shear markers from the lowest Storm Relative Velocity.

SRV Level 2 shows the shear markers from the Level 2 SRV.

Mosaic forms product composites from multiple sites. These continue to update as new products arrive.

Max posts the highest levels from the selected Mosaic. 94 FasTrac Millennium Users Guide May 2003 Controlling Your Radar

New Lapse clears the screen each time you create a time-lapse with the Max option on.

Include in Lapse moves the shear markers in time lapses, along with the displayed radar. Otherwise, the markers lock to the latest location. If you select Mosaic, Max and New Lapse simultaneously, the system displays the requested product lapse without erasing the prior frame. 6.3.2 Adjusting Shear Marker Settings Select Setup > Data > Shear Markers to open the Shear Marker Options menu. Animation Speed lets you change the rotation speed of the shear markers. Low Level Lock Appearance lets you choose to make your low-level shear markers red only or red and yellow. Other Options lets you choose to disable the rotation animation, give black outlines to the shear markers, or change the minimum radius of the shear markers, as measured in pixel s. Edit Colors opens the Shear Circle Colors menu, where you may edit the high and low level colors. As the menu explains, you only need to edit the top and bottom colors for each level. 95 Controlling Your Radar FasTrac Millennium Users Guide May 2003 6.3.3 Using the Advanced Baron Chart Any Advanced BSI Data Products you may purchase include an Advanced Baron Chart for NEXRAD products. You can open the Advance d Baron Chart with the Setup > Data >

Baron Chart command. The Advanced Baron Chart allows you to change the default colors of any NEXRAD products you have. You ry may also display the Pixel Que status messages for NEXRAD products. The Reflectivity, Velocity, and Turbulence palettes are defaults. Use these options to configure the display for real-time radar data. If a product does not have palette, the program uses the Refl ectivity product, by default. its own Choose the NEXRAD product you want to edit from the pull-down list on top of the menu. The default level colors appear in the fourth column, along with a table describing their Pixel Query values. OK save saves your changes permanently. OK No save makes temporary changes that disappear when you reboot. Cancel returns the palette to original settings. Add lets you configure a new NEXRAD product by entering a name and the four-letter or number product code. Duplicate opens the Duplicate Palette menu, which lets you copy color palettes from one product to another. Change lets you edit the cursor products name or product code. Remove lets you delete the cursor products name or, if the code is standard, the code. Defaults resets the selections to the default settings. Gradient lets you quickly use a gradient for level colors. Rain, Ice, and Snow let you select the precipitation type for the reflectivity column. Use embedded table indicates that the standard table of level descriptions are used for the selected products. 96 FasTrac Millennium Users Guide May 2003 Controlling Your Radar One of the important issues to remember when adding a Baron Chart entry is that the Baron Chart does not expect the elevation digit to be appended when you enter the product code. When you right-click on a button in the NEXRAD panel, the product code that appears has the elevation code appended. For example, if you right-click on a button that is configured to display one-hour rain products, you will see something like 4e Rain 1hr as the configuration text. Users often see this and think they need to type 4e0 as the product code in the Baron Chart. In fact, the proper code is 4e since the extra 0 in the button configuration merely indicates that the product does not vary with elevation. 6.3.4 Customizing Product and Time Marquees product names and generation times on your views. Open this panel by selecting Setup > Data > NexRad Stats. The product info display panel allows you to control the display of NEXRAD

Show product name toggles the display of the product name marquee.

The X and Y textboxes control how many pixels to the right and down, respectively, from the upper left corner that the product name marquee appears. The W field controls the width in pixels of the product name marquee, while the H field controls the height in pixels of the marquee.

Show product generation time toggles the display of the product generation time marquee.

The X and Y textboxes control how many pixels to the right and down, respectively, from the upper left corner that the product generation time marquee appears. The W field controls the width in pixels of the product generation time marquee, while the H field controls the height in pixels of the marquee. Move together when dragging lets you move the product name marquee and the product generation time marquee simultaneously. When you select this option and click OK, you can move both displays at one time by left-clicking in an area on or between the product name marquee and product generation time marquee (this area is defined by the corners of the marquees that are farthest apart) and dragging the cursor to the new position. Otherwise, you can reposition either display separately, by clicking and dragging. 97 Controlling Your Radar FasTrac Millennium Users Guide May 2003 6.4 Utilizing Multiple Real-Time Radars Via Network The Network America system augments your real-time Doppler data by linking to multiple Doppler sites (including your own real-time radar), letting you monitor numerous meteorological scenarios, including severe weather, more closely. 6.4.1 Using Network America 1. Open NetRad to display the NetRad interface. 2. Select Setup > Main Setup to open the NetRad Setup menu. 3. Click the Add Site button, and select up to twenty-one locations. 4. Upon completion, click OK. 5. Open FasTrac. 6. Select Radar > Multisweep to open the Multisweep menu, displayed to the right. 7. Select the desired sites by clicking on them or by pressing Select All to enable all the listed sites. 8. When you have selected the sites you want, click OK. 9. To turn off Network America, go back to the Radar menu and select Stop Multisweep. 6.4.2 Changing the Width of the Radar Sweep Cursor 1. Open the View Misc panel. 2. Set the Radar Cursor Width parameter to 1 to display the standard width. Set the parameter to 2 to double the width, and set the value to 0 to remove the radar sweep. 3. Click Update at the bottom of the panel to make the changes. You can save the view with the cursor set to the selected width. This will always display the setting. If you do not save the view, it will revert to the previous setting. 98 FasTrac Millennium Users Guide May 2003 Controlling Your Radar 6.5 Comparing Base Reflectivity and Composite Reflectivity Base reflectivity shows the intensities at each of the elevation angles. In the following example, base reflectivity 1-4 shows a small storm event very far off, but undershoots the closer storm. The elevations for the four-base reflectivity NEXRAD products are also depicted. BASE REFLECTIVITY 99 Controlling Your Radar FasTrac Millennium Users Guide May 2003 Composite reflectivity shows the greatest intensity regardless of height in storms. In the following example, the greatest intensities for the storm further from the radar are shown, both aloft and closer to the ground. The composite image also reveals another storm closer to the radar. COMPOSITE REFLECTIVITY 100 FasTrac Millennium Users Guide May 2003 Controlling Your Radar 6.6 Points to Remember

Use the Radar Control panel to control your real-time, non-Baron radar.

Use the RADACS Control panel to control your Baron radar.

Use the NEXRAD Main panel to control your NEXRAD radar data.

Use the Advanced Baron Chart to set color schemes for NEXRAD data.

Base reflectivity shows the intensities at each of the elevation angles and should be used to view storms that are far from the radar.

Composite reflectivity shows the greatest intensity, regardless of height, and should be used to view storms that are relatively close. 101 Glossary Anti-Alias An option that provides a smoothing effect to the pixels used in text. Auto Scan An option in the StormScan setup menu that automatically updates the status of Storm Cell Information and Tracking (SCIT) indicators when new radar data is available. azimuth The angle of horizontal deviation, measured clockwise in degrees, from one point on a map to another. base view A saved view that acts as a starting point for a zoom, pan, or time-lapse operation. bend The curve in a squall projection that indicates the shape of the storm front. circle projection A type of storm projection that indicates the communities within a storm and their distance, in miles, from the storms center. creating a storm track The action of clicking and dragging to create a fan, circle, or squall projection. cut off range A range that defines when a parameter appears on a view. Any view with a view range at or below that cut-off range shows the parameter; any view with a view range larger than the cut-off range will not show the parameter. database A collection of associated data. dynamic sizing An option available only for Street Spotter text. This option, which is available when you select Setup Street Spotter, makes the system automatically select a font size that fits the length of the line when labeling a street in Street Spotter mode. It also proportionally changes the text size when you zoom in or out of a view. extrusion A text option that places a shadow behind each letter at a user-defined angle. This option is available when you select Setup Fonts commands. fan projection A fan-shaped storm projection used to track a single storm cell. Select Storm >

Add > Fan to create a fan projection. fanout This parameter determines the degree to which a fan-type storm tracks border expands from the base to the end, to account for the possibility of the storm not moving in a straight line. The value is set on the Storm Track panel and has a maximum width of 40 degrees. frames These are extra images added automatically by SEQUENCER when creating zooms, pans, and time lapses. The extra images provide a smooth transition between the starting and ending view. GL-1 Glossary FasTrac Millennium Users Guide May 2003 FutureScan This is an optional module that predicts and displays the intensity and location changes of precipitation fields. High Definition Data Processing (HDDP) This feature smoothes out the pixelated appearance of NEXRAD radar data. hot buttons A set of 20 buttons, directly above the view area, that lets you execute various features with a single left click. Some hot buttons also have right-click features. Ingestor program A separate program that receives local or NEXRAD radar data and makes it available on your system. intensity repaint - This is a SEQUENCER event that redisplays the radar sweep to depict the weather intensity. Use this only when you are switching from NEXRAD to real-time radar data. lightning An optional module that allows for the ingestion of live lightning data and the manipulation of its display. latitude The angular distance, measured north or south from a point on the map view to the equator. The main status area displays the latitude of the current cursor position. Log to file The Radar Log to File command that logs your radar files so that you can recall them later. This command is essential for replaying real-time radar data and displaying time-

lapses of real-time radar. longitude The angular distance, measured east or west from a point on the map view to the prime meridian in Greenwich, England. The main status area displays the longitude of the current cursor position. liquid database The system of databases that determines how map features such as roads, rivers, and places appear. It allows for smooth transition between views. main menus The row of pull-down lists along the top of the FasTrac window that lets you access many advanced features. map pointer A Windows-style mouse pointer tool that is used to point out things on the map. module A feature or set of features that does not come with the basic FasTrac system but can be purchased separately. Every module either adds new features or enhances existing features. multisweep The operation used by the Network America module to conduct a sweep of several radar sites simultaneously. Neighborhood Weather Net The optional module that provides non-storm related weather data, such as temperature, humidity, and air pressure. Network America The optional module that simultaneously displays data from up to 20 radar sites. Omninet.ini FasTracs main configuration file. GL-2 FasTrac Millennium Users Guide - May 2003 Glossary pan Changing the center point of a view. Previous The View Main panel command that lets you switch back to the preceding view. product Radar data that is intended to depict a certain type of weather (such as Reflectivity for rain). radius The distance, measured in miles, from the center point of a view to the top or bottom edge. radar levels Divisions in the color scheme of a radar product that indicate the severity of that product. Radar Level Pixel Query Mode The special mode that lets you see the level of a product at a specific location by placing the cursor at that location. real-time radar A privately owned radar (as opposed to a NEXRAD radar) that obtains data as it sweeps. Replay The option used to replay archived data as a time lapse. RGB The Red-Green-Blue values that compose colors. Use the Setup Colors command to specify specific RGB colors to generate a new color for a feature, such as the state boundary. Round Outlines The Setup Fonts option that gives anti-aliasing to font borders. SCIT (Storm Cell Information and Tracking) An arrow produced by StormScan that identifies specific types of storms. SEQUENCER The FasTrac feature used to group many related views together and to display them in a continuous order for various effects. Show Range The range at which individual communities will appear on a view. Use the Setup Places Database command to set this parameter for specific communities. site The name of a NEXRAD radar at a specific location. Use the NEXRAD Main panel to select a NEXRAD site. Snow Machine The optional module that displays winter weather, such as ice and snow. squall projection The storm projection that shows the direction, speed, and shape of an entire line of storms. Use the Storm Add Squall command to create a squall projection. storm marquee The box that shows the cities in the path of a storm and the estimated time that the storm will hit those places. This text box is also known as the ETA box. StormScan This is used to automatically detect and track the most severe storm cells in a region. Gl-3 Glossary FasTrac Millennium Users Guide May 2003 storm track The projection of a storms direction and speed; normally used to calculate when a storm will hit certain places. Storm Track Estimated Time of Arrival (ETA) The clock time that a storm will hit a place, based on the storms location, speed, and movement. Street Spotter The feature used to label important streets and landmarks. SWP (Severe Weather Probability) The product that provides a visual display of a set of probability values for severe storm cells. TeleTrac The module used to draw freehand lines on the screen. time lapse The SEQUENCER-created series of views that depict radar data on the same area over a period of time. turbulence A state of atmospheric flow in which random fluctuations are exhibited and cause changes in the normal flow pattern. van marquee The text box that shows the current data being received from the optional Storm Spotter Van. Vehicle SpotterTrac The optional module that utilizes a link to a mobile unit equipped with weather equipment, to establish a mobile data source. view The current map displaying on the screen. VIPIR Separate radar program that shows both NEXRAD and Baron-derived products in three-dimensional displays. zoom A change in the range of a view. GL-4 Product Glossary In this Product Glossary, B denotes Baron-generated products, while N denotes non-Baron-

generated products. All product numbers (for example, 4E) are in hexadecimal code. Italicized words are terms that are defined elsewhere in this glossary. Base and Convective Storm Products:

1-hour accumulation (4E): Shows the NEXRAD-estimated horizontal distribution of precipitation over a one-hour time period. N 3-hour accumulation (4F): Shows the NEXRAD-estimated horizontal distribution of precipitation over a three-hour time period. N Baron Button 1K (265): A special product that is designed to provide an overall assessment of a storm. It incorporates VIL density, composite shear and rain rate parameters into one product, and is displayed in 1 km by 1km pixel resolution. B base (63) and relative (64) velocity shear markers: Enables the system to display two types of rings, which are representative of the location where shear is present. A yellow ring signifies that shear is present in the upper levels (2, 3 or 4) of the atmosphere, while a red ring signifies a Low Level Lock, or shear is present near the surface (level 1). Note:

Once the shear reaches a threshold of 50 knots, a ring is displayed. B base reflectivity (13): Displays the current 150-mile reflectivity sweep of a site. Note:

Base reflectivity is only available for the first four elevations of the volume. N base reflectivity 1K (113): This is the base reflectivity product, however, instead of the pixels being shown in Azimuth-Range (AzRan) format, they are displayed in 1km by 1km

(1km2) format. B base reflectivity 300 miles (14): Displays the current 300-mile reflectivity sweep of a site. N composite reflectivity (26): Displays the greatest reflectivity in a vertical column regardless of height in a storm. Note: NEXRAD can scan up to a 19.5 elevation angle, so the greatest reflectivity within this scanning volume is reported. N composite reflectivity 1K (126): The composite reflectivity converted to a 1km by 1km product. B composite shear (25F): Shows the maximum value of shear located in the storm within the first four scanning level. B corrected radial velocity (31B): This product displays the velocity, which is result of correcting the radial velocity for various errors, including second-trip echoes and range folding. This product is also known as corrected base velocity. B corrected storm relative velocity (31C): This product displays the velocity, which is the result of correcting the storm relative velocity for various errors, including second-trip echoes and range folding. B echo tops (29): Indicates the highest level that the radar is receiving a return of at least 18 dBZ. N echo tops 1K (129): The echo tops product converted to 1 km by 1 km format. B layer 1 composite (41): Displays the greatest reflectivity in a vertical column between the surface and 24,000 feet (from mean sea level). N layer 2 composite (42): Displays the greatest reflectivity in a vertical column between 24,000 feet to 33,000 feet (from mean sea level). N layer 3 composite (5A): Displays the greatest reflectivity in a vertical column between 33,000 feet to 60,000 feet (from mean sea level). N maximum reflectivity 1K (226): Shows the greatest reflectivity measured within the first four radar scanning levels, and is converted to 1 km by 1 km resolution. B maximum shear 1K (25F): Shows the maximum value of shear located in the storm within the first four scanning levels, and is converted to 1 km by 1 km resolution. B radial velocity (1B): The average velocity of targets (i.e. rain droplets, etc.) moving towards or away from the radar beam. Radial velocity is displayed as either positive (moving away from the radar) or negative (moving towards the radar). Generally, the positive values are displayed in warm colors, while negative values are indicated by cool colors. Note:

Radial velocities are only available for the first four elevation scans of the volume. This product is also known as base velocity. N radial velocity 1K (11B): This is the radial velocity product converted to a 1km by 1km pixel format. B radial velocity shear (5F): The change in radial velocity per unit distance along a radial. Note: Basically, shear is defined as the change or variation in velocity over a specified distance. This product is also known as base velocity shear. B radial velocity shear 1K (15F): The radial velocity shear product converted to 1 km by 1 km resolution. B rain rate (266): The rate of rainfall or rainfall intensity as estimated by NEXRAD over one hour. N storm relative velocity (38): The velocity that is relative to storm movement. This product is the base velocity with the average movement of storms, which are defined by a storm-defining algorithm, being subtracted out. Therefore, the motion appears relative to the storms. Note: Storm relative velocities are only available for the first two scanning elevations of the volume. N storm relative velocity 1K (138): The storm relative velocity converted to a 1 km by 1 km pixel display. B storm relative velocity shear (61): The change in storm relative velocity per unit distance along a radial. This product is also known as relative velocity shear. B storm relative velocity shear 1K (161): The storm relative velocity shear product converted to 1 km by 1 km resolution. B storms (62): This product includes the National Weather Service SCITs (thunderstorm, hail, severe hail, mesocyclonic and TVS), in addition to the Baron-generated SCITs (storm and shear). Therefore, it enables a more comprehensive identification of severe weather that may affect a given location. B total precipitation (storm total accumulation) (50): Displays the total precipitation amount estimated by the Doppler radar after the radar mode has changed from clear-air to precipitation. To determine the estimated amount of rain, the radar uses a Z-R relationship, which matches reflectivity values to a corresponding rain rate. Note: There are specific Z-R relationships for various precipitation events. N VIL (39): The Vertically Integrated Liquid water content represents the amount of liquid water present in a cross-sectional area in the atmosphere, and is usually measured in units of kilograms per meter squared (kg/m2). B VIL 1K (139): This is the VIL product converted to a 1 km by 1 km format. B VIL density (60): The Vertically Integrated Liquid density displays the calculated value of VIL divided by echo tops ((VIL)/(echo tops)). It is reported in units of kilograms per meter cubed (kg/m3). B VIL density 1K (160): The VIL density product converted to a 1 km by 1 km resolution. B Snow/Hydrological Package Products 1-hourly (273), 3-hourly (274), 12-hourly (275) and 24-hourly (27D) liquid precipitation rate 1K: These products provide a 5-minute by 5-minute look at liquid accumulations in a 1 hour, 3 hour, 12 hour or 24 hour window. B 1-hourly (276), 3-hourly (277), 12-hourly (278) and 24-hourly (27E) mixed precipitation rate 1K: These products provide a 5-minute by 5-minute look at mixed precipitation accumulations in a 1-hour, 3-hour, 12-hour or 24-hour window. B 1-hourly (279), 3-hourly (27a), 12-hourly (27b) and 24-hourly (27F) snow rate 1K: These products provide a 5-minute by 5-minute look at snow precipitation accumulations in a 1-hour, 3-hour, 12-hour or 24-hour window. B 1-hourly (270), 3-hourly (271), 12-hourly (272) and 24-hourly (27C) total precipitation rate 1K: These products provide a 5-minute by 5-minute look at total precipitation accumulations in a 1-hour, 3-hour, 12-hour or 24-hour window. B 1-hourly (292), 3-hourly (293), 12-hourly (294) and 24-hourly winter (295) precipitation 1K: This product provides an overview of a winter weather event. In combining the 1-hourly or 3-hourly or 12-hourly or 24-hourly liquid, mixed and snow rates, it allows the user to more completely understand the intensity of the event. B flood 1K (290): This product is designed to provide insight into the potential for flooding. It incorporates the 1-hour, 3-hour and 12-hour total precipitation rates into its calculations. B heavy snow 1K (291): In combining the 1-hourly, 3-hourly and 12-hourly snow rates, this product provides an assessment of the intensity of a snow event. B past 1-hour liquid (26D), mixed (26E) and snow accumulations (26F) 1K: These products are animation sequences of imagery that depict the accumulation of liquid, mixed or snow precipitation during the past 1 hour. B past 1-hour total precipitation accumulation 1K (26C): This product is an animation sequence of imagery that depicts the growth of the total accumulated precipitation during the past 1 hour. B past 24-hour liquid (28D), mixed (28E) and snow accumulations (28F) 1K: These product are animation sequences of imagery that depict the growth of liquid, mixed or snow accumulations during the past 24 hours. B past 24-hour total precipitation accumulation (28C) 1K: This product is an animation sequence of imagery that depicts the growth of the total accumulated precipitation during the past 24 hours. B precipitation type 1K (Snow Line) (269): This product depicts the areas of snow, mixed precipitation, and rain areas. While it does not show actual precipitation, it does show what the precipitation type would be if any were falling. Although it is not really designed for display, it can be used as a product to define where the changeover points are in advance of actual precipitation. B precipitation type 4K (401): This is the precipitation type 1K product converted to a display of 4 km by 4km resolution. N Snow Machine (268): This product enables the ability to display rain, mixed precipitation and snow, as well was their respective rates. The result is a radar display where the first five levels represent liquid precipitation, the next five levels indicate mixed precipitation, and the last five levels depict snow rates. In addition, this module allows the user to see the transition of precipitation type and rate as a system moves across a viewing area. B Other Products arrows: Enables the system to display storm SCITs (an identification box and an associated arrow), which visually depict various characteristics of the storm. By right clicking on the box, an information chart appears, which contains various numerical parameters pertaining to the storm. Baron US Composite Products (3010, 3020, 3030, 3040, 3050, 3060): These products display US Radar NEXRAD status, 8 km Composite reflectivity, and 1 km quadrant composite reflectivity in the southeast, southwest, northeast and northwest, respectively.

 

 

OPERATION AND MAINTENANCE MANUAL ELEVATION OVER AZIMUTH POSITIONER AL-4017-1EBS-B For Baron Services Radars:

XDD-350C VHDD-350C HDD-350C HDD-250C VHDD-1000C BARON RADAR SERVICES, L.L.C. 4930 Research Drive Huntsville, AL 35805 PHONE: 256.881.8811 FAX: 256.881.8283 Table of Revisions REV DATE DESCRIPTION A 10/9/03 Added VHDD-1000C to front cover BY CK 1-2 TABLE OF CONTENTS SECTION 1 DESCRIPTIONS ........................................................................................................... 1 1.1 General Description...................................................................................................................... 1 1.2 1.3 Technical Description................................................................................................................... 1 Specifications ................................................................................................................................ 1 1.4 Mechanical Sub-Assemblies......................................................................................................... 1 Elevation Unit..........................................................................................................................1 Azimuth Unit ...........................................................................................................................2 1.4.1 1.4.2 1.5 Electromechanical Sub-Assemblies.............................................................................................. 2 Limit Switches.........................................................................................................................2 1.5.1 SECTION 2 INSTALLATION & OPERATION ................................................................................ 4 2.1 General.......................................................................................................................................... 4 2.2 2.3 Positioner Installation................................................................................................................... 4 Antenna Installation ..................................................................................................................... 4 2.4 Operation Instructions ................................................................................................................. 5 SECTION 3 MAINTENANCE ........................................................................................................... 7 3.1 General.......................................................................................................................................... 7 3.2 Cleaning ........................................................................................................................................ 7 Exterior Cleaning .....................................................................................................................7 Interior Cleaning ......................................................................................................................8 3.2.1 3.2.2 3.3 Lubrication ................................................................................................................................... 8 Periodicity ...............................................................................................................................8 2000 Hour or 2-Month Lubrication ..........................................................................................8 17000 Hour or 2-year Lubrication............................................................................................8 3.3.1 3.3.2 3.3.3 3.3 Electromechanical Components................................................................................................. 11 General..................................................................................................................................11 Limit Switches Maintenance ..................................................................................................11 Limit Switch Adjustment Procedure (see Figure 1) ................................................................11 3.3.2 3.3.3 3.3.4 i 3.4 Timing Belt Installation And Adjus tment ................................................................................. 13 Belt Tension (refer to Figure 2) .............................................................................................13 Sprocket Alignment ...............................................................................................................15 Belt Handling.........................................................................................................................15 Belt Storage ...........................................................................................................................15 3.4.1 3.4.2 3.4.3 3.4.4 3.5 Replacement of Azimuth Motor Assembly ................................................................................ 15 Removal of Azimuth Motor Assembly ...................................................................................15 Installation of Azimuth Motor Assembly ...............................................................................17 3.5.1 3.5.2 SECTION 4 STORAGE AND PREPARATION FOR USE .......................................................... 19 SECTION 5 REPLACEMENT PARTS .......................................................................................... 20 5.1 PARTS LIST............................................................................................................................... 20 GENERAL ............................................................................................................................20 ITEM NUMBER (ITEM No.) ................................................................................................20 DESCRIPTION .....................................................................................................................20 PART NUMBER (PART No.) ...............................................................................................20 QUANTITY (QTY) ...............................................................................................................20 ORDERING INFORMATION FOR PARTS .........................................................................21 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 APPENDIX ............................................................................................................................................. 22 LIST OF TABLE AND FIGURES TABLE 1. AL-4017-1EBS-B SPECIFICATIONS .................................................................................. 3 TABLE 2. RECOMMENDED LUBRICANTS AND LUBRICATION INTERVALS....................... 10 FIGURE 1. LIMIT SWITCH ASSEMBLY ......................................................................................... 12 FIGURE 2: RECOMMENDED BELT TENTION............................................................................... 14 FIGURE 3. AL-4017-1EBS-B POSITIONER ASSEMBLY ............................................................... 18 TABLE 3. AL-4017-1EBS-B Parts List................................................................................................. 21 ii SECTION 1 DESCRIPTIONS 1.1 General Description The Positioner AL-4017-1EBS-B is comprised of two modified ORBIT Standard AL-760's. The modifications were performed according to Baron Services specifications concerning speed, acceleration, antenna adapter and environmental conditions (see Table 1). 1.2 Technical Description The AL-4017-1EBS-B Elevation-over-Azimuth Positioner has two main units: Elevation and Azimuth. All parts are submitted to high-stress tests to ensure reliability and avoid downtime. 1.3 Specifications The specifications of the AL-4017-1EBS-B EL/AZ Positioner are listed in Table 1. 1.4 Mechanical Sub-Assemblies 1.4.1 Elevation Unit The Elevation Unit, mounted on the turntable of the Azimuth Unit, turns the upper turntable through the vertical plane. The mechanism of the Elevation Unit is as follows: A DC motor drives a worm gear through a timing belt. The worm gear drives an internal gear, an integral part of a ball race type slewing bearing assembly, which is designed and produced according to very high standards and specifications. The internal gear is the linking element between the Azimuth and Elevation Units. 1 1.4.2 Azimuth Unit The Azimuth Unit turns the Positioner through the horizontal plane. It is designed to handle vertical and radial loads. The mechanism of the Azimuth Unit is as follows: A DC motor drives a reduction worm gear through a timing belt. The pinion on the reduction gear drives an internal gear, which is an integral part of a slewing bearing assembly. The internal gear drives the turntable, which carries the Elevation unit. 1.5 Electromechanical Sub-Assemblies 1.5.1 Limit Switches The limit switches are designed to coordinate the rotation of the El axis. The limit switches are of the electric rotary cam type. Each limit switch assembly has two cams, one for UP and one for DOWN. The limit switches are normally open. 2 TABLE 1. AL-4017-1EBS-B SPECIFICATIONS ft-lbs PARAMETERS UNIT VALUE AZIMUTH BEARING MOMENT CAPACITY VERTICAL LOAD DELIVERED TORQUE WITHSTAND TORQUE NOMINAL SPEED DATA TAKE-OFF ACCURACY Azimuth Elevation Azimuth Elevation Azimuth Elevation Azimuth Elevation lbs ft-lbs ft-lbs ft-lbs ft-lbs deg/sec. deg/sec. deg. deg. 3000 800 170 170 500 500 36 36 0.07 0.07 MAXIMUM BACKLASH ELEVATION LIMIT-TO-LIMIT TRAVEL AZIMUTH TRAVEL OPERATING TEMPERATURE Azimuth Elevation deg. deg. deg. deg

C lbs 0.05 0.05

-2 to +182 Continuous

-20 to +55 950 WEIGHT Note:

When slip rings and/or rotary joints are used, limit switches are disabled. 3 SECTION 2 INSTALLATION & OPERATION 2.1 General The AL-4017-1EBS-B Elevation over Azimuth positioner is shipped as a ready-mounted unit (pedestal assembled on base riser). Unpack the system and examine it for any damage that may have occurred in transit. Check connectors, units, the base, and the body itself. The site on which the Positioner is to be placed must be adequate to support its weight. Unless otherwise stated, Positioners are dispatched with the upper turntable in the zero position and locked on zero. 2.2 Positioner Installation Using an adequate hoisting device and lifting eye, place the Positioner on the designed location and clamp it with 3/4" UNC bolts and torque to 100 ft-lbs. 2.3 Antenna Installation CAUTION To prevent injury to personnel and damage to equipment, always make sure that the SAFE/OPERATE switch on the connector panel is set to SAFE, prior to antenna installation on Positioner. a. The antenna should be fastened to the upper turntable using the specially designed antenna support. When mounting the antenna it is important to consider the Positioner's bending moment rating. The weight of an antenna assembly, wind, and/or ice-formation may all subject a Positioner, located in the open, to a bending moment. When approaching the Positioner's maximum rating, caution should 4 be exercised since the additional moment load on the antenna from wind force may be enough to exceed the maximum load rating. b. Inertia loading must also be considered since, during both acceleration and deceleration, the torque load on the drive train mechanism increases. Inertia overload causes slow starting and commensurate increase in motor current to compensate for the excessive drive torque required. Faltering, vibration, and exceeding of the torque rating on deceleration may all result from inertia overload, causing excessive gear wear and possible tooth breakage. CAUTION To avoid damage to the Positioner drive train from inertial overload, it is vital to apply speed changes slowly whenever an overload is suspected. This is because inertial torque effects are proportional to the square of the turntable speed. 2.4 Operation Instructions CAUTION Prior to any operation of the Positioner, make sure that no person or equipment is inside the Positioner rotation area. a. Set the "SAFE/OPERATE" switch to "OPERATE" position. b. Set Power Switch on the Controller to the "ON" position - "ON" lamp will illuminate. The positioner will perform a self-test by slewing in both azimuth and elevation. c. Upon completion of the self-test, choose between "LOCAL" operation

(operation by means of the Controller) or "REMOTE" operation

(operation by means of the Computer) by setting the Controller to the desired mode of operation, using the LOCAL/REMOTE switch. The Positioner and System are now ready to operate. 5 d. To operate the System, refer to the applicable Controller Operation Manual. WARNING TO PREVENT INJURY TO MAINTENANCE PERSONNEL OR DAMAGE TO EQUIPMENT, ALWAYS VERIFY THAT NO EXTERNAL VOLTAGE IS SUPPLIED TO THE POSITIONER AND THAT THE SAFE/OPERATE SWITCH IS IN THE SAFE POSITION, PRIOR TO PERFORMING ANY MAINTENANCE WORK ON THE POSITIONER. IF POWER MUST BE APPLIED FOR TEST PURPOSES, TAKE ALL THE STEPS THAT ARE NECESSARY IN INJURIES AS A RESULT OF ORDER TO AVOID ELECTRICAL OF MECHANICAL UNITS. MOVEMENT SHOCKS AND 6 SECTION 3 MAINTENANCE 3.1 General This chapter provides information necessary for maintaining the AL-4017-

1EBS-B Elevation-over-Azimuth Positioner series in optimal operating condition. Note When performing maintenance operations, the internal components such as motors, electrical devices, wires, connectors, and mechanical elements, should be visually inspected. 3.2 Cleaning The Positioner should be cleaned as often as dictated by the operating conditions. It should be kept free of dust, moisture and grease. If available, use a vacuum cleaner to remove all accumulated dust from the interior and exterior of the Positioner. 3.2.1 Exterior Cleaning Loose dust can accumulate on the exterior surface of the positioner. Remove this dust with a soft cloth or a soft bristle brush. A cloth saturated with cleaning solvent may also be used. 7 3.2.2 Interior Cleaning Loose dust in the Positioner interior must be removed due to its electrical conductivity under humid conditions. The recommended method is to use a vacuum cleaner. Remove any remaining dirt with a soft bristle brush or a cloth soaked in cleaning solvent. A cotton-tipped applicator is useful for cleaning narrow spaces. 3.3 Lubrication This section includes access information, periodicity, and lubrication procedures. 3.3.1 Periodicity Lubrication of the Positioner should be performed periodically, per the intervals listed in Table 2. 3.3.2 2,000 Hour or 2-Month Lubrication 3.3.2.1 Slewing Bearing Lubrication a. Inject 2cc of grease (see Table 2), through the grease fitting, every 60 of the Azimuth turntable rotation. For Elevation, inject grease at the end of the travel, in each direction. b. When operating under very hot or dry environmental conditions, inspect and inject grease more frequently. 3.3.3 17,000 Hour or 2-year Lubrication 3.3.3.1 Ring-Gear Lubrication a. Using a 5/32-inch Allen wrench, loosen the two screws fastening the primary limit switch assembly to the body. 8 b. Through the limit switch hole in the body apply a thin layer of grease on the gear teeth. Then, rotate the turntable a small amount and again apply a thin layer of grease on the gear teeth. Continue this rotating and greasing process until the turntable completes one full revolution. c. Remount the limit switch after rotating the turntable to its previous position. Note To achieve the previous position, verify that the angle that is displayed on the controller's console is the same angle that was displayed before the removing of the limit switch assembly. 9 Type Lubricant Manufacturer Interval Grease 165 LT Molykote GmbH Dow Corning 17,000 hours of TABLE 2. RECOMMENDED LUBRICANTS AND LUBRICATION INTERVALS Item Large ring gear Bearings Reduction gear Note:

Shell Oil Co. During overhaul 1,500 hours of operation or 2 months Isoflex LDS 18 Special A Kluber Shell Tivella Compound A Grease operation or 2 years Grease If the required Lubricants, as described in the above table, are not available in your area; please contact your Baron Services Representative for assistance. 10 3.3 3.3.2 3.3.3 3.3.4 Electromechanical Components General Common components, such as encoders and limit switches, do not usually require special servicing; such components may be serviced during general overhaul. Maintenance information for the limit switches is given in the following pages. Limit Switches Maintenance The limit switches are factory adjusted prior to shipment. However, when Positioner readjustment or change of rotation limits is necessary, the limit switches must be readjusted. To avoid damage to the internal cables (connecting the Azimuth Unit to the Elevation Unit), verify that the new adjusted turning range does not exceed the specified range. CAUTION Limit Switch Adjustment Procedure (see Figure 1) a. b. c. d. e. Turn Positioner axis to the desired limit angle (CW or CCW). Gain access to limit switch assembly. Using a 7/64" Allen wrench, release the appropriate limit switch cam fastening screw (S1 for CCW and S2 for CW). Rotate the appropriate switch cam until Positioner operation is inhibited in the desired direction and retighten the cam screw. Turn the Positioner in the opposite direction and then return it in the limit direction. Verify that Positioner operation is stopped at the desired angle. 11 FIGURE 1. LIMIT SWITCH ASSEMBLY 12 3.4 Timing Belt Installation And Adjustment The Timing belt should be installed with a snug fit, neither too tight nor too loose. The belt's positive grip eliminates the need for initial tension. Consequently, a belt, when installed with a snug fit (that is, not too tight), assures longer life, less wear on bearings and quieter operation. Preloading, often the cause of premature failure, is not necessary. 3.4.1 Belt Tension (refer to Figure 2) When torque is unusually high, a loose belt, on starting, may "jump teeth". In such a case, the tension should be increased gradually until satisfactory operation is attained. When the safety switch is in the OPERATE position, run the polarizer so that the top of the belt is slack and return the safety switch to the SAFE position. The application of a force (f) of 1.3 lbs (0.59 Kg) at the midpoint of the slack span, between the two pulleys, shall result in a deflection (d) of 0.21 inch (5.4mm). If the force (f) required to obtain the specified deflection (d) is less than specified, the belt is too loose. If the force (f) required to obtain the specified deflection (d) is greater than that specified, the belt is too tight. Adjust the motor position until the specified force and deflection measurements are obtained. 13 d = 0.21 inch (5.4 mm) f = 1.3 lbs (0.59 Kg.) FIGURE 2: RECOMMENDED BELT TENTION 14 3.4.2 Sprocket Alignment Misalignment of drive results in unequal tension and extreme edge wear. Consequently, sprocket alignment should be verified by means of a straight-edge and shafts checked to assure parallelism. On a long-center drive, due to the belt's tendency to run against one flange of the drive sprocket, it is often advisable to offset the driven sprocket slightly to compensate for this effect. On installation, the belt should never be forced or pried over the sprocket flange. Reduction of center distance usually permits the belt to slide into the sprocket easily. Otherwise, one or both sprockets must be removed. 3.4.3 Belt Handling 3.4.4 Belt Storage To assure smooth operation and to prevent premature failure, belts in storage should be protected against sharp bending or creasing. Avoid subjecting belts to extreme heat, low temperature or high humidity. 3.5 Replacement of Azimuth Motor Assembly 3.5.1 Removal of Azimuth Motor Assembly Use the following procedure to remove the Azimuth Motor Assembly

(Refer to Figure 3):

Rotate the Elevation Axis until it is at the 90 deg. vertical position;

i.e. pointing straight up. a. 15 b. c. d. e. f. g. h. i. j. k. l. m. n. Set the SAFE/OPERATE switch to the SAFE position. Remove the antenna, counterweights, and the two arms located on the Elevation Axis. Remove the four screws on each flange (8) and the screws (3) securing the Positioner to the base riser. Detach the connectors MOL1 thru MOL4, located in the base riser. Lift the Positioner off of the base riser and place it on a secure working surface; e.g. a table. Support the Positioner in a level position. Remove screws (6), cut the tie wraps located on the waveguide and remove the parts (7) from the Slip-Ring. Remove the screws (4) securing the lower plate (5) to the Azimuth unit. Separate the lower plate (5) from the Azimuth unit. Note:

The length of the wiring harness between the slip-ring and the elevation unit is long enough to allow the plate (5) to be moved away from the Azimuth unit by a distance of approximately one foot. Remove the four screws securing the motor bracket to the azimuth positioner body. Using a "heat gun", remove the LOCKTITE No. 241 epoxy from the four screws securing the motor to the bracket. Remove the four screws attaching the motor to the bracket. Carefully, remove the motor from the bracket. 16 o. Remove the pulley from the motor shaft and retain it for installation on the shaft of the new motor. 3.5.2 Installation of Azimuth Motor Assembly For new Azimuth Motor installation, follow the removal procedure in paragraph 3.6.1 in a logical reverse sequence using the following notes:

1) 2) 3) Notes:

When the lower plate (5) is assembled to the Azimuth unit, be sure that the extra length of the wire harness between the slip-ring and the elevation unit is inserted in part (1). Loose wiring inside the Azimuth unit should be secured to the waveguide by means of tie wraps. When assembling the positioner, verify that the waveguide and lower plate (5) O-ring gaskets are in good condition and are installed in their proper locations. Verify that all screws are securely fastened. After the installation procedure is completed, the new motor and gear sprockets must be aligned according to para. 3.5.2; and the tension of the belt between the new motor and the gear must be adjusted according to para. 3.5.1. 17 FIGURE 3. AL-4017-1EBS-B POSITIONER ASSEMBLY 18 SECTION 4 STORAGE AND PREPARATION FOR USE Store the Positioner in a closed place, protected from dust and rain. Once a month, rotate the Positioner at each axis, three times from limit to limit. Before using the Positioner after a long storage period, re-lubricate the bearings. Refer to lubrication instructions. 19 SECTION 5 REPLACEMENT PARTS 5.1 PARTS LIST 5.1.1 GENERAL The various parts used in the AL-4017-1EBS Positioner are listed in the following parts list table. The purpose of this part list is for identification, requisition, and issuance of spare or replacement parts. For part replacement, use only part numbers specified in this parts list. The parts list table is divided into four columns, which are described in the following paragraphs. 5.1.2 ITEM NUMBER (ITEM No.) The first column in the parts list table contains item numbers, assigned in sequence. 5.1.3 DESCRIPTION The second column contains brief descriptive information for each part. 5.1.4 PART NUMBER (PART No.) The third column lists manufacturer's part numbers. 5.1.5 QUANTITY (QTY) The fifth column lists quantity of each item used in the Positioner. 20 5.1.6 ORDERING INFORMATION FOR PARTS When ordering spare or replacement parts, state the full description of part, part number, and the desired quantity. TABLE 3. AL-4017-1EBS-B Parts List Item No. Description Part No. Qty. 1. 2. 3. 4. 5. 6. 7. 8. 9. Az. Motor Assy. El. Motor Assy. Encoder Reduction Gear Pulley (Az/El) (Motor) Belt Pulley (Az/El) (Gear) Slewing Bearing Az Power Amp. BS-104453 BS-104452 BS-104455 BS-104151 BS-104482 BS-104456 BS-104483 BS-104107 BS-104134 1 1 2 2 2 2 2 2 1 21 APPENDIX AL-4017-1EBS-B

INTERFACE CONTROL DRAWING (ICD) WIRING DIAGRAM SYSTEM LAYOUT Dwg. No. 19-0342 Dwg. No. 19-0361-1/2 Dwg. No. 19-0589 22 OPERATION AND MAINTENANCE MANUAL AL-1642-3JB Two-Axis Controller With Built-In Servo Amplifier For Baron Services Radars:

XDD-350C XDD-300X VHDD-350C VHDD-1000C BARON SERVICES, INC. 4930 Research Drive Huntsville, AL 35805 PHONE: 256.881.8811 FAX: 256.881.8283 Table of Revisions REV DATE DESCRIPTION A 10/9/03 Added VHDD-1000C to front cover BY CK TABLE OF CONTENTS SECTION 1 INTRODUCTION .................................................................................... 1 SECTION 2 FRONT PANEL OPERATION............................................................... 2 2.1 2.2 2.3 2.4 Front Panel Keypad ................................................................................................ 2 Front Panel Joystick and Fine/Coarse Switch ....................................................... 3 Front Panel Power Switch...................................................................................... 3 Front Panel Display ................................................................................................ 4 SECTION 3 REAR PANEL CONFIGURATION ....................................................... 5 3.1 Power Selection, Input, and Fuses.......................................................................... 5 3.2 Motor Fuses............................................................................................................. 5 3.3 3.3.1 3.3.2 Positioner Connectors ............................................................................................. 6 Encoder IN/OUT (J3) .............................................................................................6 Motor Power and Limits (J5) ..................................................................................6 3.4 Communication Connectors ................................................................................... 7 SECTION 4 REMOTE OPERATION.......................................................................... 8 4.1 Modes of Operation ................................................................................................ 8 Standby ..................................................................................................................8 4.1.1 Point ......................................................................................................................9 4.1.2 4.1.2.1 Single Point Commands .........................................................................................9 4.1.2.2 Repeated Point Commands (Track Mode) ..............................................................9 Home ...................................................................................................................10 4.1.3 Slew.....................................................................................................................10 4.1.4 4.1.5 Calibrate ..............................................................................................................10 4.1.6 Raster Scan Mode ................................................................................................11 4.1.6.1 Azimuth Raster Scan Mode ..................................................................................12 4.1.6.2 Elevation Raster Scan Mode.................................................................................13 4.2 4.3 4.4 Serial Protocol - Data Link Level......................................................................... 14 Serial Protocol - Commands from Host Computer to ACU................................ 15 Serial Protocol - Replies from ACU to Host......................................................... 16 4.5 4.5.1 4.5.2 4.5.3 Command codes and parameters ......................................................................... 18 General comments................................................................................................18 Parameter Limits ..................................................................................................18 Alphabetical command listing ..............................................................................19 SECTION 5 TROUBLESHOOTING......................................................................... 28 SECTION 6 MAINTENANCE.................................................................................... 30 6.1 Amplifier Adjustment........................................................................................... 30 Voltage Tests ......................................................................................................... 30 6.2 APPENDIX A................................................................................................................... 31 APPENDIX B .................................................................................................................. 42 1 INTRODUCTION link. The second This algorithm The AL-1642-3JB is a higher power version of the AL-1613-3JB Antenna Control Unit (ACU) for controlling a two-axis elevation-

over-azimuth positioner. A front panel provides manual control of the antenna from the controller through a joystick, a set of pushbuttons, and two 8-character LED displays, one for each axis. Two RS-232 serial links are provided. One link provides for remote control and parameter tuning. Modes of operation in remote control include Go-to-Point, Slew, Raster Scan, Go-to-Home Position, Standby, and Calibrate. link provides azimuth and elevation position continuously. Go-to-Point mode includes an extrapolation algorithm designed to allow the controller to closely follow a trajectory sent over the serial is used automatically when point commands are received at a sufficiently rapid rate. Most important control gains and parameters may be tuned over the serial link and stored in non-volatile memory. The AL-1642-3JB is packaged in a 4U height 19"-wide rack-

mount box which includes DC power supplies, a CPU card, an I/O card, two amplifiers for the DC motors, and the front panel card. The CPU card, based on the Intel 80960KB RISC processor, performs closed loop control of the axis positions and manages the serial protocol and front panel. The I/O card contains inputs for encoders to read axis positions, digital inputs for limit switches, digital outputs for the drive enable and analog outputs for the current references for the motors. It also contains the serial communications chip and drivers for the RS-232 communication link. The front panel card provides interfaces for the joystick, the pushbuttons, and the 8-character displays for reading the angles. The amplifiers provide closed loop velocity control of the motors, as well as protective functions, such as constant current limiting, peak and counterclockwise motion limiting. clockwise motion limiting, limiting, current 2 FRONT PANEL OPERATION The front panel is shown in Figure B-3. It consists of a joystick, a fine/coarse switch, two 8-character displays, two LEDs, three pushbuttons, and an on/off power switch. When the AL-1642-3JB is first powered on, the unit will be in REMOTE mode, permitting remote operation without access to the Controller. 2.1 Front Panel Keypad The front panel contains 3 pushbuttons with functions as follows:

REM/LOC - Toggle between remote and local modes. In remote mode, the other front panel controls are inactive and all control is by commands over the serial communications link. In local mode, commands over the serial link which could move the positioner are not accepted. This includes axis mode commands and pointing commands. Position is controlled instead through the joystick and other front panel switches. The REM/LOC switch also places the controller in Standby mode whenever it is pressed, bringing the positioner to zero velocity. CAL - This function is required because the position measurement is based on incremental encoders. It finds the mechanical zero point of the positioner and resets the angle displays accordingly. A detailed explanation of parameters that affect it is given in section 4.1.5 below. OFFSET - Set azimuth offset so that the present angle will be zero. If the positioner is moving, it is first commanded to zero velocity. If the positioner is calibrated, the offset is saved to non-volatile memory. the calibration sequence and the 2.2 2.3 Front Panel Joystick and Fine/Coarse Switch The joystick is a dual axis unit with a spring return to zero. It allows controlled movement of both axes at a wide range of velocities when in MANUAL mode. Movement of the joystick UP or DOWN causes elevation motion in the CW or CCW direction respectively. Movement to the right or left causes CW or CCW azimuth motion. The joystick is a very sensitive control unit. An excessive amount of force is not required in order to move the stick. Extreme force can cause damage to the joystick. The velocity varies with the amount the joystick is moved from its center position. A central region of approximately 10% of the joystick's total travel range gives zero velocity. The next 40% gives a velocity range which increases slowly at first and then increases rapidly. The last 50% of the travel provides a velocity which increases at a linear rate with respect to joystick position. In all ranges, a deadband of 2.5% keeps the velocity constant until a motion of at least 2.5% of the stroke length is made. A front panel velocity parameter, which may also be adjusted via the communications the maximum velocity when the FINE/COARSE switch is set to COARSE. With the FINE/COARSE switch set to FINE, the maximum velocity is reduced by a factor of 10. With a typical maximum velocity of 36 deg/sec., velocities of about 0.3 deg/sec. to 36 deg/sec. are possible in COARSE mode, and 0.03 deg/sec. to 3.6 deg/sec. in FINE mode. Zero-adjust levers are provided for each axis of the joystick. If a small velocity exists, with the joystick at the center position, this may be nulled by adjusting these levers. link, is Front Panel Power Switch This switch will switch the main power, which may be either 115 VAC or 230 VAC, depending on settings of rear panel switches described below. The switch will be illuminated when 230 VAC power is in use and the switch is in the ON position. 2.4 Front Panel Display Azimuth and Elevation angles are displayed on the front panel using 8-

character LED displays. Six of the characters provide the angle reading to a precision of 0.001 degree. The 7th character is for the sign of the angle, and the 8th character provides limit information. A rapidly blinking display (4-Hz) indicates that the axis has not completed its calibration cycle. A slowly blinking display (2-Hz), along with a letter in the limit character, indicates that a limit switch has been tripped, stopping the positioner motion. Motion is then permitted only in the direction away from the limit. L (left) indicates CCW azimuth limit (decreasing angle). R (right) indicates CW azimuth limit (increasing angle). U (up) indicates CW elevation limit, and D (down) indicates CCW elevation limit. A slowly blinking letter in the limit character, with the rest of the display not blinking, indicates that the positioner has reached the software limit maximum or minimum angle. These limit angles may be adjusted by commands over the serial communication link. The angle display may be changed by commands CCA and CCE on the serial communications link. The precision may be set to 0.1, 0.01, or 0.001 degree. The format may be set to 0-359.999 or +/-780 degrees. If desired, the limit character may be displayed (without blinking) to indicate cable wrap (when the angle is outside the center +/-180 degree area). This cable wrap feature is particularly useful with a 0-359.999 degree display format. 3 3.1 3.2 REAR PANEL CONFIGURATION The rear panel is shown in Figure B-4. It contains a power select area, power input, fuses, a connector for the cable to the positioner, two communications connectors, and a chassis ground connector. Power Selection, Input, and Fuses Power input is through the power connector J1. The switch labeled "MAINS SELECT" has two positions, 115 VAC and 230 VAC. The "MAINS SELECT" switch must be set to the proper input voltage. If this is not done, damage may result to the internal power supply used to provide DC current for the positioner motors and the electronic circuitry. Fuse F1 is for the AC input. Recommended fuses to be used are 4 Amp

"slow-blow" type for 230 VAC input, 8 Amp "slow-blow" type for 115 VAC. High breaking capacity fuse (greater than 500 Amps) should be used. Motor Fuses Fuse F2 protects the azimuth motor and fuse F3 protects the elevation motor. Current limit protection already exists in the amplifiers and is set to 5 Amps continuous and 10 Amps for peaks of less than 2 seconds. This will protect the motors from thermal overheating for ambient temperatures up to about 45 C. "Slow-blow" type fuses of 10 Amps are recommended as further protection. 3.3 3.3.1 3.3.2 Positioner Connectors The positioner connectors J3 and J5 are circular MS-type connectors which carry encoder signals, tachometer signals, limit switch signals, and power for the motors and encoders. Encoder IN/OUT (J3) For each encoder, there are 6 wires, in three sets of shielded twisted pairs. One pair is for the normal (A) pulses, one pair for the quadrature (B) pulses, and one for the index (I) pulses. For each axis, there are two wires for a home (zero-indicating) pulse which is used during the calibration operation to find an absolute reference point. 115/230 VAC is provided as input to a power supply which provides 5 Vdc power to the encoders. For each tachometer (azimuth and elevation), there are two wires. Motor Power and Limits (J5) Each motor has 6 wires, one group of three connected in parallel for DC power-high side and the second group of three connected in parallel for DC return. For each axis, there are 3 limit switch wires: one for CW limit, one for CCW limit and one for common. The CW and CCW limits will shut down the motor amplifiers from moving the motors in the direction which caused the limit. 3.4 Communication Connectors The communication connector J4 is a 25-pin D-type connector for RS-232, with pins 2,3, and 7 used for TXD, RXD, and COMMON, respectively per standard RS-232 configuration. The controller is configured as DCE (data communications equipment), since normally the host computer will be configured as DTE (data terminal equipment). This means that the controller receives data from the host on pin 2 (TXD) of the 25-pin connector and transmits data to the host on pin 3 of the 25-pin connector (RXD). Connector J6 is a 25-pin D-type connector for RS-232, configured the same as J4. The azimuth and elevation status data are transmitted via connector J6. 4 4.1 4.1.1 REMOTE OPERATION Remote operation is implemented by sending commands to the positioner via the serial link. The modes of operation available via remote control and the details of the serial protocol commands are described below. Modes of Operation The mode of operation for each axis is independent. The modes of operation are: MANUAL, STANDBY, POINT, HOME, SLEW, RASTER SCAN, and CALIBRATE. A mode command may be used to select all but the first via the remote link. Following is a description of what occurs when each mode is selected. Standby is brought to a stop at Axis the maximum allowed deceleration rate, determined by the parameter MAx. When the velocity arrives at zero, the motor amplifier is shut down if bit #12 in Control Word #2 is set. This bit should be set only for positioners which have self-locking gears, or for which there is no load imbalance which would cause the positioner to move when the amplifiers are shut down. Note that Standby may also be implemented from the Controller front panel by toggling the REMOTE/LOCAL switch. Note that if Standby is commanded before the power-up calibration has been performed, the position readings will be relative to the position at which the unit was powered-up. The front-panel display will blink at 4 Hz. repetition rate to indicate this, and the status bit in RDS (az_calibrated or el_calibrated) will be 0. 4.1.2 4.1.2.1 Point Single Point Commands Positioner moves to the axis point reference, as sent by the PTx command, and comes to rest there. The amplifier continues to supply current as needed to hold the position against external forces. If the positioner has been switched from LOCAL to REMOTE and no point command has been sent, the axis point reference is the place where the positioner came to rest. When a single PTx command is send while the ACU is in Remote and Point mode, the positioner moves to the commanded point using a trapezoidal velocity profile. If the Continuous Rotation bit (bit #5) in Control Word #1 is set, the direction of motion is the shortest route, and the user has no control over the direction. If it is not set, the direction of motion is according to the commanded values. For example, if the position is +170.000 and the user wishes to move 20 degrees CW, the commanded point must be +190.000. If he wishes to reach the same point by a 340 degree motion CCW, the commanded point must be -

170.000. The acceleration is determined by the value of the MAx parameter. The maximum speed is determined by the step size, the MVx parameter, and the "Full-Speed Step" bit (bit #6) in Control Word #2. If "Full-Speed Step" is set, the maximum speed will be the MVx parameter for all step sizes greater than MVx2/MAx. For smaller steps, the velocity profile will be triangular. If

"Full-Speed Step" is zero, the maximum velocity will be according to the formula sqrt(step*MAx/5.0), or MVx, whichever is less. For applications where there are many small, irregular position corrections being commanded, and response time is not critical, this formula provides smoother motion with good response time. 4.1.2.2 Repeated Point Commands (Track Mode) If a series of point commands are sent when in point mode, and the time delay between commands is less than the maximum update-time (UTx) parameter, the points will be interpreted as a continuous trajectory. Instead of coming to rest, the positioner extrapolates the trajectory based on the last two points 4.1.3 4.1.4 4.1.5 received and attempts to arrive at the point and velocity expected according to the extrapolated trajectory. This mode is entered after 3 points have been sent with the two time intervals between them less than the maximum update-time. As trajectory extrapolation is based on the assumption that the intended time interval was constant. If the time interval between points is more than this, the positioner begins to decelerate to zero velocity. time varies by the update than 10%, long as less the Home Positioner moves to the home point (HMx) parameter specified for the axis and comes to rest there. The amplifier continues to supply current to hold the positioner at that point against external forces. Home mode acts like a single point command, but using the HMx parameter to determine the target point instead of the PTx parameter. Slew Positioner moves at the constant velocity last commanded with a slew velocity

(SVx) command. If no slew velocity command has been sent since the controller was turned on, the slew velocity is zero. Calibrate This function is required because the position measurement is based on incremental encoders. It finds the mechanical zero point of the positioner and resets the angle displays accordingly. First, the positioner moves towards the clockwise limit switch at the go-to-limit velocity until one of three events occurs:

1) The clockwise limit switch is tripped 2) The zero indicating pulse is detected 3) The maximum clockwise calibration distance is passed In cases 2 and 3, if required, the positioner moves clockwise an additional distance to be sure that it will accelerate to the calibrate velocity before it reaches the zero-indicating pulse. 4.1.6 The positioner then moves counter clockwise at the calibrate velocity until it detects the zero-indicating pulse and continues until the first index pulse on the encoder is observed. At this point, the current angle is then set equal to the zero switch position minus the offset. The positioner then decelerates and returns to this set point. Go-to-limit velocity, calibrate velocity, maximum clockwise calibration distance, zero switch position, and offset for each axis may all be adjusted via the serial communication link. Notes:

1.If the zero switch position parameter is changed without performing a calibration, the current angle readout will not be changed until a calibration is actually performed. 2.Calibration is performed automatically upon power-up. 3.For a continuous rotation axis, as defined by bit 5 in control word #1, the clockwise movement in the calibration cycle is not performed. Instead, the axis is moved counterclockwise until the zero-indicating pulse is detected, continues until the first index pulse on the encoder is observed, and sets the current angle equal to the zero switch position minus the offset, as described above. It then decelerates and returns to this set point. Raster Scan Mode Positioner performs a raster scan using a rectangular angular profile. The Raster Scan mode is different from all the other modes in that the mode command for one axis (primary axis) also controls the operation of another axis (secondary axis). If the Raster Scan mode command is for the azimuth axis (i.e., MDA 6), the raster area is covered by scanning the azimuth axis

(primary axis) followed by stepping of the elevation axis (secondary axis) at the end of each azimuth scan. If the Raster Scan mode command is for the elevation axis (i.e., MDE 6), the raster area is covered by scanning the elevation axis (primary axis) followed by stepping of the azimuth axis

(secondary axis) at the end of each elevation scan. When a Raster Scan command has been initiated for the primary axis, mode commands for the secondary axis should not be given until the primary axis is commanded to another mode. 4.1.6.1 Seven parameters and four control bits govern the details of the raster scan performed:

RCA Center azimuth position RCE Center elevation position RRA Azimuth range scanned at constant velocity. The azimuth range will have added to it at each end an acceleration distance of 0.5*RVA*RVA/MAA. RRE Elevation range scanned RVx Scan speed of primary axis in Raster Scan mode command RSx RTx Time delay at end of each scan Step size of secondary axis Azimuth Raster Scan Mode the When the Azimuth Raster Scan mode is entered, the positioner moves to the initial corner of the raster profile at the maximum velocity (MVx). The initial corner is determined by the sign of the RVA and RSA parameters. If RVA is positive, the initial corner is the CCW corner in azimuth. If RSA is positive, the initial corner is CCW in elevation. After initial corner is reached, the positioner scans in azimuth with elevation constant until the end of the azimuth range, and decelerates to zero velocity. If the RTA parameter is nonzero, it waits for a delay time as specified by the RTA parameter. If the bit for a single-direction raster is set (Control Word #2, bit 4), the positioner then steps in elevation an amount given by the RSA parameter and returns to the azimuth starting point, both together at maximum velocity, and the azimuth scan repeats. If the single-direction bit is cleared, the elevation steps and the azimuth scans in reverse. The process is repeated until the next elevation step results in exceeding the range specified in the RRE parameter. At this point, if the Non-Stop Raster bit (Control Word #2, bit 5) is set, the positioner returns to the initial corner and the process is repeated. If Non-Stop Raster is cleared, the positioner enters Standby mode at the end of the scan. Note that parameters may be changed in the middle of a scan, but this should be done with caution. The parameter change will normally take effect at the 4.1.6.2 end of each azimuth sweep. Changes of sign in RVA or RSA, or changes to RCx or RRx may have the effect of placing the positioner outside the scan limits, in which case it will scan until it reaches maximum position (MNx or MXx) or a limit switch. Changes in RVA or RSA without a change in sign are OK. Two control bits which may affect scanning are the Fast Step bit (Control Word #2, bit #6) and the Continuous Rotation bit (Control Word #1, Bit #5). If the Fast Step bit is not set, the various step motions at the end of each azimuth scan may not proceed at their maximum velocity. The user may choose, according to his preference, for fastest completion of scanning or smoother motions between azimuth scans. If the Continuous Rotation bit is set for azimuth, all step motions at the end of azimuth scanning will be in their shortest possible direction. Therefore, in single direction scanning, the "return" motion will be in the same direction as the scan for scans greater than 180 degrees. If it is desired to scan in azimuth only; i.e., with no elevation motion, set both the elevation step size (RSA) and range (RRE) to zero. Elevation Raster Scan Mode This mode is analogous to the Azimuth Raster Scan mode, with the roles of the two axes reversed; ie., the positioner scans in elevation and steps in azimuth. When the Elevation Raster Scan mode is entered, the positioner moves to the initial corner of the raster profile at the maximum velocity

(MVx). The initial corner is determined by the sign of the RVE and RSE parameters. If RVE is positive, the initial corner is the CCW corner in elevation. If RSE is positive, the initial corner is CCW in azimuth. After the initial corner is reached, the positioner scans in elevation with azimuth constant until the end of the elevation range, and decelerates to zero velocity. If the RTE parameter is nonzero, it waits for a delay time as specified by the RTE parameter. If the bit for a single-direction raster is set (Control Word #2, bit 4), the positioner then steps in azimuth an amount given by the RSE 4.2 parameter and returns to the elevation starting point, both together at maximum velocity, and the elevation scan repeats. If the single-direction bit is cleared, the azimuth steps and the elevation scans in reverse. The process is repeated until the next azimuth step results in exceeding the range specified in the RRA parameter. At this point, if the Non-Stop Raster bit (Control Word #2, bit 5) is set, the positioner returns to the initial corner and the process is repeated. If Non-Stop Raster is cleared, the positioner enters Standby mode at the end of the scan. Note that parameters may be changed in the middle of a scan, but this should be done with caution. The parameter change will normally take effect at the end of each elevation sweep. Changes of sign in RVE or RSE, or changes to RCx or RRx may have the effect of placing the positioner outside the scan limits, in which case it will scan until it reaches maximum position (MNx or MXx) or a limit switch. Changes in RVE or RSE without a change in sign are OK. Two control bits which may affect scanning are the Fast Step bit

(Control Word #2, bit #6) and the Continuous Rotation bit (Control Word #1, Bit #5). If the Fast Step bit is not set, the various step motions at the end of each elevation scan may not proceed at their maximum velocity. The user may choose, according to his preference, for fastest completion of scanning or smoother motions between elevation scans. If the Continuous Rotation bit is set for elevation, all step motions at the end of elevation scanning will be in their shortest possible direction. If it is desired to scan in elevation only; ie., with no azimuth motion, set both the azimuth step size (RSE) and range (RRA) to zero. Serial Protocol - Data Link Level Serial communication uses asynchronous protocol with 8-bit word length, 1 start bit, 1 stop bit, even parity, and a rate of 9600 baud. Signal levels are RS-

232. 4.3 Serial Protocol - Commands from Host Computer to ACU STX (start of text, value 02 hex) ETX (end of text, value 03 hex) All commands use printable ASCII characters, plus the ASCII control codes as follows:

Each command line sent to the controller consists of an ASCII STX character, followed by up to 80 characters of commands, two checksum characters, and an ETX character. The checksum is calculated such that the sum modulo 256 of all command line bytes (excluding the STX, ETX, and checksum bytes) will be equal to the checksum characters interpreted as ASCII-HEX. The command line consists of a number of commands, each of which is either a read command or a write command. A write command consists of a 3-letter command followed by a value. The value consists of a number with an optional leading sign (+ or -), up to 8 digits, and an optional decimal point. For each parameter, there is a range of legal values. Certain commands will be received only when the controller is in the remote mode. A read command consists of a 3-letter command followed by the read-request symbol "<". Only one read request is allowed in a single command line. Any parameter may be read at any time. Several characters, such as space, tab, new-line, carriage return, comma, and semicolon, are ignored. They may be included in the command line at any place and will have no effect, other than to add to the time required to send the command line. They are not counted in the 80 character limit. However, they must be included in the checksum. These characters may be used, if desired, to provide the meaning of a command line by adding descriptive comments. If any error is detected in a command line, none of the commands in the line are executed. A full list of the commands, parameters, maximum and minimum values, and conditions governing when they may be written, is provided in section 4.5. 4.4 A typical valid command line to update the azimuth and elevation point would be:

<STX>PTA20.24PTE-14.05E9<ETX>. The calculation of the checksum E9 is given by:

<STX> excluded P 50 hex T 54 hex A 41 hex 2 32 hex 0 30 hex

. 2E hex 2 32 hex 4 34 hex P 50 hex T 54 hex E 45 hex

- 2D hex 1 31 hex 4 34 hex

. 2E hex 0 30 hex 5 35 hex

sum 3E9 hex Serial Protocol - Replies from ACU to Host All replies use printable ASCII characters, plus the ASCII control codes as follows:

Each complete command line received is answered. Typically the reply will start within 2.5 msec of receipt of the last character of the command. STX (start of text, value 02 hex) ETX (end of text, value 03 hex) ACK (acknowledge, value 06 hex) NAK (negative acknowledge, value 15 hex) If an error is detected in the command line, an error message will be returned with the control character NAK followed by two ASCII hex characters comprising an error code. Error codes are as follows:

(reserved) CL_PARITY CL_FRAME CL_OVERRUN CL_BUFOVFL CL_STRLEN CL_CHECKSUM CL_ILLEGAL CL_CFORMAT CL_UNKCMD CL_DATALONG CL_MLTREAD CL_READONLY CL_DFORMAT CL_DATAULIM CL_DATALLIM

(reserved) CL_NOTREMOTE CL_BABBLE Parity error in byte in command line. Framing error in byte in command line. Overrun error in byte in command line. Receive FIFO overflow. Command line more than 80 characters. Command line checksum error. Illegal character in command line. Illegal command format. Unknown 3-letter command mnemonic. 01 02 03 04 05 06 07 08 09 0A 0B More than 10 characters in value. 0C More than 1 read command in command 0D 0E 0F 10 11 12 13 line. Illegal data format. Data value too large. Data value too small. Controller not in remote and command line attempted to write to parameter which may be changed only in remote. Babbling transmitter. More than 80 characters read with no STX. Read only command and attempted to write. The large number of error messages listed above is intended to assist the user in debugging his communications code by pointing to the exact source of the problem. If there is no error and the command line contained no read messages, the response is a single ACK character. If there is no error and the command line contained a read message, the response is of the format:

STX <value> <checksum> ETX where the value may be 1-10 characters including a leading sign and a decimal point and the checksum is calculated as above. 4.5 4.5.1 4.5.2 Command codes and parameters General comments Below is a complete description of the command codes and their parameters, for use in designing communications programs for the host computer. In the list below, most of the commands are shown with the third letter as x. The x should be replaced by A if the command is for an azimuth parameter or with E for an elevation parameter. Certain parameters have been adjusted in the factory to work with the positioner supplied. This applies particularly to values for gear ratio, encoder pulses per revolution, and gains. These parameters should not be changed unadvisedly. Certain parameters may be written only when the controller is in REMOTE mode. This applies to mode, offset, point, and slew-velocity commands. Other than these commands, a parameter may be written at any time. It is recommended not to change control loop gains unless the positioner is in Standby mode. When a parameter is written with a normal write command, the change is made in RAM only. Parameter changes may be saved to EEPROM using the SAV command with value 1. Parameters have hard coded default values which will exist if the parameter has not been changed. These default values may also be restored by a SAV command with parameter 2. The values last stored in EEPROM may be restored by a SAV command with parameter 3, or by cycling power. Note: SAV 2 command is for factory use only, since the values restored may not be appropriate to the particular positioner to which the controller is connected. Parameter Limits For each parameter there are maximum and minimum values that will be accepted over the communication link. For angles, these values are +/-780 degrees. For velocities, the values are 0 to 10000 deg/sec. For other parameters, the limiting values are given with the command description. 4.5.3 Alphabetical command listing CBx Set value of control word #1. Bits in control word #1 have the following functions:

Value Function Bit

0=>CW feedback from motor = CW motion of axis 0 1=>CCW feedback from motor = CW motion of axis 1 1 2 3 2 4 8 4 16 5 6 32 64 7 8 128 256 0=>Positive command for CW rotation of axis. 1=>Negative command for CW rotation of axis Reserved (must be 0) 0=>Shutdown bit = 0 for shutdown 1=>Shutdown bit = 1 for shutdown Reserved (Must be 0). 0=>Limited range of rotation 1=>Continuous rotation axis 0=>Normal closed-loop control 1=>Open-loop test mode. In this case, the position feedback is ignored, and the velocity command output is 10 VDC * RVx/CVx. By changing the value of RVx, a step may be produced in the velocity command output for testing the response of the velocity loop. 0=>Normal Operation 1=>Unused Axis - Always in Shutdown 0=>Normal Operation 1=>Open-loop test mode. In this case, the position feedback is ignored, and the velocity command output is a trapezoid based on the parameters RVx, FSx, MAx, and RTx. The slope of the trapezoid is controlled by MAx, the height is 10 VDC*RVx/FSx, and the time of the flat top is RTx. The direction of the trapezoid alternates each cycle. This is used for testing the response of the velocity loop. Value must be from 0 to 511. CCx Set value of control word #2. Bits in control word #2 have the following functions:

Value Function Bit

0,1 0=>Display precision 0.1 degree 1=>Display precision 0.01 degree 2=>Display precision 0.001 degree 0-2 2 3 4 8 4 16 32 64 128 256 512 1023 2048 4096 5 6 7 8 9 10 11 12 0=>+/-780 deg display 1=>0-359.999 or +/-180 deg display 0=>No cable wrap display 1=>L,R or U,D cable wrap display 0=>Bidirectional Raster 1=>Single Direction Raster 0=>Raster Scan Once 1=>Continuous Raster Scan 0=>Soft Step in Point Mode 1=>Step at Full Speed in Point Mode Reserved (Should be 0) 0=>Normal Front Panel Display 1=>Front Panel Display Darkened 0=>9600 Baud on 2nd RS-232 Output 1=>19200 Baud on 2nd RS-232 Output 0=>0-359.999 deg display if bit 2 set 1=>+/-180 deg display if bit 2 set 0=>Full precision position on comm link 1=>Front Panel position on comm link 0=>No shutdown in Standby mode 1=>Motor amplifiers shutdown in Standby mode Value should be 0-8191. CDx CGx CLx CVx During a calibrate cycle, the positioner will operate at the go-to-limit velocity

(CGx) until the clockwise limit switch is activated, the zero indicating pulse is detected, or the maximum clockwise calibrate distance (CDx) is passed. It will then return at the calibrate velocity (CVx) until the zero-indicating pulse is observed and an index pulse occurs on the encoder. At that point, the angle will be set to equal the zero switch position (CLx). CDx sets the maximum clockwise calibrate distance in degrees. CGx sets the go-to-limit velocity, in degrees/sec. CLx sets the calibrate zero switch position, in degrees. EPx Motor encoder pulses per revolution of motor. Value must be from 1 to 1000000, with no decimal point. Default is 8000. FSx Full scale axis velocity. This is the velocity that would be achieved with 10 VDC velocity command to the amplifier (assuming no limitations due to back-EMF). It is used for converting velocity command outputs from degrees/sec to volts. FVx Front panel slew velocity from maximum joystick motion in coarse mode. Value between 0 and 10000 deg/sec. Value should be about 10-20% greater than the actual maximum velocity desired. GDx GNx The gear ratio of each axis is specified as a numerator and a denominator. GNx sets the numerator, GDx sets the denominator. Values must be from 1 to 1000000 for the numerator and 1 to 10000 for the denominator, with no decimal point. HMx Home position. Value from -720 to +720 degrees. This is the position that the axis goes to when it is placed in home mode. ILx Integral limit. Upper limit of velocity command from the integral error term in the PI position control loop. Integral error is defined as:

Ki * angle error dt Where Ki is the parameter specified below under KIx and angle error is the difference between actual and target angles. Units are in deg/sec. Value from 0 to 50. Lower limit of integral error is the same value with opposite sign. Note that the integral error term should be small relative the maximum velocity of the system. It serves primarily to correct for any zero offsets in analog components and is updated only when the position command and the position feedback are stable and when the closed loop error is within the integral window. IWx Integral window. The integral error term is updated by the integral gain only when the absolute value of the closed loop error is less than this parameter. Units are in degrees. KDx Feedforward gain in PI position control loop. The feedforward term provides a velocity command output equal to the derivative of the position command times the feedforward gain. Feedforward gain is a pure number. Normally, it is set close to 1. Value is from 0 to 2 KLx Lock gain in PI loop. Units are in 1/sec. When the positioner has arrived at its target position, within the range of the lock window, as specified by the parameter LWx, the gain is increased linearly from KPx to KLx as the error closes to 0. Value is from 0 to 20, and should normally be greater or equal to KPx. KPx Proportional gain in PI loop. Units are in 1/sec. Value is from 0 to 20 KIx Integral gain in PI loop. Units are in 1/sec/sec Value is from 0 to 20. 0 - Manual (not allowed) 1 - Standby 2 - Go to Point 3 - Go to Home 4 - Slew (Continuous Velocity) 5 - Calibrate 6 - Raster Scan LWx Lock window for use of lock gain (KLx) in place of proportional gain (KPx). Units are in degrees. MAx Maximum acceleration/deceleration. Units are in deg/sec/sec. Value is from 0.16 to 10,000.0. MDx Set operation mode. Value is as follows:

This command is accepted only when the ACU is in REMOTE mode. MNx Set minimum position. Units are in degrees. Value is from -720 to + 720 degrees. MOx Set maximum output from D/A chip. Units are fraction of full scale Value is from 0 to 1.0 MVx Set maximum velocity. Units are deg/sec. Value is 0 to 10,000 deg/sec. MXx Set maximum position. Units are in degrees. Value is from -720 to + 720 degrees. Note that for a continuous rotation axis, the minimum and maximum position should be set to less than -190 and greater than +190, respectively. OFx Set offset. Units are in degrees. Value is from -720 to +720 degrees. ACU must be in REMOTE mode to write offset. If positioner is moving, the velocity is first commanded to zero, and when the positioner stops, the offset is entered. Note: Offset for the azimuth may be also be set by the front-panel OFFSET pushbutton. In this case, a save to all parameters is performed. PTx Set pointing angle. This is the angle which will be used at the target in point mode. Units are in degrees. Value is from -720 to +720 degrees. This command is accepted only when the ACU is switched to REMOTE mode. RCx Raster scan center point in degrees. RDx Read command only. Read current angle. Value is in degrees. RDS Read status word. Value returned is 0 to 223-1; ie, 0-8388607, consisting of a sum of 23 status bits. Bits in the status word have the following values and meanings (refer to next page):

Value Meaning Bit#

0 1 2 3 4 5 6 7 8 9 10 11 12 1 2 4 8 16 32 64 128 256 512 1024 2048 4096 13 14 15 16 17 18 19 20 21 22 23-31 Unused 8192 16384 32768 65536 131072 262144 524288 1048576 2097152 4194304 Azimuth CW Limit Switch Active Azimuth CCW Limit Switch Active Azimuth Zero Limit Switch Active Azimuth Calibrated (see sec 2.1, CAL function) Azimuth Stuck (Full current, no motion) Azimuth Software CW Limit Active Azimuth Software CCW Limit Active Azimuth Encoder Fault Elevation CW Limit Switch Active Elevation CCW Limit Switch Active Elevation Zero Limit Switch Active Elevation Calibrated Elevation Stuck (Full current, no motion) Elevation Software CW Limit Active Elevation Software CCW Limit Active Elevation Encoder Fault Front Panel Switch Flickering EEPROM Memory Fault Detected Remote Mode Azimuth Joystick A/D Fault Elevation Joystick A/D Fault Azimuth Calibration Done Elevation Calibration Done RRx Raster scan range in degrees RTx RTA is the Raster Scan time delay at end of each azimuth scan in seconds. If bit #8 in control word #1 is set, RTx is the duration of the flat top of the trapezoidal open-loop velocity command output. RVx RVx is the Raster Scan velocity in deg/sec. If bit #6 or bit #8 in control word

#1 is set, RVx is the open loop velocity command output (bit #6) or the open loop velocity command output during the flat top of the trapezoid (bit #8). SAV Save/Restore commands. All other commands perform reads and writes on parameters in static RAM. Any changes made in this way will be lost when power is turned off unless they are saved to the EEPROM non-volatile memory. On powerup, if values exist in EEPROM they are used. If the EEPROM has never had values stored in it, or if a checksum error is found, the hard-coded default values are used. A SAV command with a value of 1 causes present values in RAM to be saved to EEPROM. A SAV command with a value of 2 causes default values to be restored to RAM. Note that any changes made and not yet saved to EEPROM are now lost. However, any values in EEPROM are still there and will be used next time power is cycled. Note that default values may be stored to EEPROM by a SAV 2 followed by a SAV 1 command. A SAV command with a value of 3 causes EEPROM values to be restored to RAM. STI Interval between status outputs on J6. Units are 1=2.5 msec. For example, for a status interval of 200 msec, STI parameter should be set to 80. SVx Slew velocity command. This sets the velocity in degrees/sec which will be used when Slew Mode is selected. This command is accepted only when the ACU is in REMOTE. UTx Maximum update time command. Sets time interval, in seconds, used to activate two consecutive the extrapolation algorithm is activated. Value must be between 0 and 10 seconds. the extrapolation algorithm for following a trajectory. the maximum update intervals are If time, time than less 5 TROUBLESHOOTING Is Mains Select Switch in proper position?

Is Fuse F1 OK?

Problem: No display, no LEDs, no motion on powerup Check:

Problem: Display OK but neither axis operates Check:

Is Safe/Operate switch on positioner in OPERATE mode?

Is AC Power Cord connected well?

Are cables W1 and W2 connected properly to the controller and the positioner?

Elevation axis does not operate Is Fuse F2 OK?

Problem: Azimuth axis does not operate Check:

Problem:

Check:

Problem:

Check:

Front Panel does not operate Is Fuse F3 OK?

Is Red Local LED lit? If not, press REMOTE/LOCAL switch to place in LOCAL mode. Red LED should light and Green LED should be turned off. Positioner motion is very slow FINE/COARSE switch should be in COARSE position for rapid motion. Problem:

Check:

Problem: Azimuth position reading is not correct after calibrate Check:

Problem: Azimuth axis creeps when Joystick is in zero Solution:

Problem:

After calibrate, place the controller in LOCAL mode by pressing the LOCAL/REMOTE button, point the Positioner in the azimuth direction where a reading of 0 is desired and press the offset button. Adjust small zeroing lever in the horizontal direction until no creep occurs. Elevation axis creeps when Joystick is in zero position position Solution:

Adjust small zeroing lever in the vertical direction until no creep occurs. 6 6.1 6.2 MAINTENANCE Amplifier Adjustment Verify the following settings:

T1 is at the maximum CW position. T2 is at the midpoint of the potentiometer range. Voltage Tests With respect to GND (TB1, pin 7), verify the following DC voltages:

With respect to GND (TB1, pin 8), verify the following DC voltages:

-12V +/- 0.3V

+5V +/- 0.25V

+12V +/- 0.3V TB1 (6) TB1 (5) TB1 (4) at at at 130V +/- 5V at TB1 (9) APPENDIX A AL-1642-3JB Host Software User's Guide 1. SOFTWARE The AL-1642-3JB Host Software is provided on an "as is basis", as an aid for the user, with no expressed or implied warrantees or guarantees of any kind. The following four files comprise the host software:

1) EGAVGA.BGI Loadable graphics interface file for VGA graphics routines. 2) KBRG.CF_ Configuration file for the host software. 3) KBRG.ST_ Configuration file for the host software. 4) HOST.EXE Executable code for the host software. 2. INSTALLATION 1) Copy the above four files into a directory on the hard disk (any name for the directory is acceptable). 2) Use the following procedure to run the software:

1) If COM1 is configured for communications, type HOST 1 and press ENTER key. 2) If COM2 is configured for communications, type HOST 2 and press ENTER key. 3) The Main Screen will be accessed (refer to Figure A-1) Note: The software has been run on a range of computers; from a 386DX operating at 33 MHz, without floating point coprocessor, running under DOS 5.0 to a Pentium II operating at 400 MHz running in a DOS window under Windows 95. Minimum computer requirements have not been established, but most likely a PC-XT or a lower compatible computer will not be capable of running the software. 3. MAIN SCREEN (Refer to Figure A-1) The Main Screen is divided into three sections:

1) Axes Numerical Display 2) Status Flag Display 3) Function Key Titles. The Axes Numerical Display section shows four parameters for each axis:

Point Command, Slew Velocity Command, Mode Command and Position Received. The displayed field shows the last command sent for each of these parameters, as received from the positioner. The Status Flag section of the main screen shows which flags are set from the RDS command to the AL-1642-3JB, along with titles to show their meaning. The Function Keys permit entry to the azimuth and elevation configuration screens (F1, F2;

respectively), setting of positioner azimuth and elevation modes (F3, F4; respectively), updating target point for point mode and slew velocity for slew mode (F7), and exiting from the program (F8). Before entering azimuth or elevation go-to-point mode, using F3 or F4, respectively; F7 should be utilized to introduce a target point, since otherwise the value of the target point will depend on the previous mode and last operation performed in this mode, and will not necessarily be that displayed on the screen under Azim-Point-Command or Elev-Point-

Command. When azimuth mode or elevation mode CALIBRATION is selected, using F3 or F4, respectively; the above sequence is begun again each time the command to enter the calibration mode is initiated. Figure A-1: Main Screen Azim Azim Azim Point Slew Mode Command Command Command 0.000 STATUS FLAGS AZ_CW_LIM = 0 AZ_STUCK = 0 EL_CW_LIM = 0 EL_STUCK = 0 AZ_CCW_LIM = 0 AZ_CW_SLIM = 0 EL_CCW_LIM = 0 EL_CW_SLIM = 0 AZ_ZERO_LIM = 0 AZ_CCW_SLIM = 0 EL_ZERO_LIM = 0 EL_CCW_SLIM = 0 AZ_CALIBR'D = 1 AZ_ENC_FAULT = 0 EL_CALIBR'D = 1 EL_ENC_FAULT = 0 SWTCHFLT=0 EEPRMFLT=0 AZADCFLT=0 ELADCFLT=0 REMOTE=1 AZCALDONE=1 ELCALDONE=1 CONFIG CONFIG MODE MODE SLEW VEL EXIT Elev Elev Elev Elev Point Slew Command Command Mode Position Command Received Azim Position Received 0.000 POINT 0.000 0.000 0.000 POINT 0.000 1 AZIM 2 ELEV 3 AZIM 4 ELEV 5 6 7 SETPOINT 8 PROGRAM 4. CONFIGURATION SCREENS (Refer to Figures A-2, A-3 and A-4) Each axis (azimuth or elevation) has its own set of configuration parameters. For a system that has never been configured, a set of default parameters are coded into the controller software. In addition, an EEPROM exists which allows the user to save the parameters he has configured. If parameters have been saved, they will be read from the EEPROM at powerup and used instead of the default parameters. Note that azimuth and elevation parameters are saved together; i.e., it is not possible to save the parameters for one axis only. To configure azimuth parameters, press the function key F1. The azimuth configuration screen will be loaded (refer to Figure A-2). Parameters are configured by entering the item number to the left of the parameter, and then entering the desired value. Values that are too large, too small, or of incorrect format will be rejected with an error message displayed, and the parameter will retain its previous value. To save the new parameter values, enter 55 from the keyboard. The software then initiates a command SAV1 and waits until the controller has reset the SAV parameter to zero, at which time a message "Save Confirmed" is displayed. To restore the default configuration values for the parameters, enter 66. The software initiates a command SAV2 and then displays the default values of the parameters. Note that the parameter default configuration is now restored to active use, but this does not affect the configurations that are stored in EEPROM. Also note that the default configuration may not be suitable for the positioner and load presently interfaced with the controller. (Therefore, care should be exercised when using the "66" command). To restore the parameter configuration held in the EEPROM, enter 77. The software then initiates the command SAV3 which restores the parameters to their last saved values. To exit the Configuration screen and return to the main screen, enter 88. To configure the Elevation parameters, press function key F2 on the main screen. A screen that is identical to the azimuth configuration screen, except for the title, is accessed

(refer to Figure A-3). Figure A-4 shows the azimuth or elevation configuration screen, correlated with the software remote command codes (refer to paragraph 4.5 in the main section of this manual). The lower case x is to be replaced by either A or E for azimuth or elevation axis, respectively. the parameters on Figure A-2: Azimuth Configuration Screen Default Parameter Values Azim Pedestal Parameters Azim Control Parameters 21. Maximum Acceleration.. 12.000 1. Gear Ratio Numerator... 36 22. Maximum Velocity...... 36.000 2. Gear Ratio Denominator. 1 23. Go-to-Limit Velocity.. 18.000 3. Encoder Pulses/Rev..... 8000 24. Calibrate Velocity.... 18.000 4. Control Bits Word #1... 32 25. Front Panel Velocity.. 36.000 5. Control Bits Word #2... 2149 26. Low Kp-Proport Gain... 0.997 6. Maximum Angle.......... +380.000 27. High Kp-Lock Gain..... 3.966 7. Minimum Angle.......... -380.000 28. High Kp Window........ 0.050 8. Home Position.......... 0.000 29. Kd-Differential Gain.. 1.000 9. Zero Switch Position... 0.000 30. Ki-Integral Gain...... 0.244 10. Offset................. 0.000 31. Integral Limit........ 5.000 11. Special Sts Interval... 80 32. Integral Gain Window. 500.000 12. Full Scale Velocity.... 42.000 33. Maximum Update time... 0.000 13. Maximum D/A Chip Output 1.000 14. Max CW Cal Movement.... 380.000 34. Raster Center......... 50.000 55. SAVE CONFIG TO EEPROM 35. Raster Range.......... 80.000 66. RESTORE DEFAULT CONFIG 36. Raster Vel............ 18.000 77. RESTORE EEPROM CONFIG 37. Raster Step........... 0.000 88. EXIT 38. Raster Scan Delay..... 0.000 Figure A-3: Elevation Configuration Screen Default Parameter Values ELEV Control Parameters ELEV Pedestal ParamS 21. Maximum Acceleration.. 12.000 1. Gear Ratio Numerator.... 36 22. Maximum Velocity...... 18.000 2. Gear Ratio Denominator.. 1 23. Go-to-Limit Velocity.. 3.000 3. Encoder Pulses/Rev...... 8000 4. Control Bits Word #1.... 0 24. Calibrate Velocity.... 10.000 25. Front Panel Velocity.. 18.000 5. Control Bits Word #2.... 2145 26. Low Kp-Proport Gain... 0.997 6. Maximum Angle........... 182.000 27. High Kp-Lock Gain..... 4.000 7. Minimum Angle........... -2.000 8. Home Position........... 0.000 28. High Kp Window........ 0.050 29. Kd-Differential Gain.. 1.000 9. Zero Switch Position.... 0.000 30. Ki-Integral Gain...... 0.244 10. Offset.................. 0.000 31. Integral Limit........ 5.000 11. Special Sts Interval.... 80 12. Full Scale Velocity..... 69.000 32. Integral Gain Window 500.000 33. Maximum Update time... 0.000 13. Maximum D/A Chip Output. 0.700 14. Max CW Cal Movement..... 20.000 34. Raster Center......... 20.000 55. SAVE CONFIG TO EEPROM 35. Raster Range.......... 40.000 66. RESTORE DEFAULT CONFIG 36. Raster Vel............ 18.000 77. RESTORE EEPROM CONFIG 37. Raster Step........... 5.000 88. EXIT 38. Raster Scan Delay..... 0.000 Note:

The above configuration screens list the DEFAULT values of the pedestal and control parameters for the Azimuth and Elevation Axes. Do not use these parameter values, since they may not be suitable for the positioner. Refer to the following Installation and Calibration Procedure configuration screens (Figures A-5 thru A-8) to determine which pedestal and control parameter values need to be adjusted. Figure A-4: Azimuth/Elevation Configuration Screen correlated with remote command codes Azim/Elev Pedestal Parameters Azim/Elev Control Parameters 1. Gear Ratio Numerator.... GNx 21. Maximum Acceleration..MAx 2. Gear Ratio Denominator.. GDx 22. Maximum Velocity......MVx 3. Encoder Pulses/Rev...... EPx 23. Go-to-Limit Velocity..CGx 4. Control Bits Word #1.... CBx 24. Calibrate Velocity....CVx 5. Control Bits Word #2.... CCx 25. Front Panel Velocity..FVx 6. Maximum Angle........... MXx 26. Low Kp-Proport Gain...KPx 7. Minimum Angle........... MNx 27. High Kp-Lock Gain.. KLx 8. Home Position........... HMx 28. High Kp Window........LWx 9. Zero Switch Position.... CLx 29. Kd Differential Gain..KDx 10. Offset.................. OFx 30. Ki-Integral Gain......KIx 11. Special Sts Interval.... STI 31. Integral Limit........ILx 12. Full Scale Velocity..... FSx 32. Integral Gain Window..IWx 13. Maximum D/A chip Output. MOx 33. Maximum Update time. UTx 14. Max CW Cal Movement..... CDx 34. Raster Center.........RCx 55. SAVE CONFIG TO EEPROM SAV1 35. Raster Range..........RRx 66. RESTORE DEFAULT CONFIG SAV2 36. Raster Vel............RVx 77. RESTORE EEPROM CONFIG SAV3 37. Raster Step...........RSx 88. EXIT 38. Raster Scan Delay.....RTx 5. INSTALLATIONS AND CALIBRATION PROCEDURE

(Refer to Figures A-5 thru A-8) 1) Install the positioner in an indoor environment. 2) Before connecting the controller to the positioner, use the Host computer program to verify that the configuration parameters installed in the controller memory are as listed in the applicable figure A5 thru A-8. 3) Connect the cables between the controller and the positioner. 4) Before installing the antenna and the counterweights, turn on the controller and verify that the positioner is moving smoothly and is completing the calibration procedure. Then, use the manual joystick to check the elevation software limits. (The down limit should be 2 degrees, and the upper limit should be 110 degrees). 5) Manually point the elevation axis to 90 degrees. 6) Install the arms on the positioner. 7) Install the correct number of counter weights on the back of the antenna arms as previously determined for the antenna unit. 8) Install the antenna on the positioner. 9) Point the antenna to 0 degree. 10) Connect a dc current probe on the F3 wire, and measure the current. The current should be between 0 +/-0.5 amps. If the current exceeds this value, correct the antenna balance by adjusting the counterweights (adding or removing counterweights). After completing steps 1 through 10, you can operate the positioner under load. You must observe positioner movement for both axes and verify that the operation is smooth, with no oscillations or jerking. In case of un-smooth movement, stop the positioner operation IMMEDIATELY and recheck the applicable configuration parameters and the antenna CAUTION balance. 11) Rotate the elevation axis between 0 degrees and 180 degrees. Verify that the current on the F3 wire does not exceed 1.0 amp. (When changing the rotation direction, more current may be present for a short duration of time). 12) Rotate the azimuth axis in continuous rotation. Verify that the current on the F2 wire does not exceed 1.0 Amp. 13) Operate the azimuth and elevation axes in POINT mode. Verify that both axes arrive at the desired position, with smooth deceleration and no overshoot. If overshoot occurs, configuration parameter 12 (Full Scale Velocity) may be increased or decreased up to 5 percent of the value. Do not exceed the +/-5% tolerance for the values stated in Step 13. CAUTION 6. AL-4017-1EBS-B Positioner Configuration Parameters Note:

The following parameters are listed as they appear on the computer screen. Figure A-7: Azimuth Configuration Screen for AL-4017-1EBS-B Positioner Azim Pedestal Parameters Azim Control Parameters 21. Maximum Acceleration.. 12.000 1. Gear Ratio Numerator... 36 22. Maximum Velocity...... 36.000 2. Gear Ratio Denominator. 1 23. Go-to-Limit Velocity.. 18.000 3. Encoder Pulses/Rev..... 8000 24. Calibrate Velocity.... 18.000 4. Control Bits Word #1... 32 25. Front Panel Velocity.. 36.000 5. Control Bits Word #2... 2149 26. Low Kp-Proport Gain... 0.997 6. Maximum Angle.......... +380.000 27. High Kp-Lock Gain..... 3.966 7. Minimum Angle.......... -380.000 28. High Kp Window........ 0.050 8. Home Position.......... 0.000 29. Kd-Differential Gain.. 1.000 9. Zero Switch Position... 0.000 30. Ki-Integral Gain...... 0.244 10. Offset................. 0.000 11. Special Sts Interval... 80 31. Integral Limit........ 5.000 12. Full Scale Velocity.... 42.000* 32. Integral Gain Window. 500.000 13. Maximum D/A Chip Output 1.000 33. Maximum Update time... 0.000 14. Max CW Cal Movement.... 380.000 34. Raster Center......... 50.000 55. SAVE CONFIG TO EEPROM 35. Raster Range.......... 80.000 66. RESTORE DEFAULT CONFIG 36. Raster Vel............ 18.000 77. RESTORE EEPROM CONFIG 37. Raster Step........... 0.000 88. EXIT 38. Raster Scan Delay..... 0.000

* This number may vary by +/-5%, depending on the tacho voltage level. CAUTION Do not exceed the +/-5% tolerance for the value stated in Parameter No. 12 (Full Scale Velocity). Oscillation may result from exceeding the 5% tolerance. Figure A-8: Elevation Configuration Screen for AL-4017-1EBS-B Positioner ELEV Control Parameters ELEV Pedestal ParamS 21. Maximum Acceleration.. 12.000 1. Gear Ratio Numerator.... 36 22. Maximum Velocity...... 18.000 2. Gear Ratio Denominator.. 1 3. Encoder Pulses/Rev...... 8000 23. Go-to-Limit Velocity.. 3.000 4. Control Bits Word #1.... 0 24. Calibrate Velocity.... 10.000 5. Control Bits Word #2.... 2145 25. Front Panel Velocity.. 18.000 26. Low Kp-Proport Gain... 0.997 6. Maximum Angle........... 182.000 27. High Kp-Lock Gain..... 4.000 7. Minimum Angle........... -2.000 28. High Kp Window........ 0.050 8. Home Position........... 0.000 9. Zero Switch Position.... 0.000 29. Kd-Differential Gain.. 1.000 30. Ki-Integral Gain...... 0.244 10. Offset.................. 0.000 31. Integral Limit........ 5.000 11. Special Sts Interval.... 80 32. Integral Gain Window 500.000 12. Full Scale Velocity..... 69.000*

13. Maximum D/A Chip Output. 0.700 33. Maximum Update time... 0.000 14. Max CW Cal Movement..... 20.000 34. Raster Center......... 20.000 55. SAVE CONFIG TO EEPROM 35. Raster Range.......... 40.000 66. RESTORE DEFAULT CONFIG 36. Raster Vel............ 18.000 77. RESTORE EEPROM CONFIG 37. Raster Step........... 5.000 88. EXIT 38. Raster Scan Delay..... 0.000

* This number may vary by +/-5%, depending on the tacho voltage level. CAUTION Do not exceed the +/-5% tolerance for the value stated in Parameter No. 12 (Full Scale Velocity). Oscillation may result from exceeding the 5% tolerance. APPENDIX B AL-1642-3JB (BS-104435) CONTROLLER DRAWINGS:

DRAWINGS Figure B-1: WIRING DIAGRAM Figure B-2: TOP ASSEMBLY Figure B-3: FRONT PANEL Figure B-4: REAR PANEL Figure B-5: BLOCK DIAGRAM

Dwg. No. BS-104435-1 Dwg. No. BS-104435-2 Dwg. No. BS-104435-3 Dwg. No. BS-104435-4 Dwg. No. BS-104435-5 Figure B-1: WIRING DIAGRAM

- Dwg. No. 19-0350 Figure B-2: TOP ASSEMBLY

Dwg. No. 19-0354-9/2 Figure B-3: FRONT PANEL

Dwg. No. 19-0351-9/2 Figure B-4: REAR PANEL

Dwg. No. 19-0352-9 Figure B-5:

BLOCK DIAGRAM

- Dwg. No. 20-0094 RDACS Users Guide August 2000 i RDACS Users Guide August 2000 Table of Contents 1. Introduction.. 2. RDACS Terminal Window. 3. RDACS Config. 3.1 File Pull-Down Menu.. 3.2 Connect Commands.. 3.3 A-Scope Commands.. 3.4 Control Commands 3.5 Configuration Commands 4. Configuration Commands.. 5. Installing RDACS.. 6. The radacs.ini Configuration File. 6.1 Start-Up Section. 6.2 Master Section 6.3 Site Section.. 6.4 RadPgmN Section.. 6.5 Antenna Sections... 6.6 LevelN Section 6.7 ModeN Section 6.8 AntennaCmds Section.. 1 2 3 3 4 5 8 17 36 39 41 45 50 53 57 63 67 70 91 ii RDACS Users Guide August 2000 Preface This manual describes the operating procedures for Baron Services RDACS software program that is delivered with the Neighborhood Radars Document Organization The information in this manual is organized as follows:

Section 1 describes the RDACS Terminal Window, which acts as the radar systems log and provides a few controls.

Section 2 describes the RDACS Config utility, which lets you perform a limited number of system controls from the Radar Control dialog box.

Section 3 is a step-by-step procedure for accessing RDACS controls while operating FasTrac.

Section 4 describes the installation instructions for RDACS. Related Documentation The following manual provides in-depth information about RVPtty:

RVP7 Digital IF Receiver and Doppler Signal Processor Users Manual. Describes the operating and troubleshooting procedures for SIGMET, Incs. RVP7 Doppler Signal Processor. Type Faces Italic: Indicates a document title, the first occurrence of a new term, a directory or file name, or a system response that explains what the system is doing. For Example: The monitor displays current parameters. iii RDACS Users Guide August 2000 Bold: Indicates an item in the graphical interface, such as the OK button or a command button. Courier: Indicates information you type. For example: Set the signal processor parameters by typing: SOPRM Symbols The following document conventions are used throughout this manual:

Information that is not critical to system operation but describes useful procedures or information that will optimize system operation. Very important about a command or a procedure. Critical instructions that must be followed to prevent injury or loss of data. iv RDACS Users Guide August 2000 Keyboard Conventions Alternate key. For example, ALT+x means hold down the Alternate key and press x. Control key. For example. CTRL+c means hold down the Control key and press c. Delete key. Return/enter key. Escape key. Shift key. Tab key. v ALT CTRL DEL Enter ESC SHIFT TAB RDACS Users Guide August 2000 Click Double Click Drag Enter Identify Press and hold Scroll Select Type Terminology To position the pointer on the screen, and then to press and quickly release the left mouse button. To quickly press and release a mouse button twice without moving the mouse. This action is used as a shortcut for common actions, such as activating an icon, opening a file, or selecting a word or a graphic element. To press and hold a mouse while moving the mouse. This action is used to identify a range of objects, to move objects, or to resize objects. To input information by typing or by using the mouse. To locate an element on the screen either by clicking it or by typing the name. To press and hold down a mouse button to perform an action, such as resizing a window. To move through text or graphics To click a button, a text box, an item in a list, or some other item on a dialog box, menu, or window. To key in data. To complete this action, you may also need to click OK, press ENTER, or press TAB. What to Expect from this Document This document describes how to install, start, and run the RDACS program. vi RDACS Users Guide August 2000 1. Introduction This manual describes the Radar Acquisition and Control System (RDACS), which gives users remote control over many radar system operations. The remainder of this manual is comprised of four main sections:

1. The RDACS terminal window, which is accessed by Start BSI RDACS. 2. The Radar Control dialog box, which is accessed by Start BSI Config RDACS. 3. The RDACS window that is installed in FasTrac. 4. The RDACS installation instructions. 1 RDACS Users Guide August 2000 2. RDACS Terminal Window The RDACS terminal window acts as the radar systems log and provides few controls. The main display lists the time and type of radar system commands. The commands can be issued from Config RDACS or from FasTrac real-time operations. The following window displays when you select Start taskbar on bottom of your terminal screen.) RDACS. (Start is located next to the BSI The File menu has only one subcommand, Exit. The Misc menu has three subcommands: Gparm, Log scans, and List users. 1. Gparm accesses the status information for the radar system. 2. Log scans displays information about a complete antenna scan similar to the following: Scan complete: 39 seconds, 361 rays, 0 too big, small 1.0, large 1.0 3. List users displays the following information about users who are remotely logged into your systems RDACS: ID, State, User name, Address, Log-In time, and Log-Out time. 2 RDACS Users Guide August 2000 3. RDACS Config The RDACS Config utility lets you perform a limited number of system controls from the Radar Control dialog box, which is accessed by selecting Start RDACS. Config BSI 3.1 File Pull-Down Menu The File pull-down menu has only two options: About and Exit. Select File open a message box that indicates the name of the software package, the version number, and the copyright date. Click OK to dismiss the message box. Select File Exit to terminate the RDACS Config session. About to 3 RDACS Users Guide August 2000 Disconnect to end remote control mode. 3.2 Connect Commands The Connect commands let you remotely view and control another sites RDACS. Select Connect A connect to RDACS dialog box, similar to the one shown below, displays when you Connect. You must know the server name or address, your user select Connect name, your password, and the port designator to connect remotely to RDACS. See your System Administrator for the required inputs. Auto connect. This dialog box lets you log onto the specified server A Connect to RDACS dialog box, similar to the one shown below, displays when you select Connect to remotely view and control RDACS. The controls on this dialog box are similar to the Connect to RDACS dialog box, except you automatically are connected to the specified server when you start up RDACS and you cannot save your password. 4 RDACS Users Guide August 2000 3.3 A-Scope Commands The A-Scope commands let you configure the A-Scope presentation of return data, in signal strength and in either distance or in time. You can use the A-Scope commands to display three types of radar data (reflectivity, velocity, and spectrum width) and to set the display limits. 3.3.1 A-Scope Settings The A-Scope displays the radar data, where the horizontal axis (X) displays time and the vertical axis (Y) displays signal strength. The A-Scope Settings command lets you configure the display shown when you select A-Scope The following, double-tabbed dialog box displays when you select Oscilloscope Settings:

Enable. 5 RDACS Users Guide August 2000 This Base Products section of this dialog box lets you select which radar products will be shown on the A-Scope display. When you select a radar product, you must either select the Data shown in display level units option to enable the default values or key in the Low Y and High Y values. Control Description Reflectivity Velocity Spectrum Width Data shown in display level units OK Cancel Enables the computer algorithms that measure the linear radar reflectivity factor (z) in m6/m3. Enables the computer algorithms that measure the winds in the atmosphere. Enables the computer algorithms that transform time-series data into the frequency domain. In other words, it determines the average frequency as well as the distribution of frequencies, thus providing data about storm turbulence. You must select this option to enable Default option. Accepts your changes, and returns you to the main RDACS dialog box. Ignores any changes, and returns you to the main RDACS dialog box. The X Scale portion of the dialog box controls the A-Scopes horizontal display. You must either select the Auto Scale option or specify the Low X and High X values. 6 RDACS Users Guide August 2000 Control Auto Scale Low X High X Units OK Cancel Description Automatically controls the low and high range for the horizontal axis. When selected, the Low X and High X fields are disabled. Specifies the lowest range for the horizontal axis. Specifies the highest range for the horizontal axis. Specifies the unit for the horizontal axis measurements:

miles, nautical miles, kilometers, or microseconds. Accepts your changes, and returns you to the main RDACS dialog box. Ignores any changes, and returns you to the main RDACS dialog box. 7 RDACS Users Guide August 2000 3.3.2 A-Scope Display An A-Scope Display, similar to the one pictured below, appears when you select A-

Scope Enable. It is a real-time display, reflecting the parameters you set under A-

Scope Settings. Select A-Scope Disable to remove the display and to return to the main Radar Control dialog box. 3.4 Control Commands The Control Commands let you set most of the radars controlling parameters, as described in the following subsections. Remember, some of the controls can also be changed by:

1. Editing the rdacs.ini file. 2. Performing real-time system manipulations in the FasTrac program. In either case, the last issue change is the one under which the radar system operates. 8 RDACS Users Guide August 2000 3.4.1 Quick Control A Quick Control dialog box, similar to the one shown below, displays when you select Quick. Observe the RDACS display when you issue commands form this Control dialog box, and verify that the system is operating as expected. Control Range Description Defines the maximum distance from the radar antenna to the target. You may specify the range measurement in miles, kilometers, or nautical, miles. If you have a single or double-pulse Doppler radar, range is usually 75 miles. If your system is in Log mode, range is usually 300 miles. Remember, the lower the range, the higher the resolution for closer targets. If you set a range that is greater than the maximum allowed for your radar type, RDACS uses the maximum valid range and displays the correct value. 9 RDACS Users Guide August 2000 Control Skip Mode Description Sets the radar sampling skip distance in miles. For example, a value of 2.5 means that data sampling begins 2.5 miles from the radar. Use this option to remove the display of the strong signal that is received just after the radar pulse is transmitted. A typical value for Skip lies between 0.5 to 5.0 miles (the default value is 1.0). Controls the system mode as selected from the pull-down menu: Not all modes are available for all radars. Only the available modes are displayed. Power Down turns off the radar electronics. It may take several minutes before the radar cools and the power is removed. Standby turns off the transmitter (it no longer radiates), while the radar electronics remain on. Log places the radar in long-pulse mode, which is up to 300 miles in range and provides no velocity product. Log + Turb places the radar in log mode, and the system displays turbulence from the receiver data. Long Pulse places the radar in long pulse mode, which is up to 300 miles in range. Single PRF places the system in single-pulse Doppler mode. Range is set to 75 miles and the pulse tolerance is set to +/- 16 s. VHD places the system in Very High Definition (dual-pulse) Doppler mode. Range is set to 49 miles, and pulse tolerance is set to +/- 38 s. Dual PRF places the system in dual-pulse Doppler mode. Range is set to 75 miles, and the pulse tolerance is set to

+/- 32 s. No Radiate turns off your radar system. It may take several minutes before the transmitter cools and power is removed. 10 RDACS Users Guide Control Description August 2000 Defines the antenna Scan mode: PPI, Stop, Sector, or RHI. PPI (plan position indicator) mode displays a 360-

degree sweep in azimuth at the specified elevation angle.

(This is the normal operating modes) Stop scans weather only within the specified azimuth and elevation levels. This mode is useful for investigating a particular storm cell. RHI (range-height indicator) shows the distance from the radar at the specified azimuth angle and displays the height above the radar on the vertical axis, from El 1 to El 2. (Note that RHI exaggerates the vertical size of an echo, giving a distorted impression of the actual storm. The angular resolution of the radar increases as the beamwidth decreases, so the narrower the beam, the lesser the size of the echo.) Sector performs a pie-shaped track at the set azimuth, within the specified span, at the set elevation level. Puts the new specifications into operations, and returns you to the main Radar Control window. Ignores any changes you have made, and returns you to the Main Control window. Antenna Apply Close 3.4.2 Extended Control The Extended Control dialog box is similar to the Quick Control dialog box described in Section 1.4.1 except you have two additional options: Preferred Product and Duration. 11 RDACS Users Guide August 2000 Preferred Product lets you specify which algorithms the computer applies to the decluttered, dealiased, and range-unfolded return data to produce the selected product. You can select the following items from the pull-down menu: No preference, Log intensity, Linear intensity, Velocity, or Turbulence. 1. No preference indicates that clean, quality-checked return data will be displayed. 2. Log Intensity measures reflectivity in logarithmic values. Z is the logarithmic reflectivity factor measured in units of dBZ (decibels relative to a reflectivity 1 mm6/m3 ) 3. This is a convenient method for compressing reflectivity measurements to numbers that are more convenient than the larger values of the corresponding linear intensity measurements. 4. Linear intensity measures the linear radar reflectivity factor (z) in m6/m3. 5. Velocity measures the winds in the atmosphere. 6. Turbulence measures velocity variances that exceed set thresholds. The higher the variance, the greater the turbulence. 7. Duration specifies the transmitters pulse duration measured in the specified units: seconds or cycles. 12 RDACS Users Guide August 2000 A dialog box similar to the one shown below, displays when you select Control Extended:

3.4.3 Program Control A dialog box similar to the one shown below, displays when you select Control Program:

13 RDACS Users Guide August 2000 Control Program List OK Cancel Edit Insert Delete Move Up Description Displays saved programs Accepts your changes, and returns you to the main RDACS dialog box. Ignores any changes, and returns you to the main RDACS dialog box. Lets you modify program parameters. Lets you introduce a new program. Deletes the selected program. Moves you up through the program list. Moves you down through the program list. Move Down 3.4.4 Inputs and Outputs The Input/Output control combines several functions:

1. The User Defined options let you test the Digital Signal Processors input and output buses. If everything is working correctly, the Fault indicator will remain unlit. 2. The Radiate command lets you turn on the transmitter. 3. The Fault, Filament ready, and Airflow Good indicators let you monitor system status. These indicators do not change dynamically after you open the Input/Output dialog box. You must press the Refresh Status button to update the status indicators. 4. The Reset Modulator sends a reset pulse to the modulator circuitry. This normally clears any system fault interlock logic. (If the fault condition persists, the fault interlock logic may cause a new fault again.) 14 RDACS Users Guide August 2000 A dialog box, similar to the one shown below, displays when you select Control Input/Output:

3.4.5 Resample Noise There are two types of input signals to the receiver: the signal from a particular target and the signal generated by the radar system, which is referred to as noise. The Resample Noise command measures the receiver noise so it can be subtracted from subsequent measurements. During the resampling process, the internal trigger generator is temporarily set to a special noise rate that is usually much lower than the operating rate. You must verify that no returned power is present within the sampling interval. You may have to raise the antenna during resampling to avoid thermal noise from the ground or from weather targets. After power-up, you should issue this command at least once before the system begins to receive and process data. You should also occasionally issue the command to compensate for drift, both in the radio frequency system and in the analog-to-digital converter system. Finally, you must reissue the Resample Noise command when you change the rate or range. 15 RDACS Users Guide August 2000 When you issue the Resample Noise command, lines similar to the ones shown below appear on the RDACS terminal display. Free run stopped SNOISE: Noise=1609 DiagA=0000 DaigB=0000 Imm1=42A0 Imm2=0301 Latch=0000 Free run started The following list describes each word in the listing:

Parameter Description Noise DiagA DaigB Imm1 Imm2 Latch Indicates the log of the measured noise level. Indicates the measured DC offset for the I channel. Indicates the measured DC offset for the Q channel. Indicates if failures were detected during noise sampling. Check command to verify that everything is working correctly. If failures are detected during the noise measurement, status bits will be set in the Latch word. 16 RDACS Users Guide August 2000 3.4.6 Status A current status listing, similar to the one shown below, displays when you select Status. The displayed data are accessed from the Digital Signal Processor Control

(the RVP7) and are described in the Get Processor Parameters section in the RVP7 Digital IF Receiver Users Manual. 3.5 Configuration Commands The Configuration commands let you specify the site parameters, control the antenna, and edit the RDACS.ini file. 17 RDACS Users Guide 3.5.1 Configuration Site Parameters The following dialog box displays when you select Configuration Sites:

August 2000 While most of the dialog box controls are user-definable, the fields are set during system configuration and should not be changed. The parameters correspond to the Site section of the radacs.ini file. The bottom three fields, Radar Type, Version, and Protocol, are read-only parameters that are set by the software. Review the site parameters, and click OK to dismiss the dialog box. 18 RDACS Users Guide August 2000 3.5.2 Antenna Control Settings The Antenna Control Settings dialog box controls the speed and direction of the radar antenna, as well as the data sample interval and offset rates. The following dialog box displays when you select Configuration Antenna:

The controls are self-explanatory. When you click OK to accept your changes, note that an Antenna command is reflected in the RDACS display. The commands input from the Antenna Control Settings dialog box correlate to the Antenna section in the rdacs.ini file, as shown below. 19 RDACS Users Guide 3.5.3 Editing the rdacs.ini File August 2000 The Edit Rdacs.Ini dialog box displays when you select Configuration RDACS.Ini. The top leftmost drop-down menu lets you select a section in the rdacs.ini file, which you can then view and edit, as required. The rdacs.ini file has several sections: Startup, Master, Site, RadPgm0, RadPgmAntennaStuck, CrossRefTables, six Mode tables, ModeDefault, five Level tables, Antenna, and AntennaCmds. Regardless of which section you choose to edit, there are three controls: Save/Apply, Save, and Exit. Save/Apply saves your edits and puts them into operation immediately. Save saves your edits, but they will not become effective until the next time you enter RDACS. Exit ignores your edits, asks if you want to save your edits, terminates the editing session, and returns you to the Radar Control dialog box. Section lines beginning with the # character are notes that provide important information about parts of the rdacs.ini file. The following paragraphs describe each section of the radacs.ini file. While most parameter values are not specified, important values that should be included in the rdacs.ini file are specified. 20 RDACS Users Guide August 2000 Startup Section NumUsers=

WatchDogType= Set to any value from 0 to 20 (0 disables WatchDog). When Watchdog detects that the I/O interface between the Digital IF Receiver and the RDACS computer is malfunctioning for the specified time (in seconds), the system performs a complete reset operation. TcpNoDelayUsers=

AntennaMoveTimeout=

#DIOPort=O

#DIOPort=0x02a8 DIOPort=

Logscans=

AutoFaultResetDelay=

Master Section CfgVersion=

# do not change the next three while rdacs runningNumModes NumLevels=

NumRadPgmS

# do not change the next three while rdacs running RangeResolution0=

RangeResolution1=

RangeResolution2=

RangeResolution3=

# always set to 1 SepNoiseLevels=l

# if 1, use defaults in rvp NoNoiseCmds=

21 RDACS Users Guide August 2000 Site Section The Site section of the rdacs.ini file contains many of the parameters described in Section 2.5.1, Configuring Site Parameters. These items, which are either set at system installation or are set by the software, should not be changed. RadPgm0 Section

# the mode on startup Title=

NumSteps=

AntOp0=

# this is the RdpModeNum Mode0=0xl Range0=

Skip0=

Duration0=

Az0=

E10=

EndPt0=

22 August 2000 RDACS Users Guide RadPgmAntennaStuck Section Title=Antenna Stuck NumSteps=

AntOp0=

# this is the RdpModeNum Mode0=0xO Range0=

Skip0=

Duration0=

Az0=

E1O=

EndPt0=

CrossRef Tables Section

# this section notes the mode to rdpmode xref

# it is not used by rdacs mode0=rdpmode4 powerdown mode1 =rdpmode0 standby mode2=rdpmode1 long pulse mode3=rdpmode2 single prf mode4=rdpmode3 dual prf mode5=rdpmode5 clear air

# level tables:

level0=reflectivity 5-75 dBZ level1=speed for width, level2=speed for single prf +/- 20 kts level3=speed for dual prf +/- 99 kts level4=reflectivity for clear air -28 to 28 dBZ 23 RDACS Users Guide August 2000 Mode0 Section RdpModeNum=4 Name =PowerDown Radiate=

PowerUp=

Mode1 Section RdpModeNum=0 Name=Standby Radiate=0

#force reset forces a modulator reset when

# mode is entered ForceReset=l 24 RDACS Users Guide August 2000 Mode2 Section LogThreshold=Sets the upper limit for reflectivity values. Reflectivity values below this number may be discarded. This value is always positive. CalRef1=

RdpModenUM=1 Name=LongPulse Radiate=

RAvail=

VAvail=

WAvail=

PRF=

Pulselndes=

Unfold=

FilterRange0=

Filterlndex0=

FilterRange1=

FilterIndex1=

FilterRange2 =

Filterlndex2=

FilterRange3=

Filterlndex3=

SampleSize=Specify from 1 to 256 pulses. CMS=usedefault Lsr=usedefault Dsr=usedefault Ccorthreshold=usedefault SqiThreshold=usedefault SigThreshold=usedefault ThCt1Uncorr=usedefault ThCt1Corr=usedefault ThCt1Vel=usedefault ThCt1Width=usedefault 25 RDACS Users Guide August 2000 Mode3 Section RdpModeNum=2 Name=Single PRF Radiate=

Vlevel=

RAvail=

VAvail=

WAvail=

PPF=

PulseIndex=

Unfold=

FllterRange0=

Filterlndex0=

FilterRanqe1=

Filterlndex1=

FilterRange2=

Filterlndex2=

FilterRanqe3 =

Filterlndex3=

SampleSize=Specify 1 to 256 pulses. CMS =

Lsr=

Dsr=

LogThreshold=

CcorThreshold=usedefault SqiThreshold=usedefault SigThreshold=usedefault CalRef1=usedefault ThCt1Uncorr=usedefault ThCt1Corr=usedefault ThCt1Vel=usedefault ThCt1Width=usedefault 26 RDACS Users Guide August 2000 Mode4 Section RdpModeNum=3 Name=Dual PRF Radiate VLevel=

RAvai1=

VAvail=

WAvail=

PRF=

PulseIndex=

Unfold=

FilterRange0=usedefault Filterlndex0=usedefault FilterRange1=usedefault FilterIndex1=usedefault FilterRange2=usedefault Filterlndex2=usedefault FilterRanqe3=usedefault Filterlndex3=usedefault SampleSize=usedefault CMS=usedefault Lsr=usedefault Dsr=usedefault LogThreshold=

CcorThreshold=usedefault SqiThreshold=usedefault SigThreshold=usedefault CalRef1=

ThCt1Uncorr=usedefault ThCt1Corr=usedefault ThCt1Vel=usedefault ThCt1Width=usedefault 27 RDACS Users Guide August 2000 Mode5 Section LogThreshold=

CalRef1=

RdpModeNum=5 Name=NoRadiate Radiate=

RAvail =

VAvail =

WAvail=

PRF=

PulseIndex=

Unfold=

FilterRange0=

Filterlndex0=

FilterRange1=

Filterlndex1=

FilterRange2=

Filterlndex2=

FilterRange3=

Filterlndex3=

SampleSize= Specify 1 to 256 pulses. CMS=usedefault Lsr=usedefault Dsr=usedefault CcorThreshold=usedefault SqiThreshold=usedefault SigThreshold=usedefault ThCt1Uncorr=usedefault ThCt1Corr=usedefault ThCt1Vel=usedefault ThCt1Width=usedefault 28 RDACS Users Guide August 2000 ModeDefault Section

# O=standby l=log 2=singleprf 3=dual 4=powerdown 5=user... RdpModeNum=

# mode name in fastrac and config menus Name=Default

# set if mode should radiate Radiate=

PowerUp=

# leveln table to use for color levels

# R, V, W=reflectivity, velocity, and width RLevel=

VLevel=

WLevel=

# what products are available RAvail=

VAvail=

WAvail=

# pulse width code, typ: O=2s l=.8s 2=user 3=user PulseIndex=

# trigger frequency PRF=

# maximum number of range bins ReqNumBins=

# number of bins to average to product final bin SamplesPerBin=

# up to 4 filters, range is in km. Index is 0 for # off, or 1 to 7 for increasing filtering. Lower # numbered filters should have lower ranges FilterRange0=

IndexRange0=

FilterRange1=

IndexRange1=

FilterRange2=

IndexRange2=

FilterRange3=

IndexRange3=

# procmode=1 sync command mode, =2 dynamic angle sync

# normally set to 2 ProcMode =

# unfold 0=none, 1=2:3, 2=3:4, and 3=4:5 Unfold=

29 RDACS Users Guide August 2000 ModeDefault Section

# number of pulses to average SampleSize= Specify 1 to 256 pulses.

# 0=horiz, 1=vert, 2=alternate Polar=

# clutter microsupprresion CMS=

# use three lag algorithms for width, signal power, and clutter correction R2=

# pulse end ray End=

# reflectivity speckle removal Lsr=

# doppler speckle removal Dsr=

# rangle normalization and enables gas attenuation correction Rnv=

# logslope typ=0.03 LogSlope=003

# logthreshold (must be >=0) LogThreshold=

# clutter correction threshold CcorThreshold=

# signal quality index threshold SqiThreshold=

# signal power threshold SigThreshold=

# calibration reflectivity CalRef1=

# see SOPRM input 10 doc 30 RDACS Users Guide August 2000 ModeDefault Section TopMode=Specifies the processing mode, where 0000 Pulse Pair Processing; 0001 = FFT Processing; and 0010 Random Phase Processing. AGCNumPulses=Specifies the number of pulses during one AGC integration period. Window=Specifies the type of window that is applied to time series data where 0 Rectangle; 1=Hamming; and 2=Blackman. ZER=Set to 1 to zero the clutter filters internal state variables before the delay time has elapsed. FilterStabDly=Specifies time delay before processing the next data ray. Used when dual-PRF velocity is enabled or when RVP7 has been reconfigured by user commands.

# typ thctl vals: ffff = all pass, 0000 = all fail

# AAAA=log 8888=log & ccor AOAO=log & sqi

# weights sig: 8 sqi: 4 ccor: 2 log: 1 ThCt1Uncorr=

ThCt1Corr=

ThCt1Vel=

ThCt1Width=

ThCt1ZdrRefl=

# normally leave tag inverts 0 InvTagLow= 0 InvTagHigh= 0

# gas atten GasAtten=Specifies the value for atmospheric attenuation, measured in dB/kin. When the water vapor is higher than this value, attenuation will be higher.

# zdr cal ZdrCal0ff set = Specifies reflectivity depolarization ratio.

# radar wavelength Wave length=Specifies the distance that the radar wave within one cycle.

# use uncorrected (no range correction) ref1 productRUseUncorr=

31 RDACS Users Guide August 2000 Level0 Section

# types 0=refl 1=speed Type = 0 Name=Log Units = dBZ 1=5 2=10 3=15 4=20 5=25 6=30 7=35 8=40 9=45 10=50 11=55 12=60 13=65 14=70 15=75 LeveI1 Section Type = 1 Name=Width Units=knots 1=2 2=4 3=6 4=8 5=10 6=12 7=14 8=16 9=18 10=20 11=24 12=26 13=28 14=30 15=32 32 RDACS Users Guide August 2000 Level 2 Section Type = 1 Name=Single PRF Vel Units=knots 1=-20 2=-17 3=-14 4=-11 5=-8 6=-5 7=-2 8=0 9=2 10=5 11=8 12=11 13=14 14 =17 15=20 Level3 Section Type=1 Name=Dual PRF Vel Units=knots 1=-99 2=-64 3=-5O 4=-36 5=-26 6=-20 7=-1O 8=0 9=10 10=20 11=26 12=36 13=50 14=64 15=99 33 RDACS Users Guide August 2000 LeveI4 Section Type= 0 Name=Clear Air Units =dBZ 1=-28 2=-24 3=-20 4=-16 5=-12 6=-8 7=-4 8=0 9=4 10=8 11=12 12=16 13=20 14=24 15=28 34 RDACS Users Guide August 2000 Antenna Section Type=Orbit AzSpeed=45.0 ElSpeed=6.0 AzSampleStep=1.0 AzOffset=90.0 ElOffset=0.0 Port=1 ElSampleStep=0.5 IsClockwise=1 AntennaCmds Section InitCmd1=C [500d]

#xCP vel4 acc3 boost2 prop3 inte3 diff3 zero1

#InitCmd2=ACPOO4O/200/05/006/000/350/0[r] [500d]

#InitCmd3=ECPOO4O/200/05/030/005/350/0[r] [500d]

InitCmd2=ACPOO4O/100/05/030/040/350/0[r] [500d]

InitCmd3=ECPOO2O/100/05/055/125/350/0 [r] [5OOd]

#xCL offlset5 dowrn-ccw5 up-cw5 zero1 InitCmd4=ACL [azoff] /00000/00000/000[r] [500d]

InitCmd5=ECL [eloff] /35800/09500/000[r] [500d]

AzFullCmd=G1V00000 [el] [cw] [azvel] 00000000000 [r]

StopCmd=GOV[r] [1500d] DDD [az] [el] [r]

#StopCmd=DDDO900001000 [r]

#AzSectorCmd=GCE [el] 00000 [cw] [elvel] 00000000000 [r] [1500d]

G1A [azcen] [azspn] [cw] [azvel] 00000000000 [r]

#ElSectorCmd=GCA [az] 00000 [cw] [azvel] 00000000000 [r] [1500d]

G1E [elcen] [elspn] [cw] [elvel] 00000000000 [r]

AzSectorCmd=G0 [r] [l000d] G1A [azcen] [azspn] [cw] [azvel] [el]

000000 [r]

ElSectorCmd=G0[r] [l000d] G1E [elcen] [elspn] [cw] [elvel] [az]

000000 [r]

35 RDACS Users Guide August 2000 4. RDACS Control from FasTrac This section provides a step-by-step procedure for accessing RDACS control while operating FasTrac. 1. Start the FasTrac program. 2. From the leftmost Select Panel area, select Views to open the View Main panel. 3. Under the More Settings area on the bottom of the View Main panel, select Data to open the View Data panel. Under the More Radar Settings area in the middle of the View Data panel, select Radar Control to open the RDACS Control panel. 36 RDACS Users Guide August 2000 This menu is similar to that explained in the previous sections except you have two additional options-Linear Intensities and Load Settings. 1. Linear Intensities determines which format of reflectivity data the radar uses when it is one of the Doppler modes. If you do not select this option, the radar uses Log reflectivity data. a. The use of the Linear Intensities option depends on which version of the RDACS controller executable is installed. If you have the early file, HDDE.EXE, both linear reflectivity and log reflectivity are available. Since log reflectivity data usually provides higher quality data, do not select this option. If you have a later version of the RDACS controller executable, H250S.EXE, you have access only to linear data and you must select this option. 2. Load Settings accesses a saved RDACS configuration. You can use the RDACS control program to create and save up to 10 configurations (numbers 0 through 9). Configuration 0 is loaded when you restart RDACS. You can set other configurations to your personal preferences and needs. For example, you can use a different color table to implement a clear-air mode in Configuration 1. Configurations 8 and 9 are temporary saves of the test configuration. 37 RDACS Users Guide August 2000 After configuring the RDACS, select Load Settings to open the Load RDACS dialog box. Specify the configuration number, and click OK to return to the View Data panel. Click Cancel to dismiss the dialog box and to return to the RDACS Control panel. OR 38 RDACS Users Guide August 2000 5. Installing RDACS RDACS is normally set up when your system is delivered. The following instructions are provided in case your system crashes, a new version is delivered, or some other unusual circumstance occurs. There is no separate installation program. Copying the executable file to its destination and setting up shortcuts are manual operations. The rdacs directory or folder must be created before you install RvpTty. The steps below outline one possible way to set up the shortcuts to the program. Those familiar with Microsoft Windows can use their preferred technique. 1. Copy the rdacs.exe file to your \rdacs directory. 2. RDACS will create the rdacs.ini file when it is needed. 3. Run Windows Explorer, navigate to the C. \ Windows\Start Menu\BSI folder, Shortcut to open the Create Shortcut dialog box. New and select File Note you may have to create the BSI folder. 4. Use the Browse function or key in the complete pathname for the

\rdacs\rdacs.exe file in the Command Line text box. 39 RDACS Users Guide 5. Click Next, name the shortcut, and click Finish. August 2000 6. Select Start BSI, and verify that the new shortcut is displayed. 7. Right click on the desktop; then select New Shortcut from the popup menu. 8. Use the Browse function or key in the complete pathname for the

\rdacs\rdacs.exe file in the Command Line text box. 9. Click Next, name the shortcut, and click Finish. A shortcut to RDACS will appear on the desktop. 40 RDACS Users Guide August 2000 6. The radacs.ini Configuration File The rdacs.ini configuration file contains configuration parameters for RDACS. It is in text format; therefore, you can use Notepad or any equivalent text editor to view and edit the file contents. The file is organized into sections. Section headings are on a line by themselves and appear as a bracketed keyword, as shown in the following example:

[Startup]

NumUsers=10 WatchDogType=0 TcpNoDelayUsers=ndfastrac ndlocal wbay AntennaMoveTimeout=0

#DIOPort=0

#DIOPort=0x02a8 DIOPort=PC17250 LogScans=0 AutoFaultResetDelaly=60

[Master]

CfgVersion=100

#Do not change the next three while RDACS is running NumModes=60 NumLevels=5 NumRadPgms=1

# If next are changed, RVP7 must be configured RangeResolution0=125.0 RangeResolution1=125.0 RangeResolution2+125.0 41 RDACS Users Guide August 2000 For example, in our example file, [Startup] is the first section and [Master] is the second section. Each section lists its associated variables and the current variable values separated by equal (j signs. (For example, WatchDogType=1 enables the WatchDog timer feature). Depending on the context, the value may be a real number, an integer, a hexadecimal integer, a Boolean expression, or an alphanumeric string. Note that variable names may or may not be case sensitive, depending on the context. To ensure correct interpretation, use the variable names are they are specified in this document. There are three ways to change the configuration file, listed in order of preference:

By menu commands and dialog boxes in the RDACS Config program;

By using the Configuration RDACS Config program; and Edit RDACS.ini menu command in the

By editing rdacs.ini with Notepad or an equivalent text editor. For example, most of the variables in the Antenna section can be edited indirectly via Antenna command in RDACS Config. However, the Port variable the Configuration in that section must be edited through Notepad. In the ensuing descriptions, each variable may include information on the best way to change it. If none is specified, open Edit RDACS.ini command to edit the file. RDACS Config and use the Configuration If this document discusses a variable that is not listed in your radacs.ini file, it will have the default value. The order of section variables discussed in this document is not important. In general, variables are discussed in the order in which they are processed; sometimes, variable descriptions are logically grouped. 42 RDACS Users Guide August 2000 The following table lists the major configuration sections:

Section Title Startup Master Site RadPgmN RadPgmAntennaStuck Antenna LevelN ModeN ModeDefault AntennaCmds Description System startup information Global configuration variables Site-specific configuration Saved scan programs Scan program used if antenna fails to rotate Antenna configuration Color/display level translate tables Radar operational modes Default settings for radar operational modes Optional section when a TSA antenna system is used Other sections may also appear. For example, the system may make a section called RebootRadPgm. The section and variable names are not case-sensitive; the order in which sections and variables appear is also not important. Note that sections ending in N indicate multiple sections ending in a number. In most cases, the first number used is 0. For example, radacs.ini includes the Mode0 and Mode1 sections. M and X are also be used to reference numbered sections and variables. 43 RDACS Users Guide August 2000 Description The subparagraphs describing each variable list the following items for each variable. Item Value Type Range/Units Default Value Change Dynamically Real, Integer, Hexadecimal Integer, Boolean, and/or String. Valid ranges of values/units of values, where applicable. Value used if the variable is missing from rdacs.ini Specifies where there are any restrictions on changing the variable value while RDACS is running Optional reference to RVP7 program commands (typically this is only in the ModeN section). RVP7UsersGuide Reference The following are the various Value Types:

Real-Specifies a real number, optionally with a decimal point. The number may be signed, depending on context. Any reasonable number of digits after the decimal point is allowed; however, the value may be rounded to a fixed number of significant digits.

Integer- Specifies a whole number; no decimal point is allowed. The number may be signed, depending on context.

Hexadecimal Integer- Specifies a whole number in Base 16, with a Ox prefix.

Boolean-Specifies a numeric 1 or 0 representing true or false, respectively.

String-Specifies a sequence of printable characters. Spaces may be allowed, depending on context. In some cases, more than one value type is accepted. For example, a particular configuration item may allow either an integer or the none string. The remainder of this document describes each section and each variable within that section. 44 RDACS Users Guide August 2000 6.1 Startup Section This section contains configuration variables that are related to system startup and user options. TcpNoDelayUsers [Startup]

Value Type: One or more user name strings, separated by spaces. Range/Units: User names that are listed in the users.txt file. Default Value: Empty. Change Dynamically? Yes. RDACS communicates with its users via TCP/IP, a networking protocol. When RDACS turns the radar data into packets of data to send to the users, TCP/IP may bundle several small packets of data into one larger packet. This packetizing process can increase networking efficiency but it can cause the data to lose its real-time look, especially in the case where the data is visualized as a real-time sweep, as in FasTrac. However, TCP/IP has an option to turn this bundling off on a connection-by-connection basis. When a user logs on with a name contained in the TcpNoDelayUsers list, RDACS instructs TCP/IP not to bundle packets for that user. The tradeoff is that more bandwidth is consumed on the network, so this should only be used as needed. User login names for applications that do not display real-time data, such as RdacCap, should not appear in the list. Changes to this variable while RDACS is running only affect new connections. RebootOnScsiError [Startup]

Value Type: Boolean. Range/Units: 0 (disabled) or 1 (enabled). Default Value: 1. Change Dynamically? Yes. 45 RDACS Users Guide August 2000 If the RebootOnScsiError variable is enabled (set to 1) and if (a) a fatal error occurs on the SCSI to the RVP7 or if (b) the RVP7 does not seem to be responding, the RDACS computer restarts. This allows the system to reset the SCSI hardware, and the RVP7 will issue an internal reset when it detects that the SCSI interface is being initialized. This option can be considered a watchdog on the RDACS/RVP7 interface, and it normally should be enabled. If one of the described errors occurs, an entity is made in the RDACSLog.txt file. For this to be used in an unattended environment, the RDACS computer must be configured to start RDACS (and any other desired applications) upon system boot. Also, the RVP7 configuration item Respond to SCSI Reset (the RVPtty Mc command) should be set to YES. Before initiating reboot, RDACS creates the RebootRadPgm section in the rdacs.ini file. This section contains the currently running scan program. It also contains the Active=1 variable, which lets RDACS know that it should run the scan program in the RebootRadPgm section rather than the scan program in the RadPgm0 section. DIOPort [Startup]

Value Type: Integer, hexadecimal integer, or string. Range/Units: 0, 1, 2, 3, 4, I/O port address, or the string PC17250. Default Value: Empty. Change Dynamically? No, RDACS must be stopped. 46 RDACS Users Guide August 2000 This variable defines the type of interface to the radar transmitter and status. There are three types of interfaces: (1) an ISA bus I/O card, (2) a PCI bus I/O card model PCI-

7250, or (3) the RRC1 interface board integrated in the transmitter (serial interface).

To select (1), the ISA bus I/O card, enter the port address. For example, enter DIOPort=0x260.

To select (2), the PCI bus I/O card, use DIOPort=PCI7250.

To select (3), the RRC1 interface, use 1, 2, 3, or 4 to select the COM1, COM2, COM3, or COM4 serial port interface. A value of 0 can also be used. In this case, there will be no transmitter control (the transmitter can be operated in local mode and the status will be ignored). AntennaMoveTimeout [Startup]

Value Type: Integer. Range/Units: Timeout; enter 0 to disable or enter number of seconds. Default Value: 300. Change Dynamically? No, RDACS must be stopped. If this variable is not 0, this variable specifies the timeout for taking action if antenna motion is not detected. Typically, the action is to stop radiating. The actual scan program that executes when the timeout occurs is specified in the RadPgmAntennaStuck section. 47 RDACS Users Guide August 2000 AutoFaultResetDelay [Startup]

Value Type: Integer. Range/Units: Time between consecutive faults; enter 0 to disable or enter the number of seconds. Default Value: 0. Change Dynamically? No, RDACS must be stopped. This variable is used to configure automatic attempts to radiate if the radiate operation is shut down due to a fault. When a fault is first detected, a transmitter reset is attempted in five seconds. If another fault is detected, the number of seconds specified in the AutoFaultResetDelay variable must elapse before RDACS resends the Reset signal. LogScans [Startup]

Value Type: Boolean. Range/Units: 0 (disabled) or 1 (enabled). Default Value: 0. Change Dynamically? Yes (use the RADACS Terminal windows Misc scans command). Log When this variable is set, a message displays in the log window every time the antenna passes through 0 degrees. The number of samples and the largest and smallest angles sampled are displayed. This can be useful to confirm correct antenna operation. Most of the time, it should be disabled because it quickly fills up the log file (the log file is self-maintaining but other useful information scrolls away faster). 48 RDACS Users Guide August 2000 NumUsers [Startup]

Value Type: Integer. Range/Units: 1 to 10 users. Default Value: 5. Change Dynamically? No, RDACS must be stopped. Set the number of concurrent users supported by RDACS. A typical installation could have the FasTrac, RadarNet Server, RdacCap, IRIS, and RDACS Config applications. There is no harm in just setting the maximum, 10. Consult Baron Services if more concurrent users are required. WatchDogType [Startup]

Value Type: Integer. Range/Units: 0 (disabled), 1, or 2. Default Value: 0. Change Dynamically? No, RDACS must be stopped. This setting enables using the Watchdog timer feature available on some motherboards. If the variable is set to 1, the system periodically inputs a byte on port 0x443 to enable the Watchdog timer. It is disabled by inputting a byte on port 0x43. If the variable is set to 2, the Watchdog timer is periodically enabled by outputting a

(byte) 5 on port 0x443. It is disabled by outputting a (byte) 5 on port 0x441. If Watchdog is enabled and RDACS hangs for some reason, the computer will be reset by the Watchdog hardware logic. 49 RDACS Users Guide August 2000 6.2 Master Section This section contains several global configuration variables. Two important variables are NumModes and NumLevels. These must match the number of ModeN and LevelN sections, respectively. In general, variables in this section should not be changed while RDACS is running. CfgVersion [Master]

Value Type: Integer. Range/Units: 100. Default Value: 100. Change Dynamically? No, RDACS must be stopped. Cfg Version specifies a software version tracking number that should not be changed. NumModes [Master]

Value Type: Integer. Range/Units: The number of mode sections defined. Default Value: Empty. Change Dynamically? No, RDACS must be stopped. NumModes specifies the number of mode (ModeN) sections defined in the rdacs.ini file. Each mode section specifies a particular operational configuration. By convention, the first five mode sections are Powerdown, Standby, Long Pulse, Single PRF Doppler, and Dual PRF Doppler. 50 RDACS Users Guide August 2000 NumLevels [Master]

Value Type: Integer. Range/Units: The number of level tables defined. Default Value: Empty. Change Dynamically? No, RDACS must be stopped. NumLevels specifies the number of level conversion tables (the LeveIN sections) in the rdacs.ini file. These tables are used to convert engineering units (e.g., dBZ or m/s) to color levels. By convention, four tables are defined: Level0 through Level3. Normally, Level0 is for reflectivity, Level1 is for spectrum width, LeveI2 is for single PRF velocities, and Level3 is for dual PRF velocities. RangeResolutionN (N = 0, 1, 2, or 3) [Master]

Value Type: Real. Range/Un its: Selected values from 50.0 to 133.3/meters. Default Value: 125.0. Change Dynamically? No, RDACS must be stopped. This variable specifies the range resolution for the four pulse-width configurations supported by RVP7. The specified value must agree with that configured by the Range Resolution option of the Mt<n> command of the RVP7. Valid values are 50.0, 58.3, 66.7, 75.0, 83.3 91.7, 100.0, 108.3, 116.7, 125.0, and 133.3. 51 RDACS Users Guide August 2000 SepNoiseLevels [Master]

Value Type: Boolean. Range/Units: 0 or 1. Default Value: 1. Change Dynamically? No, RDACS must be stopped. SepNoiseLevels determines if separate noise commands should be issued for each of the four possible pulse-width configurations. Normally, this should agree with the Maintain separate noise levels for each PW item of the Mp command of the RVP7. The recommended setting is 1. NoNoiseCmds [Master]

Value Type: Boolean. Range/Units: 0 or 1. Default Value: 0. Change Dynamically? No, RDACS must be stopped. Setting this variable to 1 inhibits automatic noise sampling when a pulse-width configuration is selected for the first time. The recommended setting is 0. If set to 1, the noise variables within the RVP7 must be set in Interactive Setup mode. Note that when NoNoiseCmds is set to 1, noise commands are not performed, even when explicitly commanded. 52 RDACS Users Guide August 2000 6.3 Site Section This section is used to configure site-specific parameters, such as the radar location. Although these can be changed by editing the rdacs.ini file, RDACS Config supports changing most of these parameters via the RDACS Config menu command Configuration VersionNum [Site]

Site. Value Type: Integer. Range/Units: 102. Default Value: 102. Change Dynamically? Do not change. This variable specifies the software version tracking number and should not be changed. ProtocolNum [Site]

Value Type: Integer. Range/Units: 200. Default Value: 200. Change Dynamically? Do not change. This variable specifies the protocol number and should not be changed. SiteName [Site]

Value Type: String. Range/Units: Up to 31 characters. Default Value. Test Site. Change Dynamically? Yes (use the RDACS Config Configuration command). Site SiteName can be any string that identifies the site 53 RDACS Users Guide RadarName [Site]

Value Type: String. Range/Units: Up to 31 characters. Default Value: BSI Digital Doppler. Change Dynamically? Yes. August 2000 RadarName specifies the name of the radar system. Normally, it should not be changed. RadarType [Site]

Value Type: Integer. Range/Units: 10. Default Value: 10. Change Dynamically? Do not change. RadarType specifies the numeric identifier of the radar type. Do not change this number. Capabilities [Site]

Value Type: Hexadecimal integer. Range/Units: Bit pattern. Default Value: 0. Change Dynamically? Yes. Not currently used; reserved for future expansion. 54 RDACS Users Guide August 2000 Latitude [Site]

Value Type: Real. Range/Units: Valid latitude in decimal degrees; positive for north. Default Value: 35.0 Change Dynamically? Yes (use the RDACS Config Configuration command). Site This variable specifies the latitude of the radar antenna in decimal degrees. For example, 35.25 in decimal degrees is equivalent to 35:15:00 in D: M: S format. Longitude [Site]

Value Type: Real. Range/Units: Valid longitude in decimal degrees; negative for west. Default Value: -86.0. Change Dynamically? Yes (use the RDACS Config Configuration command). Site This variable specifies the longitude of the radar antenna in decimal degrees. Note that western longitudes are negative. Altitude_AAT [Site]

Value Type: Integer. Range/Units: Signed number/meters. Default Value: 0. Change Dynamically? Yes (use the RDACS Config Configuration command). Site 55 RDACS Users Guide August 2000 Altitude_AAT specifies the antennas height, in meters, above the average terrain. This value is not used by RDACS but is passed to other programs upon request. Altitude_ASL [Site]

Value Type: Integer. Range/Units: Signed number/meters. Default Value: 0. Change Dynamically? Yes (use the RADACS Config Configuration command). Site Altitude_ASL specifies the antennas height above sea level, in meters. This value is not used by RDACS but is passed to other programs upon request. AngIe36O [Site]

Value Type: Integer. Range/Units: 16384/counts. Default Value: 16384. Change Dynamically? Do not change. This variable specifies the number of counts in 360 degrees. This is a legacy value passed to other programs and should not be changed. 56 RDACS Users Guide August 2000 6.4 RadPgmN Section RDACS continually runs a scan program... (A scan program is a series of steps.) In each step, you can specify the radiate mode and data acquisition options, the antenna operation mode, and the duration of the step. When a step is completed, the next step in the scan program executes. When the last step is completed, RDACS loops back to the first step. Many programs consist of only one step that executes forever. However, to perform volume scanning or to acquire data with different data acquisition options, you must create a multi-step program. Up to ten prepared scan programs (RadPgm0 to RadPgm9) are kept in the rdacs.ini file. These programs are best created by using the RDACS Config Control Program and Control program executed upon system startup. The RadPgmAntennaStuck section also contains a scan program. If enabled in the Startup section, this program is executed if the antenna quits turning. Typically, it is a one-step program that puts the system in Standby mode. If the system attempts to reboot to correct a fatal I/O error (if so enabled), the RebootRadPgm temporary section is created to hold the currently executing program so it can be restarted. It has the same variables as RadPgmN and includes the Active variable, which is set to 0 or 1, as needed. Note that the currently executing program is not necessarily contained in the rdacs.ini file. A program, such as FasTrac, can download its own program to be executed, and it will not be saved. These programs are typically one-step operations and continuously execute. Save Program commands in RDACS. RadPgm0 is the Load 57 RDACS Users Guide August 2000 Quick to create a simple one-step scan program; use Control To create and manage programs, use the RDACS Config Control commands. Use Control to create or edit a multi-step program. Title [RadPgmN]

Program Value Type: String. Range/Units: Up to 39 characters. Default Value: None. Change Dynamically? Yes (use the RDACS Config Control commands). Title defines the scan programs name. Some programs (in particular rdaccap.exe) may derive information about the scan program from the title. NumSteps [RadPgmN]

Value Type: Integer. Range/Units: 1 to 30/number of steps in scan program. Default Value: 1. Change Dynamically? Yes (use RDACS Config Control commands). NumSteps specifies the number of steps in the scan program. For a one-step program, the following variables should also be present: AntOp0, Mode0, Range0, Skip0, Duration0, Az0, E10, and EndPt0. For a two-step program, the variables AntOp1, Mode1 EndPt1 should be present, and so on up to a maximum of 30 steps. 58 RDACS Users Guide AntOpM [RadPgmN]

August 2000 Value Type: Integer or hexadecimal integer. Range/Units. 0 to 3 (with possible modifier of +16 or +32). Default Value: 1. Change Dynamically? Yes (use RDACS Config Control commands). This variable defines the antenna mode or operation for step M. Valid modes are:

0 - Point or stop. 1 - PPI (full azimuth revolution with fixed elevation). 2 - Azimuth sector scan with fixed elevation. 3 - RHI (elevation scan with fixed azimuth). If AntOpM is 1, then 16 or 32 may be added to the value to force CW or CCW rotation direction. If AntOpM is 2, then 32 may be added to the value to force the scan to take the long path when scanning from AzM to EndPtM. If AntOpM is 2 or 3, then 16 may be added to the value to force the scan to always start at either AzM or ElM. (Otherwise, the scan may start at EndPtM if it is closer when the step is started.) ModeM [RadPgmN]

Value Type: Integer or hexadecimal integer. Range/Units: 0 to highest mode number. Default Value: 1. Change Dynamically? Yes (use RDACS Config Control commands). ModeM defines the basic radar operational mode. The value is used to find a ModeX section that has the RdpModeNum variable equal to the M value. 59 RDACS Users Guide August 2000 Note that this number does not point directly to a ModeX section. All the ModeX sections are searched to find a section containing a matching RdpModeNum value. When searching, the preferred data modifiers described below are ignored. By convention, the following values are used: Mode0 = Standby, Mode1 = Long Pulse, Mode2 = Single PRF Doppler, Mode3 = Dual PRF Doppler and Mode4 = PowerDown. Again, this convention may be altered by changing the RdpModeNum variable in the ModeX sections; however, it is best to keep this order for legacy programs. A preferred data modifier may be added to this value: this modifier can suggest, to a display program, what to visualize when the step S is in effect. The modifiers are 16 =

Log Reflectivity, 32 = Linear Reflectivity, 48 = Velocity, and 64 = Width. This field is obsolete, and no other programs currently use this information. RangeM [RadPgmN]

Value Type: Real. Range/Units: Total range, in kilometers. Default Value: 120. Change Dynamically? Yes (use Control menu command in RDACS Config). This variable specifies the radar range. In older systems with a limited number of range bins, this field was useful in shortening the range and, thus, increasing range resolution. However, with systems that have a large number of range bins, this field can be set to the maximum allowable range (constrained by PRF). 60 RDACS Users Guide SkipM [RadPgmN]

August 2000 Value Type: Real. Range/Units: Skip zone range, in kilometers. Default Value: 1.61. Change Dynamically? Yes (use RDACS Config Control commands). This variable specifies a skip zone. Data near the radar will be blanked. This can be used to not show strong clutter areas adjacent to the radar site. Set to 0 for no skip zone. DurationM [RadPgmN]

Value Type: Integer or hexadecimal integer. Range/Units: Time in seconds or loop count. Default Value: 0. Change Dynamically? Yes (use RDACS Config Control commands). This variable can be used two ways: (1) as a counter or (2) as a timer. To use as a counter, add 32768 (0x8000) to the value. This determines how long a step will execute before moving to the next step of the scan program (or to return to the first step if the current step is the last). A value of 0 means forever and 0 is normally used in single-step scan programs. The meaning of the loop count depends on the antenna mode defined in AntOpM. If AntOpM is 0 (point), loop count mode should not be used. For 1 (PPI), each count is one-fourth of a revolution. For example, a value of 4 gives one revolution before proceeding to the next step. For 2 or 3 (azimuth and elevation sector scans), each traversal of the scan region in either direction is one count. 61 RDACS Users Guide August 2000 AzM [RadPgmN]

Value Type: Real. Range/Units: 0 to 359.99/degrees. Default Value: 0.0. Change Dynamically? Yes (use RDACS Config Control commands). This variable contains the azimuth associated with the antenna mode defined in AntOpM. If AntOpM is 0 (point), AzM defines the azimuth at which the antenna will stop. For 1 (PPI), this is not used. If AntOpM is 2 (azimuth sector scan), AzM defines one endpoint of the sector scan - the other endpoint is defined by EndPtM. If AntOpM is 3, AzM defines the fixed azimuth for the elevation scan. ElM [RadPgmN]

Value Type: Real. Range/Units: -2 to 88/degrees. Default Value: 0.0. Change Dynamically? Yes (use RDACS Config Control commands). This variable defines the elevation associated with the antenna mode defined in AntOpM. If AntOpM is 0 (point), ElM defines the elevation at which the antenna will stop. If AntOpM is 1 or 2 (PPI or azimuth sector scan), ElM defines the fixed elevation for the step. If AntOpM is 3 (RHI), ElM defines one endpoint of the elevation sector scan

- the other endpoint is set by EndPtM. 62 RDACS Users Guide EndPtM [RadPgmN]

August 2000 Value Type: Real. Range/Units: 0 to 359.99/degrees. Default Value: 0.0. Change Dynamically? Yes (use RDACS Config Control commands). This variable defines the endpoint when the antenna mode is a sector scan. If AntOpM is 2 (azimuth sector scan), EndPtM defines the second azimuth. If AntOpM is 3

(elevation sector scan or RHI), EndPtM defines the second elevation. It is not used for other AntOpM values. 6.5 Antenna Section This section contains settings affecting the antenna operation. The type of antenna and the serial port to be used can be set in this section, as well as the antenna speed, sampling angle, and offset corrections. Other than the Type and Port variables, the recommended way to change these variables is to use the RDACS Config Configuration Type [Antenna]

Antenna command. Value Type: String. Range/Units: Either None, TSA, or Orbit. Default Value: TSA. Change Dynamically? No, RDACS must be stopped. This variable defines the type of antenna. Type selects the command set used to communicate with the antenna controller. If None is selected, no antenna control command will be issued. 63 RDACS Users Guide August 2000 Port [Antenna]

Value Type: Integer. Range/Units: 0, 1, 2, 3, or 4/COM port number. Default Value: 2. Change Dynamically? No, RDACS must be stopped. This variable defines the COM port (serial port) used to communicate with the antenna controller. If 0 is selected, no antenna control command will be issued. AzSpeed [Antenna]

Value Type: Real. Range/Units: 1 to 36/degrees/second. Default Value: 6.0. Change Dynamically? Yes (use RDACS Config Configuration command). Antenna This variable defines the azimuth speed used in PPI and azimuth sector scan modes. Depending on the controller, it may or may not also affect the speed used to slew to a fixed azimuth. ElSpeed [Antenna]

Value Type: Real. Range/Units: 1 to 36/degrees/second. Default Value: 6.0. Change Dynamically? Yes (use RDACS Config Configuration command). Antenna 64 RDACS Users Guide August 2000 This variable defines the elevation speed used in RI-IT scan modes. Depending on the controller, it may or may not also affect the speed used to slew to a fixed elevation. AzSampleStep [Antenna]

Value Type: Real. Range/Units: 0.1 to 2/degrees. Default Value. 1.0. Change Dynamically? Yes (use RDACS Config Configuration command). Antenna This variable defines the angular width of a sampled radial of radar data for azimuth scan modes (PPI and azimuth sector scan). For example, if the value is 1.0 degree and the antenna mode is PPI, 360 radials will be produced for each antenna revolution. This variable can be set to a smaller value, but if the network link between RDACS and its users is slow and the antenna speed is fast, the bandwidth must be considered. Other factors include the number of range bins and the processing speed capabilities of RDACS users. ElSampleStep [Antenna]

Value Type: Real. Range/Units: 0.1 to 2/degrees. Default Value: 1.0 Change Dynamically? Yes (use RDACS Config Configuration command). Antenna This variable defines the angular width of a sampled radial of radar data for the elevation scan mode (RHI). For example, if the low elevation is 0.0 degrees, the upper elevation is 40 degrees, the ElSampleStep is 0.5 degrees, and the antenna mode is RHI, 80 radials will be produced for each scan cycle. When lowering this number, factors to consider include the network link speed between RDACS and its users, the antenna speed, the number of range bins, and the processing speed capabilities of RDACS users. 65 RDACS Users Guide AzOffset [Antenna]

August 2000 Value Type: Real. Range/Units: -359.9 to 359.9/degrees. Default Value: 0.0. Change Dynamically? Yes (use RDACS Config Configuration command). Antenna This variable is used to correct for the difference between the antenna pedestals azimuth zero point and 0 degrees (0 degrees is north and 90 degrees is east). For example, if the antenna is pointing at 0 degrees, the displays indicate 10 degrees, and the current AzOffset is 6, AzOffset should be changed to -4. ElOffset [Antenna]

Value Type: Real. Range/Units: -359.9 to 359.9/degrees. Default Value: 0.0. Change Dynamically? Yes (use RDACS Config Configuration command). Antenna This variable is used to correct for the difference between the antenna pedestals elevation zero point and 0 degrees (0 degrees is on the horizon and 90 degrees is up). For example, if the antenna is pointing at 0 degrees, the displays indicate 2 degrees, and the current ElOffset is 0, ElOffset should be changed to -2. 66 RDACS Users Guide IsClockwise [Antenna]

August 2000 Value Type: Boolean. Range/Units: 0 (CCW) or 1 (CW). Default Value: 1. Change Dynamically? Yes (use RDACS Config Configuration command). Antenna This variable sets the default antenna direction when the antenna scan mode is PPI. 6.6 LevelN Section This section is repeated multiple times (for example, Level0, Level1...Leveln). Each instance is a conversion table that translates engineering units to display, or color, levels. There are three types of products emanating from the RVP7: (1) R - reflectivity,

(2) V - velocity, and (3) W - spectrum width. At least three Level table sections should be created, one for each product table. In practice, additional tables can be created with different thresholds to better match the range of values encountered in a particular mode. For example, if two different modes acquire velocities at different PRFs, the range of unambiguous velocities will be different and it may be desirable to map these into different display levels. For a given mode, which is specified in the ModeM section, the desired LevelN section is selected by the RLevel, VLevel, and WLevel variables. For example, if in Mode3 and VLevel=2, the threshold values in Level2 are used for velocities in Mode3. The total number of level tables is recorded in the NumLevels variable in the Master section. If you add or remove a section, be sure to update NumLevels. 67 RDACS Users Guide August 2000 Type [LeveIN]

Value Type: Integer. Range/Units: 0 (reflectivity) or 1 (velocity). Default Value: 0. Change Dynamically? No, RDACS must be stopped. Type defines whether the level table is used for reflectivities or velocities. Set Type to 0 for a reflectivity level table or set to 1 for a velocities table. Set Type to 1 for both velocity and width products. Name [LeveIN]

Value Type: String. Range/Units: Up to 31 characters. Default Value: None. Change Dynamically? No, RDACS must be stopped. Name provides an arbitrary string describing the table (for example, Name=Single PRF Velocity). Units [LeveIN]

Value Type: String. Range/Units: One of the strings described below. Default Value: dBZ or m/s, depending on Type setting. Change Dynamically? No, RDACS must be stopped. 68 RDACS Users Guide August 2000 The translate values in a level table can be in one of several different units. Units define the units for these values. If Type=0, then this maybe one of the following values: dBZ, mm/hr, or in/hr. If Type=1, the following values are allowed: m/s, km/hr, mph, or knots. The spelling and spacing of these strings are critical. For example, do not add spaces around the /in m/s. The native units used by the signal processor are dBZ and m/s. When these units are specified, no conversion of the threshold values in the 1, 2 ... 15 variables takes place. Otherwise, the threshold values are converted from the appropriate units before they are used. To convert from dBZ to rate (mm/hr), the following is used: rate = pow (10.0, (dbz/10 log10 (200.0)) /1.6). 1, 2... 15[LeveIN]

Value Type: Real. Range/Units: Varies. Default Value: None. Change Dynamically? Yes. These variables contain the threshold values for the level table. For example, if you want Level1 section to represent 5 to 10 dBZ and the Units variable is dBx , set variable 1 to 5 and set variable 2 to 10. 69 RDACS Users Guide August 2000 6.7 ModeN Section This section contains all of the variables used to define an operational mode except for antenna scan mode and range. Multiple sections (Mode0, Mode1 ModeN) may be used. The total number of modes is defined by the NumModes variable in the Master section. The parameters contained in the ModeN section include radar products collected, radiate on/off, pulse width, PRF, and filter options. Many, but not all, parameters flow directly to the RVP7. A ModeN section is referenced from the currently executing scan program. From the users point of view, the modes are named (see the Name variable). By convention, the following relationships are established for the first five modes:

Mode0- Powerdown.

Mode1-Standby.

Mode2-Long Pulse.

Mode3-Single PRF Doppler.

Mode4-Dual PRF Doppler. In the first two modes, radiate is off. Mode2 is characterized by a long pulse width at a low PRF; therefore, no velocities are acquired. Mode3 and Mode4 use a narrow pulse width at a higher PRF and the full suite of products (R, V, and W) is acquired. Note: The total number of mode sections is recorded in the NumModes variable in the Master section. If you add or remove a section, be sure to update NumModes. 70 RDACS Users Guide August 2000 New mode sections cannot be created while RDACS is running. However, every setting can be modified in an existing mode. To add a new mode, stop RDACS and edit the radacs.ini file. Use Copy and Paste to copy the ModeN section most like the one you will be creating to a new section. Update the mode number in the new section, and update NumModes in the Master section. You can now change the rest of the variables, or you can restart RDACS and use RDACS Config to change the variables. If a variable is not defined in a ModeN section, the ModeDefault section is searched for the same variable. Further, all variables in a ModeN section can have the usedefault value. This also forces the system to search the ModeDefault section for the actual value to use. Name [ModeN]

Value Type: String. Range/Units: Up to 39 characters. Default Value: NoName. Change Dynamically? Yes (connected users must reconnect to see change). This variable names the mode. It is not used internally except for status display. It is passed to user applications so that it can be presented to the operator in the list of available modes (e.g., see the RDACS Config Control Quick command). 71 RDACS Users Guide RdpModeNum [ModeN]

August 2000 Value Type: Integer. Range/Units: See text. Default Value: 0. Change Dynamically? Yes (connected users must reconnect to see change). When a scan program is defined, it contains a mode number that does not directly refer to a ModeN section. Instead, it refers to a ModeN section with a matching RdpModeNum variable. The reason for this extra layer of indirection is that some older legacy programs have the following hard coded modes: 0=Standby, 1 Long Pulse, 2 Single PRF Doppler, 3 = Dual PRF Doppler and 4 = PowerDown. The following table lists the resulting RdpModeNum value when following all conventions:

Section Mode0 Mode1 Mode2 Mode3 Mode4 Name Powerdown Standby Long Pulse Single PRF Doppler Dual PRF Doppler RdpModeNum 4 0 1 2 3 For example, if you are adding a new mode, Mode5, you can establish a one-to-one relationship between the mode section number and the RdpModeNum variable (older programs cannot access the new modes). 72 RDACS Users Guide August 2000 Radiate [ModeN}

Value Type: Boolean. Range/Units: 0 (no) or 1 (radiate). Default Value: 0. Change Dynamically? Yes. This variable defines whether the transmitter is enabled for the mode. Typically, set to 1 unless a Powerdown or Standby mode is being defined. PowerUp [ModeN]

Value Type: Boolean. Range/Units: 0 (powerdown) or 1 (powerup). Default Value: 0. Change Dynamically? Yes. This variable determines whether system power is supplied to all circuits (including filament voltage). If PowerUp is set to 0, some circuits are powered down (if the system supports Powerdown). Note that exiting a Powerdown mode may require waiting for filament warm-up. AutoReset [ModeN]

Value Type: Boolean. Range/Un its: 0 (no) or 1 (yes). Default Value: 0. Change Dynamically? Yes. If AutoReset is set to 1 and a fault condition exists, a Reset command is issued to the transmitter. This is only done once, when the mode is first selected. To reiterate the Reset operation, see AutoFaultResetDelay in the Startup section. 73 RDACS Users Guide ForceReset [ModeN]

Value Type: Boolean. Range/Units: 0 (no) or 1 (yes). Default Value: 0. Change Dynamically? Yes. August 2000 If ForceReset is set to 1, a Reset command is issued to the transmitter when the mode is first selected. For repeated attempts to reset faults, see AutoFaultResetDelay in the Startup section. RLevel, VLevel, and WLevel [ModeN]

Value Type: Integer. Range/Units: 0 to Number of LeveIN sections. Default Value: 0. Change Dynamically? Yes. These variables select which level translate table is used for R, V, and W products respectively. For example, if VLevel=2, the Level2 section will be used to convert velocities from engineering units to display levels. RAvail, VAvail, and WAvail [ModeN]

Value Type: Boolean. Range/Units: 0 (not available) or 1 (available). Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: Bits 11-14 in the PROC command. 74 RDACS Users Guide August 2000 These variables specify which of the R, V, and W products should be processed for delivery to user applications. Normally, for a low PRF where the unambiguous velocity is low, only RAvail is set. For a higher PRF, all three variables should be set to 1. RUseUncorr [ModeN]

Value Type: Boolean. Range/Units: 0 (use corrected) or 1 (use uncorrected). Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: Bits 13-14 in the PROC command. Normally, RVP7 delivers corrected reflectivity, for which all processing is applied. Set this variable to 1 to deliver uncorrected reflectivity. ReqNumBins [ModeN]

Value Type: Integer. Range/Units: 0 - 2000. Default Value: 500. Change Dynamically? Yes. RVP7 Users Guide Reference: LRMSK command. This variable defines the approximate number of range bins that will be used for delivered products. The actual number used will be a few bins smaller than requested, depending on the skip zone range, the bin resolution, and the SamplesPerBin variable. 75 August 2000 RDACS Users Guide SamplesPerBin [ModeN]

Value Type: Integer. Range/Units: 1 to 256. Default Value: 1. Change Dynamically? Yes. RVP7 Users Guide Reference: LRMSK command. This variable defines the number of adjacent bins to be averaged. A value of 1 specifies no averaging: the number of bins requested will be the same number delivered. PulseIndex [ModeN]

Value Type: Integer. Range/Units: 0 to 3/index to RVP7 pulse-width tables Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SETPWF command, Bits 8-9. This variable selects one of four pulse-width configurations stored at the RVP7. By convention, a value of 0 selects long pulse and 1 selects short pulse. The remaining entries can be used for other pulse widths. PRF [ModeN]

Value Type: Integer. Range/Units: 0 to several thousand/Hertz. Default Value: 500. Change Dynamically? Yes. RVP7 Users Guide Reference: SETPWF command, Input 1. 76 August 2000 RDACS Users Guide FilterRangeM (M = 0 to 3) FilterlndexM (M = 0 to 3) [ModeN]

Value Type: Real (range) and Integer (index). Range/Units: km (range) and index. Default Value: 0.0 and 0. Change Dynamically? Yes. RVP7 Users Guide Reference: LFILT command. Use these variables to configure clutter filters. Up to four filters may be defined, with arbitrary range. The FilterlndexM variables define which filter is selected. A value of 0 is off, while 1 to 7 selects progressively more rejective filters. The range of successive FilterRangeM variables should increase; set to 0 if the filter is not used. For example, to use a highly rejective filter for the first 15 km, a moderate filter for the next 30 km, and no filter for the remainder, the variables would be:

FilterRange0=1 5.0 Filterlndex0=6 FilterRange1=45.0 Filterlndex0=2 FilterRange2=0 Filterlndex2=0 FilterRange3=0 Filterlndex3=0 77 RDACS Users Guide August 2000 Unfold [ModeN]

Value Type: Integer. Range/Units: 0 to 3. Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: PROC command, Bits 8-9. This variable enables dual-PRF unfolding based on the set value from the following table:

Unfold 0 1 2 3 Meaning No unfolding Ratio of 2:3 Ratio of 3:4 Ratio of 4:5 ProcMode [ModeN]

Value Type: Integer. Range/Units: 1 (synchronous) or 2 (free running). Default Value: 2. Change Dynamically? Yes. RVP7 Users Guide Reference: PROC command, Bits 5-6. This variable specifies whether the synchronous mode or the free running mode should be used (see RVP7 Users Guide). In almost all cases, you should set ProcMode to 2. 78 RDACS Users Guide SampleSize [ModeN]

August 2000 Value Type: Integer. Range/Units: 1-256. Default Value. 25. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 1. This variable specifies the number of pulses to be averaged. Rnv [ModeN]

Value Type: Boolean. Range/Units: 0 (off) or 1 (on). Default Value: 1. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 2, Bit 0. This variable enables range correction of reflectivity data. It also enables intervening gas attenuation correction. Dsr [ModeN]

Value Type: Boolean. Range/Units: 0 (off) or 1 (on). Default Value: 1. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 2, Bit 1. This variable enables the Doppler speckle remover. When Dsr=1, speckles in velocity and width data are removed. 79 RDACS Users Guide Lsr [ModeN]

August 2000 Value Type: Boolean. Range/Units: 0 (off) or 1 (on). Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 2, Bit 2. This variable enables the reflectivity speckle remover. When Lsr=1, speckles in corrected and uncorrected reflectivity data are removed. End [ModeN]

Value Type: Boolean. Range/Units: 0 (off) or 1 (on). Default Value: 1. Change Dynamically? Yes. RVP7 Users Guide Reference: SQPRM command, Input 2, Bit 3. When End is set to 1, the ENDRAY_ output is pulsed at the end of each ray. This is not used by RDACS. R2 [ModeN]

Value Type: Boolean. Range/Units: 0 (off) or 1 (on). Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 2, Bit 7. When R2=1, the system uses three lag algorithms (R0, R1, and R2) for width, signal power, and clutter correction. 80 RDACS Users Guide August 2000 CMS [ModeN]

Value Type: Boolean. Range/Units: 0 (off) or 1 (on). Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 2, Bit 8. This variable enables clutter microsupprresion prior to being averaged together in range.

(Clutter microsupprresion is the rejection of individual range bins based on excessive clutter.) Polar [ModeN]

Value Type: Integer. Range/Units: 0 to 2. Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 2, Bits 12-13. This variable specifies polarization: 0 = horizontal, 1 = vertical or 2 = alternating. LogSlope [ModeN]

Value Type: Real. Range/Units: N/A. Default Value: 0.03. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 3. 81 RDACS Users Guide August 2000 This variable specifies the multiplicative constant used to covert signal power in dB to units of the time-series outputs (which are not used by RDACS). Also, one-fourth of this value is used to generate the Log of Measured Noise Level output from RVP7s GPARM command. The recommended value is 0.03. LogThreshold [ModeN]

Value Type: Real. Range/Units: >=0/dB. Default Value: 0.5. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 4. This variable sets the LOG threshold for reflectivity values. This is only used if enabled in the ThCtlxxx variables. CcorThreshold [ModeN]

Value Type: Real. Range/Units: <0/dB. Default Value: -25.0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 5. This variable sets the clutter correction threshold. Any correction that is more negative than this value results in thresholding of data if enabled via the ThCtlxxx variables. 82 RDACS Users Guide SqiThreshold [ModeN]

August 2000 Value Type: Real. Range/Units: 0 to 1. Default Value: 0.5. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 6. This variable sets the signal quality index (SQl) threshold. Any SQl that is less than this value results in thresholding of data if it has been enabled via the ThCtlxxx variables. SigThreshold [ModeN]

Value Type: Real. Range/Units: dB. Default Value: 10.0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 7. When the estimate of the signal-to-noise ratio (SIG) falls below this value, data will be thresholded if enabled via the ThCtlxxx variables. CalRefI [ModeN]

Value Type: Real. Range/Units: < 0. Default Value: -22.0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 8. 83 RDACS Users Guide August 2000 This variable sets the calibration reflectivity, which is referenced to 1.0 km. Changes in this variable result in a one-to-one change in the output reflectivity data levels. For example, if the reflectivity level tables specify 5 dBZ levels, a 5 dB change in this will be reflected as a shift of one level. AGCNumPulses [ModeN]

Value Type: Integer. Range/Units: 1 to 255. Default Value: 8. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 9, Bits 0-7. This variable specifies the number of AGC pulses averaged. TopMode [ModeN]

Value Type: Integer. Range/Units: 0 to 2. Default Value: 0. Change Dynamically? Yes. R VP7 Users Guide Reference: SQPRM command, Input 9, Bits 8-11. This variable specifies the signal processing mode used by the RVP7: 0 = pulse pair processing, 1 FFT processing, and 2 random phase processing. 84 RDACS Users Guide August 2000 FilterStabDly [ModeN]

Value Type: Integer. Range/Units: Pulses. Default Value: 10. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 10, Bits 0-7. This variable specifies a delay introduced prior to processing the next radial of data whenever dual PRF velocity unfolding is enabled or when the RVP7 has been reconfigured. The delay permits clutter filter transients to settle down following PRF and gain changes. ZER [ModeN]

Value Type: Boolean. Range/Units: 0 (off) or 1 (on). Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 10, Bit 8. If ZER1, digital clutter filters internal state variables are reset to 0 prior to waiting the time specified in FilterStabDly. 85 RDACS Users Guide Window [ModeN]

August 2000 Value Type: Integer. Range/Units: 0 to 2. Default Value: 1. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 10, Bits 9-10. This variable specifies the type of window that is applied to time-series data prior to computing power spectra via a digital Fourier transform. The values are 0 = rectangular, 1 = Hamming, and 2 = Blackman window. ThCtlUncorr [ModeN]

Value Type: Integer or hexadecimal integer. Range/Units: Bit pattern (16 bits). Default Value: 0xAAAA. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 11. This variable specifies threshold control for uncorrected reflectivity. The following steps describe how the bit patterns in the ThCtlxxx variables are used:

1. After a radial has been acquired, compute value x as follows:

Add 1to x if data passes LOG threshold.

Add 2 to x if data passes CCOR threshold.

Add 4 to x if data passes SQl threshold.

Add 8 to x if data passes SIG threshold. 2. Now x will have the value 0 to 15. It will be 0 if the data was below all thresholds;

it will be 15 if it was above them all. 3. Use x to index into the bit pattern, and select one bit. If that bit is set, pass or keep the range data. If the bit is clear, then fail or discard the data. 86 RDACS Users Guide August 2000 The following table lists values of the ThCtlxxx variable for selected combinations of acceptance criteria:

Value (Hex) Criteria FFFF 0000 AAAA 8888 A0A0 F0F0 FAFA C0C0 F000 C000 FFF0 CCC0 All pass (threshold disabled) All fail LOG LOG and CCOR LOG and SQI SQI LOG or SQI CCOR and SQI SQI and SIG CCOR and SQI and SIG SQI or SIG CCOR and (SQI or SIG) ThCtlCorr [ModeN]

Value Type: Integer or hexadecimal integer. Range/Units: Bit pattern (16 bits). Default Value: 0x8888. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 12. This variable specifies threshold control for uncorrected reflectivity. See ThCtlUncorr for the meaning of this value. 87 RDACS Users Guide ThCtIVeI [ModeN]

August 2000 Value Type: integer or hexadecimal integer. Range/Units: Bit pattern (16 bits). Default Value: 0xC0C0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 13. This variable specifies the threshold control for velocity. See ThCtlUncorr for the meaning of this value. ThCtlWidth [ModeN]

Value Type: Integer or hexadecimal integer. Range/Units: Bit pattern (16 bits). Default Value: 0xC000. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 14. This variable specifies threshold control for width. See ThCtlUncorr for the meaning of this value. InvTagLow InvTagHigh [ModeN]

Value Type: Integer or hexadecimal integer. Range/Units: Bit pattern (16 bits). Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Inputs 15 and 16. 88 RDACS Users Guide August 2000 This variable specifies whether selected TAG inputs to the RVP7 should be inverted. All current hardware requires that both these values be 0. GasAtten [ModeN]

Value Type: Real. Range/Units: dB. Default Value: 0.016. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 17. This variable specifies the compensation for beam losses due to absorption by atmospheric gases. Set to 0 to disable. This value is used only if the Rnv variable is also set. ThCtIZdrRefI [ModeN]

Value Type: Integer or hexadecimal integer. Range/Units: Bit pattern (16 bits). Default Value: 0xAAAA. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 18. This variable specifies the threshold control for differential reflectivity. See ThCtlUncorr for the meaning of this value. 89 RDACS Users Guide August 2000 ZdrCalOffset [ModeN]

Value Type: Real. Range/Units: signed/dB. Default Value: 0. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 19. This variable specifies the offset to be added to all reflectivity polarization ratio (ZDR) measurements. Wavelength [ModeN]

Value Type: Real. Range/Units: cm. Default Value. 5.3. Change Dynamically? Yes. RVP7 Users Guide Reference: SOPRM command, Input 20. This variable specifies the radars wavelength, in centimeters. 90 RDACS Users Guide August 2000 6.8 AntennaCmds Section This section is only used for the TSA antenna system (the Type variable in the Antenna section must be set to TSA). The variables in this section hold script-like strings with replaceable parameters that are used to construct the command strings sent via the serial port to the TSA antenna. Firmware evolution in the ISA antenna controller has rendered the default values obsolete. Consult Baron Services or the ISA documentation before changing this section. In the script-like strings, replaceable parameters are denoted by a keyword in brackets. The keywords are listed and described in the table below. In all cases where a numeric quantity is created, it is 0 padded on the left to create the specified number of digits. Keyword No. of Digits Meaning az azvel azvel2 azv100 azcen azspn el elvel elvel2 elv100 cw xd r azoff eloff Target azimuth * 100 Azimuth speed Azimuth speed Azimuth speed * 10 Target azimuth center * 100 Target azimuth span * 100 Target elevation * 100 Elevation speed Elevation speed Elevation speed * 100 1 if clockwise rotation; else 0 Delay x milliseconds Add end of line codes Azimuth offset Elevation offset 5 4 2 4 5 5 5 4 2 4 1 N/A N/A 5 5 91 August 2000 RDACS Users Guide InitCmdM (M = 1 to 9; TSA antenna only) [AntennaCmds]

Value Type: String. Range/Units: Up to 150 characters. Default Value: C [r] [30d] C[r] [30d]. Change Dynamically? Yes. This command can be used to specify up to nine initialization command strings. These strings are sent to the antenna controller on startup and when a variable is changed in the Antenna section of the rdacs.ini file. AzFuIICmd [AntennaCmds]

Value Type: String. Range/Units: Up to 150 characters. Default Value: G 1 V00000 [el] [cw] [azvel] 00000000000[r] [30d] G 1 V[r] [30d]. Change Dynamically? Yes. This variable is used to build the antenna controller command string to enable continuous rotation in azimuth. 92 RDACS Users Guide StopCmd (TSA antenna only) [AntennaCmds]

Value Type: String. Range/Units: Up to 150 characters. Default Value: G0[r] [30d] DDD [az] [el] [r] [30d]. Change Dynamically? Yes. August 2000 This variable is used to build the antenna controller command string to enable pointing at a fixed azimuth and elevation. AzSectorCmd (ISA antenna only) [AntennaCmds]

Value Type: String. Range/Units: Up to 150 characters. Default Value: GCE [el] 00000[cw] [elvel] [r] [30d] G1A [azcen] [azspn] [cw]

[azvel] [r] [30d] G1A[r] [30d]. Change Dynamically? Yes. This variable is used to build the antenna controller command string to enable azimuth sector scan. ElSectorCmd (TSA antenna only) [AntennaCmds]

Value Type: String. Range/Units: Up to 150 characters. Default Value: GCA [az] 00000[cw] [azvel] [r] [30d] G1E [elcen] [elspn] [cw] [elvel]

[r] [30d] G1E[r] [30d]. Change Dynamically? Yes. This variable is used to build the antenna controller command string to enable elevation sector scan

(RHI). 93

 

 

DRAFT RVP8 Digital IF Receiver/Doppler Signal Processor Users Manual May 2003

Copyright 2003 SIGMET, Inc. The designs and descriptions contained in this manual may not be copied, translated or reproduced in any form without the prior written consent of SIGMET, Inc. RVP8 Users Manual 12 May 2003 Table of Contents Table of Contents 1.3 RVP8 IF Signal Processing Hardware Limited Warranty Preface 1. Introduction and Specifications 1.1 System Configuration Concepts 1.2 Comparison of Analog vs Digital Radar Receivers 1.3.1 IFD Data Capture and Timing 1.3.2 Burst Pulse Analysis for Amplitude/Frequency/Phase 1.3.3 Rx Board and CPU IF to I/Q Processing 1.2.1 What is a Digital IF Receiver?

1.2.2 Magnetron Receiver Example 1.2.3 Klystron or TWT Receiver and Transmit RF Example 1.1.1 IFD IF Digitizer 1.1.2 Digital Receiver PCI Card (RVP8/Rx) 1.1.3 Mother Board or Single-Board Computer (SBC) 1.1.4 Digital Transmitter PCI Card (RVP8/Tx) 1.1.5 I/O-62 PCI Card and I/O Panel

. 1.4.1 General Processing features 1.4.2 RVP8 Pulse Pair Time Domain Processing 1.4.3 RVP8 DFT/FFT Processing 1.4.4 Random Phase Processing for 2nd Trip Echo 1.4.5 Polarization Mode Processing 1.4.6 Output Data 1.8.1 IFD Digitizer Module 1.8.2 RVP8/Rx PCI Card 1.8.3 RVP8/Tx PCI Card 1.8.4 SIGMET I/O-62 PCI Card 1.8.5 RVP8 Standard Connector Panel 1.8.6 RVP8 Processing Algorithms 1.5.1 Radar Control Functions 1.5.2 Power-Up Setup Configuration 1.5.3 Built-In Diagnostics 1.6 Support Utilities and Available Application Software 1.7 Open Architecture and Published API 1.8 RVP8 Technical Specifications 1.5 RVP8 Control and Maintenance Features 1.4 RVP8 Weather Signal Processing x xi 11 14 19 110 113 113 115 117 117 118 120 121 121 122 123 125 126 129 129 130 130 130 131 131 132 132 133 134 135 135 136 137 138 139 140 i RVP8 Users Manual 12 May 2003 Table of Contents 2. Hardware Installation 2.1 Overview and Input Power Requirements 2.2 IFD IF Digitizer Module Installation 2.3 RVP8 Chassis 1.8.7 RVP8 Input/Output Summary 1.8.8 Physical and Environmental Characteristics 2.2.1 IFD Introduction 2.2.2 IFD Revision History 2.2.3 IFD Power, Size and Physical Mounting Considerations 2.2.4 IFD I/O Summary 2.2.5 IFD Adjustments and Test/Status Indicators 2.2.6 IFD Input A/D Saturation Levels 2.2.7 IF Bandwidth and Dynamic Range 2.2.8 IF Gain and System Performance 2.2.9 Choice of Intermediate Frequency 2.2.10 IFD Analog AFC Output Voltage (Optional) 2.2.11 IFD Reference Clock Input (Optional) 2.2.12 Coax Uplink and Fiber Downlink

. 2.3.1 RVP8 Chassis Overview 2.3.2 Power Requirements, Size and Physical Mounting 2.3.3 Main Chassis Direct Connections 2.3.4 Connector Panel I/O Connections 2.3.5 Power-Up Details (Alan) Draft 2.3.6 Socket Interface 3.1.1 Initial Entry and Help List 3.1.2 Factory, Saved, and Current Settings 3.1.3 Processor Reset Command 3.1.4 V View Internal Status 3.1.5 Burst-In / IF-In Swap Command 2.4.1 Example Hookup to a CTI MVSR-xxx STALO 2.4.2 Example Hookup to a MITEQ MFS-xxx STALO 2.5.1 Using the IFD Coax Uplink 2.5.2 Using the (I,Q) Digital Data Stream (Alan) 3.2.1 Physical-Level I/O Examiner 3.2.2 Application-Level I/O Examiner 142 143 21 21 22 22 23 24 25 26 28 29 211 213 214 215 217 218 218 218 219 220 223 224 227 229 231 232 232 235 31 31 31 32 33 33 35 37 37 37 310 3.2 Host Computer I/O Debugging 3.3 View/Modify Dialogs 2.4 Digital AFC Module (DAFC) 2.5 RVP8 Custom Interfaces 3. TTY Nonvolatile Setups (draft) 3.1 Overview of Setup Procedures ii RVP8 Users Manual 12 May 2003 Table of Contents 4. Plot-Assisted Setups 3.3.1 Mc Board Configuration 3.3.2 Mp Processing Options 3.3.3 Mf Clutter Filters 3.3.4 Mt General Trigger Setups 3.3.5 Mt<n> Triggers for Pulsewidth #n 3.3.6 Mb Burst Pulse and AFC 3.3.6.1 AFC Motor/Integrator Option 3.3.7 M+ Debug Options 3.3.8 Mz Transmitter Phase Control 4.1 Oscilloscope Connections 4.2 P+ Plot Test Pattern 4.3 General Conventions Within the Plot Commands 4.4 Pb Plot Burst Pulse Timing 4.4.1 Interpreting the Burst Timing Plot 4.4.2 Available Subcommands Within Pb 4.4.3 TTY Information Lines Within Pb 4.4.4 Recommended Adjustment Procedures 4.5 Ps Plot Burst Spectra and AFC 4.5.1 Interpreting the Burst Spectra Plots 4.5.2 Available Subcommands Within Ps 4.5.3 TTY Information Lines Within Ps 4.5.4 Computation of Filter Loss 4.5.5 Recommended Adjustment Procedures 4.6 Pr Plot Receiver Waveforms 4.6.1 Interpreting the Receiver Waveform Plots 4.6.2 Available Subcommands Within Pr 4.6.3 TTY Information Lines Within Pr

. 310 313 316 318 321 325 332 333 334 41 42 43 44 46 46 47 48 49 411 411 413 415 417 420 423 423 425 426 51 54 54 55 56 57 59 59 511 511 511 512 513 5.2 Video (I and Q) Signal Processing 5.2.1 Time Series 5.2.2 IIR Clutter Filter for PPP-Mode 5.2.3 Autocorrelations for PPP-Mode 5.2.4 Range averaging and Clutter Microsuppression 5.1.1 FIR (Matched) Filter 5.1.2 Automatic Frequency Control (AFC) 5.1.3 Burst Pulse Tracking 5.1.4 Interference Filter 5.1.5 Large-Signal Linearization 5.1.6 Correction for Tx Power Fluctuations 5. Processing Algorithms (draft) 5.1 IF Signal Processing iii RVP8 Users Manual 12 May 2003 Table of Contents 5.3 Thresholding 5.6 Dual PRF Velocity Unfolding 5.7 Optional Dual Polarization- ZDR, PHIDP, KDP, LDR, ... 5.3.1 Threshold Qualifiers 5.3.2 Adjusting Threshold Qualifiers 5.3.3 Speckle Filters 5.4 Reflectivity Calibration 5.5 Dual PRT Processing Mode 5.5.1 DPRT-1 Mode 5.5.2 DPRT-2 Mode 5.2.5 Reflectivity 5.2.6 Velocity 5.2.7 Spectrum Width Algorithms 5.2.8 Signal Quality Index (SQI threshold) 5.2.9 Clutter Correction (CCOR threshold) 5.2.10 Weather Signal Power (SIG threshold) 5.2.11 Signal to Noise Ratio (LOG threshold)

. 5.7.1 Overview of Dual Polarization 5.7.2 Radar System Considerations 5.7.3 RVP8 Dual-Channel Receiver Approach 5.7.4 Overview of Processing Algorithms 5.7.5 Case 1: Fixed Transmit: Dual-Channel Receiver 5.7.6 Case 2: Simultaneous Dual Transmit and Receive (STAR mode) 5.7.7 Case 3: Alternating H/V Transmit: Single-Channel Receiver 5.7.8 Case 4: Alternating H/V Transmit: Dual-Channel Receiver 5.7.10 KDP Calculation 5.7.11 Standard Moment Calculations (T, Z, V, W) 5.7.12 Thresholding of Polarization Parameters 5.7.13 Calibration Considerations 5.9.1 Overview 5.9.2 Algorithm 5.9.3 Tuning for Optimal Performance 5.8.1 Overview 5.8.2 FFT Implementation 5.10 Signal Generator Testing of the Algorithms 5.10.1 Linear Ramp of Velocity with Range 5.10.2 Verifying PHIDP and KDP 5.10.3 Verifying RHOH, RHOV, and RHOHV 5.9 Random Phase 2nd Trip Processing 5.8 FFT Mode 513 515 515 516 517 518 518 519 519 520 521 525 530 530 531 532 536 536 538 540 542 545 546 547 548 549 550 560 561 564 564 565 570 570 570 571 575 575 576 576 iv RVP8 Users Manual 12 May 2003 Table of Contents 6. Host Computer Commands 6.1 No-Operation (NOP) 6.2 Load Range Mask (LRMSK) 6.3 Setup Operating Parameters (SOPRM) 6.4 Interface Input/Output Test (IOTEST) 6.5 Interface Output Test (OTEST) 6.6 Sample Noise Level (SNOISE) 6.7 Initiate Processing (PROC) 6.8 Load Clutter Filter Flags (LFILT) 6.9 Get Processor Parameters (GPARM) 6.10 Load Simulated Time Series Data (LSIMUL) 6.11 Reset (RESET) 6.12 Define Trigger Generator Output Waveforms (TRIGWF) 6.13 Define Pulse Width Control Bits and PRT Limits (PWINFO) 6.14 Set Pulse Width and PRF (SETPWF) 6.15 Load Antenna Synchronization Table (LSYNC) 6.16 Set/Clear User LED (SLED) 6.17 TTY Operation (TTYOP) 6.18 Load Custom Range Normalization (LDRNV) 6.19 Read Back Internal Tables and Parameters (RBACK) 6.20 Pass Auxiliary Arguments to Opcodes (XARGS) 6.21 Configure Ray Header Words (CFGHDR) 6.22 Configure Interference Filter (CFGINTF) 6.23 Set AFC level (SETAFC) 6.24 Set Trigger Timing Slew (SETSLEW) 6.25 Hunt for Burst Pulse (BPHUNT) 6.26 Configure Phase Modulation (CFGPHZ) 6.27 Set User IQ Bits (UIQBITS) 6.28 Custom User Opcode (USRINTR and USRCONT)

. 61 62 62 64 610 611 611 613 621 622 631 633 633 634 636 636 638 638 640 641 642 642 643 644 644 645 645 646 647 v RVP8 Users Manual 12 May 2003 Table of Contents A. Software: Basics, Installation and Backup A.1 Overview A.2 Basics of Login, Logout and Shutdown A.5.1 System Backup A.5.2 System Recovery A.5.3 Transferring a backup file from the RVP8 hard disk A.2.1 Power up procedure A.2.2 Local and remote login A.2.3 Default operator and root login passwords A.2.4 Login procedure A.2.5 Logout procedure A.2.6 Poweroff shutdown procedure A.3 Software Installation A.3.1 When to perform software installation A.3.2 Preparing for the installation A.3.3 Installing the system software A.4 System Software Configuration A.4.1 Configuring the softplane.conf file A.5 System Backup and Recovery

. A1 A1 A2 A2 A2 A2 A3 A4 A4 A5 A5 A5 A6 A10 A11 A17 A17 A21 A22 A24 A24 A24 A24 A25 A28 A29 A31 A31 A32 B1 B2 B7 B8 B9 B10 B11 B12 B28 B31 C1 D1 A.6 Software Upgrade and Support A.6.1 Where to get software upgrades A.6.2 When should I upgrade A.6.3 How should I upgrade A.6.4 Getting the network upgrade files A.6.5 Starting the install utility A.6.6 Using the install utility A.7 Network Basics B.1 Main Chassis General Description B.1.1 Main Chassis Front Panel B.1.2 Main Chassis Back Panel B.1.3 Main Chassis Back Panel Power Section B.1.4 Main Chassis Back Panel PC I/O Section B.1.5 Main Chassis Back Panel PCI Card Section B.2 I/O-62 and Connector Panel B.3 IFD Module (RVP8 Only) B.4 DAFC Module (RVP8 only) A.7.1 Default Out Of The Box Configuration A.7.2 Making Changes to Default Configuration C. Clutter Filter Characteristics (DRAFT) D. References and Credits B. RVP8/RCP8 Packaging vi RVP8 Users Manual 12 May 2003 Table of Contents E. Installation and Test Procedure (DRAFT) E.1 Installation Check E.2 Power-Up Check E.3 Setup Terminal E.4 Setup V Command (Internal Status) E.5 Setup Mc Command (Board Configuration) E.6 Setup Mp Command (Processing Options) E.7 Setup Mf Command (Clutter Filters) E.8 Setup Mt Command (General Trigger Setup) E.9 Initial Setup of Information for Each Pulse Width E.10 Setup Mb Command (Burst Pulse and AFC) E.11 Setup M+ Command (Debug Options) E.12 Setup Mz Command (Transmitter Phase Control) E.13 Display Scope Test E.14 Burst Pulse Alignment E.15 Bandwidth Filter Adjustment E.16 Digital AFC Voltage Alignment (Optional) E.17 Analog AFC Voltage Alignment (Optional) E.18 MFC Functional Test and Tuning (Optional) E.19 AFC Functional Test (Optional) E.20 Input IF Signal Level Check E.21 Dynamic Range Check E.22 Receiver Bandwidth Check E.23 Receiver Phase Noise Check E.24 Hardcopy of Final Setups E.25 IFD Stand-alone SigGen Bench Test

. E1 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 E13 E14 E15 E16 E17 E18 E19 E21 E22 E23 E24 E26 E28 E29 E30 Index

. Index1 vii RVP8 Users Manual 12 May 2003 Figures Table of Contents Figure 11: Analog vs Digital Receiver for Magnetron Systems Figure 12: Analog vs Digital Receiver for Klystron Systems Figure 13: IF to I/Q Processing Steps Figure 14: I/Q Processing for Weather Moment Extraction Figure 21: Calibration Plot for a Stand-alone 14-Bit IFD Figure 22: Tradeoff Between Dynamic Range and Sensitivity Figure 23: Assembly Diagram of the DAFC Figure 24: Recommended Receiving Circuit for the Coax Uplink Figure 25: Timing Diagram of the IFD Coax Uplink Figure 26: Timing diagram of the (I,Q) Data Stream Figure 41: Oscilloscope Display of Test Pattern Figure 42: Successful Capture of the Transmit Burst Figure 43: Example of a Filter With Excellent DC Rejection Figure 44: Example of a Poorly Matched Filter Figure 45: Example of a Filter With Poor DC Rejection Figure 46: Example of Combined IF Sample and LOG Plot Figure 47: Example of a Noisy High Resolution Pr Spectrum Figure 51: Flow Diagram of RVP8 Processing Figure 52: Linearization of Saturated Signals Above +4dBm Figure 53: Model Intensity Curve Figure 54: Illustration of Losses that Affect LOG Calibration Figure 55: Dual PRF Concepts Figure 56: Example of Dual PRF Trigger Waveforms Figure 57: Dual Receiver Magnetron Case Figure 58: Comparison of Pulse Pair and FFT Clutter Filters Figure 59: FFT Processing 50 pulse example Figure 510: Effect of Windowing on FFT Response to Ground Clutter Figure 511: Example of FFT Clutter Filter in Frequency Domain Figure 512: Random Phase Processing Algorithm Figure B1: Main Chassis- Front Panel Figure B2: Main Chassis- Back Panel Figure B3: Main Chassis- Right Side View Figure B4: Main Chassis Internal Cabling Figure B5: RVP8 I/O-62 Connector Panel Figure B6: RCP8 I/O-62 Connector Panel Figure B7: RVP8/IFD Module Figure B8: IFD Front Panel Figure B9: View of DAFC Module Figure C1: 40 dB IIR Clutter Filter Responses Figure C2: 50 dB IIR Clutter Filters Responses

. 119 120 123 126 210 211 227 232 233 236 43 46 411 420 422 423 425 53 510 525 528 533 535 540 564 566 567 568 574 B3 B4 B5 B6 B14 B15 B29 B30 B31 C3 C4 viii RVP8 Users Manual 12 May 2003 Tables Table of Contents Table 11: Examples of Dual PRF Velocity Unfolding Table 21: Differences Among Versions of the IFD Table 22: IFD I/O Connections Table 23: IFD Toggle Switch Settings Table 24: IFD LED Indicator Interpretations Table 25: IFD Internal Jumper Settings Table 26: Direct Connections to RVP8 Main Chassis Table 27: DAFC Protocol Jumper Selections Table 28: Pinout for the CTI MVSR-xxx STALO Table 29: Bit Assignments for the IFD Coax Uplink Table 51: Algebraic Quantities Within the RVP8 Processor Table 52: Algorithm Results for +16dB Interference Table 53: Algorithm Results for +26dB Interference Table 62: RVP8 Status Output Words Table B1: J1 AZ INPUT Table B2: J2 AZ OUTPUT Table B3: J3 RVP8: PHASE OUT; RCP8 CONTROL Table B4: J4 EL INPUT Table B5: J5 EL OUTPUT Table B6: J6 RELAY Table B7: J7: RVP8 SPARE; RCP8 BITE 19:0 Table B8: J8: RVP8 SPARE; RCP8 ANALOG IN Table B9: J9 RVP8: MISC I/O ; RCP8: PED/STATUS Table B10: J10 SERIAL Table B11: J11 SERIAL Table B12: J12 SD Table B13: RVP8 BNC Connector Pin Assignments Table B14: RCP8 BNC Connector Pin Assignments Table C1: Doppler 40dB Clutter Filter Coefficients Table C2: Doppler 50dB Clutter Filter Coefficients

. 128 23 25 26 26 27 219 228 230 233 52 58 59 622 B16 B17 B18 B19 B20 B21 B22 B23 B24 B25 B25 B26 B27 B27 C1 C2 ix RVP8 Users Manual April 2003 Preface Hardware Limited Warranty SIGMET, Inc. warrants its IRIS hardware (RVP8 and RCP8) to function according to the hardware Users Manual documentation for a period of one year following delivery. In the event of a failure during the warranty period, the customer should notify SIGMET to obtain a Return Authorization. Upon receiving the Return Authorization from SIGMET, the customer ships the failed unit to SIGMET by pre-paid freight. SIGMET, at its option, will repair or replace the defective unit within 30 days and return the unit to the customer. Damage caused by fire, flood, lightning, or other catastrophe, and damage caused by misuse or abuse are not covered by this warranty. In no event shall SIGMET, Inc. be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the hardware or documentation provided by SIGMET, Inc. SIGMET, Inc. makes no warranty, either express or implied, with respect to any of the hardware or documentation, as to the quality, performance, merchantability, or fitness for a particular purpose. x RVP8 Users Manual April 2003 Preface Preface This manual provides technical information on the RVP8 digital receiver and Doppler signal processor. About This Manual This manual is used primarily by engineers for installation and troubleshooting, or by users interested in understanding the signal processing features, algorithms, and control and data formats. Chapter 1, Introduction and Specifications, describes the major features of the RVP8 signal processor and gives its technical specifications. Chapter 2, Hardware Installation, discusses the electrical issues involved with installing the RVP8 processor and IFD receiver module. This includes power supply connections, radar analog and digital signal interfaces and computer interface connections. Software installation is covered in a separate Appendix. Chapter 3, TTY Nonvolatile Setups, continues the installation discussion by describing how to use the local TTY to configure the actual operation of the RVP8. This includes a detailed description of the (approximately one hundred) setup parameters that affect the operation of the RVP8. Chapter 4, Plot-Assisted Setups, completes the installation discussion by using the oscilloscope plotting modes to configure and align the radar receiver, and measure its performance. Chapter 5, Processing Algorithms, gives mathematical descriptions of the processing algorithms implemented in the RVP8 signal processor. This information can be useful to those writing their own interface to the RVP8, or for those who want to learn more about the internal workings of the signal processor. Chapter 6, Host Computer Commands, contains a description of the digital commands that the host computer must use to set up and control the RVP8 processor. The introductory section discusses processor I/O in general, and gives an overview of how to set up the RVP8 for recording data. Each command is then detailed in subsequent sections. The appendixes give information on software installation and backup, the RVP8 standard chassis, and clutter filter characteristics. xi RVP8 Users Manual April 2003 Preface Where to Find More Information The following manuals are also available from SIGMET, Inc.:

IRIS Installation Manual IRIS Radar Manual IRIS Product & Display Manual IRIS Utilities Manual IRIS Programmers Manual The RCP8 Users Manual Describes the procedures for installing and upgrading IRIS and the specific hardware and software configuration for your facility. Describes the IRIS/Radar software. This manual is for radar operators. Describes the IRIS/Analysis product generation software and the IRIS/Display software. Describes the utility programs for system alignment, calibration, installation and testing. Describes the data formats and library routines used by IRIS. This manual is for programmers who want to access IRIS data or interface to IRIS processes. Describes the installation, operation and technical details of the Radar Control Processor. The RCP8 is an interface between the IRIS software and miscellaneous hardware such as the antenna and transmitter. SIGMET, Inc. encourages you to send your comments and/or corrections to:

SIGMET, Inc. 2 Park Drive, Suite 1 Westford, Massachusetts 01886 USA FAX (978)6929575 EMAIL support@sigmet.com Documentation Conventions The following conventions are used throughout this manual:

prompt Some features of the RVP8 operate by displaying questions and waiting for you to type an answer. The text of prompts is displayed in bold, monospaced type. This margin icon indicates a note that may be of interest to the reader. This margin icon indicates a note that is important to the reader. This margin icon indicates a caution or warning to the reader. xii RVP8 Users Manual May 2003 Introduction and Specifications 1. Introduction and Specifications The RVP8 Lineage SIGMET Inc. has a 20-year history of supplying innovative, high-quality signal processing products to the weather radar community. The history of SIGMET products reads like a history of weather radar signal processing:

Year 1981 Model FFT Units Sold 10 1985 RVP5 161 1986 PP02 12 1992 RVP6 150 1996 RVP7

>200 2003 RVP8 Major Technical Milestones First commercial FFT-based Doppler signal processor for weath-

er radar applications. Featured Simultaneous Doppler and inten-

sity processing. First single-board low-cost Doppler signal processor. First com-

mercial application of dual PRF velocity unfolding algorithm. First high-performance commercial pulse pair processor with 18.75-m bin spacing and 1024 bins. First commercial floating-point DSP-chip based processor. First commercial processor to implement selectable pulse pair, FFT or random phase 2nd trip echo filtering. First commercial processor to implement fully digital IF process-

ing for weather radar. First digital receiver/signal processor to be implemented using an open hardware and software architecture on standard PC hard-

ware under the Linux operating system. Public APIs are pro-

vided so that customers may implement their own custom proc-

essing algorithms. Much of the proven, tested, documented software from the highly-successful RVP7 (written in C) is ported directly to the new RVP8 architecture. This allows SIGMET to reduce time-to-market and produce a high-quality, reliable system from day one. However, the new RVP8 is not simply a re-hosting of the RVP7. The RVP8 provides new capabilities for weather radar systems that, until now, were not available outside of the research community. Advanced Digital Transmitter Option For example, the RVP8 takes the next logical step after a digital receiver- a digitally synthesized IF transmit waveform output that is mixed with the STALO to provide the RF waveform to the transmitter amplifier (e.g., Klystron or TWT). The optional RVP8/Tx card opens the door for advanced processing algorithms such as pulse compression, frequency agility and phase agility that were not possible before, or done in more costly ways. 11 RVP8 Users Manual May 2003 Introduction and Specifications Open Hardware and Software Design Compared to previous processors that were built around proprietary DSP chips, perhaps the most innovative aspect of the RVP8 is that it is implemented on standard PC hardware and software that can be purchased from a wide variety of sources. The Intel Pentium/PCI approach promises continued improvement in processor speed, bus bandwidth and the availability of lowcost compatible hardware and peripherals. The performance of an entry level RVP8 (currently dual 2.4 GHz Pentium processors) is 6 times faster than the fastest RVP7 ever produced (with two RVP7/AUX boards). Aside from the open hardware approach, the RVP8 has an open software approach as well. The RVP8 runs in the context of the Linux operating system. The code is structured and public APIs are provided so that research customers can modify/replace existing SIGMET algorithms, or write their own software from scratch using the RVP8 software structure as a foundation on which to build. The advantage of the open hardware and software PCI approach is reduced cost and the ability for customers to maintain, upgrade and expand the processor in the future by purchasing standard, low cost PC components from local sources. SoftPlane HighSpeed I/O Interconnect There are potentially many different I/O signals emanating from the backpanel of the RVP8. Most of these conform to well-known electrical and protocol standards (VGA, SCSI, 10BaseT, RS-232 Serial, PS/2 Keyboard, etc.), and can be driven by standard commercial boards that are available from multiple vendors. However, there are other interface signals such as triggers and clocks that require careful timing. These precise signals cannot tolerate the PCI bus latency. For signals that have mediumspeed requirements (~1 microsec latency) for which the PCI bus is inappropriate; and others that require a highspeed (~ 1 ns latency) connection that can only be achieved with a dedicated wire, the RVP8 Softplane provides the solution. Physically, the Softplane is a 16-wire digital daisy-chain bus that plugs into the tops of the RVP8/Rx, RVP8/Tx, and I/O boards. The wires connect to the FPGA chips on each card, and the function of each wire is assigned at runtime based on the connectivity needs of the overall system. The Softplane allocates a dedicated wire to carry each high-speed signal; but groups of medium-speed signals are multiplexed onto single wires in order to conserve resources. Even though there are only 16 wires available, the Softplane is able to carry several high-speed signals and hundreds of mediumspeed signals, as long as the total bandwidth does not exceed about 600MBits/sec. The Softplane I/O is configured at runtime based on a file description rather than custom wiring such as wirewrap. Neither the PCI backplane nor the physical Softplane are customized in any way. Since there is no custom wiring, a failed board can be replaced with a generic offtheshelf spare, and that spare will automatically resume whatever functions had been assigned to the original board. Similarly, if the chassis itself were to fail, then simply plugging the boards into another generic chassis would restore complete operation. Cards and chassis can be swapped between systems without needing to worry about custom wiring. 12 RVP8 Users Manual May 2003 Introduction and Specifications Standard LAN Interconnection for Data Transfer or Parallel Processing For communication with the outside world, the RVP8 supports as standard a 10/100/1000 Base T Ethernet. For most applications, the 100 BaseT Ethernet is used to transfer moment results (Z, T, V, W) to the applications host computer (e.g., a product generator). However, the gigabit Ethernet is sufficiently fast to allow UDP broadcast of the I and Q values for the purpose of archiving and/or parallel processing. In other words, a completely separate signal processor can ingest and process the I and Q values generated by the RVP8. 13 RVP8 Users Manual May 2003 Introduction and Specifications 1.1 System Configuration Concepts The hardware building blocks of an RVP8 system are actually quite few in number:

RVP8/IFD IF Digitizer Unit- This is a separate sealed unit usually mounted in the receiver cabinet. The primary input to the IFD is the received IF signal. In addition, the IFD has channels to sample the transmit pulse and to take in an external clock to phase lock the A/D conversion with the transmit pulse (not used for magnetron systems).

RVP8/Rx Card- A PCI long format card mounted in the chassis. It connects to the IFD by a fiberoptic downlink and a coax uplink which can be up to 100m distant. In addition, there are two BNC trigger input/output (programmable).

I/O-62 Card and Connector Panel- These handle all of the various I/O associated with a radar signal processor, such as triggers, antenna angles, polarization switch controls, pulse width control, etc. The Connector Panel is mounted on either the front or rear of the equipment rack and a cable (supplied) connects the panel to the I/O-62.

Optional RVP8/Tx card- This supplies two IF output signals with programmable frequency, phase and amplitude modulation. In the simplest case, it supplies the COHO which is then mixed up with the STALO to generate the transmit RF for Klystron or TWT systems. This card is not necessary for magnetron systems.

PC Chassis and Processor with various peripherals- a robust 6U rack mount unit with either a mother board or single board computer (SBC) in a passive back plane. There is a diagnostic front panel display, disk (mechanical or flash), CDRW, keyboard, mouse and optional monitor for local diagnostic work. Dual or triredundant power supplies are used and there are redundant fans as well. This modular hardware approach allows the various components to be mixed and matched to support applications ranging from a simple magnetron system to an advanced dual polarization system with pulse compression. Typically SIGMET supplies turn-key systems, although some OEM customers who produce many systems purchase individual components and integrate them by themselves. This allows OEM customers to put their own custom stamp on the processor and even their own custom software if they so choose. For the turnkey systems provided by SIGMET, the basic chassis is a 6U rackmount unit as described above. A 2U chassis can be provided for applications for which space is limited. A very low cost approach is to use a desk side PC, but this is not recommended for applications that require long periods of unattended operation. To illustrate various RVP8 configurations, some typical examples are shown below. For clarity, all the examples show the singleboard computer approach. A mother board approach is equivalent. 14 RVP8 Users Manual May 2003 Introduction and Specifications RVP8 Configuration Example: Basic Magnetron System Digital STALO IF Signal IF Magnetron Burst Optional DAFC IFD 14-Bit Triggers COAX Uplink Fiber Downlink RVP8/Rx SBC RS232C Antenna Angles 10/100 BaseT LAN Interface Utilities Mouse Monitor Keyboard Example 1: Basic Magnetron System The building blocks required to construct the basic system are:

IFD- IF Digitizer installed in the radar receiver cabinet. This can be located up to 100 meters from the RVP8 main chassis (fiber optic connection). The DAFC (Digital AFC) is an option to interface to a digitally controlled STALO. Like the RVP7, the RVP8 provides full AFC with burst pulse auto-tracking.

RVP8/Rx- The digital receiver collects digitized samples from the IFD and does the processing to obtain I/Q. It also provides two trigger connections configurable for input or output.

SBC Card- Single Board Computer with dual SMP processors (PC) running Linux. The figure above shows a basic magnetron system constructed with an IFD, and two PCI cards. A standard RS-232 serial input (included with the SBC) is used for obtaining the antenna angles and the output/input trigger is provided directly from the Rx card. This system has 5 times the processing power of the fastest version of the previous generation processor (RVP7/Main board plus 2 RVP7/AUX boards) so that it is capable of performing DFT processing in 2048 rangebins with advanced algorithms such as random phase 2nd trip echo filtering and recovery. 15 RVP8 Users Manual May 2003 Introduction and Specifications RVP8 Configuration Example: High Performance Klystron IF Signal Reference Clock IF Tx Waveform Pulse width Triggers Parallel or Synchro AZ Parallell or Synchro EL IFD 14-Bit COAX Uplink Fiber Downlink RVP8/Rx Digitally Synthesized COHO IF Tx Waveform RVP8/Tx Connector Panel 10/100/1000 Base T Utilities Mouse Monitor Keyboard I/O62 SBC Example 2: Klystron System with Digital Tx In this case, the IFD can receive a master clock from the radar system (e.g., the COHO). This ensures that the entire system is phase locked. As compared to the previous example there are two additional cards shown in this example:

RVP8/Tx- The digital transmitter card provides the digital Tx waveform. A second output can be used to provide a COHO in the event that the RVP8 is used to provide the system master clock. In any case, the IF transit waveform and the A/D sampling are phase locked.

SIGMET I/O-62 card for additional triggers, parallel, synchro or encoder AZ and EL angle inputs, pulse width control, spot blanking control output, etc. These signals are brought in via the connector panel. The figure shows the SIGMET SoftPlane which carries time-critical I/O such as clock and trigger information which is not appropriate for the PCI bus. These signals are limited to the cards provided by SIGMET, i.e., the SoftPlane is not connected to any of the standard commercial cards. 16 RVP8 Users Manual May 2003 Introduction and Specifications RVP8 Configuration Example: Dual Polarization Magnetron System Digital STALO Horizontal IF Signal IF Magnetron Burst Synch Clock Vertical IF Signal Polarization Control Pulse Width Control Triggers Parallel or Synchro AZ Parallell or Synchro EL Optional DAFC IFD 14-Bit Horz IFD 14-Bit Vert COAX Uplink Fiber Downlink COAX Uplink Fiber Downlink Connector Panel 10/100/1000 BaseT LAN Utilities Mouse Monitor Keyboard RVP8/Rx RVP8/Rx I/O62 SBC Example 3: Dual Polarization Magnetron System In this system 2 IFDs and two RVP8/Rx cards are used for the horizontal and vertical channels of a dual-channel receiver. The legacy RVP7 technique of using a single IFD and two IF frequencies for the horizontal and vertical channels (e.g., 24 and 30 MHz) is also supported by the RVP8. In the case of either dual or single IFDs, there is a synch clock provided by either the STALO reference frequency (e.g., 10 MHz) or by the RVP8 itself. The RVP8 supports calculation of the complete covariance matrix for dual pol, including ZDR, PHIDP (KDP), RHOHV, LDR, etc. Which of these variables is available depends on whether the system is a singlechannel switching system (alternate H and V), a STAR system (simultaneous transmit and receive) or a dual channel switching system (co and cross receivers). Note that for the special case of a single channel switching system, only one IFD is required. 17 RVP8 Users Manual May 2003 COTS Accessories Introduction and Specifications Aside from the basic PCI cards required for the radar application, there are additional cards that can be installed to meet different customer requirements, e.g.,

10/100BaseT Ethernet card for additional network I/O (e.g., a backup network).

RS-232/RS-422 serial cards for serial angles, remote TTY control, etc.

Sound card to synthesize audio waveforms for wind profiler applications.

GPS card for time synch.

IEEE 488 GPIB card for control of test equipment. The bottom line is that the PCI open hardware approach provides unparalleled hardware flexibility. In addition, the availability of compatible low-cost replacement or upgrade parts is assured for years into the future. 18 RVP8 Users Manual May 2003 1.1.1 IFD IF Digitizer Introduction and Specifications The IFD 14bit IF digitizer is a totally sealed unit for optimum lownoise per-

formance. The use of digital components within the IFD is minimized and the unit is carefully grounded and shielded to make the cleanest possible digital capture of the input IF signal. Because of this, the IFD achieves the theoretical minimum noise level for the A/D convertors. There are 3 inputs to the IFD:

IF signal in the nominal ranges of 20 -34, 38-52 and 56-70 MHz. The user simply enters the system IF frequency as a setup parameter.

IF Burst Pulse for magnetron or IF COHO for Klystron.

Optional reference clock for system synchronization. For a Klystron system, the COHO can be input. Magnetron systems do not require this signal. This clock can even come from the RVP8/Tx card itself. All of these inputs are on SMA connectors. The IF signal input is made imme-

diately after the STALO mixing/sideband filtering step of the receiver where a traditional log receiver would normally be installed. The required signal lev-

el for both the IF signal and burst is +6.5 dBm for the strongest expected input signal. A fixed attenuator or IF amplifier may be used to adjust the signal level to be in this range. Digitizing is performed for both the IF signal and burst/COHO channels at approximately 36 MHz to 14bits. This provides 92 to 102 dB of dynamic range (depending on pulse width) without using complex AGC, dual A/D ranging or down mixing to a lower IF frequency. The uplink from the RVP8/Rx is an SMA input on 75Ohm shielded cable. This carries timing and AFC information back to the IFD. The data downlink to the RVP8/Rx card is a fiber optic cable. The IFD may be separated from the Rx Board by up to 100 meters. The RVP8 provides comprehensive AFC support for tuning the STALO of a magnetron system. Alternatively, the magnetron itself can be tuned by a motorized tuning circuit controlled by the RVP8. Both analog (+10V) and digital tuning (with optional DAFC to 24 bits) are supported. 19 RVP8 Users Manual May 2003 Introduction and Specifications 1.1.2 Digital Receiver PCI Card (RVP8/Rx) The RVP8/Rx card receives the digitized IF samples from the IFD via the fiber optic link. The advantage of this design is that the receiver electronics (LNA, RF mixer, IF preamp, and IFD) can be located as far as 100meters away from the RVP8 main chassis. This makes it possible to choose optimum locations for both the IFD and the RVP8, e.g., the IFD could be mounted on the antenna itself, and the processor box in a nearby equipment room. The RVP8/Rx is 100% compatible with the 14bit RVP7/IFD, but it also includes hooks for future IFDs operating at higher sampling clock rates. Two additional BNC connectors are included on the boards faceplate. These can be used for trigger input, programmable trigger output, or a simple LOG analog ascope waveform. A remarkable amount of computing power is resident on the receiver board, in the form of an FIR filter array that can execute 6.9 billion multiply/accumulate cycles per second. These chips serve as the first stage of processing of the raw IF data sam-

ples. Their job is to perform the downconversion, bandpass, and deconvolution steps that are required to produce (I,Q) time series. The time series data are then trans-

ferred over the PCI bus to the SBC for final processing. The FIR filter array can buffer as much as 80 microsec of 36MHz IF samples, and then compute a pair of 2880point dot products on those data every 0.83 microsec. This could be used to produce over-sampled (I,Q) time series having a range resolution of 125meters and a bandwidth as narrow as 30Khz. The same computation could also yield independent 125meter time series data from an 80 microsec compressed pulse whose transmit bandwidth was approximately 1MHz. Finer range resolutions are also possible, down to a minimum of 25meters. A special feature of the RVP8/Rx is that the bin spacing of the (I,Q) data can be set to any desired value between 25 and 2000 meters. Range bins are placed accurately to within +2.2 meters of any selected grid, which does not have to be an integer multiple of the sampling clock. However, when an integer multiple (N x 8.333meters) is selected, the error in bin placement effectively drops to zero. Dual polarization radars that are capable of simultaneous reception for both horizontal and vertical channels can be interfaced to the RVP8 using a separate RVP8/Rx and IFD for each channel. Note that the multiplexed dual IF approach used for the RVP7 with a single IFD can also be used. One of the primary advantages of the digital receiver approach is that wide linear dynamic range can be achieved without the need for complex AGC circuits that require both phase and amplitude calibration. 110 RVP8 Users Manual May 2003 Calibration Plot for RVP8/IFD Introduction and Specifications The figure above shows a calibration plot for a 14bit IFD with the digital filter matched to a 2 microsecond pulse. The performance in this case is >100 dB dynamic range fully linear. The RVP8 performs several real time signal corrections to the I/Q samples from the Rx, including:

Amplitude Correction- A running average of the transmit pulse power in the magnetron burst channel is computed in real-time by the RVP8/Rx. The individual received I/Q samples are corrected for pulsetopulse deviations from this average. This can substantially improve the phase stability of a magnetron system to improve the clutter cancelation performance to near Klystron levels. Phase Correction- The phase of the transmit waveform is measured for each pulse (either the burst pulse for magnetron systems or the Tx Waveform for coherent systems). The I/Q values are adjusted for the actual measured phase. The coherency achievable is better than 0.1 degrees by this technique. Large Signal Linearization- When an IF signal saturates, there is still considerable information in the signal since only the peaks are clipped. The proprietary large signal linearization algorithm used in the RVP8 provides an extra 3 to 4 dB of dynamic range by accounting for the effects of saturation. The RVP8/Rx card provides the same comprehensive configuration and test utilities as the RVP7, with the difference that no external host computer is required to run the utilities. These utilities can be run either locally or remotely over the network! Some examples are shown below:

111 RVP8 Users Manual May 2003 Introduction and Specifications Digital IF Band Pass Design Tool Burst Pulse Alignment Tool Received Signal Spectrum Analysis Tool The builtin filter design tool makes it easy for anyone to design the optimal IF filter to match each pulse width and application. Simply specify the impulse response and pass band and the filter appears. The user interface makes it easy to wid-

en/narrow the filter with simple keyboard com-

mands. There is even a command to automatical-

ly search for an optimal filter. This display can also show the actual spectrum of the transmit burst pulse for quality control and comparison with the filter. The quality assessment of the transmit burst pulse and its precise alignment at range zero are easy to do, either manually using this tool and/or automatically using the burst pulse auto-track feature. This performs a 2D search in both time and frequency space if a valid burst pulse is not detected. The automatic tracking makes the AFC robust to startup temperature changes and pulse width changes that can effect the magnetron frequency. AFC alignment/check is now much easier since it can be done manually from a central maintenance site or fully automatically. The RVP8 provides plots of the IF signal versus range as well as spectrum analysis of the signal as shown in this example. In the past, these types of displays and tools re-

quired that a highly-skilled engineer transport some very expensive test equipment to the radar site. Now, detailed analysis and configuration can all be done from a central maintenance facil-

ity via the network. For a multi-radar network this results in substantial savings in equipment, time and labor. 112 RVP8 Users Manual May 2003 Introduction and Specifications 1.1.3 Mother Board or Single-Board Computer (SBC) The dual-CPU Pentium mother board or single-board computer (SBC) acts as the host to the Linux operating system and provides all of the compute resources for processing the I/Q values that are generated by the RVP8/Rx card. Standard keyboard, mouse and monitor connections are on the Rx backpanel, along with a 10/100/1000 BaseT Ether-

net port. The system does not require that a keyboard, mouse or monitor be connected which is typically the case at an unattended site. An SBC example is shown on the left. Motherboards and SBCs are available from many vendors, at various speeds Typical-

ly the SBC is equipped with 128 MB RAM. The RVP8 chassis has a front bay for either a >20 GB hard disk or a Flash Disk. The Flash Disk approach is well suited to applica-

tions where highreliability is important. CDRW is also provided for software mainte-

nance. Note that the latest versions of the RVP8 software and documentation can al-

ways be down-loaded from SIGMETs web site for FREE. The SBC also plays host for SIGMETs RVP8 Utilities which provide test, configura-

tion, control and monitoring software as well as builtin on-line documentation. 1.1.4 Digital Transmitter PCI Card (RVP8/Tx) Many of the exciting new meteorological applications for the RVP8 are made possible by its ability to function as a digital radar transmitter. The RVP8/Tx PCI card synthe-

sizes an output waveform that is centered at at the radars intermediate frequency. This signal is filtered using analog components, then upconverted to RF, and finally am-

plified for transmission. The actual transmitter can be a solid state or vacuum tube de-

vice. The RVP8 can even correct for waveform distortion by adaptively predistort-

ing the transmit waveform, based on the measured transmit burst sample. The Tx card has a BNC output for the IF Tx waveform. In addition, there is a second output for an auxiliary signal or clock, or for a clock input. At the bottom of the card is a 9pin connector for arbitrary I/O (e.g., TTL, RS422, additional clock). The RVP8 digital transmitter finds a place within the overall radar system that exactly complements the digital receiver. The receiver samples an IF waveform that has been downconverted from RF, and the transmitter synthesizes an IF waveform for upcon-

version to RF. The beauty of this approach is that the RVP8 now has complete control over both halves of the radar, making possible a whole new realm of matched Tx/Rx processing algorithms. Some examples are given below:

Phase Modulation- Some radar processing algorithms rely on modulating the phase of the transmitter from pulse to pulse. This is traditionally done using an external IF phase modulator that is operated by digital control lines. While this usually works well, it requires additional hardware and cabling within the radar cabinet, and the 113 RVP8 Users Manual May 2003 Introduction and Specifications phase/amplitude characteristics may not be precise or repeatable. In contrast, the RVP8/Tx can perform precise phase modulation to any desired angle, without requiring the use of external phase shifting hardware.

Pulse Compression- There is increasing demand for siting radars in urban areas that also happen to have strict regulations on transmit emissions. Often the peak transmit power is limited in these areas; so the job for the weather radar is to somehow illuminate its targets using longer pulses at lower power. The problem, of course, is that a simple long pulse lacks the ability (bandwidth) to discern targets in range. The remedy is to increase the Tx bandwidth by modulating the overall pulse envelope, so that a reasonable range resolution is restored. The exceptional fidelity of the RVP8/Tx waveform can accomplish this without introducing any of the spurious modulation components that often occur when external phase modulation hardware is used.

Frequency Agility- This has been well studied within the research community, but has remained out of the reach of practical weather radars. The RVP8/Tx changes all of this, because frequency agility is as simple as changing the center frequency of the synthesized IF waveform. Many new Range/Doppler unfolding algorithms become possible when multiple transmit frequencies can coexist. Frequency agility can also be combined with pulse compression to remedy the blind spot at close ranges while the long pulse is being transmitted.

COHO synthesis- The RVP8/Tx output waveform can be programmed to be a simple CW sine wave. It can be synthesized at any desired frequency and amplitude, and its phase is locked to the other system clocks. If you need a dedicated oscillator at some random frequency in the IF band, this is a simple way to get it. 114 RVP8 Users Manual May 2003 Introduction and Specifications 1.1.5 I/O-62 PCI Card and I/O Panel The SIGMET I/O-62 is a short format PCI card that provides extensive I/O capabilities for the RVP8. A typical installation would have one I/O-62 and an RVP8 Connector Panel shown above. The Softplane is used to interconnect the I/O 62 with other SIG-

MET PCI cards. Note that the identical card is used in the SIGMET RCP8 radar/anten-

na control processor which in general does not use the Softplane connection. The I/O-62 has a single 62-position, high-density D connector. This is attached to the RVP8 Connector Panel (typically mounted on the front or back of the rack which holds the RVP8). A standard 1:1 cable connects the remote panel to the I/O-62 card in the RCP8 chassis. The standard connector panel provided by SIGMET meets the needs of most radar sites. The best part is that the I/O-62 is configurable in software, i.e., there is no need to open the chassis to configure jumpers or switches. This means that when a spare board is added, there is no need to perform hardware configuration or custom wiring. The physical I/O lines are summarized in the system specifications section. ESD Protection Features Since the I/O lines are connected to the radar system, there is a potential for lightning or other ESD type damage. This is addressed aggressively by the I/O-62 in two ways:

Every wire is protected by a Tranzorb diode which transitions from an open to a full clamp between 27 to 35 VDC. Additionally, the Connector Panel uses Tranzorb diodes on every I/O line for double protection.

High-voltage tolerant front-end receivers/drivers are used. All components connected to the external pins can tolerate up to 40V. For example, the TTL and wide range inputs use protectors that normally look like 100 Ohm resistors, but open at high voltage. 115 RVP8 Users Manual May 2003 Run Time FPGA Configuration Introduction and Specifications The SIGMET I/O-62 card is built around a 100KGate FPGA which, in addition to driving the I/O signals on the 62-position connector, also coordinates the PCI and Softplane traffic. These chips are SRAMbased, meaning that they are configured at run time. This allows the FPGA code to be automatically upgraded during each RVP8 code release without needing to physically reprogram any parts. The boards basic I/O services use up only 40% of the complete FPGA. The leftover space makes it possible to add smart processing right on the I/O-62 board to handle custom needs. For example the 16bit floatingpoint (I,Q) data in the previous example could be reformatted into a 32bit fixedpoint stream. Other examples include generating custom serial formats, data debouncing, and signal transition detection. In general, I/O functions that would either be tedious or inappropriate for the host computer SBC can likely be moved onto the I/O-62 card itself. 116 RVP8 Users Manual May 2003 Introduction and Specifications 1.2 Comparison of Analog vs Digital Radar Receivers 1.2.1 What is a Digital IF Receiver?

A digital IF receiver accepts the analog IF signal (typically 30 MHz), processes it and outputs a stream of wide dynamic range digital I and Q values. These quantities are then processed to obtain the moment data (e.g., Z, V, W or polarization variables). Additionally, the digital receiver can accept the transmit pulse burst sample for the purpose of measuring the frequency, phase and power of the transmit pulse. The functions that can be performed by the digital receiver are:

IF band pass filtering I and Q calculation over wide dynamic range

Phase measurement and correction of transmitted pulse for magnetron systems from burst sample

Amplitude measurement and correction of transmitted pulse from burst sample

Frequency measurement for AFC output from burst sample The digital approach replaces virtually all of the traditional IF receiver components with flexible software-controlled modules that can be easily adapted to function for a wide variety of radars and operational requirements. The digital receiver approach made a very rapid entry into the weather radar market. Up until the about 1997 weather radars were not supplied with digital receivers. Today in 2003 nearly all new weather radars and weather radar upgrades use the digital receiver approach. Much of this rapid change is attributed to the previous generation RVP7 which is the most widely sold weather radar signal processor of all time. The number one advantage of a digital receiver is that it achieves a wide linear dynamic range

(e.g., >95dB depending on pulse width) without having to use AGC circuits which are complex to build, calibrate and maintain. However, there are other advantages as well:

Lower initial cost by eliminating virtually all IF receiver components.

Lower life cycle cost do to reduced maintenance.

Selectable IF frequency.

Software controlled AFC with automatic alignment.

Programmable band pass filter

Dual or multiple IF multiplexing

Improved remote monitoring down to the IF level. The following sections compare the digital receiver approach to the analog receiver approach. This illustrates the advantages of the digital approach and what functions are performed by a digital receiver. 117 RVP8 Users Manual May 2003 Introduction and Specifications 1.2.2 Magnetron Receiver Example A typical analog receiver for a magnetron system is shown in the top portion of Figure 11. The received RF signal from the LNA is first mixed with the STALO (RFIF) and the resulting IF signal is applied to one of several bandpass filters that match the width of the transmitted pulse. The filter selection is usually done with relays. The narrow band waveform is then split. Half is applied to a LOG amplifier having a dynamic range of 80100dB, from which a calibrated measurement of signal power can be obtained. The LOG amplifier is required because it is almost impossible to build a linear amplifier with the required dynamic range. However, phase distortion within the LOG amplifier renders it unsuitable for making Doppler measurements;

hence, a separate linear channel is still required. The linear amplifier is fed from the other half of the bandpass filter split. It may be preceded by a gain control circuit (IAGC) which adjusts the instantaneous signal strength to fall within the limited dynamic range of the linear amplifier. The amplitude and phase characteristics of the IAGC attenuator must be calibrated so that the I and Q samples may be corrected during processing. The IF output from the linear amplifier is applied to a pair of mixers that produce I and Q. The mixer pair must have very symmetric phase and gain characteristics, and each must be supplied with an accurate 0-degree and 90-degree version of the Coherent Local Oscillator

(COHO). The later is usually obtained by sampling a portion of the transmitted pulse, and then phase locking an oscillator (COHO) that continues to ring afterward. Phase locked COHOs of this sort can be very troublesome they often fail to lock properly, drift with age, and fail to maintain coherence over the full unambiguous range. The transmit burst that locks the COHO is also used by the Automatic Frequency Control (AFC) loop. The AFC relies on an FM discriminator and low pass filter to produce a correction voltage that maintains a constant difference between the magnetron frequency and the reference STALO frequency. The AFC circuit is often troublesome to set and maintain. Also, since it operates continuously, small phase errors are continually being introduced within each coherent processing interval. In contrast, the RVP8 digital receiver is shown in to lower portion of Figure 11. The only old parts that still remain are the microwave STALO oscillator, and the mixer that produces the transmit burst. The burst pulse and the analog IF waveform are cabled directly into the IFD on SMA coax cables. Likewise, the AFC control voltage is also a simple direct connection either with analog tuning (+10V from IFD) or digital control via the optional DAFC interface. These cables constitute the complete interface to the radars internal signals; no other connections are required within the receiver cabinet. 118 RVP8 Users Manual May 2003 Introduction and Specifications Figure 11: Analog vs Digital Receiver for Magnetron Systems Classic Analog Receiver for Magnetron Analog RF From LNA Analog IF X IF Filters Matched to Pulse Widths BPF BPF BPF BPF Split STALO AFC Signal Split Digital Atten IAGC Control Bits From IAGC Logic Linear Amp LOG Quad Phase Detector LOG I Q Line Drivers Phase Locked IF IF Tx Sample COHO Low Q Locking COHO AFC Split RF Tx Burst Analog RF From LNA X X RVP8 Magnetron Interface Analog IF Split STALO RF Tx Burst X IF Digitizer IFD Fiber Optic Downlink COAX Uplink IF Tx Sample

+10V Analog AFC RVP8/Rx 24 bits Digital AFC Control DAFC Optional 119 RVP8 Users Manual May 2003 Introduction and Specifications 1.2.3 Klystron or TWT Receiver and Transmit RF Example A typical analog receiver for a klystron system is shown in the top portion of Figure 12. The arrangement of components is similar to the magnetron case, except that the COHO operates at a fixed phase and frequency, a phase shifter is included for 2nd trip echo filtering and there is no AFC feedback required. The phase stability of a Klystron system is better than a magnetron, but the system is still constrained by limited linear dynamic range, IAGC inaccuracy, quad phase detector asymmetries, phase shifter inaccuracies, etc. The RVP8/Tx card now plays the role of a programmable COHO. The digitally synthesized transmit waveform can be phase, frequency and amplitude modulated (no separate phase shifter is required) and even produce multiple simultaneous transmit frequencies. These capabilities are used to support advanced algorithms, e.g., range/velocity ambiguity resolution or pulse compression for low power TWT systems. Figure 12: Analog vs Digital Receiver for Klystron Systems Classic Receiver and Transmit RF for Klystron Analog RF From LNA Analog IF X Split STALO BPF BPF BPF BPF Transmit RF To Klystron Analog RF From LNA X X LOG Quad Phase Detector IF COHO Split Digital Atten IAGC Control Bits From IAGC Logic Linear Amp Phase Shifter Control Bits LOG I Q Line Drivers Analog IF RVP8 Klystron Interface Split STALO X X RF Tx Sample Transmit RF To Klystron IF Digitizer IFD Fiber Optic Downlink COAX Uplink Optional CLK IF Tx Sample Digital Synthesized IF (smart COHO) RVP8/Rx RVP8/Tx 120 D f RVP8 Users Manual May 2003 Introduction and Specifications 1.3 RVP8 IF Signal Processing 1.3.1 IFD Data Capture and Timing The RVP8 design concept is to perform very little signal processing within the IFD digitizer module itself. This is to minimize the presence of digital components that might interfere with the clean capture of the IF signals. The digitized IF and burst pulse samples are multiplexed onto the fiber channel link which provides the digital data to the RVP8/Main board at approximately 540-MBits/sec. The 14-bit samples are encoded for transmission over a fiber channel link. This optical link allows the IFD to be as far as 100 meters away from the RVP8/Main board and provides an added degree of noise immunity and isolation. The uplink input from the RVP8/Main board provides the timing for multiplexing the burst pulse sample with the IF signal. In addition, it is used to set the AFC DAC or digital output level, and to perform self tests. The sample clock oscillator in the IFD is selected to be very stable. The sample clock serves a similar function to the COHO on a traditional Klystron system, i.e., it is the master time keeper. Because of this the IFD sample clock is used to phase lock the entire RVP8, i.e., the Rx, Tx, IO-62 boards and the SoftPlane are all phase locked to the IFD sample clock. Designers have two choices for factory configuration of the IFD sample clock:

A fixed crystal frequency selected to achieve a desired range resolution. The standard range resolution corresponds to 25 m increments.

A very narrow band VCXO (50 ppm) selected to lock to an input reference signal from the radar, and provide a desired range resolution. SIGMET stocks VCXOs for 25 m range resolution increments for reference inputs of 10, 20, 30 and 60 MHz. Custom frequency VCXOs are available on request. Examples of external reference signal sources are an external COHO, external STALO reference or perhaps even a GPS clock). 121 RVP8 Users Manual May 2003 Introduction and Specifications 1.3.2 Burst Pulse Analysis for Amplitude/Frequency/Phase The burst pulse analysis provides the ampli-

tude, frequency and phase of the transmitted pulse. The phase measurement is analogous to the COHO locking that is performed by a tradi-

tional magnetron radar. The difference is that the phase is known in the digital technique, so that range dealiasing using the phase modula-

tion techniques is possible. Amplitude mea-

surement (not performed by traditional radars) can provide enhanced performance by allow-

ing the I and Q values to be corrected for variations in the both the average and the pulse-

to-pulse transmitted power. In addition, a warning is issued if the burst pulse amplitude falls below a threshold value. The burst pulse data stream is first analyzed by an adaptive algorithm to locate the burst pulse power envelope (e.g. 0.8 sec). The algorithm first does a coarse search for the burst pulse in the time/frequency domain (by scanning the AFC) and then does a fine search in both time and frequency, to assure that the burst is centered at range 0 and is at the required IF value. The power-weighted phase of the burst pulse and the total burst pulse power is then computed. The power weighted average phase is used to make the digital phase correction. Phase jitter for magnetron systems with good quality modulator and STALO is better than 0.5 degrees RMS, as measured on actual nearby clutter targets. For Klystron systems, the phase locking is better than 0.1 degree RMS. The burst pulse frequency is also analyzed to calculate the frequency error from the nominal IF frequency. For magnetron systems, the error is filtered with a selectable time constant which is typically set to several minutes to compensate for slow drift of the magnetron. The digital frequency error is sent via the uplink to the IFD in the receiver cabinet where a DAC converts it into an analog output to the magnetron STALO. Optionally, a DAFC unit can be Teed off the uplink cable to interface to Klystron systems do not require the AFC. 122 RVP8 Users Manual May 2003 Introduction and Specifications 1.3.3 Rx Board and CPU IF to I/Q Processing Figure 13: IF to I/Q Processing Steps IF to I/Q Processing Steps IFD Fiber Optic Downlink Digitized IF Signal and Tx Burst Sample IFD COAX Uplink Timing and digital AFC Fiber Optic Receiver Digital IF IF Tx Samples Digital AFC RVP8/Rx Digital FIR Bandpass Filter Digital Quad Phase and Decompression I/Q Signal I/Q Tx Burst PCI AFC Servo Frequency IF Tx Samples I/Q Signal I/Q Tx Burst CPU I/Q Moment Processing Amplitude/

Phase Correction I/Q Interference Filter I/Q Time Series API Tx Burst Pulse Analysis UDP Broadcast I/Q Samples to recording system or separate processing system 1000 BaseT Ethernet The RVP8/Rx board performs the initial processing of the IF digital data stream and outputs I and Q data values to the host computer via the PCI bus. In addition, the frequency, phase and amplitude of the burst pulse are measured. The functions performed by the processor are:

Reception of the digital serial fiber optic data stream.

Band pass filtering of the IF signal using configurable digital FIR filter matched to the pulsewidth.

Range gating and optional coherent averaging (essentially performed during the band pass filtering step). 123 RVP8 Users Manual May 2003 Introduction and Specifications

Computation of I and Q quadrature values (also performed during the band pass filtering step).

Transmit burst sample frequency, phase and amplitude calculation

I and Q phase and amplitude correction based on transmit burst sample. Interference rejection algorithm.

AFC frequency error calculation with output to IFD for digital or analog control of STALO (for magnetron systems). The advantage of the digital approach is that the software algorithms for these functions can be easily changed. Configuration information (e.g., processor major mode, PRF, pulsewidth, gate spacing, etc.) is supplied from the host computer. The digital matched filter that computes I and Q is designed in an interactive man-

ner using a TTY and oscilloscope for graph-

ical display. The filters passband width and impulse response length are chosen by the user, and the RVP8 constructs the filter coefficients using built-in design software. The frequency response of the filter can be displayed and compared to the frequency content of the actual transmitted pulse. Microwave energy can come from a variety of transmitters such as ground-based, ship-based or airborne radars as well as communications links. These can cause substantial interference to a weather radar system. Interference rejection is provided as standard in the RVP8. Three different interference rejection algorithms are supported. The RVP8/Rx board places the wide dynamic range I and Q samples directly on the PCI bus where they are sent to the processor section of the PC (e.g., dual Pentium processors on a single-board computer or motherboard). The I/Q values are then processed on the Pentium processors to extract the moment information (Z, V, W and optional polarization parameters). The I and Q values can also be placed on a gigabit Ethernet line (1000 BaseT) which is provided directly on the processor board. This means that there is no second PCI bus hit required to send the data to a recording system or a completely separate processing system. 124 RVP8 Users Manual May 2003 Introduction and Specifications 1.4 RVP8 Weather Signal Processing The processing of weather signals by the RVP8 is based on the algorithms used in the previous generation RVP7 and RVP6. However, the performance of the RVP8 allows a different approach to some of the processing algorithms, especially the frequency domain spectrum processing. All of the algorithms start with the wide dynamic range I and Q samples that are obtained from the Rx card over the PCI bus. The resulting intensity, radial velocity, spectrum width and polarization measurements are then sent to a separate host computer to serve as input for applications such as:

Quantitative Rainfall Measurement

Vertical Wind Profiling

ZDR Hail Detection

Tornado Detection and Microburst Detection

Gust Front Detection

Particle Identification

Target Detection and Tracking

General Weather Monitoring To obtain the basic moments, the RVP8 offers the option of several major processing modes:

Pulse Pair Mode Time Domain Processing

DFT/FFT Mode Frequency Domain Processing

Random Phase Mode for 2nd trip echo filtering

Polarization Mode Processing Note that the RVP8 is the first commercial processor to perform discrete Fourier transforms

(DFT) as well as fast Fourier transforms (FFT). FFT is more computationally efficient than DFT, but the sample size is limited to be a power of two (16, 32, 64, ...) This is too restrictive on the scan strategy for a modern Doppler radar since this means, for example, that a one degree azimuth radial must be constructed from say exactly 64 input I/Q values. The RVP8 has the processing power such that when the sample size is not a power of 2, a DFT is performed instead of an FFT These modes share some common features that are described first, followed by descriptions of the unique features of each mode. 125 RVP8 Users Manual May 2003 Introduction and Specifications 1.4.1 General Processing features Figure 14 shows a block diagram of the processing steps. These are discussed below. Autocorrelations The autocorrelations R0, R1 and R2 are produced by all three processing modes. However, the way that they are produced is different for the three modes, particularly with regard to the filtering that is performed.

Pulse Pair Mode Filtering for clutter is performed in the time domain. Autocorrelations are computed in the time domain.

DFT/FFT Mode Filtering for clutter is performed in the frequency domain by an adaptive algorithm. Autocorrelations are computed from the inverse transform.

Random Phase Filtering for clutter and second trip echo is performed in the frequency domain by adaptive algorithms. Autocorrelations are computed from the inverse transform. Figure 14: I/Q Processing for Weather Moment Extraction RVP8 Standard Moment Processing Steps Time Series API I Q Clutter Filter Autocorrelations Pulse Pair, FFT/DFT, Random Phase Modes T Z V W Thresholding Speckle Filter 10/100/1000 BaseT Ethernet To Applications Host Computer Clutter Micro Suppression and Range Averaging T0 R0 R1 R2 Moment and Threshold Calculations T0 R0 R1 R2 T Z V W SQI LOG SIG CCOR The use of the R2 lag provides improved estimation of signal-to-noise ratio and spectrum width. Processors that do not use R2 cannot effectively measure the SNR and spectrum width. 126 RVP8 Users Manual May 2003 Introduction and Specifications Time (azimuth) Averaging The autocorrelations are based on input I and Q values over a selectable number of pulses between 8, 9, 10, ...,256. Any integer number of pulses in this interval may be used including DFT/FFT and random phase modes. Selectable angle synchronization using the input AZ and EL tag lines assures that all possible pulses are used during averaging for each, say, 1 degree interval. This minimizes the number of wasted pulses for maximum sensitivity. Azimuth angle synchronization also assures the accurate vertical alignment of radial data from different elevation angles in a volume scan (see below). TAG Angle Samples of Azimuth and Elevation During data acquisition and processing it is usually necessary to associate each output ray with an antenna position. To make this task simpler the RVP8 samples 32 digital input TAG lines, once at the beginning and once at the end of each data acquisition period. These samples are output in a four-word header of each processed ray. When connected to antenna azimuth and elevation, the TAG samples provide starting and ending angles for the ray, from which the midpoint could easily be deduced. Since the bits are merely passed on to the user, any angle coding scheme may be used. The processor also supports an angle synchronization mode, in which data rays are automatically aligned with a user-defined table of positions. For that application, angles may be input either in binary or BCD. Range Averaging and Clutter Microsuppression To improve the accuracy of the reflectivity measurements, the RVP8 can perform range averaging. When this is done, autocorrelations from consecutive range bins are averaged, and the result is treated as if it were a single bin. This type of averaging is useful to lower the number of range bins that the host computer must process. Range averaging of the autocorrelations may be performed over 2, 3, 4, ..., 16 bins. Prior to range averaging, any bins that exceed the selectable clutter-to-signal threshold are discarded. This prevents isolated strong clutter targets from corrupting the range average, which improves the sub-clutter visibility. Moment Extraction The autocorrelations serve as the basis for the Doppler moment calculations,

Mean velocity from Arg [ R1 ]

Spectrum width from |R1| and |R2| assuming Gaussian spectrum

dBZ from R0 with correction for ground clutter, system noise and gaseous attenuation. Uses calibration information supplied by host computer. dBT identical to dBZ except without ground clutter. These are the standard parameters that are output to the host computer on the high-speed Ethernet interface. 127 RVP8 Users Manual May 2003 Introduction and Specifications Thresholding The RVP8 calculates several parameters that are used to threshold (discard) bins with weak or corrupted signals. The thresholding parameters are:

Signal quality index (SQI=|R1|/R0)

LOG (or incoherent) signal-to-noise ratio (LOG)

SIG (coherent) signal-to-noise ratio

CCOR clutter correction These parameters are computed for each range bin and can be applied in AND/OR logical expressions independently for dBZ, V and W. Speckle Filter The speckle filter can be selected to remove isolated single bins of either velocity/width or intensity. This feature eliminates single pixel speckles which allows the thresholds to be reduced for greater sensitivity with fewer false alarms (speckles). Both a 1D (single azimuth ray) and 2D

(3 azimuth rays by 3 range bins) are supported. Velocity Unfolding A special feature of the RVP8 processor is its ability to unfold mean velocity measurements based on a dual PRF algorithm. In this technique two different radar PRFs are used for alternate N-pulse processing intervals. The internal trigger generator automatically produces the correct dual-PRF trigger, but an external trigger can also be applied. In the later case, the ENDRAY_ output line provides the indication of when to switch rates. The RVP8 measures the PRF to determine which rate (high or low) was present on a given processing interval, and then unfolds based on either a 2:3, 3:4 or 4:5 frequency ratio. Table 11 gives typical unambiguous velocity intervals for a variety of radar wavelengths and PRFs. Table 11: Examples of Dual PRF Velocity Unfolding Unambiguous Velocity (m/s) for Various Radar Wavelengths PRF1 PRF2 Unambiguous Range (km) 500 1000 2000 500 1000 2000

333 667 1333 300 150 75 300 150 75 3 cm 3.75 7.50 15.00 7.50 15.00 30.00 128 5 cm 6.25 12.50 25.00 12.50 25.00 50.00 10 cm 12.50 25.00 50.00 25.00 50.00 100.00 No U f ldi Unfolding Two Ti Times Unfolding Unfolding RVP8 Users Manual May 2003 Introduction and Specifications PRF1 PRF2 Unambiguous Range (km) 3 cm 5 cm 10 cm 500 1000 2000 500 1000 2000 375 750 1500 400 800 1600 300 150 75 300 150 75 11.25 22.50 45.00 15.00 30.00 60.00 18.75 37.50 75.00 25.00 15.00 100.00 37.50 75.00 150.00 50.00 100.00 200.00 Three Times U f ldi Unfolding Four Ti Times Unfolding Unfolding 1.4.2 RVP8 Pulse Pair Time Domain Processing Pulse pair processing is done by direct calculation of the autocorrelation. Prior to pulse pair processing, the input I and Q values are filtered for clutter using a a time domain notch filter. Filters of various selectable widths are available for either 40 or 50 dB stop band attenuation. The filtered I/Q values are processed to obtain the autocorrelation lags R0, R1 and R2. The unfiltered power is also calculated (T0). The autocorrelations are then sent to the range averaging and moment extraction steps. 1.4.3 RVP8 DFT/FFT Processing The DFT/FFT mode allows clutter cancelation to be performed in the frequency domain. DFT is used in general, with FFTs used if the requested sample size is a power of 2. Three standard windows are supported to provide the best match of window width to the spectrum dynamic range:

Rectangular

Hamming

Blackman After the FFT step, clutter cancelation is done using a selectable fixed width filter that interpolates across the noise or any overlapped weather or an adaptive filter which automatically determines the optimal width. This technique preserves overlapped weather as compared to time domain notch filters which will always attenuate overlapped weather to some extent, depending on the spectrum width. After clutter cancelation, R0, R1 and R2 are computed by inverse transform and these are used for moment estimation. 129 RVP8 Users Manual May 2003 Introduction and Specifications 1.4.4 Random Phase Processing for 2nd Trip Echo Second trip echoes can be a serious problem for applications that require operation at a high PRF. Second trip echoes can appear separately or can be overlaid on first trip echoes (second trip obscuration). The random phase technique separates the first and second trip echoes so that:

In nearly all cases, the 2nd trip echo can be removed from the first trip even in the case of overlapped 1st and 2nd trip echoes. The benefit is a clean first trip display.

The 2nd trip echoes can be recovered and placed at their proper range at 1st trip/2nd trip signal ratios of up to 40 dB difference for overlapped echoes. Because of the wide dynamic range of weather echoes, this power limit will sometimes be exceeded. The technique requires that the phase of each pulse be random. Digital phase correction is then applied in the processor for the first and second trips. The critical step is the adaptive filter which removes the echo of the other trip to increase the SNR. Magnetrons have a naturally random phase. For Klystron radars, a digitally controlled precision IF phase shifter is required. The RVP8 provides an 8-bit RS422 output for the phase shifter. For more information on the technique refer to Joe, et. al., 1995. 1.4.5 Polarization Mode Processing Polarization processing uses a time domain autocorrelation approach to calculate the various parameters of the polarization co-variance matrix, i.e., ZDR, LDR, PHIDP, RHOHV, PHIDP

(KDP), etc. In addition, the standard moments T, V, Z, W are also calculated. Which parameters are available and which algorithms are used to calculate them depends on the type of polarization radar, e.g., single channel switching, simultaneous transmit and receive (STAR), dual channel switching. SIGMET, Inc. is licensed by US National Severe Storms Laboratory

(NSSL) to use the STAR hardware and processing techniques and algorithms. Polarization measurements require special calibration of the ZDR and LDR offsets. The use of a clutter filter for the polarization variables can sometimes bias the derived parameters. Because of this, the user decides whether or not to use filtered or unfiltered time series. 1.4.6 Output Data The RVP8 output data for standard moment calculations consist of mean radial velocity (V), Spectrum Width (W), Corrected Reflectivity(Z or dBZ) and Uncorrected Reflectivity (T or dBT). Other data outputs include I/Q time series, DFT/FFT power spectrum points and polarization parameters. The output can be made in either 8 or 16-bit format. 8-bit format is preferred over 16-bit format for most applications since the accuracy is more than adequate for an operational radar system, and the data communications are reduced by 50%. 16-bit formats are sometimes used by research customers for data archive purposes. Note that time series and FFT are always 16-bit formats. All data formats are documented in Chapter 6 of this manual. A standard output is the I/Q time series on gigabit network (1000 BaseT). These are sent via UDP broadcast to an I/Q archiving system or even a completely independent parallel processing system. 130 RVP8 Users Manual May 2003 Introduction and Specifications 1.5 RVP8 Control and Maintenance Features 1.5.1 Radar Control Functions The RVP8 also performs several important radar control functions:

Trigger generation- up to 6 programmable triggers.

Pulsewidth control (four states controlled by four bits).

Angle/data synchronization- to collect data at precise azimuth intervals (e.g., every 0.5, 1, 1.5 degrees) based on the AZ/EL angle inputs.

Phase shifter- to control the phase on legacy Klystron systems. New or upgrade Klystron or TWT systems can use the RVP8/Tx card to provide very accurate phase shifting.

ZDR switch control- for horizontal/vertical or other polarization switching scheme.

AFC output (digital or analog) based on the burst pulse analysis for magnetron systems. Pulsewidth and trigger control are both built into the RVP8. Four TTL output lines can be programmed to drive external relays that control the transmitter pulsewidth. The internal trigger generator drives six separate lines, each of which can be programmed to produce a desired waveform. The trigger generator is unique in that the waveforms are stored in RAM and can be modified interactively by user software. Thus, precisely delayed and jitter-free strobes and gates can easily be produced. For each pulsewidth there is a corresponding maximum trigger rate that can be generated. Note, however, that the RVP8 can also operate from an external user-supplied trigger. In either case, the processor measures the trigger period between pulses so that user software can monitor it as needed. The RVP8 also supports trigger blanking during which one or more (selectable) of the transmit triggers can be inhibited. Trigger blanking is used to avoid interference with other electronic equipment and to protect nearby personnel from radiation hazard. There are two techniques for this:

2D AZ/EL sector blanking areas can be defined in the RVP8 itself.

An external trigger blanking signal (switch closure to ground, TTL or RS422) can be supplied, for example from a proximity switch that triggers when the antenna goes below a safe elevation angle or connected to the radome access hatch. 131 RVP8 Users Manual May 2003 Introduction and Specifications 1.5.2 Power-Up Setup Configuration The RVP8 stores on disk an extensive set of configuration information. The purpose of these data is to define the exact configuration of the RVP8 upon startup. The setup information can be accessed and modified using either a local keyboard and monitor, or over the network. For multiple radar networks, the configuration management can be centrally administered by copying tested master configuration files to the various network radars. It is not necessary to go to the radar to change ROMs as was the case for previous generation processors. 1.5.3 Built-In Diagnostics On power-up, the RVP8 performs a sequence of internal self-tests. The test sequence requires about four seconds to perform, and tests approximately 95% of the internal digital circuitry. Errors are isolated to specific sections of the board as much as possible. If any check fails, the user can be certain that some component is not functioning correctly. However, there is a very small chance that even a defective board may pass all the tests; the failure may be in one of the few areas that can not be checked. The RVP8 displays the test results on the LED front panel (for a standard SIGMET chassis). In this way, there is immediate visual confirmation of the diagnostic tests, even if the host computer has not yet been connected. The local keyboard and monitor or a networked workstation can be used to see the test results in the TTY menus or even invoke a powerup reset and test. 132 RVP8 Users Manual May 2003 Introduction and Specifications 1.6 Support Utilities and Available Application Software The RVP8 system includes a complete set of tools for the calibration, alignment and configuration of the RVP8. These includes the following utilities:

ascope- a comprehensive utility for manual signal processor control and data display of moments, times series and Doppler spectra. ascope includes a realistic signal simulator capable of producing both first and second trip targets. Recording/playback of time series and moments is included as well.

dspx- an ASCII text-based program to access and control the signal processor, including providing access to the local setup menus. speed- a performance measuring utility.

DspExport- exports the RVP8 to another workstation over the network. This allows utilities on a remote network to run locally, as opposed to exporting the utility display window over the network. setup- interactive GUI for creating/editing the RVP8 configuration files. zauto- calibration utility for use with a test signal generator.

These tools can be run locally on the RVP8 itself or over the network from a central maintenance facility. The DspExport utility improves the performance of the utilities for network applications by letting them be run on the workstation that is remote from the RVP8. Note that standard XWindow export is of course supported but requires more bandwidth. In addition, complete radar application software can be purchased from SIGMET:

IRIS/Radar on a separate PC, interfaces to the RVP8 by 100 BaseT Ethernet. IRIS/Radar controls both the RVP8 and the SIGMET RCP8 radar/antenna control processor. The package provides complete local and remote control/monitoring, data processing and communication for a radar system. IRIS/Analysis (and options) runs on a separate PC, often at a central site. One IRIS/Analysis can support up to 20 radar systems. This functions as a radar product generator (RPG) to provide outputs such as CAPPI, rain accumulations, echo tops, automatic warning and tracking, etc. Optional software packages are provided for special applications: wind shear and microburst detection, hydrometeorology with raingage calibration and subcatchments, composite, dual Doppler and 3D Display. IRIS/Web provides IRIS displays to network users on standard PCs (Windows or Linux) running Netscape or Internet Explorer. IRIS/Display can display products sent to it and, with password authorization, can serve as a remote control and monitoring site for networked radar systems. Features such as looping, crosssection, track, local warning, annotation, etc. are all provided by IRIS/Display. Note that both IRIS/Analysis and IRIS/Radar have all of the capabilities of IRIS/Display in addition to their own functions. This means that any IRIS system can display products. 133 RVP8 Users Manual May 2003 Introduction and Specifications 1.7 Open Architecture and Published API The RVP8 is largely software compatible with the RVP7, and uses the same published API opcode interface that has evolved over the years from the RVP5, RVP6, and RVP7 products. Driver code that has been written for the RVP7 can be easily adapted to the RVP8. The 16bit I/O command protocols are identical, and the data formats are unchanged. What is different is that the RVP8 supports an Ethernet interface rather than only a SCSI interface. SIGMET provides a free source code example for the driver in C. In addition to assuring backward compatibility, SIGMET also recognizes that certain users may require the ability to write their own signal processing algorithms which will run on the RVP8. To accommodate this, the RVP8 software is organized to allow separately compiled plug-in modules to be statically linked into the running code. The application program interface (API) allows user code to be inserted at the following stages of processing:

Tx/Rx waveform synthesis and matched filter generation The API allows the transmit waveforms to be defined from pulse to pulse, along with the corresponding FIR coefficients that will extract (I,Q) from that Tx waveform. This allows users to experiment with arbitrary waveforms for pulse compression and frequency agility.

Time series and spectra processing from (I,Q)- The API allows you to modify the default time series and spectra data, e.g., to perform averaging or windowing in a different way.

Parameter generation from (I,Q)- This is probably where the greatest activity will occur for usersupplied code. The API allows you to redefine how the standard parameters (dBZ, Velocity, Width, PHIDP, etc.) are computed from the incoming

(I,Q) time series. You may also create brand new parameter types that are not included in the basic RVP8 data set. Note that the standard SIGMET algorithms are not made public in this model. Rather, the interface hooks and development tools are provided so that users can add their own software extensions to the RVP8 framework. Many of the library routines that are fundamental to the RVP8 are also documented and can be called by user code; but the source to these routines is not generally released. Development tools which are not under public license must be purchased separately by the customer. While most customers will use the signal processing software supplied by SIGMET, the new open software architecture approach employed by the RVP8 will be very useful to those research customers who want to try innovative new approaches to signal processing, or to those OEM manufacturers who are interested in having their own custom stamp on the product. 134 RVP8 Users Manual May 2003 Introduction and Specifications 1.8 RVP8 Technical Specifications 1.8.1 IFD Digitizer Module Input Signals

IF Received Signal: 50, + 6.5 dBm max IF Magnetron Burst or COHO: 50, +6.5 dBm max

Optional Reference Clock: 260 MHz 10 to 0 dBm IF Ranges

6 to 16MHz, 20-34 MHz, 38-52 MHz, 56-70 MHz Linear Dynamic Range

90 to >100dB depending on pulsewidth/bandwidth filter A/D Conversion

Resolution 14 bit with jitter <2.5 picosec

Sampling rate 33.5 to 39.5 MHz (selectable, standard is 35.975 MHz) AFC Output

Analog 10 to +10V

Optional Digital AFC (DAFC) with up to 24 programmable output bits.

Automatic 2-D (time/frequency) burst pulse search and fine tracking algorithms. Fiber Optic Down Link

540 MHz optical link, 62.5/125-micron multimode ST cable. Coax Uplink

75 electrically isolated (16K) from receivers ground. Maximum Separation from RVP8/Rx

100 meters, with automatic calibration of round trip time and range correction. 135 RVP8 Users Manual May 2003 1.8.2 RVP8/Rx PCI Card Pulse Repetition Frequency Introduction and Specifications

50 Hz to 20 KHz +0.1%, continuously selectable. IF Band Pass Filter

Programmable Digital FIR with software selectable bandwidth. Built-in filter design software with graphical user interface. Impulse Response

Up to 3024 FIR filter taps, corresponding to approximately 84 sec impulse response length for 36 MHz IF samples. These very long filters are intended for use with pulse compression. Range Resolution

Minimum bin spacing of 25 meters selectable in N*8.33 meter steps. Bins can be positioned in a configurable range mask with resolution of N* the fundamental bin spacing, or arbitrarily to an accuracy of 2.2 meters. Maximum Range

Up to 1024 km Number of Range Bins

Full unambiguous range at minimum resolution or 2048 range bins (whichever is less). Electrical and Optical Interfaces

Receives fiber-optic downlink from the RVP8/IFD, and generates the 75 coax uplink to the RVP8/IFD.

BNC #1 for trigger output (12V, 75), or pretrigger input. BNC #2 for trigger output (12V, 75). Data Output via PCI Bus

16bit I and Q values 14-bit raw IF samples 136 RVP8 Users Manual May 2003 Introduction and Specifications 1.8.3 RVP8/Tx PCI Card Analog Waveform Applications

Digitally synthesized IF transmit waveform for pulse compression, frequency agility, and phase modulation applications.

Master clock or COHO signal to the radar; can be phase locked or free running, arbitrary frequency. Analog Output Waveform Characteristics

Two independent, digitally synthesized, analog output waveforms (BNC). These two outputs are electrically identical and logically independent IF waveform synthesizers that can produce phase modulated CW signals, finite duration pulses, compressed pulses, etc.

Can drive up to +12dBm into 50.

14-bit interpolating TxDAC provides 71dB Signal-to-Noise Ratio. IF center frequency selectable from 8 to 32.4 MHz, and from 48.6 to 75MHz.

Signal bandwidth as large as 15MHz for wideband/multiband Tx applications.

Total harmonic distortion less than 74dB.

Waveform pre-emphasis compensates for both static and dynamic Tx nonlinearities. Other I/O signals

Clock In/Out 50 SMA connector. This can receive a CW reference frequency to which the RVP8/Tx can lock to a P/Q frequency multiple (much like the RVP8/IFD can lock to an external reference). This connector can also supply the TxData Clock, optionally divided by some N between 1 and 16, in order to supply external circuitry with +10dBm clock reference at 50.

9-pin D connector supporting four RS-422 differential signals for miscellaneous input and output with SoftPlane support.. Each line pair can operate as a transmitter or as a receiver depending on whats needed. Possible uses are: alternate reference clock input, gating input for CW modes, additional trigger outputs, external phase shift requests, etc. 137 RVP8 Users Manual May 2003 Introduction and Specifications 1.8.4 SIGMET I/O-62 PCI Card

Short format PCI card with 62-position D connector. Multiple cards may be installed.

Includes D/A, A/D, discrete inputs and outputs (TTL, wide range, RS422, etc.) See summary table below. I/O pin assignment mapping by softplane.conf file.

Standard or custom remote backpanels available.

ESD protection using Tranzorb silicon avalanche diode surge suppression and high-voltage tolerant components. SIGMET I/O-62 Summary of Electrical Interfaces Qty Description 40 Lines configurable in groups of 8 to be either inputs or outputs. The electrical specifications are software defined within each group as follows:

Single-ended TTL input or output with softwareconfigured pull-up or pull-down resistors for inputs.

Wide range inputs (27VDC, threshold +2.5VDC), often used for lamp voltage status inputs.

RS-422/485 @ 10 MBit/sec (requires two lines each). RS-422 receivers can be configured in software to have 100 termination between each pair. 8 2 2 2 4 2 8 A/D convertors configurable as 0, 4, or 8 convertors, 2V, 12 bits @ 10 MHz, These lines are shared with some of the 40 I/O lines listed above. D/A convertors, 10V 1 MHz update rate, output can drive a 75 load. SPDT relays on the board. These are often used for switching high power relays. Contacts are diode protected. RS-232C full duplex lines (Tx and Rx) 12V 75 trigger drivers . Power/Ground pairs of 12V power (filtered, fused) for external equipment or remote backpanel use (up to 24 W total). Polyfuse technology acts like a circuit breaker with auto reset in the event of an overload. Ground wires for signal grounds from the remote back panel. 138 RVP8 Users Manual May 2003 Introduction and Specifications 1.8.5 RVP8 Standard Connector Panel

Mounts on front or rear of standard 19 EIA rack

Connects to I/O-62 via 1:1 62pin 1.8m cable (provided).

Provides standard inputs and outputs required by most weather radars such as triggers, polarization control, pulse width control and antenna angles.

Az and El synchro and reference inputs (nominal 100V 60 Hz)

3 internal relays and 4 12V relay control signals for switching external devices.

Programmable scope test points with source waveforms selectable in software.

Diagnostic power supply and self test LEDs for troubleshooting. RVP8 Connector Panel Summary J-ID Label J1 J2 J3 J4 J5 J6 Type AZ INPUT DBF25 AZ OUTPUT DBF25 PHASE OUT DBF25 EL INPUT DBF25 EL OUTPUT DBF25 DBF25 RELAY J7 J8 J9 J10 J11 J12 J13 J14 J15 J16 J17 J18 SPARE SPARE DBF25 DBF25 MISC I/O DBF25 SERIAL SERIAL SD TP1 TP2 TRIG1 TRIG2 TRIG3 TRIG4 DBF9 DBF9 Modular BNC BNC BNC BNC BNC BNC Description Up to 16bits of parallel TTL binary or BCD angle Up to 16bits of parallel TTL binary or BCD angle Up to 8bits of parallel TTL or RS422. Angles are configurable. Up to 16bits of parallel TTL binary or BCD angle Up to 16bits of parallel TTL binary or BCD angle 3 internal relays, contact rating 0.5 A continuous. The switching load is 0.25 A and 100V, with the additional constraint that the total power not exceed 4VA. 4, 12V relay control signals, up to 200mA.

(Note that external relays should be equipped with proper diode protection to shunt the back EMF). 20 additional TTL I/O lines each configurable to be input or output. 10 differential analog inputs, up to 20V max multiplexed into A/D convertor sampling each at >1000 Hz. 7 additional RS422 lines and 2 each dedicated (nonmultiplexed) A/D inputs (580V with pot adjust) and D/A outputs (10V). RS232C RS232C 3 x 4 matrix connector for AZ and EL synchro and reference inputs Programmable scope test point. 75 Ohms Programmable scope test point. 75 Ohms 12V trigger into 75 Ohms 12V trigger into 75 Ohms 12V trigger into 75 Ohms 12V trigger into 75 Ohms 139 RVP8 Users Manual May 2003 Introduction and Specifications 1.8.6 RVP8 Processing Algorithms Input from Rx Board

16bit I/Q samples

Optional dual-channel I/Q samples (e.g., for polarization systems or dual frequency systems) IQ Signal Correction Options

Amplitude jitter correction based on running average of transmit power from burst pulse. Interference correction for single pulse interference

Saturation correction (3 to 5 dB) Primary Processing Modes

Poly-Pulse Pair (PPP)

FFT

Random or Phase Coded 2nd trip echo filtering/recovery

Optional Polarization with full co-variance matrix (ZDR, PHIDP, LDR, RHOHV, etc.)

Optional Pulse Compression Processing Options

FIR Clutter filters (40 and 50 dB) in pulse pair mode.

Adaptive width clutter filters in FFT and phase coded 2nd trip mode.

Velocity De-Aliasing: Dual PRF Velocity unfolding at 3:2, 4:3 and 5:4 PRF ratios or Dual PRT Velocity processing for selectable inter-pulse intervals.

Range De-aliasing:

Phase coding method (random phase for magnetron) Frequency coding method (not available for magnetron)

Scan angle synchronization for data acquisition.

Pulse integration up to 1024

Corrections for gaseous attenuation and 1/R2.

Up to 4 pulse widths Data Outputs

dBZ Calibrated equivalent radar reflectivity 8 or 16 bits 140 RVP8 Users Manual May 2003 Introduction and Specifications

V Mean radial velocity 8 or 16 bits

W Spectrum width 8 or 16 bits

Time series I/Q 16 bits each per sample

FFT Doppler Spectrum output option in FFT mode 16 bits per component

Optional:

ZDR, PHIDP, RHOHV, LDR, RHO 8 or 16 bits Data Quality Thresholds

Signaltonoise ratio

(SNR) Used to reject bins having weak signals. Typically applied to dBZ.

Signal quality index

(SQI) Used to reject bins having incoherent

(nonDoppler) signals. Typically applied to mean velocity and width.

Cluttertosignal ratio

(CSR) Used to reject range bins having very strong clutter.

Speckle Filter or noise Typically applied to mean velocity, width and dBZ. 2D filter removes singlebin targets such as aircraft Fills isolated missing pixels as well. 141 RVP8 Users Manual May 2003 Introduction and Specifications 1.8.7 RVP8 Input/Output Summary Digital IF Serial Stream Input

On fiber optic cable from IFD for signal and burst sample. 16bits @ 36 MHz

(nominal). Ethernet or SCSI-2 Input/Output from Host Computer

Data output of calibrated dBZ, V and W during normal operation. Diagnostic output of I and Q or FFT Doppler spectrum. Signal processor configuration and verification readback is performed via the SCSI or Ethernet interface. RS-232C Serial Data I/O

For real time display/monitoring or data remoting.

Serial AZ/EL angle tag input using standard SIGMET RCP format. AZ/EL Parallel Tag Line Inputs

Up to 16bit each parallel TTL binary or BCD angles. Trigger Output

6 TTL triggers on 75 BNC or 10V on 75 BNC (selectable for each trigger). Triggers are programmable with respect to trigger start, trigger width and sense

(normal or inverted). Optional ZDR Control

RS-422 differential control for polarization switch. 142 RVP8 Users Manual May 2003 Introduction and Specifications 1.8.8 Physical and Environmental Characteristics Packaging

Motherboard Configuration 4U rackmount with 6 PCI slots

Single Board Computer Configuration 4u rackmount with 14 PCI slots

Custom PC configurations available or packaged by customer.

Dimensions of standard 4U chassis 43.2 wide x 43.2 long x 17.8 cm high 17 wide x 17 long x 7.00 inch high

Dimensions IF Digitizer 2.5 wide x 10.9 long x 23.6 cm high 1 wide x 4.3 long x 9.3 inch high

Redundant Power Supplies. Three hotswap modules with audio failure alarm. Input Power

IFD 100240 VAC 4763 Hz autoranging

Main Chassis 60/50 Hz 115/230 VAC Manual Switches Power Consumption

RVP8/Main Processor 180 Watts with Rx and SBC

RVP8/IFD IF Digitizer 12 Watts Environmental

Temperature

Humidity 0C (32F) to 50C (122F) 0 to 95% noncondensing Reliability

MTBF>50,000 hours (based on actual RVP7 field data). 143 RVP8 Users Manual May 2003 Hardware Installation 2.4.2 Example Hookup to a MITEQ MFS-xxx STALO The electrical interface for this STALO uses a 25-pin D connector with the following pin assignments

GROUND on pins 1 and 2.

Four BCD digits of 1KHz, 10KHz, 100KHz, and 1MHz frequency steps, using Pins <25:22>, <21:18>, <17:14>, <13:10>.

Seven binary bits of representing 10MHz steps, Bits<0:6> on Pins<9:3>. First configure the IFD pins themselves. Pins 1 and 2 are ground, and are connected with wirewrap wire to the nearby ground posts. Pins 3 through 25 all are signal pins, so we plug in a jumper for each of these 23 pins. We will use pinmap uplink protocol, so H3 and H4 are removed; and a x1 on-board crystal, so H2 is also removed. In this example we will assume that we wish to control the STALO in 20KHz steps from 1.350GHz to 1.365GHz. This can be done with the following setups from the Mb section:

AFC span [100%,+100%] maps into [ 1350000 , 1365000 ]

AFC format 0:Bin, 1:BCD, 2:8B4D: 2, ActLow: NO AFC uplink protocol 0:Off, 1:Normal, 2:PinMap : 2 PinMap Table (Type 31 for GND, 30 for +5) Pin01:GND Pin02:GND Pin03:22 Pin04:21 Pin05:20 Pin06:19 Pin07:18 Pin08:17 Pin09:16 Pin10:15 Pin11:14 Pin12:13 Pin13:12 Pin14:11 Pin15:10 Pin16:09 Pin17:08 Pin18:07 Pin19:06 Pin20:05 Pin21:GND Pin22:GND Pin23:GND Pin24:GND Pin25:GND FAULT status pin (0:None): 0, ActLow: NO We map the AFC interval into a numeric span from 1350000 to 1365000, and choose the 8B4D mixed-radix encoding format. The STALO itself has 1KHz frequency steps, but the AFC servo will be easier to tune if we intentionally degrade this to 20KHz. This is done simply by grounding all four of the 1KHz BCD input lines, plus the LSB of the 10KHz BCD digit. A more creative use for one of these unused pins would be to remove the pin 25 jumper, wirewrap pin 25 to ground (so the STALO sill reads it a logic low), and assign pin 25 as a fault status input. That pin could then be connected to an external fault line, if the STALO has one. 231 RVP8 Users Manual May 2003 Hardware Installation 2.5 RVP8 Custom Interfaces This section describes some additional points of interface to the RVP8. These hookups are less conventional than the standard interfaces described earlier in this chapter, but they sometimes can supply exactly what is needed in exactly the right place. For the most part, these custom interfaces are merely taps into existing internal signals that would not normally be seen by the user. 2.5.1 Using the IFD Coax Uplink The Coax Uplink is the IFDs single line of communication from the RVP8/Rx processor board. All of the information that is needed by the IFD arrives through this uplink; and as such, this signal might contain information that is also useful for other parts of the radar system. In particular, it is a convenient source of digital AFC, along with reset and other status bits, plus limited trigger timing information. The uplink is a single digital transmission line that carries a hybrid serial protocol. The two logic states, zero and one are represented by 0-Volt and +15-Volt (open circuit) electrical levels. The output impedance of the uplink driver is approximately 55W

. When the cable is terminated in 75W approximately 8.6-Volts. by an internal resistor in the IFD, the overall positive voltage swing will be The electrical characteristics of the uplink have been optimized for balanced groundless reception, so that external noise and ground loop currents will not be introduced into the IFD. The recommended eavesdropping circuit is shown in Figure 24, and consists of a high speed comparator (Maxim MAX913, or equivalent) and input conditioning resistors. Both the shield and the center conductor of the coax uplink feed the comparator through 33KW resistors; no direct ground attachment is made to the shield itself. The 500W the local ground reference, and the 47KW signal into a bipolar range for the comparator. resistor supplies a bias to shift the unipolar uplink resistors provide isolation Figure 24: Recommended Receiving Circuit for the Coax Uplink 500 GND 33K 33K Coax Uplink Input Max913 or equiv. Received TTL Signal 500 47K GND

+5V 232 RVP8 Users Manual May 2003 Hardware Installation The uplink signal, shown in Figure 25, is periodic at the radar pulse repetition frequency, and conveys two distinct types of information to the IFD. The signal is normally low most of the time (to minimize driver and termination power), but begins a transition sequence at the beginning of each transmitted pulse. Figure 25: Timing Diagram of the IFD Coax Uplink

burst

s

s

s

s

s 1 2 3 4 5 6 7 8 9 10... The first part of each pulse sequence is a variable length burst window which is centered on the transmitted pulse itself, and which has a duration burst approximately 800ns greater than the length of the current FIR matched filter. The burst window defines the interval of time during which the IFD transmits digitized burst pulse samples, rather than digitized IF samples, on its fiber downlink. The exact placement and width of the burst window will depend on the trigger timing and digital filter specifications that the user has chosen, usually via the Pb and Ps plotting setup commands. Following the burst window is a fixed-length sequence of 25 serial data bits which convey information from the RVP8/Rx board. The first four data bits form a characteristic (0,1,1,0) marker pattern. The first zero in this pattern effectively marks the end of the variable length burst window, and the other three bits should be checked for added confidence that a valid bit sequence is being received. Table 29 defines the interpretation of the serial data bits. Table 29: Bit Assignments for the IFD Coax Uplink Bit(s) Meaning 14 520 21 22 2324 25 Marker Sequence (0,1,1,0). This fixed 4-bit sequence identifies the start of a valid data sequence following the variable-length burst window. 16-bit multi-purpose data word, MSB is transmitted first (See below) Reset Request. This bit will be set in just one transmitted sequence whenever an RVP8 reset occurs. If set, then interpret the 16-bit data word as 4-bits of command and 12-bits of data, rather than as a single 16-bit quantity (See below) Diagnostic select bits. These are used by the RVP8 power-up diagnostic routines; they will both be zero during normal operation. Green LED Request; 0=Off, 1=On. The state of this bit normally follows the Fiber Detect LED on the RVP8/Rx board. 233 RVP8 Users Manual May 2003 Hardware Installation The period s of the serial data is (64 faq) , where faq is the acquisition clock frequency given in the Mc section of the RVP8 setup menu. For the default clock frequency of 35.975MHz, the period of the serial data will be 1.779m sec. The logic that is receiving the serial data should first locate the center of the first data bit at (0.5 s) past the falling edge at the end of the burst window. Subsequent data bits are then sampled at uniform s intervals. The actual data sampling rate can be in error by as much as one part in 75 while still maintaining accurate reception. This is because the data sequence is only 25-bits long, and hence, the last data bit would still be sampled within 1/3 bit time of its center. Having this flexibility makes it easier to design the receiving logic. For example, if a 5MHz or 10MHz clock were available, then sampling at 1.8m sec intervals (1:85 error) would be fine. Likewise, one could sample at 1.75m sec based on a 4MHz or 8MHz clock (1:61 error), but only if the first sample were moved slightly ahead of center so that the sampling errors were equalized over the 25-bit span. Interpreting the Serial 16-bit Data Word The serial 16-bit data word has several different interpretations according to how the RVP8 has been configured, and whether Bit #22 of the uplink stream is set or clear. The evolution of these different formats has been in response to new features being added to the IFD (Section 2.2), and the production of the DAFC Digital AFC Module (Section 2.4). The original use of the uplink data word was simply to convey a 16-bit AFC level, generally for use with a magnetron system. Bit #22 is clear in this case, and the word is interpreted as a linear signed binary value. The use of this format is discouraged for new hardware designs, but it will always remain available to guarantee compatibility with older equipment. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 16Bit AFC Level | AFC16

Level 0111111111111111 (most positive AFC voltage) 0000000000000000 (center AFC voltage) 1000000000000000 (most negative AFC voltage) When the IFD is jumpered for phase locking to an external reference clock, then Bit #22 will be clear and the data word conveys the PLL clock ratio, and the Positive/Negative deviation sign of the Voltage Controlled Crystal Oscillator (VCXO). This format is commonly used with klystron systems, especially when the RVP8 is locking to an external trigger. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Pos| Numerator 1 | Denominator 1 | PLL16

Note that the AFC-16 and PLL-16 formats can never be interleaved for use at the same time, since there would be no way to distinguish them at the receiving end. Finally, an expanded format has been defined to handle all future requirements of the serial uplink. Bit #22 is set in this case, and the data word is interpreted as a 4-bit command and 12-bit data value. A total of 16x12=192 auxiliary data bits thus become available via sequential transmission of one or more of these words. The CMD/DATA words can also be used along with one of the AFC-16 or PLL-16 formats, since Bit #22 marks them differently. 234 RVP8 Users Manual May 2003 Hardware Installation 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Command | Data | CMD/DATA

Commands #1, #2, and #3 control the 25 output pin levels of the DAFC board. These transmissions may be interspersed with the PLL-16 format in systems that require both clock locking and AFC, e.g., a dual-receiver magnetron system using a digitally synthesized COHO. Note that the entire 25-bits of pin information are transferred synchronously to the output pins only when CMD=3 is received. This assures that momentary invalid patterns will not be produced upon arrival of CMD=1 or CMD=2 when the output bits are changing. CMD=1 Data<0>

Data<6>

Data<11:7>

CMD=2 Data<11:0>

CMD=3 Data<11:0>

DAFC output pin 25 Fault Input is active high Which pin to use for Fault Input (0:None) DAFC output pins 24 through 13 DAFC output pins 12 through 1 These three digital AFC pinmap commands are recommended as a replacement for the original AFC-16 format in all new hardware designs. If you only need 12-bits of linear AFC, then map the AFC range into the 2048 to +2047 numeric span, and select binary coding format (See Section 3.3.6); the 12-bit data with CMD=3 will then hold the required values. To get a full 16-bit value, use a 32768 to +32767 span and extract the full word from both CMD=2 and CMD=3. Of course, other combinations of bit formats and number of bits (up to 25) are also possible. Command #4 is used to control some of the internal features of the IFD. Bits <4:0> configure the on-board noise generator so that it adds a selectable amount of dither power to the A/D converters. This noise is bandlimited using a 10-pole lowpass filter so that most of the energy is within the 150KHz to 900KHz band, with negligible residual power above 1.4MHz. Each of the five bits switch in additional noise power when they are set, with the upper bits making successively greater contributions. Bits <6:5> permit the IF-Input and Burst-Input signals to be reassigned on the fiber downlink. CMD=4 Data<4:0>

Data<6:5>

Built-in noise generator level IF-Input and Burst-Input selection 00 : Normal 10 : Burst Always 01 : Swap IF/Burst 11 : IF Always 2.5.2 Using the (I,Q) Digital Data Stream (Alan) The (I,Q) data stream that is computed by the FIR filter chips is communicated in real time to the central CPU. The IBD<17:0> data bus and IBDCLK clock signals are sourced on the P3 96-pin DIN connector of the RVP8. These TTL signals are normally kept internal to the RVP8, but some users may have a need to tap into them directly, e.g., to feed a separate data processor with the demodulated I and Q. Making the electrical connections to the (I,Q) data stream is especially easy with the RxNet7 packaging of the RVP8, since the complete set of signals are driven onto a dedicated 68-pin connector on its backpanel. Moreover, special PECL drivers on that connector make it possible 235 RVP8 Users Manual May 2003 Hardware Installation to run the cable over distances as great as ten meters. Please see the RxNet7 Users Manual for full details, as this is the recommended approach for driving the (I,Q) data out to an external device. If the RVP8s internal TTL signals are to be used directly, the physical connections must be made in such a way that no more than 12cm of additional wire length is added at the backplane. One way to do this would be to plug a custom driver board into an unused RVP8/AUX slot, from which the IBDxxx signals could be accessed. Another approach would be to mount the RVP8 board(s) in a completely custom backplane enclosure which also includes the users equipment that receives the (I,Q) data stream. The timing of the clock and data lines is shown in Figure 26 for the interval of time after the start of each transmitted pulse. The 18-bit data bus conveys two special code words at the beginning of each pulse, followed by (I,Q) for the Burst/COHO sample, followed by (I,Q) from the receiver. The receiver data continue to flow until the next transmitted pulse restarts the sequence anew, after a brief (approximately one range bin) clearing period. The data bus can be sampled on either the falling or rising edge of the clock, as there is an enforced 28ns data hold time after each rising clock edge. Using the rising clock edge will give the greatest data setup time, and this is usually preferred. Figure 26: Timing diagram of the (I,Q) Data Stream New Pulse Code Trigger Code Burst I Burst Q Bin #1 I Bin #1 Q IBD<17:0> Data Bus Clearing Period

(after last pulse) 28ns 82ns Range Bin Spacing IBDCLK Data Clock The New Pulse code is a unique 18-bit value that signifies the start of each new pulse of data. This is the only code or data word in which the MSB is zero. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 |

The Trigger Code follows immediately after the New Pulse code. It has a 1 in its MSB, and three different bit fields encoded into its low byte. These fields give information about the pulse itself. Codes that are not listed below are reserved, and will never appear on the data bus. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 0 0 0 0 0 0 0 | Flags | Bank | Waveform |

The 2-bit Flags field tells how this pulse will be used internally by the RVP8. This information is probably irrelevant to the external data processor, if all that it is doing is eavesdropping on the received data. 236 RVP8 Users Manual May 2003 Hardware Installation 01 This is the final pulse of a collection of pulses that will contribute to the next pro-

cessed ray. The 3-bit Bank field tells the major classification of the pulse. 000 001 010 111 Normal pulse Low PRF pulse during Dual-PRF mode Blanked transmitter version of a normal pulse Pulse used for receiver noise measurement (SNOISE Command) The 3-bit Waveform field indicates the minor classification of the pulse. 000 001 000-111 Normal pulse, or first pulse in a multi-part pulse sequence. Indicates that this is an alternate pulse. This is the V channel for a single-

channel polarization radar in which the receive or transmit polarization alternates pulse to pulse from H to V. This is also the longer PRT pulse whenever DPRT (Dual-PRT) mode is running. These incrementing codes will be output for the first eight pulses of any custom trigger pattern that the user has defined (See Section 6.14). If the custom pattern is more than eight pulses long, the 111 code will be held until the end of the se-

quence. The (I,Q) data for the Burst/COHO sample, as well as for the receiver samples, all have the same floating point format consisting of a 2-bit unsigned exponent (Exp) and 15-bit signed mantissa

(Man). 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 | Exp | Floating Point Mantissa (Signed) |

This format does not rely on a hidden bit in the mantissa. Rather, the mantissa is simply a 15-bit (generally unnormalized) value between 16384 and +16383, and the encoded floating point value is:

Value Man 16Exp Note that the exponent shifts the value not in increments of one bit, but rather, by four bits (by factors of 16). The mantissa will always be the largest integer (i.e., greatest relative precision) that will fit into the fifteen available bits. The overall dynamic range is 90dB while maintaining at least 66dB SNR within each sample. However, the format also gracefully underflows by allowing the mantissa to become small when Exp=0. This greatly extends the dynamic range into weak signals for which high relative precision is not required on each sample. The usable dynamic range of values over the entire receiver span is therefore approximately 125dB. 237 RVP8 Users Manual May 2003 Hardware Installation 2.4.2 Example Hookup to a MITEQ MFS-xxx STALO The electrical interface for this STALO uses a 25-pin D connector with the following pin assignments

GROUND on pins 1 and 2.

Four BCD digits of 1KHz, 10KHz, 100KHz, and 1MHz frequency steps, using Pins <25:22>, <21:18>, <17:14>, <13:10>.

Seven binary bits of representing 10MHz steps, Bits<0:6> on Pins<9:3>. First configure the IFD pins themselves. Pins 1 and 2 are ground, and are connected with wirewrap wire to the nearby ground posts. Pins 3 through 25 all are signal pins, so we plug in a jumper for each of these 23 pins. We will use pinmap uplink protocol, so H3 and H4 are removed; and a x1 on-board crystal, so H2 is also removed. In this example we will assume that we wish to control the STALO in 20KHz steps from 1.350GHz to 1.365GHz. This can be done with the following setups from the Mb section:

AFC span [100%,+100%] maps into [ 1350000 , 1365000 ]

AFC format 0:Bin, 1:BCD, 2:8B4D: 2, ActLow: NO AFC uplink protocol 0:Off, 1:Normal, 2:PinMap : 2 PinMap Table (Type 31 for GND, 30 for +5) Pin01:GND Pin02:GND Pin03:22 Pin04:21 Pin05:20 Pin06:19 Pin07:18 Pin08:17 Pin09:16 Pin10:15 Pin11:14 Pin12:13 Pin13:12 Pin14:11 Pin15:10 Pin16:09 Pin17:08 Pin18:07 Pin19:06 Pin20:05 Pin21:GND Pin22:GND Pin23:GND Pin24:GND Pin25:GND FAULT status pin (0:None): 0, ActLow: NO We map the AFC interval into a numeric span from 1350000 to 1365000, and choose the 8B4D mixed-radix encoding format. The STALO itself has 1KHz frequency steps, but the AFC servo will be easier to tune if we intentionally degrade this to 20KHz. This is done simply by grounding all four of the 1KHz BCD input lines, plus the LSB of the 10KHz BCD digit. A more creative use for one of these unused pins would be to remove the pin 25 jumper, wirewrap pin 25 to ground (so the STALO sill reads it a logic low), and assign pin 25 as a fault status input. That pin could then be connected to an external fault line, if the STALO has one. 231 RVP8 Users Manual May 2003 Hardware Installation 2.5 RVP8 Custom Interfaces This section describes some additional points of interface to the RVP8. These hookups are less conventional than the standard interfaces described earlier in this chapter, but they sometimes can supply exactly what is needed in exactly the right place. For the most part, these custom interfaces are merely taps into existing internal signals that would not normally be seen by the user. 2.5.1 Using the IFD Coax Uplink The Coax Uplink is the IFDs single line of communication from the RVP8/Rx processor board. All of the information that is needed by the IFD arrives through this uplink; and as such, this signal might contain information that is also useful for other parts of the radar system. In particular, it is a convenient source of digital AFC, along with reset and other status bits, plus limited trigger timing information. The uplink is a single digital transmission line that carries a hybrid serial protocol. The two logic states, zero and one are represented by 0-Volt and +15-Volt (open circuit) electrical levels. The output impedance of the uplink driver is approximately 55W

. When the cable is terminated in 75W approximately 8.6-Volts. by an internal resistor in the IFD, the overall positive voltage swing will be The electrical characteristics of the uplink have been optimized for balanced groundless reception, so that external noise and ground loop currents will not be introduced into the IFD. The recommended eavesdropping circuit is shown in Figure 24, and consists of a high speed comparator (Maxim MAX913, or equivalent) and input conditioning resistors. Both the shield and the center conductor of the coax uplink feed the comparator through 33KW resistors; no direct ground attachment is made to the shield itself. The 500W the local ground reference, and the 47KW signal into a bipolar range for the comparator. resistor supplies a bias to shift the unipolar uplink resistors provide isolation Figure 24: Recommended Receiving Circuit for the Coax Uplink 500 GND 33K 33K Coax Uplink Input Max913 or equiv. Received TTL Signal 500 47K GND

+5V 232 RVP8 Users Manual May 2003 Hardware Installation The uplink signal, shown in Figure 25, is periodic at the radar pulse repetition frequency, and conveys two distinct types of information to the IFD. The signal is normally low most of the time (to minimize driver and termination power), but begins a transition sequence at the beginning of each transmitted pulse. Figure 25: Timing Diagram of the IFD Coax Uplink

burst

s

s

s

s

s 1 2 3 4 5 6 7 8 9 10... The first part of each pulse sequence is a variable length burst window which is centered on the transmitted pulse itself, and which has a duration burst approximately 800ns greater than the length of the current FIR matched filter. The burst window defines the interval of time during which the IFD transmits digitized burst pulse samples, rather than digitized IF samples, on its fiber downlink. The exact placement and width of the burst window will depend on the trigger timing and digital filter specifications that the user has chosen, usually via the Pb and Ps plotting setup commands. Following the burst window is a fixed-length sequence of 25 serial data bits which convey information from the RVP8/Rx board. The first four data bits form a characteristic (0,1,1,0) marker pattern. The first zero in this pattern effectively marks the end of the variable length burst window, and the other three bits should be checked for added confidence that a valid bit sequence is being received. Table 29 defines the interpretation of the serial data bits. Table 29: Bit Assignments for the IFD Coax Uplink Bit(s) Meaning 14 520 21 22 2324 25 Marker Sequence (0,1,1,0). This fixed 4-bit sequence identifies the start of a valid data sequence following the variable-length burst window. 16-bit multi-purpose data word, MSB is transmitted first (See below) Reset Request. This bit will be set in just one transmitted sequence whenever an RVP8 reset occurs. If set, then interpret the 16-bit data word as 4-bits of command and 12-bits of data, rather than as a single 16-bit quantity (See below) Diagnostic select bits. These are used by the RVP8 power-up diagnostic routines; they will both be zero during normal operation. Green LED Request; 0=Off, 1=On. The state of this bit normally follows the Fiber Detect LED on the RVP8/Rx board. 233 RVP8 Users Manual May 2003 Hardware Installation The period s of the serial data is (64 faq) , where faq is the acquisition clock frequency given in the Mc section of the RVP8 setup menu. For the default clock frequency of 35.975MHz, the period of the serial data will be 1.779m sec. The logic that is receiving the serial data should first locate the center of the first data bit at (0.5 s) past the falling edge at the end of the burst window. Subsequent data bits are then sampled at uniform s intervals. The actual data sampling rate can be in error by as much as one part in 75 while still maintaining accurate reception. This is because the data sequence is only 25-bits long, and hence, the last data bit would still be sampled within 1/3 bit time of its center. Having this flexibility makes it easier to design the receiving logic. For example, if a 5MHz or 10MHz clock were available, then sampling at 1.8m sec intervals (1:85 error) would be fine. Likewise, one could sample at 1.75m sec based on a 4MHz or 8MHz clock (1:61 error), but only if the first sample were moved slightly ahead of center so that the sampling errors were equalized over the 25-bit span. Interpreting the Serial 16-bit Data Word The serial 16-bit data word has several different interpretations according to how the RVP8 has been configured, and whether Bit #22 of the uplink stream is set or clear. The evolution of these different formats has been in response to new features being added to the IFD (Section 2.2), and the production of the DAFC Digital AFC Module (Section 2.4). The original use of the uplink data word was simply to convey a 16-bit AFC level, generally for use with a magnetron system. Bit #22 is clear in this case, and the word is interpreted as a linear signed binary value. The use of this format is discouraged for new hardware designs, but it will always remain available to guarantee compatibility with older equipment. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 16Bit AFC Level | AFC16

Level 0111111111111111 (most positive AFC voltage) 0000000000000000 (center AFC voltage) 1000000000000000 (most negative AFC voltage) When the IFD is jumpered for phase locking to an external reference clock, then Bit #22 will be clear and the data word conveys the PLL clock ratio, and the Positive/Negative deviation sign of the Voltage Controlled Crystal Oscillator (VCXO). This format is commonly used with klystron systems, especially when the RVP8 is locking to an external trigger. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Pos| Numerator 1 | Denominator 1 | PLL16

Note that the AFC-16 and PLL-16 formats can never be interleaved for use at the same time, since there would be no way to distinguish them at the receiving end. Finally, an expanded format has been defined to handle all future requirements of the serial uplink. Bit #22 is set in this case, and the data word is interpreted as a 4-bit command and 12-bit data value. A total of 16x12=192 auxiliary data bits thus become available via sequential transmission of one or more of these words. The CMD/DATA words can also be used along with one of the AFC-16 or PLL-16 formats, since Bit #22 marks them differently. 234 RVP8 Users Manual May 2003 Hardware Installation 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Command | Data | CMD/DATA

Commands #1, #2, and #3 control the 25 output pin levels of the DAFC board. These transmissions may be interspersed with the PLL-16 format in systems that require both clock locking and AFC, e.g., a dual-receiver magnetron system using a digitally synthesized COHO. Note that the entire 25-bits of pin information are transferred synchronously to the output pins only when CMD=3 is received. This assures that momentary invalid patterns will not be produced upon arrival of CMD=1 or CMD=2 when the output bits are changing. CMD=1 Data<0>

Data<6>

Data<11:7>

CMD=2 Data<11:0>

CMD=3 Data<11:0>

DAFC output pin 25 Fault Input is active high Which pin to use for Fault Input (0:None) DAFC output pins 24 through 13 DAFC output pins 12 through 1 These three digital AFC pinmap commands are recommended as a replacement for the original AFC-16 format in all new hardware designs. If you only need 12-bits of linear AFC, then map the AFC range into the 2048 to +2047 numeric span, and select binary coding format (See Section 3.3.6); the 12-bit data with CMD=3 will then hold the required values. To get a full 16-bit value, use a 32768 to +32767 span and extract the full word from both CMD=2 and CMD=3. Of course, other combinations of bit formats and number of bits (up to 25) are also possible. Command #4 is used to control some of the internal features of the IFD. Bits <4:0> configure the on-board noise generator so that it adds a selectable amount of dither power to the A/D converters. This noise is bandlimited using a 10-pole lowpass filter so that most of the energy is within the 150KHz to 900KHz band, with negligible residual power above 1.4MHz. Each of the five bits switch in additional noise power when they are set, with the upper bits making successively greater contributions. Bits <6:5> permit the IF-Input and Burst-Input signals to be reassigned on the fiber downlink. CMD=4 Data<4:0>

Data<6:5>

Built-in noise generator level IF-Input and Burst-Input selection 00 : Normal 10 : Burst Always 01 : Swap IF/Burst 11 : IF Always 2.5.2 Using the (I,Q) Digital Data Stream (Alan) The (I,Q) data stream that is computed by the FIR filter chips is communicated in real time to the central CPU. The IBD<17:0> data bus and IBDCLK clock signals are sourced on the P3 96-pin DIN connector of the RVP8. These TTL signals are normally kept internal to the RVP8, but some users may have a need to tap into them directly, e.g., to feed a separate data processor with the demodulated I and Q. Making the electrical connections to the (I,Q) data stream is especially easy with the RxNet7 packaging of the RVP8, since the complete set of signals are driven onto a dedicated 68-pin connector on its backpanel. Moreover, special PECL drivers on that connector make it possible 235 RVP8 Users Manual May 2003 Hardware Installation to run the cable over distances as great as ten meters. Please see the RxNet7 Users Manual for full details, as this is the recommended approach for driving the (I,Q) data out to an external device. If the RVP8s internal TTL signals are to be used directly, the physical connections must be made in such a way that no more than 12cm of additional wire length is added at the backplane. One way to do this would be to plug a custom driver board into an unused RVP8/AUX slot, from which the IBDxxx signals could be accessed. Another approach would be to mount the RVP8 board(s) in a completely custom backplane enclosure which also includes the users equipment that receives the (I,Q) data stream. The timing of the clock and data lines is shown in Figure 26 for the interval of time after the start of each transmitted pulse. The 18-bit data bus conveys two special code words at the beginning of each pulse, followed by (I,Q) for the Burst/COHO sample, followed by (I,Q) from the receiver. The receiver data continue to flow until the next transmitted pulse restarts the sequence anew, after a brief (approximately one range bin) clearing period. The data bus can be sampled on either the falling or rising edge of the clock, as there is an enforced 28ns data hold time after each rising clock edge. Using the rising clock edge will give the greatest data setup time, and this is usually preferred. Figure 26: Timing diagram of the (I,Q) Data Stream New Pulse Code Trigger Code Burst I Burst Q Bin #1 I Bin #1 Q IBD<17:0> Data Bus Clearing Period

(after last pulse) 28ns 82ns Range Bin Spacing IBDCLK Data Clock The New Pulse code is a unique 18-bit value that signifies the start of each new pulse of data. This is the only code or data word in which the MSB is zero. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 |

The Trigger Code follows immediately after the New Pulse code. It has a 1 in its MSB, and three different bit fields encoded into its low byte. These fields give information about the pulse itself. Codes that are not listed below are reserved, and will never appear on the data bus. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 0 0 0 0 0 0 0 | Flags | Bank | Waveform |

The 2-bit Flags field tells how this pulse will be used internally by the RVP8. This information is probably irrelevant to the external data processor, if all that it is doing is eavesdropping on the received data. 236 RVP8 Users Manual May 2003 Hardware Installation 01 This is the final pulse of a collection of pulses that will contribute to the next pro-

cessed ray. The 3-bit Bank field tells the major classification of the pulse. 000 001 010 111 Normal pulse Low PRF pulse during Dual-PRF mode Blanked transmitter version of a normal pulse Pulse used for receiver noise measurement (SNOISE Command) The 3-bit Waveform field indicates the minor classification of the pulse. 000 001 000-111 Normal pulse, or first pulse in a multi-part pulse sequence. Indicates that this is an alternate pulse. This is the V channel for a single-

channel polarization radar in which the receive or transmit polarization alternates pulse to pulse from H to V. This is also the longer PRT pulse whenever DPRT (Dual-PRT) mode is running. These incrementing codes will be output for the first eight pulses of any custom trigger pattern that the user has defined (See Section 6.14). If the custom pattern is more than eight pulses long, the 111 code will be held until the end of the se-

quence. The (I,Q) data for the Burst/COHO sample, as well as for the receiver samples, all have the same floating point format consisting of a 2-bit unsigned exponent (Exp) and 15-bit signed mantissa

(Man). 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 | Exp | Floating Point Mantissa (Signed) |

This format does not rely on a hidden bit in the mantissa. Rather, the mantissa is simply a 15-bit (generally unnormalized) value between 16384 and +16383, and the encoded floating point value is:

Value Man 16Exp Note that the exponent shifts the value not in increments of one bit, but rather, by four bits (by factors of 16). The mantissa will always be the largest integer (i.e., greatest relative precision) that will fit into the fifteen available bits. The overall dynamic range is 90dB while maintaining at least 66dB SNR within each sample. However, the format also gracefully underflows by allowing the mantissa to become small when Exp=0. This greatly extends the dynamic range into weak signals for which high relative precision is not required on each sample. The usable dynamic range of values over the entire receiver span is therefore approximately 125dB. 237 RVP8 Users Manual May 2003 Hardware Installation 2.4.2 Example Hookup to a MITEQ MFS-xxx STALO The electrical interface for this STALO uses a 25-pin D connector with the following pin assignments

GROUND on pins 1 and 2.

Four BCD digits of 1KHz, 10KHz, 100KHz, and 1MHz frequency steps, using Pins <25:22>, <21:18>, <17:14>, <13:10>.

Seven binary bits of representing 10MHz steps, Bits<0:6> on Pins<9:3>. First configure the IFD pins themselves. Pins 1 and 2 are ground, and are connected with wirewrap wire to the nearby ground posts. Pins 3 through 25 all are signal pins, so we plug in a jumper for each of these 23 pins. We will use pinmap uplink protocol, so H3 and H4 are removed; and a x1 on-board crystal, so H2 is also removed. In this example we will assume that we wish to control the STALO in 20KHz steps from 1.350GHz to 1.365GHz. This can be done with the following setups from the Mb section:

AFC span [100%,+100%] maps into [ 1350000 , 1365000 ]

AFC format 0:Bin, 1:BCD, 2:8B4D: 2, ActLow: NO AFC uplink protocol 0:Off, 1:Normal, 2:PinMap : 2 PinMap Table (Type 31 for GND, 30 for +5) Pin01:GND Pin02:GND Pin03:22 Pin04:21 Pin05:20 Pin06:19 Pin07:18 Pin08:17 Pin09:16 Pin10:15 Pin11:14 Pin12:13 Pin13:12 Pin14:11 Pin15:10 Pin16:09 Pin17:08 Pin18:07 Pin19:06 Pin20:05 Pin21:GND Pin22:GND Pin23:GND Pin24:GND Pin25:GND FAULT status pin (0:None): 0, ActLow: NO We map the AFC interval into a numeric span from 1350000 to 1365000, and choose the 8B4D mixed-radix encoding format. The STALO itself has 1KHz frequency steps, but the AFC servo will be easier to tune if we intentionally degrade this to 20KHz. This is done simply by grounding all four of the 1KHz BCD input lines, plus the LSB of the 10KHz BCD digit. A more creative use for one of these unused pins would be to remove the pin 25 jumper, wirewrap pin 25 to ground (so the STALO sill reads it a logic low), and assign pin 25 as a fault status input. That pin could then be connected to an external fault line, if the STALO has one. 231 RVP8 Users Manual May 2003 Hardware Installation 2.5 RVP8 Custom Interfaces This section describes some additional points of interface to the RVP8. These hookups are less conventional than the standard interfaces described earlier in this chapter, but they sometimes can supply exactly what is needed in exactly the right place. For the most part, these custom interfaces are merely taps into existing internal signals that would not normally be seen by the user. 2.5.1 Using the IFD Coax Uplink The Coax Uplink is the IFDs single line of communication from the RVP8/Rx processor board. All of the information that is needed by the IFD arrives through this uplink; and as such, this signal might contain information that is also useful for other parts of the radar system. In particular, it is a convenient source of digital AFC, along with reset and other status bits, plus limited trigger timing information. The uplink is a single digital transmission line that carries a hybrid serial protocol. The two logic states, zero and one are represented by 0-Volt and +15-Volt (open circuit) electrical levels. The output impedance of the uplink driver is approximately 55W

. When the cable is terminated in 75W approximately 8.6-Volts. by an internal resistor in the IFD, the overall positive voltage swing will be The electrical characteristics of the uplink have been optimized for balanced groundless reception, so that external noise and ground loop currents will not be introduced into the IFD. The recommended eavesdropping circuit is shown in Figure 24, and consists of a high speed comparator (Maxim MAX913, or equivalent) and input conditioning resistors. Both the shield and the center conductor of the coax uplink feed the comparator through 33KW resistors; no direct ground attachment is made to the shield itself. The 500W the local ground reference, and the 47KW signal into a bipolar range for the comparator. resistor supplies a bias to shift the unipolar uplink resistors provide isolation Figure 24: Recommended Receiving Circuit for the Coax Uplink 500 GND 33K 33K Coax Uplink Input Max913 or equiv. Received TTL Signal 500 47K GND

+5V 232 RVP8 Users Manual May 2003 Hardware Installation The uplink signal, shown in Figure 25, is periodic at the radar pulse repetition frequency, and conveys two distinct types of information to the IFD. The signal is normally low most of the time (to minimize driver and termination power), but begins a transition sequence at the beginning of each transmitted pulse. Figure 25: Timing Diagram of the IFD Coax Uplink

burst

s

s

s

s

s 1 2 3 4 5 6 7 8 9 10... The first part of each pulse sequence is a variable length burst window which is centered on the transmitted pulse itself, and which has a duration burst approximately 800ns greater than the length of the current FIR matched filter. The burst window defines the interval of time during which the IFD transmits digitized burst pulse samples, rather than digitized IF samples, on its fiber downlink. The exact placement and width of the burst window will depend on the trigger timing and digital filter specifications that the user has chosen, usually via the Pb and Ps plotting setup commands. Following the burst window is a fixed-length sequence of 25 serial data bits which convey information from the RVP8/Rx board. The first four data bits form a characteristic (0,1,1,0) marker pattern. The first zero in this pattern effectively marks the end of the variable length burst window, and the other three bits should be checked for added confidence that a valid bit sequence is being received. Table 29 defines the interpretation of the serial data bits. Table 29: Bit Assignments for the IFD Coax Uplink Bit(s) Meaning 14 520 21 22 2324 25 Marker Sequence (0,1,1,0). This fixed 4-bit sequence identifies the start of a valid data sequence following the variable-length burst window. 16-bit multi-purpose data word, MSB is transmitted first (See below) Reset Request. This bit will be set in just one transmitted sequence whenever an RVP8 reset occurs. If set, then interpret the 16-bit data word as 4-bits of command and 12-bits of data, rather than as a single 16-bit quantity (See below) Diagnostic select bits. These are used by the RVP8 power-up diagnostic routines; they will both be zero during normal operation. Green LED Request; 0=Off, 1=On. The state of this bit normally follows the Fiber Detect LED on the RVP8/Rx board. 233 RVP8 Users Manual May 2003 Hardware Installation The period s of the serial data is (64 faq) , where faq is the acquisition clock frequency given in the Mc section of the RVP8 setup menu. For the default clock frequency of 35.975MHz, the period of the serial data will be 1.779m sec. The logic that is receiving the serial data should first locate the center of the first data bit at (0.5 s) past the falling edge at the end of the burst window. Subsequent data bits are then sampled at uniform s intervals. The actual data sampling rate can be in error by as much as one part in 75 while still maintaining accurate reception. This is because the data sequence is only 25-bits long, and hence, the last data bit would still be sampled within 1/3 bit time of its center. Having this flexibility makes it easier to design the receiving logic. For example, if a 5MHz or 10MHz clock were available, then sampling at 1.8m sec intervals (1:85 error) would be fine. Likewise, one could sample at 1.75m sec based on a 4MHz or 8MHz clock (1:61 error), but only if the first sample were moved slightly ahead of center so that the sampling errors were equalized over the 25-bit span. Interpreting the Serial 16-bit Data Word The serial 16-bit data word has several different interpretations according to how the RVP8 has been configured, and whether Bit #22 of the uplink stream is set or clear. The evolution of these different formats has been in response to new features being added to the IFD (Section 2.2), and the production of the DAFC Digital AFC Module (Section 2.4). The original use of the uplink data word was simply to convey a 16-bit AFC level, generally for use with a magnetron system. Bit #22 is clear in this case, and the word is interpreted as a linear signed binary value. The use of this format is discouraged for new hardware designs, but it will always remain available to guarantee compatibility with older equipment. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 16Bit AFC Level | AFC16

Level 0111111111111111 (most positive AFC voltage) 0000000000000000 (center AFC voltage) 1000000000000000 (most negative AFC voltage) When the IFD is jumpered for phase locking to an external reference clock, then Bit #22 will be clear and the data word conveys the PLL clock ratio, and the Positive/Negative deviation sign of the Voltage Controlled Crystal Oscillator (VCXO). This format is commonly used with klystron systems, especially when the RVP8 is locking to an external trigger. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Pos| Numerator 1 | Denominator 1 | PLL16

Note that the AFC-16 and PLL-16 formats can never be interleaved for use at the same time, since there would be no way to distinguish them at the receiving end. Finally, an expanded format has been defined to handle all future requirements of the serial uplink. Bit #22 is set in this case, and the data word is interpreted as a 4-bit command and 12-bit data value. A total of 16x12=192 auxiliary data bits thus become available via sequential transmission of one or more of these words. The CMD/DATA words can also be used along with one of the AFC-16 or PLL-16 formats, since Bit #22 marks them differently. 234 RVP8 Users Manual May 2003 Hardware Installation 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Command | Data | CMD/DATA

Commands #1, #2, and #3 control the 25 output pin levels of the DAFC board. These transmissions may be interspersed with the PLL-16 format in systems that require both clock locking and AFC, e.g., a dual-receiver magnetron system using a digitally synthesized COHO. Note that the entire 25-bits of pin information are transferred synchronously to the output pins only when CMD=3 is received. This assures that momentary invalid patterns will not be produced upon arrival of CMD=1 or CMD=2 when the output bits are changing. CMD=1 Data<0>

Data<6>

Data<11:7>

CMD=2 Data<11:0>

CMD=3 Data<11:0>

DAFC output pin 25 Fault Input is active high Which pin to use for Fault Input (0:None) DAFC output pins 24 through 13 DAFC output pins 12 through 1 These three digital AFC pinmap commands are recommended as a replacement for the original AFC-16 format in all new hardware designs. If you only need 12-bits of linear AFC, then map the AFC range into the 2048 to +2047 numeric span, and select binary coding format (See Section 3.3.6); the 12-bit data with CMD=3 will then hold the required values. To get a full 16-bit value, use a 32768 to +32767 span and extract the full word from both CMD=2 and CMD=3. Of course, other combinations of bit formats and number of bits (up to 25) are also possible. Command #4 is used to control some of the internal features of the IFD. Bits <4:0> configure the on-board noise generator so that it adds a selectable amount of dither power to the A/D converters. This noise is bandlimited using a 10-pole lowpass filter so that most of the energy is within the 150KHz to 900KHz band, with negligible residual power above 1.4MHz. Each of the five bits switch in additional noise power when they are set, with the upper bits making successively greater contributions. Bits <6:5> permit the IF-Input and Burst-Input signals to be reassigned on the fiber downlink. CMD=4 Data<4:0>

Data<6:5>

Built-in noise generator level IF-Input and Burst-Input selection 00 : Normal 10 : Burst Always 01 : Swap IF/Burst 11 : IF Always 2.5.2 Using the (I,Q) Digital Data Stream (Alan) The (I,Q) data stream that is computed by the FIR filter chips is communicated in real time to the central CPU. The IBD<17:0> data bus and IBDCLK clock signals are sourced on the P3 96-pin DIN connector of the RVP8. These TTL signals are normally kept internal to the RVP8, but some users may have a need to tap into them directly, e.g., to feed a separate data processor with the demodulated I and Q. Making the electrical connections to the (I,Q) data stream is especially easy with the RxNet7 packaging of the RVP8, since the complete set of signals are driven onto a dedicated 68-pin connector on its backpanel. Moreover, special PECL drivers on that connector make it possible 235 RVP8 Users Manual May 2003 Hardware Installation to run the cable over distances as great as ten meters. Please see the RxNet7 Users Manual for full details, as this is the recommended approach for driving the (I,Q) data out to an external device. If the RVP8s internal TTL signals are to be used directly, the physical connections must be made in such a way that no more than 12cm of additional wire length is added at the backplane. One way to do this would be to plug a custom driver board into an unused RVP8/AUX slot, from which the IBDxxx signals could be accessed. Another approach would be to mount the RVP8 board(s) in a completely custom backplane enclosure which also includes the users equipment that receives the (I,Q) data stream. The timing of the clock and data lines is shown in Figure 26 for the interval of time after the start of each transmitted pulse. The 18-bit data bus conveys two special code words at the beginning of each pulse, followed by (I,Q) for the Burst/COHO sample, followed by (I,Q) from the receiver. The receiver data continue to flow until the next transmitted pulse restarts the sequence anew, after a brief (approximately one range bin) clearing period. The data bus can be sampled on either the falling or rising edge of the clock, as there is an enforced 28ns data hold time after each rising clock edge. Using the rising clock edge will give the greatest data setup time, and this is usually preferred. Figure 26: Timing diagram of the (I,Q) Data Stream New Pulse Code Trigger Code Burst I Burst Q Bin #1 I Bin #1 Q IBD<17:0> Data Bus Clearing Period

(after last pulse) 28ns 82ns Range Bin Spacing IBDCLK Data Clock The New Pulse code is a unique 18-bit value that signifies the start of each new pulse of data. This is the only code or data word in which the MSB is zero. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 |

The Trigger Code follows immediately after the New Pulse code. It has a 1 in its MSB, and three different bit fields encoded into its low byte. These fields give information about the pulse itself. Codes that are not listed below are reserved, and will never appear on the data bus. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 0 0 0 0 0 0 0 | Flags | Bank | Waveform |

The 2-bit Flags field tells how this pulse will be used internally by the RVP8. This information is probably irrelevant to the external data processor, if all that it is doing is eavesdropping on the received data. 236 RVP8 Users Manual May 2003 Hardware Installation 01 This is the final pulse of a collection of pulses that will contribute to the next pro-

cessed ray. The 3-bit Bank field tells the major classification of the pulse. 000 001 010 111 Normal pulse Low PRF pulse during Dual-PRF mode Blanked transmitter version of a normal pulse Pulse used for receiver noise measurement (SNOISE Command) The 3-bit Waveform field indicates the minor classification of the pulse. 000 001 000-111 Normal pulse, or first pulse in a multi-part pulse sequence. Indicates that this is an alternate pulse. This is the V channel for a single-

channel polarization radar in which the receive or transmit polarization alternates pulse to pulse from H to V. This is also the longer PRT pulse whenever DPRT (Dual-PRT) mode is running. These incrementing codes will be output for the first eight pulses of any custom trigger pattern that the user has defined (See Section 6.14). If the custom pattern is more than eight pulses long, the 111 code will be held until the end of the se-

quence. The (I,Q) data for the Burst/COHO sample, as well as for the receiver samples, all have the same floating point format consisting of a 2-bit unsigned exponent (Exp) and 15-bit signed mantissa

(Man). 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 | Exp | Floating Point Mantissa (Signed) |

This format does not rely on a hidden bit in the mantissa. Rather, the mantissa is simply a 15-bit (generally unnormalized) value between 16384 and +16383, and the encoded floating point value is:

Value Man 16Exp Note that the exponent shifts the value not in increments of one bit, but rather, by four bits (by factors of 16). The mantissa will always be the largest integer (i.e., greatest relative precision) that will fit into the fifteen available bits. The overall dynamic range is 90dB while maintaining at least 66dB SNR within each sample. However, the format also gracefully underflows by allowing the mantissa to become small when Exp=0. This greatly extends the dynamic range into weak signals for which high relative precision is not required on each sample. The usable dynamic range of values over the entire receiver span is therefore approximately 125dB. 237 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 3. TTY Nonvolatile Setups (draft) The RVP8 provides an interactive setup menu that can be accessed either from a serial TTY, or from the host computer interface. Most of the RVP8s operating parameters can be viewed and modified with this menu, and the settings can be saved in non-volatile RAM so that they take effect immediately on power-up. This permits custom trigger patterns, pulsewidth control, matched FIR filter specs, PRF, etc., to be configured by the user in the field. The TTY menu also gives access to a collection of graphical setup and monitoring procedures that use an ordinary oscilloscope as a synthesized visual display. The burst pulse and receiver waveforms can be examined in detail (both in the time and frequency domain) and the digital FIR filter can be designed interactively to match the characteristics of the transmitted pulse. 3.1 Overview of Setup Procedures This section describes basic operations within the setup menus such as making TTY connections, entering and exiting the menus, and saving and restoring the configurations. The setup TTY should be plugged into the modular 6-pin phone jack located at the top edge of the RVP8 board. The electrical interface may be either RS232 or RS423. If the phone jack connection is inconvenient, the terminal may be wired directly to the TIOXMT and TIORCV signals on the P2 96-pin connector. The TTY should be configured for 7-bit or 8-bit data (the MSB is always zeroed), no parity, and either one or two stop bits. With jumper JP4 in the AB position, the interface runs at 9600 baud; in the BC position the rate is 1200 baud (factory default), or some other rate set via the menu. Thus, the AB setting always makes a reliable 9600 baud connection, even if the the alternate rate is accidently set to a bad or forgotten value. Note: the reliable 9600 baud rate requires that the crystal located at X1 have a frequency of 4.9152MHz. 3.1.1 Initial Entry and Help List The interactive setup menu is invoked by pressing the Escape key on the TTY. If that key can not be found on the keyboard, you can sometimes use Control [ to generate the ESC code. The RVP8 then responds with the following banner and command prompt. SIGMET Incorporated, USA RVP8 Digital IF Signal Processor Rev.A/01 RVP8>

The banner identifies the RVP8 product, and gives the hardware version of the board (e.g., Rev.A) and software version (e.g., 01). This information is important whenever RVP8 support is required, and it is also repeated in the printout of the V command (See below). The Q command is used to exit from the menus and to restart the RVP8 with the (possibly changed) set of current values. It is important to quit from the menus before attempting to resume normal RVP8 operation. Portions of the RVP8 command interpreter remain running while the menus are active (so that the TTYOP command works properly), but the processor as a whole will not function until the menus are exited. 31 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) From the command prompt, typing help or ? gives the following list of available commands. Command List:

F: Use Factory Defaults S: Save Current Settings R: Restore Saved Settings M: Modify/View Current Settings Mb Burst Pulse and AFC Mc Board Configuration Mf Clutter Filters Mp Processing Options Mt<n> Trigger/Timing <for PW n>

Mz Transmitter Phase Control M+ Debug Options P: Plot with Oscilloscope Pb Burst Pulse Timing Ps Burst Spectra and AFC Pr Receiver Waveforms P+ Visual Test Pattern V: View Jumpers and Status

?: Cmd list (?? Settings list)

*: Reboot <Max Slaves> <+>

~: Swap Burst/IF Inputs on IFD Q: Quit 3.1.2 Factory, Saved, and Current Settings The current settings are the collection of setup values with which the RVP8 is presently operating; the saved settings are the collection of values stored in non-volatile RAM. The saved settings are restored (made current) each time the RVP8 is powered up. The S command saves the current settings into the non-volatile RAM, and the R command restores those non-volatile values so that they become the current settings. The F command initializes the current settings with factory default values. Thus, F followed by S saves factory defaults in non-volatile RAM, so that the RVP8 powers up in its original configuration as shipped. The RVP8 retains all of its saved settings when new ROM upgrades are installed; the new version of code will automatically use all of the previous saved values. However, if the RVP8 detects that the new release requires a setup parameter that did not exist in the previous release, then a factory default value will automatically be filled in for that parameter. A warning is printed whenever this occurs (See also, Section 3.1.4). There is also support for intermediate minor releases of RVP8 code. Each ROM has a major version number (the one that it always had), plus a minor version number for intermediate unofficial releases. The minor number starts from zero at the time of each official release, and then increments until the next official release. The RVP8 includes the minor release 32 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) number (if it is not zero) in the printout of the V command. Likewise, the minor release number of the code that last saved the nonvolatile RAM is also shown. This is an improvement over having to check the date of the code to determine which minor release was running. Note that the RVP8 does not actually begin using the current settings until after the Q command is entered, so that the processor exits the TTY setup mode and returns to normal operation. 3.1.3 Processor Reset Command The * command may be used to reset the signal processor from the TTY. This can be handy when the other methods of reset (power-up, parallel interface reset signal, or SCSI bus reset) can not easily be done. The command is robust in that pressing the Escape key followed by *, followed by two Returns, always resets the RVP8. There are certain wait conditions from which a TTY ESC does not immediately enter the setup monitor. However, the above four-key sequence always forces a full reset. The RVP8 diagnostics can run in a continuous loop that is useful during production burnin testing. In this mode the complete set of powerup tests is repeated approximately once per second. The green LEDs on the RVP8/Main and RVP8/AUX boards will blink on each run as a progress indicator. All red LEDs will initially be on, but each will begin to blink if any diagnostic ever fails on that board. A line of text is also printed to the setup TTY to show the progress of the tests and a summary of any errors. The RVP8s Perpetual Diagnostic Loop maintains a histogram of receiver IF-Input noise levels in 1dB steps from 85dBm to 72dBm. You can view the accumulated noise distribution by typing N while the diagnostic loop is running. This feature is intended for use during factory burn-in and testing of RVP8/IFD units. This special test mode can be started in two ways. One is to powerup the processor with the RVP8/Main I/O jumpers JP17JP22 in the (somewhat illegal) pattern: JP17:BC, JP18:BC, JP19:AB, JP20:AB, JP21:AB, JP22:AB. This method has the advantage of not requiring a TTY connection. The second method is to reset the processor from the local TTY monitor using the

*+ command. This is the normal reset command, but with a plus sign (debugging) suffix. 3.1.4 V View Internal Status The V command allows you to view some internal status within the RVP8. This information is available for inspection only, and can not be changed from the TTY. The view listing begins with the banner:

Jumpers and Internal Status and then prints the following lines:

Rev.B board, ROM V14.12 from Mon Jul 12 19:29:07 1999 This line shows the revision level of the RVP8 board, the ROM code version, and the date and time that this release was compiled. This lets you know the age of the release, even if the release notes have been misplaced. The date can also be helpful in keeping track of unofficial interim releases. 33 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Values were last saved using ROM version V14 This line tells which version of RVP8 code was the last to write into the non-volatile RAM. It is printed only if that last version was different from the ROM version that is currently running. The information is included so that a smart upgrade can often be done, i.e., values that did not exist in the prior release can be filled in with a guess that is better than merely taking the factory default. Warning: 3 automatic defaults were inserted. This warning will appear (accompanied by a beep) if one or more automatic factory defaults were required when the non-volatile RAM was last restored. It is likely that these automatic defaults will be acceptable operating values; but it would be wise to check the release notes to see what new parameters were added, and to decide on their proper settings. The warning will disappear once the S command is issued. This is because the missing saved slots are then filled in with valid values. Diagnostics: PASS Slave DSP Count: 3 If errors were detected by the powerup diagnostics then an error bitmask will be shown on the first line. The word PASS indicates that no errors were detected. The slave DSP count is also shown, which is the number of processors that were detected during the powerup sequence (and which will be used during subsequent processing). The RVP8 main board has three slave DSPs, and the each RVP8/AUX board supplies ten more. Up to two RVP8/AUX boards may be attached at the same time (23 slave DSPs total) for extremely intensive processing applications. An itemized list (consisting of bit pattern and text) is printed whenever any of the powerup diagnostics fail. The possible messages that might appear are:

0x00000001 : No fiber downlink signal detected 0x00000002 : 16Bit AFC level read/write 0x00000004 : IF Receiver reset request not sent 0x00000008 : I/O FIFO full before 4096 writes 0x00000010 : I/O FIFO not full after 4096 writes 0x00000020 : Transmit phase latch bits 0x00000040 : Downlink local counter test 0x00000080 : Receiver status bits & switches 0x00000100 : Test byte pattern from receiver 0x00000200 : Test word pattern from receiver 0x00000400 : NonVolatile RAM 0x00 and 0xFF flags 0x00000800 : UART read/write check 0x00001000 : External RAM check 0x00002000 : SCSI controller chip error 0x00004000 : Range mask RAM and addressing 0x00008000 : I&Q FIFO interrupt & trigger flags 0x00010000 : I&Q FIFO data bits 0x00020000 : FIR processing of ramp pattern 0x00040000 : Boot words not accepted by first slave 0x00080000 : No reply slave DSP count 0x00100000 : Invalid count of slave DSPs 0x00200000 : Global communication port tests 34 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 0x00400000 : Internal tests failed on some slave 0x00800000 : Trigger Generator RAM and addressing 0x01000000 : Excessive coax/fiber round trip jitter 0x02000000 : No sync found in round trip test 0x04000000 : Internal error in compile/link Coax/Fiber/Pipeline Delay: 0.624 usec (Stdev: 0.014 usec) During bootup the RVP8 measures the round trip delay along 1) the coax uplink to the receiver module, 2) the pipeline delays within the receiver module, 3) the optical fiber downlink to the main board, and 4) pipeline delays in the data decoding hardware. The time shown is accurate to within 14ns, and is used internally to insure that the absolute calibration of trigger and burst pulse timing remains unaffected by the distance between the main board and the receiver module. You may freely splice any lengths of coax and fiber without affecting the calibrations; the delay time will change, but the trigger and burst calibrations will remain constant. The standard deviation of the measured delay is also shown. If the coax uplink and fiber downlink cables are run properly this variation should be less than the period of the acquisition clock, e.g., 0.028 sec for the standard 35.975MHz rate. Larger errors may indicate a problem in the cabling. A diagnostic error bit is set if the error is greater than two acquisition clock periods. IFD:Okay, Burst Pwr:48.6 dBm, Freq:35.975 MHz RVP8/IFD and connecting cables are all working properly This line summarizes the receiver status and Burst input signal parameters. The status may show:

Okay NoFiber Problem in DownLink fiber cable from RVP8/IFD > RVP8/Main UpErr Problem in UpLink COAX cable from RVP8/Main > RVP8/IFD NoPLL RVP8/IFD PLL is not locked to external user-supplied clock reference DiagSW RVP8/IFD test switches are not in their normal operating position Reset by: Software Uptime: 0days 00:49:22 This line lists the origin of the last processor reset, as well as the total time that has elapsed since that reset occurred. The running time is given in days, followed by hours : minutes : seconds. The timer wraps around after approximately 180-days of continuous operation. The cause of the last reset will be one of the following:

1) Power-Up 3) SCSI Bus Reset 5) RESET OpCode with Rst bit 7) BOOT OpCode 9) TTY * command 11) Burn-In Self Tests 2) External RESET line 4) RESET OpCode with Pwr bit 6) RESET OpCode with Dig bit 8) Internal Watchdog 10) IFD Power Sequencing 3.1.5 Burst-In / IF-In Swap Command The ~ command swaps the Burst and IF inputs at the IFD. Requests to toggle the state are made from the top level as follows:

35 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) RVP8> ~

IFD Burst/IF Inputs are: SWAPPED RVP8> ~

IFD Burst/IF Inputs are: NORMAL The selection remains in effect for the duration of the setup session, but then returns to NORMAL upon exiting the TTY monitor. The ~ command is very handy because it allows the Pb, Pr, and Ps plotting commands to easily run with one input or the other. Here are two examples of how this might be useful.

When checking the range alignment on a Klystron system, the Pb plot can not be used in the usual way to center the Tx burst because a continuous-wave COHO

(rather than a burst pulse) is typically used as the phase reference in these systems. However, if you swap the Burst and IF inputs, you can then use the Pb command to view and center the received leakage of the Tx pulse, and thus locate range zero.

When setting up the AFC loop, you can use your RF signal generator to simulate the transmitters frequency, and then run the loop with swapped RVP8/IFD inputs. The AFC servo will then hunt and follow the siggen frequency supplied via the receiver. You can then make step changes in that frequency to verify that the loop responds properly. Note that the same input swapping function is also available via the RVP8/IFD toggle switches. However, those switches may be located far away from the operators terminal; hence, the command interface is still a valuable addition. The ~ command can only be used with the new Rev.D RVP8/IFD; the command is unimplemented, and will not even show up in the Help list, when earlier receivers are connected. 36 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 3.2 Host Computer I/O Debugging The RVP8 supports two very powerful monitoring functions that are helpful in debugging the I/O interface to the host computer. One examines the physical layer of the interface, i.e., the electrical handshake and data lines themselves. The other examines the application layer, i.e., the 16-bit opcodes and data that define the RVP8s application programming interface. 3.2.1 Physical-Level I/O Examiner The RVP8 has TTY support for debugging the physical level of the host computers SCSI or Parallel interface. The X (eXamine) command allows you to watch all incoming 16-bit words as they arrive from the host computer. In addition, you may also send 16-bit words back the other way. The X command is only available from the RS232 hardware TTY interface; it can not (obviously) be used via chat mode over the same I/O interface that it trying to examine. As such, the X command will not even be listed in the RVP8s top level help menu during a chat mode session. While the X command is running, any words that arrive from the computer will immediately be printed in hex format, along with an address (word counter, starting from zero) at the start of each line. Meanwhile, the W subcommand can be used to write individual words back to the computer, and the Q subcommand will exit the I/O examiner entirely. Note: When the X command is running, the RVP8 does not interpret the incoming 16-bit words as commands and arguments. Data sent to the RVP8 are discarded after being printed; and output from the RVP8 will occur only if the W subcommand is manually used. The X command is intended to debug the physical layer of the computer interface in a very controlled manner. The following dialog was captured in response to the host computer writing 100, 200, 300

(decimal) to the RVP8. The W subcommand was then used twice to output a 0x4000 and 0x8000 from the RVP8, and the computer then sent the values 1, 2, 3, 4, 5. RVP8> X Host Computer I/O Debug Monitor Q: Exit the monitor W: Output a word to the computer 0x0000: 0x0064 0x00C8 0x012C Output Word : 0x4000 Output Word : 0x8000 0x0003: 0x0001 0x0002 0x0003 0x0004 0x0005 3.2.2 Application-Level I/O Examiner The RVP8 has TTY support for debugging the application level of the host computers SCSI or Parallel interface. The Real Time TTY Monitor (RTM, see Section 3.3.7) can be configured to expose the computers complete I/O stream while the RVP8 is running and processing commands in its normal manner. Because of the enormous amount of TTY output that can be 37 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) generated by this option, all other RTM selections are disabled whenever host computer I/O is being monitored. Also, those other RTM selections would interfere with the multi-line formatting of the I/O text. The TTY printout shows incoming opcodes called out by name, and subsequent input and output words formatted into a table. The data are printed in Hex, twelve words per line, and include a word offset (origin zero) at the start of each line. The offset is reset to zero at the start of each new input or output sequence. Lines of data that are repeats of identical values will be skipped with a ... indication. This shortens and simplifies the printout; but more importantly, it reduces TTY overhead so that the processor is less I/O bound. Also for this reason, the 0x Hex prefix is omitted during the possibly lengthy printing of the data word tables. Note: As with all other Real Time TTY Monitor (RTM) functions, the RVP8 remains completely functional while host computer I/O is being monitored. However, unlike all other RTM functions, the I/O monitor will stall the main processor whenever the TTY becomes I/O bound; and the performance of the RVP8 will be degraded, perhaps severely. It is recommended that you configure the TTY for 38.4-KBaud to minimize the serial I/O delays. The following sample transactions were captured in response to starting the IRIS/Open ZAUTO utility. An I/O RESET and diagnostic OTEST are first performed. The pulse width selection bits and maximum trigger rates are then set with PWINFO, and angle sync is disabled with LSYNC. The header words for processed data are decided using CFGHDR, operational parameters are loaded with SOPRM, and final RVP8 parameters are read back with GPARM. Finally, the trigger rate is set using SETPWF, and a dummy range mask consisting of a single bin is setup with LRMSK. Opcode 0x008C (RESET) Opcode 0x0004 (OTEST) Output Words 0: 0001 0002 0004 0008 0010 0020 0040 0080 0100 0200 0400 0800 12: 1000 2000 4000 8000 Opcode 0x000F (PWINFO) Input Words 0: 8421 012C 0BB8 0FA0 1F40 Opcode 0x0011 (LSYNC) Opcode 0x005F (CFGHDR) Input Words 0: 0001 0000 Opcode 0x0002 (SOPRM) Input Words 0: 0019 000F 07AE 0008 FE70 0080 00A0 0000 0003 000A AAAA 8888 12: C0C0 C000 0000 0000 0000 AAAA 0000 2710 Opcode 0x0009 (GPARM) Output Words 0: 1200 0001 0960 FFFF FFFF 0D5B 0000 0000 0000 4284 0000 0000 12: 0019 743D 0007 0000 0000 230B 0032 5DC0 0BB8 1770 1D4C 2EE0 24: 8421 0000 2EE0 2EE0 0960 0960 000F 07AE 0008 FE70 0080 00A0 36: 0000 0000 0000 0000 0000 0000 0001 000E 0000 000E 0000 0D5B 48: 8000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 60: 0000 0000 0000 0000 38 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Opcode 0x0010 (SETPWF) Input Words 0: 2EE0 Opcode 0x0001 (LRMSK) Input Words 0: 0001 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 12: ... 504: 0000 0000 0000 0000 0000 0000 0000 0000 This RTM option to monitor computer I/O is automatically disabled at powerup, and therefore can not be saved permanently. This is to avoid confusing situations in which the monitor is accidently left running the RVP8 would appear to be working, but at a puzzling level of degraded performance. 39 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 3.3 View/Modify Dialogs The M command may be used to view, and optionally to modify, all of the current settings. The current value of each parameter is printed on the screen, and the TTY pauses for input at the end of the line. Pressing Return advances to the next parameter, leaving the present one unchanged. You may also type U to move back up in the list, and Q to exit from the list at any time. Typing a numeric or YES/NO response (as appropriate to the parameter) changes the parameters value, and displays the line again with the new value. All numbers are entered in base ten, and may include a decimal point and minus sign. In some cases, several parameters are displayed on one line, in which case, as many parameters are changed as there are new values entered. In all cases, the numbers are checked to be within reasonable bounds, and an error message (listing those bounds) is printed if the limits are exceeded. Note that changes to the settings (generally) do not take effect until after the Q command is typed, at which point the RVP8 exits the local TTY menu and resumes its normal processing operations. Since the number of setup questions is large, follow the M command with a second letter to select the subcategory, i.e., Mb (Burst Pulse and AFC), Mc (Board Configuration), Mf (Clutter Filters), Mp (Processing Options), Mt (Triggers and Timing), Mz (Transmitter Phase Control), M* (Stand-alone Settings) or M+ (Debug Options). The M command by itself prints the entire set of questions so that you can make a hard copy. The M command always works from the current parameter values, not from the saved values in non-volatile RAM. If the host computer has modified some of the current values, then you will see these changes as you skip through the setup list. However, typing S at that point would save all of the current settings and would, perhaps, make many changes to the original non-volatile settings. In general, to make an incremental change to the saved settings, first type R to restore all of the saved values, then use M to make the changes starting from that point, and S to save the new values. A listing of the parameters that can be viewed and modified with the M command is detailed in the following subsections. In each case, the line of text is shown exactly as it appears on the TTY with the factory default settings. A definition of each parameter is given and, if applicable, the lower and upper numeric bounds are shown. 3.3.1 Mc Board Configuration This set of commands configure general properties of the RVP8/IFD and RVP8/Main boards. Acquisition clock: 35.9751 MHz This is the frequency of the oscillator at U5 in the IF receiver module. Except for custom receivers, this will always be 35.9751 MHz; which gives a fundamental sample spacing of 1/240 km (approximately 4.17 meters). Limits: 33.33 to 41.67 MHz Dual simultaneous receivers are being used: NO Answer this question Yes if the RVP8 will be processing simultaneous signals from two separate receivers. Answering No will revert to normal operation with just a single receiver. 310 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) DualLNA/Rcvr singlechannel switched mode: NO For dual-polarization single-receiver systems, this question decides whether you have a single LNA and IF-Amplifier that switches between H&V (the typical case); or two separate receivers, each hard wired to H and V, with switching performed after the IF amplifiers. The question affects how noise levels are measured and applied to the data. Synthesize LOG video output waveform: YES Upper 100.0 dB will occupy 85.0% of voltage span Force freerunning video mode: NO Plot data from secondary receiver: NO The RVP8 supports the option of sourcing a LOG Video analog output signal from the backpanel of the main chassis. There are two ways that this signal can be configured:

Self-Triggering, Free-Running Mode This is the default mode that is available on all RVP8 boards. The output signal is periodic at approximately the PRF of the radar, but is free-running, i.e., not actually synchronized with the radar trigger. A synthetic 1.0 sec wide, full scale, trigger pulse is embedded at the zero-range start of each LOG Video waveform. This marker can easily trigger an oscilloscope if the scopes trigger level is set just below the maximum LOG Video voltage level.

Waveform Locked to Radar Trigger This mode requires a (one-wire) hardware modification to the Rev.B RVP8/Main board. The LOG Video waveform then becomes locked to the radar trigger, so that the LOG signal can be displayed on any device that already receives the radar trigger. In either case, the LOG Video output signal is unipolar, ranging from approximately 0.0V to 3.0V. It is active during all data processing modes that the host computer might request, as well as during the idle time between scans. The signal is absent

(zero), however, during the short intervals of time that the RVP8 is being reconfigured by the host computer, or when the RVP8s local TTY setups are being used. The time resolution of the synthesized LOG Video signal is fixed at 1.0 sec per bin. This is independent of the actual range resolution of the FIR matched filter. Whatever (I,Q) data are actually being computed by the FIR front end are selected for a nearest fit to each 1.0 sec synthetic output cell. The maximum number of incoming FIR range bins that can be selected among is 5460. Thus, for example, the maximum range of the LOG Video signal would be 682km when the FIR range resolution is 125meters. Answer the first question Yes if you would like the RVP8/Main board to synthesize and drive the LOG Video output signal. The cost of doing this is that one of the slave DSP chips will be removed from the normal Doppler processing chain, and dedicated to the task of LOG Video generation. On a single-board system, the 311 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) three available slave DSPs would be reduced to two; whereas on a dual-board system, the 13 available DSPs would be reduced to 12. Obviously, the percentage penalty is less in a larger system. The second question decides how the overall dynamic range of the receiver will fit into the 12-bit unipolar output voltage span of the DAC that produces the LOG Video waveform. The default setting calls for the upper 100dB of dynamic range to occupy 85% of the output voltage span. This means that the strongest IF input signal would produce 85% of the maximum DAC voltage (approximately 2.55 Volts); 50dB down would be 42.5%, and 100dB down would be 0%, i.e., zero volts. If you are using a self-triggering LOG Video waveform, then the 15% of headroom provided by the default settings leaves room for the embedded trigger pulse. However, if your RVP8 has the hardware modification required to synchronize the LOG Video to the system trigger, then the full 100% of the DAC voltage span can freely be used. The third setup question can be used to force freerunning mode on an RVP8 that has the hardware modification. This question is included mostly for testing purposes. The last question only appears in dual-receiver mode. Answer Yes if you would like the LOG video analog output signal to be based on the data from the secondary receiver rather than from the primary receiver. Scope plots Holdoff ratio: 0.50, Stroke: 1000.0 usec The oscilloscope plotting commands are described in Chapter 4. This question allows you to vary the amount of holdoff time that is inserted between each drawing stroke, as well as the stroke length itself. Try increasing the holdoff if your scope is not triggering reliably. Longer holdoffs make it easier for the scope to find the initial trigger point, but may introduce visible flicker. To reduce flicker, try decreasing the stroke duration from its default value of 1000 microseconds. Limits: Holdoff 0.05 to 5.00, Stroke 100 to 10000 sec. PWINFO command enabled: No The Pulsewidth Information user interface command can be disabled, thus further protecting the radar against inappropriate combinations of pulsewidth and PRF. This is a more safe setting in general, and is even more important when DPRT triggers are being generated. It can also be useful when running user code that is not yet fully debugged. TRIGWF command enabled: NO The Trigger Waveform user interface command can be disabled if you want to prevent the host computer from overwriting the RVP8s stored trigger specifications. This is the default setting, based on the assumption that the built-in plotting commands would be used to configure the triggers. Answering YES will allow new waveforms to be loaded from the host computer. RVP7 Emulation: No The RVP8 implements a reasonably precise emulation of the RVP7 command set. This mode is useful because it allows an RVP8 to be plugged directly into a software system that used to run with an RVP7. All of the configuration steps that are new and 312 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) unique to the RVP8 can be handled by the local TTY and Scope setups, thus making no demands on the users system code for support. Answer this question YES for maximum compatibility with old driver software. However, if you are running IRIS version 6.11 or higher, then answer NO to enable using new RVP8 features as they are developed. The RVP8 returns a version number of 35 when the processor is running in RVP7 compatibility mode. This fudged value will appear in the SCSI Inquiry Command reply, and in the GPARM parameter packet. Elsewhere, the correct RVP8 ROM version number will always appear. The reason for doing this is so that the RVP8 appears (to the host computer) to be a modern RVP7 with all of the latest opcodes and features. 3.3.2 Mp Processing Options Major Mode- 0:User, 1:PPP, 2:FFT : 0 The top level RVP8 operating modes are described in the documentation of SOPRM command word #9. This question allows you to use the mode that has been selected by that command, or to force the use of a particular mode. Window- 0:User, 1:Rect, 2:Hamming, 3:Blackman : 0 Whenever power spectra are computed by the RVP8, the time series data are multiplied by a (real) window prior to computation of the Fourier Transform. You may use whichever window has been selected via SOPRM word #10, or force a particular window to be used. R2 Processing- 0:Never, 1:User, 2:Always : 1 Controls R0/R1 versus R0/R1/R2 processing. Selecting 0 unconditionally disables the R2 algorithms, regardless of what the host computer requests in the SOPRM command. Likewise, selecting 2 unconditionally enables R2 processing. These choices allow the RVP8 to run one way or the other without having to rewrite the user code. This is useful for compatibility with existing applications. Clutter Microsuppression- 0:Never, 1:User, 2:Always : 1 Controls whether individual cluttery bins are rejected prior to being averaged in range. Same interpretation of cases as for R2 Processing above. 2D Final Speckle/Unfold 0:Never, 1:User, 2:Always : 1 The Doppler parameter modes (PPP, FFT, etc) include an optional 3x3 interpolation and speckle removal filter that is applied to the final output rays. This 2-dimensional filter examines three adjacent range bins from three successive rays in order to assign a value to the center point. Thus, for each output point, its eight neighboring bins in range and time are available to the filter. Only the dBZ, dBT, Vel, and Width data are candidates for this filtering step; all other parameters are processed using the normal 1-dimensional (three bins in range) speckle remover. See Section 5.3.3 for more details. 313 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Unfold Velocity (VhVl) 0:Never, 1:User, 2:Always : 0 This question allows you to choose whether the RVP8 will unfold velocities using a simple (Vhigh Vlow) algorithm, rather than the standard algorithm described in Section 5.6. Bit-11 of SOPPRM word #10 is the host computers interface to this function when the 1:User case is selected (See Section 6.3). Note: This setup question is included for research customers only. The standard unfolding algorithm should still be used in all operational systems because of its lower variance. For this reason, the factory default value of this parameter is 0:Never. Process w/ custom trigs 0:Never, 1:User, 2:Always : 0 This question allows you to choose whether the RVP8 will attempt to run its standard processing algorithms even when a custom trigger pattern has been selected via the SETPWF command. Generally it does not make sense to do this, so the default setting is 0:Never. Bit-12 of OPPRM word #10 is the host computers interface to this function when the 1:User case is selected (See Section 6.3). Minimum freerunning ray holdoff: 100% of dwell This parameter controls the rate at which the RVP8 processes free-running rays in the FFT, DPRT, and Random Phase modes. This prevents rays from being produced at the full CPU limit or I/O limit of the processor (whichever was slower); which could result in highly overlapping data being output at an unusably fast rate. Note that this behavior will only occur when one of these non-PPP modes is chosen, and is then allowed to run without angle syncing. Such is likely the case for IRIS manual scans or during Passive IRIS mode. To make these free-running modes more useful, you may establish a minimum holdoff between successive rays, expressed as a percentage of the number of pulses contributing to each ray. Choosing 100% (the default) will produce rays whose input data do not overlap at all, i.e., whose rate will be exactly the PRF divided by the sample size. Choosing 0% will give the unregulated behavior in which no minimum overlap is enforced and rays may be produced very quickly. Limits: 0 to 100%

Linearized saturation headroom: 4.0 dB The RVP8 uses a statistical saturation algorithm that estimates the real signal power correctly even when the IF receiver is overdriven (i.e., for input power levels above

+4dBm). The algorithm works quite well in extending the headroom above the top end of the A/D converter, although the accuracy decreases as the overdrive becomes more severe. This parameter allows you to place an upper bound on the maximum extrapolation that will ever be applied. Choosing 0dB will disable the algorithm entirely. Limits: 0 to 6dB Apply amplitude correction based on Burst/COHO: YES Time constant of mean amplitude estimator: 70 pulses The RVP8 can perform pulse-to-pulse amplitude correction of the digital (I,Q) data stream based on the amplitude of the Burst/COHO input. Please see Section 5.1.6 for a complete discussion of this feature. 314 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Limits: 10 to 500 pulses IFD builtin noise dither source: 57.0dBm This question will only appear if the processor is attached to a Rev.D RVP8/IFD that includes an out-of-band noise generator to supply dither power for the A/D converters. The available power levels are { Off, 57dBm, 37dBm, 32dBm, 27dBm, 22dBm, 19dBm }. The closest available level to your typed-in value will be used. You can observe the band-limited noise easily in the Pr plot to confirm its amplitude and spectral properties. For standard operation, we recommend running at 57dBm. The problem higher levels of dither level is that, for certain choices of (I,Q) FIR filter, the stopband of the filter may not give enough attenuation to preserve the RVP8/IFDs inherent noise level. For example, the factory default 1MHz bandwidth Hamming filter has a stopband attenuation near DC of approximately 43dB. You can see this graphically at the right edge of the Ps menu. The in-band contribution of dither power is therefore approximately (37dBm) 43dB = 80dBm, which exceeds the A/D converters 1MHz bandwidth noise of 81.5dBm. TAG bits to invert AZ:0000 EL:0000 TAG scale factors AZ:1.0000 EL:1.0000 TAG offsets (degrees) AZ:0.00 EL:0.00 The incoming TAG input bits may be selectively inverted via each of the 16-bit words. The values are displayed in Hex. Setting a bit will cause the corresponding AZ (bits 015) or EL (bits 1631) lines to be inverted. Note that the SOPRM command also specifies TAG bits to invert. Both specifications are XORed together to yield the net inversion for each TAG line. The overall operations are performed in the order listed. Incoming bits are first inverted according to the two 16-bit XOR masks. This yields an unsigned 16-bit integer value which is then multiplied by the signed scale factor. The result is interpreted as a 16-bit binary angle (in the low sixteen bits), to which the offset angle is finally added. As an example, suppose that the elevation angle input to the RVP8 was in an awkward form such as unsigned integer tenths of degrees, i.e., 0x0000 for zero degrees, 0x000a for one degree, 0x0e06 for minus one degree, etc. If we apply a scale factor of 65536/3600 = 18.2044 to these units, we will get 16-bit binary angles in the standard format. If we further suppose that the input angle rotated backwards, we could take care of this too using a multiplier of 18.2044. Interference Filter 0:None, Alg.1, Alg.2, Alg.3: 1 Threshold parameter C1: 10.00 dB Threshold parameter C2: 12.00 dB The RVP8 can optionally apply an interference filter to remove impulsive-type noise from the demodulated (I,Q) data stream. See Section 5.1.4 for a complete description of this family of algorithms. 315 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Polarization Params Filtered:YES NoiseCorrected:YES PhiDP Negate: NO , Offset:0.0 deg KDP Length: 5.00 km T/Z/V/W computed from: HXmt:YES VXmt:YES T/Z/V/W computed from: CoRcv:YES CxRcv:NO The first question decides whether all polarization parameters will be computed from filtered or unfiltered data, and whether noise correction will be applied to the power measurements. The second and third questions define the sign and offset corrections for DP and the length scale for KDP. The fourth and fifth questions control how the standard parameters (Total Reflectivity, Corrected Reflectivity, Velocity, and Width) are computed in a multiple polarization system. Answering YES to H-Xmt and/or V-Xmt means that data from those transmit polarizations should be used whenever there is more than one choice available. Thus, these selections only apply to the Alternating and Simultaneous transmit modes. Likewise, answering YES to Co-Rcv and/or Cx-Rcv means to use the received data from the co-channel or cross-channel. The receiver question will only appear when dual simultaneous receivers have been configured. A typical installation might use H-Xmt:YES, V-Xmt:YES, Co-Rcv:YES, Cx-Rcv:NO. This will compute (T/Z/V/W) from the co-polarized receiver using both H&V transmissions. Including both transmissions will decrease the variance of (T/Z/V/W);

although some researchers prefer excluding V-Xmt because that is more standard in the literature. Also, if your polarizations are such that the main power is returned on the cross channel, then you will probably want Co-Rcv:NO and Cx-Rcv:YES. DualRx Sum H+V Time Series: NO In dual-receiver systems, you may choose whether the (H+V) time series data consist of the sum of the H and V samples or the concatenation of half the H samples followed by half the V samples. The later is more useful when custom software is being used to analyze the data from the two separate receive channels. 3.3.3 Mf Clutter Filters Doppler Filter Set- 0:40dB, 1:50dB, 2:Saved : 0 The RVP8 has two built-in IIR Doppler clutter filter sets; one set having 40dB of stopband attenuation, and the other having 50dB. This question chooses which set is loaded on powerup. 316 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Spectral Clutter Filters Filter #1 Type:0(Fixed) Width:1 EdgePts:2 Filter #2 Type:0(Fixed) Width:2 EdgePts:2 Filter #3 Type:0(Fixed) Width:3 EdgePts:3 Filter #4 Type:0(Fixed) Width:4 EdgePts:3 Filter #5 Type:1(Variable) Width:1 EdgePts:2 Hunt:2 Filter #6 Type:1(Variable) Width:2 EdgePts:2 Hunt:2 Filter #7 Type:1(Variable) Width:3 EdgePts:3 Hunt:3 These questions define the heuristic clutter filters that operate on power spectra during the FFT-type major modes. Filter #0 is reserved as all pass, and is not redefinable here. For filters #1 through #7, enter a digit to choose the filter type, followed by however many parameters that type requires. Fixed Width Filters (Type 0) These are defined by two parameters. The Width sets the number of spectral points that are removed around the zero velocity term. A width of one will remove just the DC term; a width of two will remove the DC term plus one point on either side; three will remove DC plus two points on either side, etc. Spectral points are removed by replacing them with a linear interpolating line. The endpoints of this line are determined by taking the minimum of EdgeMinPts past the removed interval on each side. Variable Width, Single Slope (Type 1) The RVP8 supports variable-width frequency-domain clutter filters. These filters perform the same spectral interpolation as the fixed-width filters, except that their notch width automatically adapts to the clutter. The new filters are characterized by the same Width and EdgePts parameters in the Mf menu, except that the Width is now interpreted as a minimum width. An additional parameter Hunt allows you to choose how far to extend the notch beyond Width in order to capture all of the clutter power. Setting Hunt=0 effectively converts a variable-width filter back into a fixed-width filter. The algorithm for extending the notch width is based on the slope of adjacent spectral points. Beginning (Width1) points away from zero, the filter is extended in each direction as long as the power continues to decrease in that direction, up to adding a maximum of Hunt additional points. If you have been running with a fixed Width=3 filter, you might try experimenting with a variable Width=2 and Hunt=1 filter. Perhaps the original fixed width was actually failing at times, but you were reluctant to increase it just to cover those rare cases. In that case, try selecting a variable Width=2 and Hunt=2 filter as an alternative. In general, make your variable filters wider by increasing Hunt rather than increasing Width. This will preserve more flexibility in how they can adapt to whatever clutter is present. Residual clutter LOG noise margin: 0.15 dB/dB Whenever a clutter correction is applied to the reflectivity data, the LOG noise threshold needs to be increased slightly in order to continue to provide reliable qualification of the corrected values. The reason for this is that the uncertainty in the corrected reflectivity becomes greater after the clutter is subtracted away. 317 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) For example, if we observe 20dB of total power above receiver noise, and then apply a clutter correction of 19dB, we are left with an apparent weather signal power of

+1dB above noise. However, the uncertainty of this +1dB residual signal is much greater than that of a pure weather target at the same +1dB signal level. The Residual Clutter LOG Noise Margin allows you to increase the LOG noise threshold in response to increasing clutter power. In the previous example, and with the default setting of 0.15dB/dB, the LOG threshold would be increased by 19x0.15

= 2.85dB. This helps eliminate noisy speckles from the corrected reflectivity data. Whitening Parameters Noise threshold for replacing a point: 1.20 Replacement value multiplier: 0.5000 SNR in tails, for determining width: 0.25 These questions control the adaptive whitening filter that is used by the Random Phase processing algorithms. A spectral point will be whitened if the ratio of its power to the noise power exceeds the Noise threshold for replacing a point. The whitened point will consist of a complex value whose ARG is identical to that of the original point, and whose MAG is the product of the noise level with the Replacement value multiplier term. The nominal spectral width of the whitened region is a function of the power and width of the coherent signal, and the noise level. Assuming a Gaussian model, the SNR in tails... value is the ratio of the coherent power in the tails of the distribution to the noise level. RPhase SQI Threshold Slope:0.50 Offset:0.05 The two values in this question define a secondary SQI threshold that is used to qualify the LOG data during Random Phase processing. The secondary SQI level is computed by multiplying the primary user-supplied SQI threshold by the SLOPE, and adding the OFFSET. See also Section 5.9.3. Limits: SLOPE: 0.0 to 2.0, OFFSET 2.0 to 1.0 3.3.4 Mt General Trigger Setups These questions are accessed by typing Mt with no additional arguments. They configure general properties of the RVP8 trigger generator Pulse Repetition Frequency: 500.00 Hz This is the Pulse Repetition Frequency of the internal trigger generator. Limits: 50 to 6000Hz. Transmit pulse width: 0 Limits: 0 to 3 Use external pretrigger: NO PreTrigger active on rising edge: YES PreTrigger fires the transmitter directly: NO When an external pretrigger is applied to the TRIGIN input of the RVP8, either the rising or falling edge of that signal initiates operation. This decision also affects which signal edge becomes the reference point for the pretrigger delay times given in the Mt<n> section. 318 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Answer the second sub-question according to whether the radar transmitter is directly fired by the the external pretrigger, rather than by one of the RVP8s trigger outputs. In other words, answer YES if the transmitter would continue running fine even if the RVP8 TRIGIN signal were removed. This information is used by the L and R subcommands of the Pb plotting command, i.e., when slewing left and right to find the burst pulse, the pretrigger delay will be affected rather than the start times of the six output triggers. 2way (Tx+Rx) total waveguide length: 0 meters Use this question to compensate for the offset in range that is due to the length of waveguide connecting the transmitter, antenna, and receiver. You should specify the total 2-way length of waveguide, i.e., the span from transmitter to antenna, plus the span from antenna to receiver. The RVP8 range selection will compensate for the additional waveguide length to within plus-or-minus half a bin, and works properly at all range resolutions. POLAR0 is high for vertical polarization : NO POLAR1 is high for vertical polarization : NO These questions define the logical sense of the two polarization control signals POLAR0 and POLAR1. In a dual-polarization radar POLAR0 should be used to select one of two possible states (nominally horizontal and vertical, but any other polarization pair may also be used). The control signal will either remain at a fixed level, or will alternate from pulse to pulse with a selectable transition point (See Section 3.3.5). POLAR1 is identical to POLAR0, but may be configured with a different polarity and switch point. This second signal could be used if the radars polarization switch required more than one control line transition when changing states. Quantize trigger PRT to ((1 x AQ) + 0) clocks It is possible to control the exact quantization of the PRT of the internal trigger generator. Normally the trigger PRT is chosen as the closest multiple of AQ (the acquisition clock period) that approximates the requested period. This question allows the possible PRTs to be constrained to ((N x AQ) + M) clock cycles. This feature can be useful for synchronous receiver systems in which the trigger period must be some exact multiple of the COHO period. Blank output triggers according to TAG#0 : NO Blank when TAG input is high : NO Blank triggers 1:YES 2:YES 3:YES 4:YES 5:YES 6:YES These questions control trigger blanking based on the TAG0 input line. You first select whether the trigger blanking feature is enabled; and then optionally choose the polarity of TAG0 that will result in blanking, and which subset of the six user definable triggers are to be blanked. Blank output triggers during noise measurement : NO The RVP8 can inhibit the subset of blankable trigger lines whenever a noise measurement is taken. This will be forced whenever trigger blanking (based on TAG0) is enabled, but it can also be selected in general via this question. Since noise triggers must be blanked whenever trigger blanking is enabled, this question only appears if trigger blanking is disabled. 319 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) This question permits the state of the triggers during noise measurements to be consistent and known, regardless of whether the antenna happens to be within a blanked sector; and you have the additional flexibility of choosing blanked noise triggers all the time. RxFixed Triggers: #1:N #2:N #3:N #4:N #5:N #6:N P0:N P1:N Z:N You have explicit control over which RVP8 trigger outputs are timed relative to the transmitter pre-fire sequence, versus those which are relative to the actual received target ranges. Triggers in the first category will be moved left/right by the L/R keys in the Pb plot, and will also be slewed in response to Burst Pulse Tracking. Triggers in the second category remain fixed relative to receiver range zero, and are not affected by the L/R keys or by tracking. This question specifies which triggers are Tx-relative and which are Rx-relative. Answer with a sequence of Y or N responses for each of the six trigger lines, for the two polarization control lines, and for the timing of the phase control lines. You should answer No for any trigger that is involved with the pre-fire timing of the transmitter. If you enable the Burst Pulse Tracker (Section 5.1.3) you will probably want to assign a Yes to some of your triggers so that they remain fixed relative to the burst itself. It is very helpful to have these two categories of trigger start times. Triggers that fire the transmitter, either directly or indirectly, should all be moved as a group when hunting for the burst pulse and moving it to the center of the FIR window. However, triggers that function as range strobes should be fixed relative to range zero, i.e., the center of that window, and the center of the burst. This distinction becomes important when the transmitters pre-fire delay drifts with time and temperature. Replace triggers with alternate waveforms: YES Trigger #1 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #2 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #3 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #4 0:Normal, 12:Pol01, 36:PW03 : 1 Trigger #5 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #6 0:Normal, 12:Pol01, 36:PW03 : 4 These questions make it possible to reassign the waveforms that are driven onto the six user trigger (TRIG16) BNC outputs on the backpanel of the RVP8. This makes it easier to adapt the external cabling of the RVP8 so as to make better use of the available BNC connectors and related 15V drivers. You may substitute either of the two polarization control lines or the four pulsewidth control lines in place of any of the six normal triggers. In the example above, triggers #1, #2, #3, and #5 are all driven with their normal waveforms. However trigger #4 will have a copy of the POLAR0 polarization control line, and trigger #6 will have a copy of the PWBW1 pulsewidth control line. Neither POLAR0 nor PWBW1 themselves are changed by these assignments. Whenever any of the six user trigger lines is reassigned from its normal setting, the plot of that trigger within the Pb command will show a hashed line across the screen. This is a graphical reminder that that trigger has been replaced by some other waveform. 320 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Merge triggers to create composite waveforms: YES Merge Trigger #1 into : #1: #2: #3: #4: #5: #6:

Merge Trigger #2 into : #1: #2: #3: #4: #5: #6:

Merge Trigger #3 into : #1:Y #2: #3: #4: #5: #6:

Merge Trigger #4 into : #1: #2:Y #3: #4: #5: #6:

Merge Trigger #5 into : #1: #2:Y #3: #4: #5: #6:

Merge Trigger #6 into : #1: #2: #3: #4: #5: #6:

These questions allow you to merge the six user triggers together; resulting in trigger patterns that can be much more complex. In this example, Trigger #3 will be merged into Trigger #1; Trigger #3 will be unaltered, and Trigger #1 will be the OR of itself with Trigger #3. Likewise, Triggers #4 and #5 will be merged into Trigger #2 so that the later will contain three distinct pulses within each PRT. Answer each question with a sequence of up to six Y or N responses in order to set the merged destinations for each trigger line. Note that the six triggers are still defined in the usual way in the Mt<n> menu, i.e., start time, width, etc. The only change is that you may now combine these individual pulse definitions into a more complex composite output waveform. 3.3.5 Mt<n> Triggers for Pulsewidth #n These questions are accessed by typing Mt, with an additional argument giving the pulsewidth number. They configure specific trigger and FIR bandpass filter properties for the indicated pulsewidth only. Trigger #1 Start: 0.00 usec

#1 Width: 1.00 usec High:YES Trigger #2 Start: 0.00 usec + ( 0.500000 * PRT )

#2 Width: 10.00 usec High:YES Trigger #3 Start: 3.00 usec

#3 Width: 1.00 usec High:YES Trigger #4 Start: 2.00 usec

#4 Width: 1.00 usec High:YES Trigger #5 Start: 1.00 usec

#5 Width: 1.00 usec High:YES Trigger #6 Start: 5.00 usec + (0.001000 * PRT )

#6 Width: 2.00 usec High:NO These parameters list the starting times (in microseconds relative to range zero), the widths (in microseconds), and the active sense of each of the six triggers generated by the internal trigger generator. Setting a width to zero inhibits the trigger on that line. The Start Time can include an additional term consisting of the pulse period times a fractional multiplier between 1.0 and +1.0. This allows you to produce trigger patterns that would not otherwise be possible, e.g., a trigger that occurs half way 321 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) between every pair of transmitted pulses, and remains correctly positioned regardless of changes in the PRF Enter this multiplier as 0 if you do not wish to use this term, and it will be omitted entirely from the printout.. In the above example, Trigger #2 is a 10.0 sec active-high pulse whose leading edge occurs precisely halfway between the zero-range of every pair of pulses. Likewise, Trigger #6 is a 2.0 sec active-low pulse whose falling edge is nominally 5.0 sec prior to range zero, but which is advanced by 1.0 sec for every millisecond of trigger period. All other triggers behave normally, and have fixed starting times that do not vary with trigger period. Some subtleties of these variable start times are:

The PRT multipliers can only be used in conjunction with the RVP8s internal trigger generator. The PRT-relative start times are completely disabled whenever an external trigger source is chosen from the Mt menu.

When PRT-relative triggers are plotted by the Pb command, the active portion of the trigger will be drawn cross-hatched and at a location computed according to the current PRF. The cross-hatching serves as a reminder that the actual location of that trigger may vary from its presently plotted position.

The PRT multiplier for a given pulse is applied to the interval of time between that pulse and the next one. This distinction is important whenever the RVP8 is generating multiple-PRT triggers, e.g., during DPRT mode, or during Dual-PRF processing. Multipliers from 0.0 to +1.0 are generally safe to use because they shift the trigger into the same pulse period that originally defined it. For example, a start time of (0.0 sec + (0.98 * PRT)) would position a trigger 98%

of the way up to the next range zero. But, if 0.98 were used, and if the period of the previous pulse was shorter than the current one, then that shorter period would become incorrect (longer) as a result of having to fit in the very early trigger. A small but important detail is built into the algorithm for producing the six user trigger waveforms. It applies whenever a) the trigger period is internally determined, i.e., the external pretrigger input is not being used, and b) the overall span of the six trigger definitions combined does not fit into that period. What happens in this case is that any waveforms that do not fit will be zeroed (not output) so that the desired period is preserved. This means that you can define triggers with large positive start times, and they will pop into existence only when the PRF is low enough to accommodate them. For example, if Trigger #2 is defined as a 200.0sec pulse starting at +400.0sec, then that trigger would be suppressed if the PRF were 2000Hz, but it would be present at a PRF of 1000Hz. Whenever a trigger does not completely fit within the overall period it is suppressed entirely. Thus, even though the +400.0sec start time is still valid at 2000Hz, the entire 200.0sec pulse would not fit, and so the pulse is eliminated altogether. Start limits: 5000 to 5000 sec. Width limits: 0 to 5000 sec. 322 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Maximum number of Pulses/Sec: 2000.0 Maximum instantaneous PRF : 2000.0 (/Sec) These are the PRF protection limits for this pulsewidth. The wording of the Maximum number of Pulses/Sec question serves as a reminder that the number shown is not only an upper bound on the PRF, but also a duty cycle limit when DPRT mode is enabled. The Maximum instantaneous PRF question allows you to configure the maximum instantaneous rate at which triggers are allowed to occur, i.e., the reciprocal of the minimum time between any two adjacent triggers. This parameter is included so that you can limit the maximum DPRT trigger rate individually for each pulsewidth. Note that the maximum instantaneous PRF can not be set lower than the maximum number of pulses per second. PRF limits: 50 to 20000Hz. External pretrigger delay to range zero: 3.00 usec Range Zero is time at which the signal from a target at zero range would appear at the radar receiver outputs. This parameter adjusts the delay from the active edge of the external trigger to range zero. It is important that this delay be correct when the RVP8 is operating with an external trigger, since the zero range point is a fixed time offset from that trigger. When the transmitter is driven from the internal trigger signals, those signals themselves are adjusted (see Burst Pulse alignment procedures) to accomplish the alignment of range zero. Limits: 0.1 to 500 sec. Range resolution: 125.00 meters The range resolution of the RVP8 is determined by the decimation factor of the digital matched FIR filter that computes I and Q. This decimation factor is the ratio of the filters input and output data rates, and can be any integer from six to sixteen. The Acquisition Clock (See Mc Section) sets the input data rate. At its standard frequency of 35.9751MHz, the available range resolutions (in meters) are:

50.0, 58.3, 66.7, 75.0, 83.3, 91.7, 100.0, 108.3, 116.7, 125.0, and 133.3. The ranges that are selected by the bit mask in the LRMSK command are spaced according to the range resolution that is chosen here. Also, the upper limit on the impulse response length of the matched FIR filter (see below) is constrained by the range resolution. If you choose a range resolution that can not be computed at the present filter length, then a message of the form: Warning: Impulse response shortened from 72 to 42 taps will appear. Limits: 50.0 to 133.3 meters. FIR-Filter impulse response length: 1.33 usec The RVP8 computes I and Q using a digital FIR (Finite Impulse Response) matched filter. The length of that filter (in microseconds) is chosen here. At the standard Acquisition Clock rate of 35.9751MHz, a 1.00 microsecond impulse response corresponds to a filter that is 36 taps long. The filter length should be based on several considerations:

323 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft)

It should be at least as long as the transmitted pulsewidth. If it were shorter, then some of the returned energy would be thrown away when I and Q are computed at each bin. The SNR would be reduced as a result. It should be at least as long as the range bin spacing. The goal here is to choose the longest filter that retains statistical independence among successive bins. If the filter length is less than the bin spacing, then no IF samples would be shared among successive bins, and those bins would certainly not be correlated. It should be slightly longer than either of the above bounds would imply, so that the filter can do a better job of rejecting out-of-band noise and spurious signals. The SNR of weak signals will be improved by doing this. In practice, a small degree of bin-to-bin correlation is acceptable in exchange for the filter improvements that become possible with a longer impulse response. The FIR coefficients taper off to zero on each end; hence, the power contributed by overlapping edge samples is minimal. SIGMET recommends beginning with an impulse response length of 1.21.5 times the pulsewidth or bin spacing, whichever is greater. The maximum possible filter length is bounded according to the range resolution that has been chosen; a finer bin spacing leaves less time for computing a long filter. For the RVP8 Rev.A processor, the filter length must be less than 2.92 sec at 125-meter resolution; for Rev.B and higher this limit increases to 6.67 sec. NOTE: Cascade filter software is being contemplated that will extend the maximum impulse response length to at least 50 sec. This is of interest when very long

(uncoded CW) transmitted pulses are used. FIR-Filter prototype passband width: 0.503 MHz This is the passband width of the ideal lowpass filter that is used to design the matched FIR bandpass filter. The actual bandwidth of the final FIR filter will depend on 1) the filters impulse response length, and 2) the design window used in the process. The actual 3dB bandwidth will be:

Larger than the ideal bandwidth if that bandwidth is narrow and the FIR length is too short to realize that degree of frequency discrimination. In these cases it may be reasonable to increase the filter length.

Smaller than the ideal bandwidth if the FIR length easily resolves the frequency band. This is because of the interaction within the filters transition band of the ideal filter and the particular design window being used. For example, for a Hamming window and sufficiently long filter length, the ideal bandwidth is an approximation of the 6dB (not 3dB) attenuation point. Hence, the 3dB width is narrower than the ideal prototype width. This parameter should be tuned using the TTY output and interactive visual plot from the Ps command. The actual 3dB bandwidth is shown there, so that it can be compared with the ideal prototype bandwidth. Limits: 0.05 to 10.0 MHz. 324 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Output control 4bit pattern: 0001 These are the hardware control bits for this pulsewidth. The bits are the 4-bit binary pattern that is output on PWBW0:3 Bit Limits: 0 to 15 (input must be typed in decimal) Current noise level: 75.00 dBm Powerup noise level: 75.00 dBm or Current noise levels PriRx: 75.00 dBm, SecRx: 75.00 dBm Powerup noise levels PriRx: 75.00 dBm, SecRx: 75.00 dBm These questions allow you to set the current value and the power-up value of the receiver noise level for either a single or dual receiver system. The noise level(s) are shown in dBm, and you may alter either one from the TTY. The power-up level(s) are assigned by default when the RVP8 first starts up, and whenever the RESET opcode is issued with Bit #8 set. Likewise, the current noise level is revised whenever the SNOISE opcode is issued. These setup questions are intended for applications in which the RVP8 must operate with a reasonable default value, up until the time that an SNOISE command is actually received. They may also be used to compare the receiver noise levels during normal operation, which serves as a check that each FIR filter is behaving as expected when presented with thermal noise. Transmitter phase switch point: 1.00 usec This is the transition time of the RVP8s phase control output lines during random phase processing modes. The switch point should be selected so that there is adequate settling time prior to the burst/COHO phase measurement on each pulse. This question only appears if the PHOUT[0:7] lines are actually configured for phase control (See Section 3.3.1). Limits: 500 to 500 sec. Polarization switch point for POLAR0: 1.00 usec Polarization switch point for POLAR1: 1.00 usec The RVP8s POLAR0 and POLAR1 digital output lines control the polarization switch in a dual-polarization radar. During data processing modes in which the polarization alternates from pulse to pulse, the transition points of these control signals are set by these two questions. The values are in microseconds relative to range zero; the same units used to define the start times of the six user triggers. The logical sense of POLAR0 and POLAR1 is set by questions described in Section 3.3.4. Limits: 500 to 500 sec. 3.3.6 Mb Burst Pulse and AFC These questions are accessed by typing Mb. They set the parameters that influence the phase and frequency analysis of the burst pulse, and the operation of the AFC feedback loop. Receiver Intermediate Frequency: 30.0000 MHz This is the center frequency of the IF receiver and burst pulse waveform. The RVP8 can operate at an intermediate frequency from any of the three alias bands 2232MHz, 4050MHz, and 5868MHz. These bands are delineated by 4MHz 325 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) safety zones on either side of integer multiples of half the RVP8/IFDs 36MHz sampling frequency. The value entered here implicitly defines the band, and hence, the boundaries of the 18MHz window in which the IF is assumed to fall. Limits: 22 to 68 MHz. Primary Receiver Intermediate Frequency: 30.0000 MHz Secondary Receiver Intermediate Frequency: 24.0000 MHz These alternate questions will replace the previous question whenever the RVP8s dual-receiver mode is selected. You should enter the two intermediate frequencies for your primary and secondary (nominally horizontal and vertical polarized) receivers. Note that you can easily swap receiver channels merely by exchanging the two frequency values. IF increases for an approaching target: YES The intermediate frequency is derived at the receivers front end by a microwave mixer and sideband filter. The filter passes either the lower sideband or the upper sideband, and rejects the other. Depending on which sideband is chosen, an increase in microwave frequency may either increase (STALO below transmitter) or decrease

(STALO above transmitter) the receivers intermediate frequency. This question influences the sign of the Doppler velocities that are computed by the RVP8. PhaseLock to the burst pulse: YES This question controls whether the RVP8 locks the phase of its synthesized I and Q data to the measured phase of the burst pulse. For an operational magnetron system this should always be YES, since the transmitters random phase must be known in order to recover Doppler data. The NO option is appropriate for non phase modulated Klystron systems in which the RVP8/IFD sampling clock is locked to the COHO. It is also useful for bench testing in general. In these NO cases the phase of I and Q is determined relative to the stable internal sampling clock in the RVP8/IFD module. Minimum power for valid burst pulse: 15.0 dBm This is the minimum mean power that must be present in the burst pulse for it to be considered valid, i.e., suitable for input into the algorithms for frequency estimation and AFC. The reporting of burst pulse power is described in Section 4.4; the value entered here should be, perhaps, 8 dB less. This insures that burst pulses will still be properly detected even if the transmitter power fades slightly. The mean power level of the burst is computed within the narrowed set of samples that are used for AFC frequency estimation. The narrow subwindow will contain only the active portion of the burst, and thus a mean power measurement is meaningful. The full FIR window would include the leading and trailing pulse edges and would not produce a meaningful average power. Since radar peak power tends to be independent of pulse width, this single threshold value can be applied for all pulsewidths. Limits: 60 to +10 dBm. Design/Analysis Window 0:Rect, 1:Hamming, 2:Blackman : 1 You may choose the window that is used in 1) the design of the FIR matched filter, and 2) the presentation of the power spectra for the various scope plots. Choices are rectangular, Hamming, and Blackman; the Hamming window being the best overall 326 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) choice. The Blackman window is useful if you are trying to see plotted spectral components that are more than 40dB below the strongest signal present. It is especially useful in the Pr plot when a long span of data are available. FIR filters designed with the Blackman window will have greater stopband attenuation than those designed with the Hamming window, but the wider main lobe may be undesirable. The rectangular window is included mostly as a teaching tool, and should never be used in an operational setting. Settling time (to 1%) of burst frequency estimator: 5.0 sec The burst frequency estimator uses a 4th order correlation model to estimate the center frequency of the transmitted pulses. Each burst pulse will typically occupy approximately one microsecond; yet the frequency estimate feeding the AFC loop needs to be accurate to, perhaps, 10KHz. Obviously this accuracy can not be achieved using just one pulse. However, several hundred of the (unbiased) individual estimates can be averaged to produce an accurate mean. This averaging is done with an exponential filter whose time constant is chosen here. Limits: 0.1 to 120 seconds. Lock IFD sampling clock to external reference: NO This question determines the usage of the shared SMA connector that is labeled AFC/(CLK) on the RVP8/IFD. It is generally not necessary to phase lock the IFD sampling clock to the radar system clock, since very good stability is obtained from the burst phase measurements during normal operation. However, two cases that benefit from clock locking are 1) using the RVP8 in a klystron system where an external trigger is provided, and 2) dual-receiver systems in which computation of

DP is important. The following two questions will appear only if you have requested that the IFD sampling clock be locked to an external clock reference. See Section 2.2.11 for a description of the hardware setups that must accompany this selection. PLL ratio of (1/1) ==> Input reference at 17.9876 MHz The VCXO phase-locked-loop (PLL) in the RVP8/IFD can work with any input reference clock whose frequency is a rational multiple (P/Q) of half the desired sampling frequency, i.e., center frequency of the VCXO. This question allows this ratio to be established. In general, the best PLL performance will be attained when the ratio is reduced to lowest terms, e.g., use a ratio of 6/5 rather than 12/10. Limits: 1 to 128 for both numerator and denominator. VCXO has positive frequency deviation: YES Most VCXOs have positive frequency deviation, i.e., their output frequency increases with increasing input control voltage. This question will generally be answered yes, but is included to accommodate the other case as well. The PLL will not lock, and will be completely unstable, if the wrong choice is made. Enable AFC and MFC functions: YES AFC is required in a magnetron system to maintain the fixed intermediate frequency difference between the transmitter and the STALO. AFC is not required in a klystron system since the transmitted pulse is inherently at the correct frequency. 327 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) The following rather long list of questions will appear only if AFC and MFC functions have been enabled. AFC Servo 0:DC Coupled, 1:Motor/Integrator : 0 The AFC servo loop can be configured to operate with an external Motor/Integrator frequency controller, rather than the usual direct-coupled FM control. This type of servo loop is required for tuned magnetron systems in which the tuning actuator is moved back and forth by a motor, but remains fixed in place when motor drive is removed. These systems require that the AFC output voltage (motor drive) be zero when the loop is locked; and that the voltage be proportional to frequency error while tracking. Please see Section 3.3.6.1 for more details. Wait time before applying AFC: 10.0 sec After a magnetron transmitter is first turned on, it may be several seconds or even minutes until its output frequency becomes stable. It would not make sense for the AFC loop to be running during this time since there is nothing gained by chasing the startup transient. This question allows you to set a holdoff delay from the time that valid burst pulses are detected to the time that the AFC loop actually begins running. Limits: 0 to 300 seconds. AFC hysteresis -- Inner: 5.0 KHz, Outer: 15.0 KHz These are the frequency error tolerances for the AFC loop. The loop will apply active feedback whenever the outer frequency limit is exceeded, but will hold a fixed level once the inner limit has been achieved. The hysteresis zone minimizes the amount of thrashing done by the feedback loop. The AFC control voltage will remain constant most of the time; making small and brief adjustments only occasionally as the need arises. AFC outer tolerance during data processing: 50.0 KHz In general, the AFC feedback loop is active only when the RVP8 is not processing data rays. This is because the Doppler phase measurements are seriously degraded whenever the AFC control voltage makes a change. To avoid this, the AFC loop is only allowed to run in between intervals of sustained data processing. This is fine as long as the host computer allows a few seconds of idle time every few minutes; but if the RVP8 were constantly busy, the AFC loop would never have a chance to run. This question allows you to place an upper bound on the frequency error that is tolerated during sustained data processing. AFC is guaranteed to be applied whenever this limit is exceeded. Limits: 15 to 4000 KHz. AFC feedback slope: 0.0100 D-Units/sec / KHz AFC minimum slew rate: 0.0000 DUnits/sec AFC maximum slew rate: 0.5000 D-Units/sec These questions control the actual feedback computations of the AFC loop. The overall span of the AFC output voltage is set by Gain and Offset potentiometers on the RVP8/IFD module (See Section 2.2.10). The control level that is applied to the AFCs 16-bit Digital-to-Analog converter is specified here in D-Units, i.e., 328 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) arbitrary units ranging from 100 to +100 corresponding to the complete span of the D/A converter. Since the DUnit corresponds in a natural way to a percentage scale, the shorter % symbol is sometimes used. AFC feedback will be applied in proportion to the frequency error that the algorithm is attempting to correct. The feedback slope determines the sensitivity and time constant of the loop by establishing the AFCs rate of change in (D-Units / sec) per thousand Hertz of frequency error. For example, a slope of 0.01 and a frequency error of 30KHz would result in a control voltage slew of 0.3 D-Units per second. At that rate it would take approximately 67 seconds for the output voltage to slew one tenth of its total span (20 D-Units / (0.3 D-Units / sec) = 67 sec). AFC is intended to track very slow drifts in the radar system, so response times of this magnitude are reasonable. Keep in mind that the feedback slew is based on a frequency error which itself is derived from a time averaging process (see Burst Frequency Estimator Settling Time described above) . The AFC loop will become unstable if a large feedback slope is used together with a long settling time constant, due to the phase lag introduced by the averaging process. Keep the loop stable by choosing a small enough slope that the loop easily comes to a stop within the inner hysteresis zone. See Section 3.3.6.1 for more information about these slope and slew rate parameters. AFC span [100%,+100%] maps into [ 32768 , 32767 ]

AFC format 0:Bin, 1:BCD, 2:8B4D: 0, ActLow: NO AFC uplink protocol 0:Off, 1:Normal, 2:PinMap : 1 The RVP8s implementation of AFC has been generalized so that there is no difference between configuring an analog loop and a digital loop. The AFC feedback loop parameters are setup the same way in each case; the only difference being the model for how the AFC information is made available to the outside world. Many types of interfaces and protocols thus become possible according to how these three questions are answered. AFC output follows these three steps:

The internal feedback loop uses a conceptual [100%,+100%] range of values. However, this range may be mapped into an arbitrary numeric span for eventual output. For example, choosing the span from 32768 to +32767 would result in 16-bit AFC, and 0 to 999 might be appropriate for 3-digit BCD; but any other span could also be selected from the full 32-bit integer range.

Next, an encoding format is chosen for the specified numeric span. The result of the encoding step is another 32-bit pattern which represents the above numeric value. SIGMET will make an effort to include in the list of supported formats all custom encodings that our customers encounter from their vendors. Available formats include straight binary, BCD, and mixed-radix formats that might be required by a specialized piece of equipment. The 8B4D format encodes the low four decimal digits as four BCD digits, and the remaining upper bits in binary. For example, 659999 base-10 would encode into 0x00419999 Hex.

Finally, an output protocol is selected for the bit pattern that was produced by encoding the numeric value. The bits may be written to the eight RVP8/Main 329 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) backpanel RS232 outputs, or sent on the uplink as a value to be received by the RVP8/IFD and converted to an analog voltage. Yet another option is for the bits to be sent on the uplink and received by the RVP8/DAFC board, which supports arbitrary remapping of its output pins. To summarize: the internal AFC feedback level is first mapped into an arbitrary numeric span, then encoded using a choice of formats, and finally mapped into an arbitrary set of pins for digital output. We are hopeful that this degree of flexibility will allow easy hookup to virtually any STALO synthesizer that one might encounter. PinMap Table (Type 31 for GND, 30 for +5) Pin01:00 Pin02:01 Pin03:02 Pin04:03 Pin05:04 Pin06:05 Pin07:06 Pin08:07 Pin09:08 Pin10:09 Pin11:10 Pin12:11 Pin13:12 Pin14:13 Pin15:14 Pin16:15 Pin17:16 Pin18:17 Pin19:18 Pin20:19 Pin21:20 Pin22:21 Pin23:22 Pin24:23 Pin25:24 FAULT status pin (0:None): 0, ActLow: NO These questions only appear when the PinMap uplink protocol has been selected. The table assigns a bit from the encoded numeric word to each of the 25 pins of the RVP8/DAFC module. For example, the default table shown above simply assigns the low 25 bits of the encoded bit pattern to pins 1-25 in that order. You may also pull a pin high or low by assigning it to +5 or GND. Note that such assignments produce a logic-high or logic-low signal level, not an actual power or ground connection. The latter must be done with actual physical wires. One of the RVP8/DAFC pins can optionally be selected as a Fault Status indicator. You may choose which pin to use for this purpose, as well as the polarity of the incoming signal level. Note that the standard RVP8/DAFC module only supports the selection of pins 1, 3, 4, 13, 14, and 25 as inputs. This setup question allows you to choose any pin, however, because it does not know what kind of hardware may be listening on the uplink and what its constraints might be. Burst frequency increases with increasing AFC voltage: NO If the frequency of the transmit burst increases when the AFC control voltage increases, then answer this question Yes; otherwise answer No. When this question is answered correctly, a numerical increase in the AFC drive (DUnits) will result in an increase in the estimated burst frequency. If the AFC loop is completely unstable, try reversing this parameter. Mirror AFC voltage on 0:None, 1:I, 2:Q : 0 AFC/MFC can be mirrored on a backpanel output of the main chassis using this question. When either I or Q is selected, the AFC/MFC voltage will be present on the corresponding BNC output, and the other output will be used for scope plotting. This configuration would be useful, for example, in a dual-receiver magnetron system that needs a phase locked acquisition clock in the RVP8/IFD, but also needs an AFC tuning voltage to control the transmit frequency. When None is selected, scope plotting will revert to its normal Q output. 330 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) The voltage range of the I and Q outputs is approximately 1 Volt, and is not adjustable. When AFC/MFC is mirrored on these lines, you will probably need to add an external Op-Amp circuit to adjust the voltage span and offset to match your RF components. We also recommend that you add significant low-pass filtering

(cutoff at 3Hz) to remove any power line noise or crosstalk that may be originating within the RVP8/Main chassis. Enable Burst Pulse Tracking: YES This question enables the Burst Pulse Tracking algorithm that is described in Section 5.1.3. Remarkably, for such an intricate new feature, there are no additional parameters to configure. The characteristic settling times for the burst are already defined elsewhere in this menu, and the tracking algorithm uses dynamic thresholds to control the feedback. Enable Time/Freq hunt for missing burst: No Number of frequency intervals to search: 5 Settling time for each frequency hop: 0.25 sec Automatically hunt immediately after being reset: YES Repeat the hunt every: 60.00 sec These questions configure the process of hunting for a missing burst pulse. The trigger timing interval that is checked during Hunt Mode is always the maximum

+20sec; hence no further setup questions are needed to define the hunting process in time. The hunt in frequency is a different matter. The overall frequency range will always be the full 100% to +100% AFC span; but the number of subintervals to check must be specified, along with the STALO settling time after making each AFC change. With the default values shown, AFC levels of 66%, 33%, 0%, +33%, and

+66% will be tried, with a one-quarter second wait time before checking for a valid burst at each AFC setting. You should choose the number of AFC intervals so that the hunt procedure can deduce an initial AFC level that is within a few megaHertz of the correct value. The normal AFC loop will then take over from there to keep the radar in tune. For example, if your radar drifts considerably in frequency so that the AFC range had to be as large as 35MHz, then choosing fifteen subintervals might be a good choice. The hunt procedure would then be able to get within 2.3MHz of the correct AFC level. The settling time can usually be fairly short, unless you have a STALO that wobbles for a while after making a frequency change. Note that hunting in frequency is not allowed for Motor/Integrator AFC loops, and the two AFC questions will be suppressed in that case. The RVP8 can optionally begin hunting for a missing burst pulse immediately after being reset, but before any activity has been detected from the host computer. This might be useful in systems that both drift a lot and generally have their transmitter On. However, this option is really included just as a work around; the correct way for a burst pulse hunt to occur is via an explicit request from the host computer which knows when the pulse really should be present. Blindly hunting in the absence of that knowledge can not be done because there are many reasons why the burst pulse may legitimately be missing, e.g., during a radar calibration. 331 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) The automatic hunt for the burst pulse will always run at least once whenever the feature is enabled. The automatic hunting ceases, however, as soon as any activity is detected from the host computer. Only use this feature on radars with a serious drift problem in their burst pulse timing. Simulate burst pulse samples: NO The RVP8 can simulate a one microsecond envelope of burst samples. This is useful only as a testing and teaching aid, and should never be used in an operational system. A two-tone simulation will be produced when the RVP8 is setup in dual-receiver mode. The pulse will be the sum of two transmit pulses at the primary and secondary intermediate frequencies. To make the simulation more realistic, the two signal strengths are unequal; the primary pulse is 3dB stronger than the secondary pulse. Frequency span of simulated burst: 27.00 MHz to 32.00 MHz The simulated burst responds to AFC just as a real radar would. The frequency span from minimum AFC to maximum AFC is given here. 3.3.6.1 AFC Motor/Integrator Option The question AFC Servo 0:DC Coupled, 1:Motor/Integrator selects whether the AFC loop runs in the normal manner (direct control over frequency), or with an external Motor/Integrator type of actuator. The question AFC minimum slew request:... provides additional control when interfacing to mechanical actuators whose starting and sustaining friction needs to be overcome. The DC-Coupled AFC loop questions (changes shown in bold) are:

AFC Servo 0:DC Coupled, 1:Motor/Integrator : 0 Wait time before applying AFC: 10.0 sec AFC hysteresis Inner: 5.0 KHz, Outer: 15.0 KHz AFC outer tolerance during data processing: 50.0 KHz AFC feedback slope: 0.0100 DUnits/sec / KHz AFC minimum slew rate: 0.0000 DUnits/sec AFC maximum slew rate: 0.5000 DUnits/sec and the Motor/Integrator loop questions are:

AFC Servo 0:DC Coupled, 1:Motor/Integrator : 1 Wait time before applying AFC: 10.0 sec AFC hysteresis Inner: 5.0 KHz, Outer: 15.0 KHz AFC outer tolerance during data processing: 50.0 KHz AFC feedback slope: 1.0000 DUnits / KHz AFC minimum slew request: 15.0000 DUnits AFC maximum slew request: 90.0000 DUnits Notice that the physical units for the feedback slope and slew rate limits are different in the two cases. In the DC-Coupled case the AFC output voltage controls the frequency directly, so the units for the feedback and slew parameters use D-Units/Second. In the Motor/Integrator case, the AFC output determines the rate of change of frequency; hence D-Units are used directly. The above example illustrates typical values that might be used with a Motor/Integrator servo loop. The feedback slope of 1.0 D-Units/KHz means that a frequency error of 100KHz would produce the full-scale (100 D-Units) AFC output. But this is modified by the minimum and maximum slew requests as follows:

332 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft)

A zero D-Unit output will always be produced whenever AFC is locked.

When AFC is tracking, the output drive will always be at least 15 D-Units. This minimum non-zero drive should be set to the sustaining drive level of the motor actuator, i.e., the minimum drive that actually keeps the motor turning.

When AFC is tracking, the output drive will never exceed 90 D-Units. This parameter can be used to limit the maximum motor speed, even when the frequency error is very large. The AFC Motor/Integrator feedback loop works properly even if the motor has become stuck in a cold start, i.e., after the radar has been turned off for a period of time. The mechanical starting friction can sometimes be larger than normal, and additional motor drive is required to break out of the stuck condition. But once the motor begins to turn at all, then the normal AFC parameters (minimum slew, maximum slew, feedback slope) all resume working properly. The algorithm operates as follows:

Whenever AFC correction is being applied, the RVP8 calculates how long it would take to reach the desired IF frequency at the present rate of change. For example, if we are 1MHz away from the desired IF frequency, and the measured rate of change of the IF burst frequency is 20KHz/sec, then it will be 50 seconds until the loop reaches equilibrium.

Whenever the AFC loop is in Track-Mode, but the time to equilibrium is greater than two minutes, then the Minimum Slew parameter will be slowly increased. The idea is to gradually increase the starting motor drive whenever it appears that the IF frequency is not actually converging toward the correct value, i.e., the motor is stuck.

As soon as the frequency is observed to begin changing, such that the desired IF would be reached in less than two minutes, then the Minimum Slew parameter is immediately put back to its correct setup value. The loop then continues to run properly using its normal setup values. Manual Frequency Control (MFC) operates unchanged in both of the AFC servo modes. Whenever MFC is enabled in the Ps command, it always has the effect of directly controlling the output voltage of the AFC D/A converter. The MFC mode can be useful when testing the motor response under different drive levels, and when determining the correct value for the minimum slew request. 3.3.7 M+ Debug Options A collection of debugging options has been added to the RVP8 to help users with the development and debugging of their applications code. For the most part, these options should remain disabled during normal radar operation. These questions are included so that the RVP8 can be placed into unusual, and perhaps occasionally useful, operating states. 333 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Noise level for simulated data: 50.0 dB This is the noise level that is assumed when simulated I and Q data are injected into the RVP8 via the LSIMUL command. The noise level is measured relative to the power of a full-scale complex (I,Q) sinusoid, and matches the levels shown on the slide pots of the ASCOPE digital signal simulator. Limits: 100dB to 0dB Simulate output rays: NO Answering YES to this question causes the RVP8 to output bands of simulated data. The bands can occupy a selectable range interval, and span a selectable interval of data values. Start bin:0, Width:10 bins, Bands:16 This question is only asked if we are simulating output rays. The Start Bin chooses the bin number (origin zero) where the simulated bands will begin. The width of each band (in bins), and the total number of bands are also selected. The upper limit for all parameters is the maximum bin count for the RVP8 (which depends on board configuration, and number of attached RVP8/AUX boards). Limits: Start: 0-Max, Width: 1-Max, Bands: 1-Max Start data value:0, Increment:16 This question is only asked if we are simulating output rays. The data value that will be assigned to the first simulated band, and the data increment from one band to the next, are selected. The permissible values are from 0 to 65535, i.e., the full unsigned 16-bit integer range. This full range is useful when simulating 16-bit output data; for the more typical 8-bit output formats, only the low byte of the start and increment are significant. Limits: 0 to 65535 3.3.8 Mz Transmitter Phase Control These questions are used to configure the 8-Bit phase modulation codes that may be used to control the phase of a coherent transmitter. The RVP8 will output a pseudo-random sequence of phase codes that are chosen from a specified set of available codes, i.e., all 8-bit patterns that are valid for the phase modulation hardware. The random sequence is output only when the RVP8 is in one of its random phase processing modes (time series or parameter). At all other times, a fixed idle phase code pattern is output. See also Sections 3.3.1 and 3.3.5 where related phase control questions are found. 8Bit code to output when idle: 0x00 This is the bit pattern to be output whenever the RVP8 is not in a random phase processing mode. Note that this idle code does not have to be one of the activecodes that are enabled below. Selection of Valid 8-Bit States 000F: Y 334 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 101F:

202F:

303F:

404F:

505F:

606F:

707F:

808F:

909F:

A0AF:

B0BF:

C0CF:

D0DF:

E0EF:

F0FF:

This set of questions defines the subset of active 8-bit codes that are valid states for the transmit phase modulator. Answer each line with a sequence of Ys or Ns to indicate whether the corresponding 8-bit code is enabled. Only the codes that appear with a Y will be used by the RVP8; the indicates an unused code. The character was used instead of N so that the visual contrast of the printed table would be improved. As an example, if your klystron transmitter has an octant phase modulator that is controlled by three digital lines, you might enable phase codes zero through seven, and then cable the modulator to the low three bits of the 8-bit code. The upper five bits would not need to be used in this case. 335 RVP8 Users Manual April 2003 MidSamp PlotAssisted Setups Also indicates the RMS power within the passband of the FIR filter, but using only the raw IF samples in the exact center of the chosen interval. The computation of Total Power is performed using the same subset of central IF samples that are used to compute Filtered Power. This smaller subset of IF samples comes about because filtering the data requires a convolution with the current FIR filter, and this computation does not produce results all the way to the edges of the input data. This is the same reason that the LOG plots do not extend across the full screen. Because of this definition, it is valid to intercompare the Total Power and Filtered Power. The two numbers will match exactly as long as all of the incoming power falls within the passband of the FIR filter. The difference between the two powers can be used as a measure of the filter loss for a given pulse shape, i.e., the portion of signal that is lost outside of the filters passband. Note: The Total, Filtered, and MidSamp values represent true RMS power (i.e., variance), and not merely a sum-of-squares. Thus, any DC offset present in the A/D converter will not affect these power levels. 427 RVP8 Users Manual May 2003 Hardware Installation 2. Hardware Installation 2.1 Overview and Input Power Requirements This chapter describes how to install the RVP8 hardware. Topics include mechanical installation and siting, electrical specifications of the interface signals, system-level considerations and the standard connector panel that is provided. There are three major modules supplied with the RVP8. These are:

IFD (IF Digitizer) Input Power 4763 Hz 100240 VAC Auto-ranging Typically mounted in the radar receiver cabinet. Main Chassis Input Power 60/50 Hz 115/230 VAC Manual Switches Usually mounted in 19 EIA rack. I/O-62 Connector Panel Usually mounted in 19 EIA rack within 2 m of Main Chassis Much of the RVP8 I/O is configured via software. This makes the unit very flexible. Also, since there is virtually no custom wiring, it is very easy to insert spare modules and circuit cards. The software configuration of the I/O is described in Appendix A. This section, in conjunction with Appendix B, describes the physical installation of the hardware. WARNING: The Main Chassis redundant power supplies are NOT auto-ranging like the IFD. These are factory configured for the expected voltage, but should be VERIFIED by the customer before power is applied to the system. 21 RVP8 Users Manual May 2003 Hardware Installation 2.2 IFD IF Digitizer Module Installation 2.2.1 IFD Introduction The IFD IF digitizer is housed in an electrically sealed solid metal enclosure to achieve good immunity to external electrical noise. The internal circuitry has been designed to minimize the number of digital components, and it is carefully grounded and shielded to make the cleanest possible samples of the input IF signal. The unit is cooled by direct conduction of heat through the metal chassis; there are no openings required for airflow. The IFD replaces all of the IF receiver components that are found in a traditional analog receiver system, i.e., S Band Pass Filters S LOG Receiver S AFC Circuit S AGC or IAGC circuit S Quad Phase Detector S COHO (on magnetron systems) S Line drivers for base band video Indeed, one of the most time consuming parts of an upgrade is often the removal of old components. Many customers choose to simply bypass them and leave them in place. In some cases there will be other receiver modifications required to match the IFD signal input specifications. For example, IF attenuators or an IF amplifier are sometimes required. If you are doing an upgrade of an older system, you might want to consider purchase of a new STALO which can make significant improvements in Doppler performance. You should carefully document and red-line your system schematics to reflect any changes to the receiver. 22 RVP8 Users Manual May 2003 Hardware Installation 2.2.2 IFD Revision History There have been several versions and evolutions of the IFD. Table 21 summarizes the differences among all of the versions that have been manufactured so far. This document covers only the 14bit units although the previous generation 12bit units are compatible with the RVP8 as well. Table 21: Differences Among Versions of the IFD Rev.B Rev.C Analog Devices AD9042, 12Bits Rev.D AD6644, 14Bits A/D saturation at +4.5dBm A/D saturation at +6.0dBm 76dBm/MHz 93dB at 0.5MHz 82dBm/MHz 101dB at 0.5MHz No Yes (shared with AFC connector) None. The A/D dither power must be supplied from wideband thermal noise in the RF/IF chain. Power Supplies

+5V, +12V, 12V None AFC/Clock I/O AFC-16 AFC-16 & PLL-16 Built-in noise source supplies A/D dither power in the 200900KHz range.

+5V Only. +12/15V required only for analog AFC output AFC/Clock I/O Dither and Config Selections Supports full set of protocols defined in Section 2.5.1 A/D Chip Input Signal Level A/D Noise Density Dynamic Range Ext-Clock Noise Generator Jumpers

(Table 25) Uplink Protocols First Production March 1997 April 1998 December 2000 23 RVP8 Users Manual May 2003 Hardware Installation 2.2.3 IFD Power, Size and Physical Mounting Considerations The IFD is a compact sealed module with dimensions 23.6 x 10.9 x 3.0 cm. (9.3 x 4.3 x 1.2 in). The unit is designed to be mounted on edge such that the 23.6 x 3.0 cm. surface is flush on the back of the receiver cabinet with 10.9 cm. protrusion into the cabinet. The unit is typically placed where a traditional LOG receiver would be installed. The IFD is cooled by direct conduction through its metal enclosure. It should be positioned so that air can freely convect around it, or bolted to a larger surface that will conduct the heat away. The power supply module is separate and can be mounted nearby in the radar cabinet, or it can be attached directly to the IFD using a special mounting bracket. The power supply and bracket will add 3.3 cm. (1.3 in) of overall width to the receiver module. The power supply is a low noise, low ripple, switching unit; the input voltage range is 100240 VAC 4763 Hz, autoranging. The IFD has an internal 3-stage power supply input filter to minimize interference from the power cable. Nonetheless, it is still good practice to insure that the four supply wires (+5V, 12V, +12V, and Ground) be kept short and twisted together. A ferrite choke around the supply wires near the terminal strip is also recommended. Important: The inductive filtering components inside the IFD introduce a slight voltage drop in the +5V supply. To produce the correct internal voltage, the supply voltage measured at the external terminal block should be 5.23V for Rev.D boards, and 5.17V for Rev.C and earlier boards. Mounting space should also be reserved for the external analog anti-alias filters. These filters can be mounted in the radar cabinet itself, or they can be attached directly to the IFD on the opposite side of the power supply. The filters and mounting bracket will add 2.0 cm. (0.8 in) of overall width. 24 SMA SMA SMA J1 IFIN J2 BURST

(COHO) J3 AFC

(CLK) J4 UPLINK RVP8 Users Manual May 2003 Hardware Installation 2.2.4 IFD I/O Summary The connectors on the IFD are labelled as shown in the table below. The connections to the IFD are as follows:

Table 22: IFD I/O Connections IFD I/O Summary Connector Label Style Description IF signal from LNA/mixer; via an antialiasing filter centered at IF (supplied by SIGMET). 50W, + 6.5 dBm max IF Tx sample from waveguide tap and mixer; via an antialiasing filter centered at IF (supplied by SIG MET). 50W, +6.5 dBm max Reference 2.2.6 2.2.7 2.2.8 2.2.9 2.2.6 AFC output (+-10V) or reference clock input for co herent systems (2-60 MHz -10 to 0 dBm). The func tion of the connector is controlled by jumper selec tion within the IFD. 2.2.10 AFC 2.2.11 CLK SMA/BNC Connects to the RVP8 Main Chassis by 75 Ohm 2.2.12 shielded cable. The connector is SMA with an SMA/

BNC adapter provided. J5 ST FIBEROUT 62.5/125 micron multimode optical cable terminated in type ST connectors. IFD cam be located up to 100m from the RVP8 Main Chassis. 2.2.12 Since they share the same connector, the case of analog AFC output and reference clock input is not supported. However, this is a very rare occurrence since an analog AFC output is used for magnetron systems and a reference clock input is typically used for fully coherent TWT and Klystron systems. 25 RVP8 Users Manual May 2003 Hardware Installation 2.2.5 IFD Adjustments and Test/Status Indicators The IFD is packaged in a tight metal enclosure for maximum noise immunity. The only adjustments on the module are the internal gain and offset pots that adjust the AFC analog output. Two switches on the unit provide standalone test features to verify the proper functioning of the IFD and to assist with setting the voltage span of the AFC DAC. Table 23: IFD Toggle Switch Settings SW1 SW2 Function A A A B B B C C C A B C A B C A B C AFC Test Low Voltage AFC Test Midpoint Voltage AFC Test High Voltage Swap Burst and IF Input Signals Normal Operation (also labeled as run) Reserved (fiber test pattern) Reserved Reserved (fiber test pattern) Reserved (fiber test pattern) Two LEDs provide information on the status of the module and the status of the communication to the RVP8 (fiber channel and uplink). Table 24: IFD LED Indicator Interpretations Red (Uplink) Green (Ready) Meaning Blink Blink On On Blink Off Off On Reset sequence (powerup, or from uplink) Uplink is dead (no signal from RVP8/Rx) Uplink is alive, but downlink is dead Normal Operation (IFD and Main are both okay) 26 RVP8 Users Manual May 2003 Hardware Installation The internal jumper settings are summarized in the following table. Please also refer to Sections 2.2.10 and 2.2.11 for more information on setting up the AFC or External Clock options. Table 25: IFD Internal Jumper Settings JP1 JP2 JP3 JP4 Rev.B N/A Rev.C Rev.D AB: AFC Voltage Output BC/Open: External Clock Input 50W/Open Termination N/A N/A N/A Reserved BC: External Clock Open: AFC Voltage Output AB: Dither Applied to Burst Input BC: No Dither on Burst 27 RVP8 Users Manual May 2003 Hardware Installation 2.2.6 IFD Input A/D Saturation Levels There are two analog signals that must be supplied to the IFD:

S S IF receiver signal IF Tx Sample (Burst Pulse) for magnetron, or COHO reference for klystron. Both of these inputs are on SMA connectors. The IF signal should be driven by the front-end mixer/LNA/IF-Amp. components, similar to the way that a LOG receiver would normally be installed. The magnetron burst pulse or klystron COHO reference is also derived in the same manner as a traditional analog receiver. Note: Even for fully coherent Klystron and TWT systems, SIGMET recommends the use of an actual IF Tx sample. If this is not possible, then the COHO is used instead. If there is phase modulation, then the phase-shifted COHO should be input. The A/D input saturation level for both the IF-Input and Burst-Input is +6 dBm (4.5 dBm for Rev.C or earlier). In almost all installations an external anti-alias filter is installed on both of these inputs. These filters (if supplied by SIGMET) are mounted externally on one side of the IFD, and have an insertion loss of approximately 12dB. Thus, the input saturation level will be

+8dBm measured at the filter inputs. For the burst pulse or COHO reference it is important not to exceed the A/D saturation level. This reference signal should be strong enough so that most of the bits in the A/D converter are used effectively, but it should also allow a few deciBels below the saturation level for safety. The recommended power level is in the range 12 to +1 dBm, measured as described in section E.14. This is important for making a precise phase measurement on each pulse. In contrast, for the IF receiver input it is permissible (in fact desirable) to occasionally exceed the A/D input saturation level at the strongest targets. The RVP8 employs a statistical linearization algorithm to derive correct power levels from targets that are as much as 6dB above saturation. The actual IF signal level should be established by weak-signal and noise considerations (see below), rather than by working backwards from the saturation level. 28 RVP8 Users Manual May 2003 Hardware Installation 2.2.7 IF Bandwidth and Dynamic Range The RVP8 performs best with a wide bandwidth IF input signal. This is because a wideband signal can be made free of phase distortions within the (relatively narrow) matched passband of the received signal. The RVP8 uses an external analog anti-aliasing filter at each of its IF and Burst inputs. The purpose of these filters is to block frequencies that would otherwise alias into the matched filter passband. The anti-alias filters have a nominal passband width of 14 MHz centered at 30MHz, i.e. from 23MHz to 37MHz. This is the recommended operating bandwidth for the IF signal, although the RVP8 will still work successfully with lesser IF bandwidth. At the 36MHz sampling rate the quantization noise introduced by LSB uncertainties is spread over an 18MHz bandwidth. For an ideal 14-bit A/D converter that saturates at +6dBm the effective quantization noise level would be:

)6dBm * 20log(214) * 10log(18MHz 1MHz

) + *90 dBm MHz If samples from this ideal converter were processed with a digital filter having a bandwidth of 1MHz, then an input signal at 90dBm would have a signal-to-noise ratio of 0dB. A narrower FIR passband (corresponding to a longer transmitted pulse) would decrease the quantization noise even further, so that 0dB SNR would be achieved at even lower input power. In practice, the 14-bit A/D converter used inside the IFD does not behave quite this well. The Analog Devices AD6644 chip has been measured to have a wideband SNR of 76dB, i.e., 8dB less than the 84dB range expected for an ideal converter. The above calculation for noise density thus becomes:

)6dBm * 76dB * 10log(18MHz 1MHz

) + *82 dBm MHz Indeed, the RVP8s receiver power monitor described in Section 4.6 will show a filtered power level of approximately 82dBm when the FIR bandwidth is 1MHz and the IFD inputs are terminated in 50Ohms. The inverse correspondence between filter bandwidth and the 0dB SNR signal level leads to an interesting and useful property of wideband digital receivers: they can operate over a dynamic range that is much greater than the inherent SNR of their A/D converter would imply. If this particular A/D chip were performing direct conversion at base band it would have a dynamic range of only 76dB. However, by utilizing the extra bandwidth of the converter, the RVP8 is able to extend the dynamic range to approximately 100dB. To understand this, begin with the 88dB interval between the converters +6dBm saturation level and the 82dBm 0dB SNR level at 1MHz bandwidth. Add to this:

S S 6dB for the statistical linearization that is performed on signals that exceed the saturation level. The RVP8 can recover signal power accurately even when the A/D converter is driven beyond saturation. Velocity data will also be valid, but spectral width may be overestimated. 4dB for usable dynamic range below the 0dB SNR level. In practice, a coherent signal at 4dB SNR can easily be measured when 25 or more pulses are used. 29 RVP8 Users Manual May 2003 Hardware Installation Thus, the overall dynamic range at 1MHz bandwidth (approx. 1 msec transmit pulse) is 88+6+4

= 98dB. For a 0.5 msec pulse the dynamic range would be reduced to 95dB; but it would increase to 101dB for a 2.0 msec pulse. An actual calibration curve demonstrating this performance is shown in Figure 21, for which the RVP8s digital bandwidth was set to 0.53MHz and external signal generator steps of 1dB were used over the full operating range. Figure 21: Calibration Plot for a Stand-alone 14-Bit IFD 20 10 0 10 20 30 40 50 60 70 80 90 100 100 90 1-dB Compression Point 1-dB Detection Threshold Overall Dynamic Range of 101dB 70 10 80 Input Power in dBm Measured at IFD IF-Input 50 40 30 20 60 0 10 20 210 RVP8 Users Manual May 2003 Hardware Installation 2.2.8 IF Gain and System Performance The previous discussion was concerned with measuring the dynamic range of a stand-alone IFD. We will now examine how the unit performs in the context of a complete radar receiver. We assume that an LNA/Mixer has already been selected that offers an appropriate balance between price and noise figure. Having chosen these front-end components, the only parameter that remains to be determined is the total RF/IF gain between the antenna waveguide and the IFD. Assume that the thermal noise (kT) of the system is 114dBm/MHz, and that the noise figure of the LNA/Mixer is 2dB. We wish to bring this 112dBm/MHz noise level up into the working range of the IFD so that the received echoes can be optimally processed. However, in trying to select the required gain, we realize that we must make a tradeoff between preserving the receiver sensitivity that has been established by the LNA, and preserving the overall dynamic range of the IFD. This is the exact same tradeoff that is made in traditional multi-stage analog receiver systems that include a wide dynamic range LOG receiver. Figure 22: Tradeoff Between Dynamic Range and Sensitivity

) B d

y t i v i t i s n e S r e v i e c e R f o n o i t c u d e R 10 9 8 7 6 5 4 3 2 1 0 0 1 Recommended Operating Region

) D F I N

A N L N

0 1 g o l 0 1

R o i t a R r e w o P 8 9 10 2 3 4 5 6 7 Reduction of IFD Dynamic Range (dB) The solid red curve in Figure 22 shows that these two variables interact in a symmetric manner, so that any operating point (x,y) is always matched by a dual operating point at (y,x). To understand the construction of this plot, let NIFD represent the stand-alone (terminated input) 211 RVP8 Users Manual May 2003 Hardware Installation noise power of the IFD over some bandwidth. Similarly, let NLNA represent the LNA/Mixer thermal noise power over that same bandwidth, and after amplification by all RF and IF stages. Note that NIFD is primarily due to the quantization noise that is introduced by the A/D converter, whereas NLNA has its origins in the fundamental thermal noise of the receiving system. The reduction of receiver sensitivity is the amount by which the LNA thermal noise is increased over the original level established by the front-end components:

1 ) NIFD NLNA 1 ) NLNA NIFD DSensitivity + 10 log10( NLNA

) NIFD ) * 10 log10( NLNA ) + 10 log10 Likewise, the reduction of RVP8 dynamic range is the amount by which the IFD quantization noise is increased over its stand-alone value:

DDynamicRange + 10 log10( NLNA

) NIFD ) * 10 log10( NIFD ) + 10 log10 Note that both of these quantities depend only on the ratio of the two powers; hence, the two NIFD ). equations define a parametric relationship in the dimensionless variable R + ( NLNA Figure 22 was created by sweeping the value of R from 1/9 to 9. The solid red curve shows the locus of ( DDynamicRange, DSensitivity ) points, and the dashed green curve shows R itself

(expressed in dB) as a function of DDynamicRange . For example, when the LNA noise power is equal to the IFD noise power, R is 1.0 (0dB) and there will be a 3dB reduction in both sensitivity and dynamic range. The recommended operating region is the portion of the curve that limits the loss of sensitivity to between 1.4dB and 0.65dB. The attendant loss of dynamic range will fall between 5.5dB and 8.5dB respectively. Each axis of the plot has an important physical interpretation within the radar system. S The horizontal axis is equivalent to the increase in the RVP8s report of filtered power when the IF-Input coax cable is connected versus disconnected. This is an easy quantity to measure, and thus provides a simple way to check the overall gain of the LNA/Mixer/IF components. S The vertical axis is equivalent to a worsening of the LNA/Mixer noise figure. This can also be interpreted as the amount of transmit power that is, in some sense, wasted when observing very weak echoes. If you have installed an expensive LNA with a very low noise figure, then you will want to pick an operating point that makes the most of preserving that investment. Figure 22 can be used to calculate the net gain that is required by the front-end components, and to predict the final system performance:

1. Choose an operating point that balances your need for sensitivity versus dynamic range. For this example, we will allow a 1dB loss of sensitivity from the theoretical limit of the LNA/Mixer, and will assume a bandwidth of 0.5MHz. 2. For a 1dB loss of sensitivity, the DDynamicRange is first determined from the solid red curve as 7dB. The required noise ratio R is then read vertically on the dashed green curve as 6.1dB. 212 RVP8 Users Manual May 2003 Hardware Installation 3. Thus, the RF/IF gain must bring the front-end thermal noise at 112dBm/MHz up to a level that is 6.1dB higher than the IFD noise density of 82dBm/MHz. The gain is therefore (82dBm/MHz + 6dB) (112dBm/MHz) = 36dB. Note that this gain does not depend on bandwidth, and therefore will be correct for all pulsewidth/bandwidth combinations. 4. The dynamic range for the complete system at 0.5MHz bandwidth may now be calculated as 101dB 7dB = 94dB. 5. After assembling all of the RF and IF components we can check whether we achieved the correct gain by verifying a 7dB rise (independent of bandwidth) in RVP8 filtered power when the IF-Input cable is connected versus disconnected. Keep in mind when designing your RF and IF components that the final amplifier driving the IFD must be capable of driving up to +14dBm, so that signals above saturation can be correctly measured. 2.2.9 Choice of Intermediate Frequency The RVP8 does not assume any particular relationship between the A/D sample clock and the receivers intermediate frequency. You may operate at any IF that is at least 2MHz away from any multiple of half the 35.9751MHz sampling rate (nominally 18, 36, 54, 72 MHz). The valid frequency bands are thus:

6-16MHz, 20-34 MHz, 38-52 MHz, 56-70 MHz There are many reasons for staying clear of the Nyquist frequency multiples. Most of these considerations would apply to all types of digital processors, and are not specific to the RVP8. As an example of what can go wrong at the Nyquist frequencies, suppose that an intermediate frequency of 35MHz was used. This is only 1MHz away from the (approximately) 36MHz sampling rate. The external anti-alias filter must now be designed much more carefully since a spurious input signal at 37MHz would be aliased into the valid 35MHz band. If the valid signal bandwidth were 2MHz, then the anti-alias filter would have the difficult task of passing 3436MHz free of distortion while rejecting everything above 36MHz. The filters transition zone would have to be very sharp, and this is difficult to achieve. Another problem that would arise with a 35MHz IF on a magnetron system would be the RVP8s computation of AFC. If the processor can not distinguish 37MHz from 35MHz, then it can not tell the difference between the STALO being correctly on frequency, versus being 2MHz too high. The symmetric AFC tracking range would be reduced to the very small interval 3436MHz. For similar reasons (i.e., transition band width), the digital FIR filter itself also becomes difficult to design when its passband is near a Nyquist multiple. But there is an additional constraint that the digital filter should have a very large attenuation at DC. This is so that fixed offsets in the A/D converter do not propagate into the synthesized I and Q data. Since 36MHz is aliased into DC, we are left with the contradictory requirements of a zero very close to the edge of the filters passband. 213 RVP8 Users Manual May 2003 Hardware Installation 2.2.10 IFD Analog AFC Output Voltage (Optional) An analog AFC voltage is produced by a 16-bit DAC whose output limits are 10V to +10V. Gain and Offset potentiometers on the IFD module set the actual operating span within these limits. Use the switch settings described below to force the low, center, and high voltages to be output, and then adjust the two potentiometers so that the desired voltage span is achieved. The Offset adjustment is independent of the Gain adjustment. Hence, a good strategy is to first set the switches for the midpoint voltage, and adjust the Offset potentiometer so that the center IF frequency is produced by the STALO mixer. Then, adjust the Gain potentiometer for the desired tuning range around that center point. The midpoint voltage will not change as you vary the overall span. AFC voltage output is always enabled on Rev.B (and earlier) IFD boards. On Rev.C (and later) boards, the AFC function shares the same connector with the optional reference clock input (See Section 2.2.11). AFC can be enabled on a Rev.C board as follows:

S Remove U14 S Install U11, U12, U13 S Set JP1 to its AB position, which is also labeled AFC. S Install fixed frequency stable 35.975MHz oscillator at U5. The instructions are similar for a Rev.D board except that you do not need to remove U14, and you must check that no jumper has been placed on JP3/BC. Additional information about using AFC can be found in Sections 2.4, 3.3.6, and 5.1.2. 214 RVP8 Users Manual May 2003 Hardware Installation 2.2.11 IFD Reference Clock Input (Optional) When the RVP8 is used in a klystron system, or in any type of synchronous radar, the radar COHO is supplied to the IFD so that the processor can digitally lock to it. The COHO phase is measured at the beginning of each transmitted pulse, and is used to lock the subsequent (I,Q) data for that pulse. The COHO phase is measured relative to the IFDs own internal stable sampling clock, which is nominally 35.975MHz. The internal sampling clock itself is not affected by the application of the COHO. Rather, A/D samples of the COHO are obtained at the fixed sampling rate, and the (I,Q) data are digitally locked downstream in the RVP8 IF-to-I/Q processing chain (see Figure 13). The procedure is identical to the manner in which phase is recovered in a magnetron system, except that the COHO signal is used in place of a sample of the transmit burst. There are two special concerns that may come up when the RVP8 is used in the above manner within a synchronous radar system. Both concerns are the result of the IFDs sampling clock being asynchronous with the radar system clock. S RVP8 Generates the Radar Trigger The trigger signals supplied by the RVP8 are synchronous with the IFD data sampling clock. This is accomplished by a clock recovery PLL on the RVP8/Rx that provides on-board timing which is identical to the sampling clock in the IFD. However, since the IFD sampling clock is asynchronous with the radar clock(s), the RVP8 trigger outputs are likewise asynchronous. The result is that each transmitted pulse envelope will be triggered independently of the COHO phase. The transmitted pulse is still synchronous but the precise alignment of the amplitude modulated envelope will vary. In almost all cases, the exact placement of the transmitters amplitude envelope does not affect the overall system stability, nor the ability of the RVP8 to reject ground clutter and to process multi-mode return signals. For this reason, a synchronous radar system that is triggered using the RVP8 triggers will still perform optimally using the standard digital COHO locking techniques. In spite of this, however, some system designers may still prefer that the amplitude envelope itself be locked to the COHO. S RVP8 Receives the Existing Radar Trigger When an external trigger is supplied to the RVP8, the processor synchronizes its internal range bin selection circuitry to that external trigger. The placement of the range bins themselves, however, is always synchronous with the IFDs 35.975MHz acquisition clock. The result is that 27.8ns of jitter is introduced in the placement of the RVP8s range bins relative to the transmitted pulse itself. The effect of this synchronization jitter is that targets appear to be fluctuating in range by approximately 4.2 meters. Although this is small relative to the range bin spacing itself, and thus does not affect the range accuracy of the data, the effect on overall system stability is more severe. Using both numerical modeling and actual field measurements, we have found that sub-clutter visibility of a msec pulse may be limited to approximately 43dB as a result of this 27.8ns range jitter. 215 RVP8 Users Manual May 2003 Hardware Installation This falls quite short of the usual expectations of a synchronous radar system in which clutter rejection of 5560dB should be attainable. The solution to either of the above concerns is to provide some means for the IFDs internal sampling clock to be phase locked to the radar system. If the RVP8 provides the radar triggers, then those triggers would become synchronous with the radar COHO; and if the RVP8 receives an external trigger, then its range bin clock would be synchronous with that external trigger, and thus, there will be no synchronization jitter in the range bins. The Rev. C version of the IFD offers the option of locking its sampling clock to an external system clock reference. This results in an RVP8 that is fully synchronous with the existing radar timing. Rather than being derived from a fixed-frequency oscillator, the phase locked IFD sampling clock is driven by a custom Voltage-Controlled-Crystal-Oscillator (VCXO). This oscillator can have a center frequency in the 33.5 to 39.5MHz range, which is any rational multiple P/Q of twice the input reference frequency, where P and Q are integers between 1 and 128 (See also, Section 3.3.6). The tuning range of the VCXO is purposely kept very narrow (to improve the clock stability), and is restricted to approximately +/50ppm. Thus, the input reference clock frequency must be precisely specified so as to stay within these limits. The reference clock input frequency range is 260 MHz, and the input power level level must be between 10 and 0dBm. Use the following configuration to allow a Rev.C IFD to lock its sampling clock to an external reference:

S Install U14 S Remove U11, U12, U13 S Set JP1 to its BC position to terminate the reference input in 50W, or leave the jumper open to achieve a high-impedance input (approx. 5KW). S Install custom Voltage-Controlled-Crystal-Oscillator (VCXO) at U5. Please contact SIGMET for assistance in specifying this device. For a Rev.D board the instructions are similar except that you do not need to remove any components, and should place a jumper on JP3/BC Warning: As noted in the previous section, for Rev.C boards U14 Must Be Removed whenever the VCXO phase lock mode is not being used, i.e., when the normal free-running crystal is installed. 216 RVP8 Users Manual May 2003 Hardware Installation 2.2.12 Coax Uplink and Fiber Downlink There are two cable links between the IFD module and the RVP8 Main Chassis:

S Copper coax cable uplink from the RVP8/Rx board. Provides timing information for the burst pulse window, and 16-bit data for setting the AFC output level. S Optical fiber downlink to the RVP8/Rx board. The receiver and burst pulse data samples are encoded into a 540MHz serial stream. The uplink input from the RVP8 is an SMA input from a 75W shielded cable (e.g., RG59 cable).. This cable is electrically isolated from the receivers ground (40KW isolation) so that noise picked up by the cable will not be coupled into the receiver circuitry. The downlink uses a 62.5/125 micron multimode optical cable terminated in type ST connectors. The coax and fiber cables can be any length up to 100 meters apiece. The RVP8 measures the round trip cable delays each time it boots up, and then uses that information to correct for range and timing offsets due to cable length. 217 RVP8 Users Manual May 2003 Hardware Installation 2.3 RVP8 Chassis 2.3.1 RVP8 Chassis Overview The RVP8 main chassis can assume a variety of forms depending on the customer requirements. Appendix B describes a standard SIGMET system. A typical unit supplied by SIGMET contains at least the following:

S A dual CPU on either motherboard or SBC in a passive PCI backplane S RVP8/Rx Card S I/O-62 Card and Connector Panel The system is also shipped with an integrated hard disk drive (HDD), 1.44 MB floppy (FDD) and CDRW unit. Note some installations may use a flash disk drive instead of an HDD. There is an LED display panel on the front of the chassis that is used to report system status. 2.3.2 Power Requirements, Size and Physical Mounting WARNING: The Main Chassis redundant power supplies are NOT auto-ranging like the IFD. These are factory configured for the expected voltage, but should be VERIFIED by the customer before power is applied to the system. There a three redundant power supplies The standard SIGMET chassis is a 19 EIA 4U rackmount unit, 17 (43 cm) deep. The chassis is usually mounted in a nearby equipment rack on rack slides (provided as standard). The connector panel is usually mounted on either the front or the rear of the same rack. The standard cable provided to connect the I/O-62 card in the main chassis to the connector panel is 6 feet long (1.8 m) . The power requirements are 100240 VAC 4763 Hz. The system is autoranging, i.e., there are no switches or jumpers that must be set. 218 RVP8 Users Manual May 2003 Hardware Installation 2.3.3 Main Chassis Direct Connections The direct connections to the RVP8 chassis are made either to the back of the unit to PCI cards (e.g., left) or to the remote connector panel. The direct connections are summarized in the table below. Table 26: Direct Connections to RVP8 Main Chassis IFD I/O Summary Connector Label Style Description Rx Card Connections Uplink Fiber Trig Out/In Trig Out BNC ST BNC BNC COAX Uplink from IFD (75 shielded cable) Fiberoptic downlink (orange cable) Trigger outputs (12V, 75 ) or pretrigger input (1.8V threshold, 75 ) SBC or Motherboard Connections Network RJ45 10/100/1000 BaseT TCP/IP Keyboard Mouse Monitor PS/2 PS/2 VGA I/O62 Connections Standard PC Keyboard Standard PC Mouse Standard PC Video Monitor

<no label> DB62F SIGMETsupplied cable to IO62/CP remote panel Optional Tx Card IF Out 1 IF Out 2 CLK Misc BNC BNC BNC Two independently synthesized IF output waveforms, up to +12dBm 8 75MHz into 50 , 875MHz. into 50 Optional input or output reference clock (50 ) DB9F Four optional RS422 clocks or control lines 219 RVP8 Users Manual May 2003 Hardware Installation 2.3.4 Connector Panel I/O Connections Most of the connections between the radar and the RVP8 are made using the RVP8 Connector Panel which connects to the I/O-62 by 1.8m (6 foot) cable. The panel is usually mounted on the front or the back of the same 19 EIA rack that contains the RVP8 chassis. The I/O-62 cable may be plugged into either the front or the back of the connector panel to optimize the cable run. The table in Section 1.8.5 provides a summary of the I/O for each connector. Detailed pinout assignments are given in Appendix C. Descriptions of the various signals are provided below. J1 & J4- AZ/EL Input: TTL parallel angles Thirty two TTL-Level input lines. These are sampled by the RVP8, and the bits accompany each processed output ray (See PROC command, Section 6.7). The inputs can also be read directly via the GPARM command (See Section 6.9). The RVP8 supports an antenna synchronizing mode and inserts the AZ and EL start and stop angles into the ray header of each radial (nominally 1 degree). Whenever antenna angle data are required, the processor reads the azimuth lines up to ten times in a row (spaced by 0.5 msec) until two successive values compare equal. This is done so that unsynchronized input data will be latched in a valid state. If after ten retries the lines were never observed in a consistent state, then the last observed state is used. Sampling for elevation is identical. The format can be BCD or binary angle. Detailed pin assignments are given in Appendix B. J2 & J5- AZ/EL Output: TTL parallel angles These provide output of the AZ and EL angles in TTL BCD or binary angle format. Detailed pin assignments are given in Appendix B. This feature could output the parallel angles to a separate antenna controller for example. J3- PHASE OUT: 8-bit RS422 phase shifter control output Can be used as differential RS422 or as singleended TTL. This is used to control a phase shifter for coherent systems that use phase modulation, but do not have a Tx card. This is typically used for legacy systems. J6- RELAY: Control for external equipment Often, external equipment in the radar will require relay control (e.g., power on, radiate on, environmental systems, reset lines, slow polarization switch). This connector has connections for 3 internal relays that are on the connector panel itself. The maximum current through the relay contacts is 0.5 A continuous. The switching load is 0.25 A and 100V, with the additional constraint that the total power not exceed 4VA. 220 RVP8 Users Manual May 2003 Hardware Installation If larger current and voltage loads are required, then the connector panel relays can be used to switch external relays provided by the customer. Another alternative is to use the additional 4, 12V relay signals (up to 200mA) that are also supported on this connector. Hazard: External relays must be equipped with proper diode protection against back-EMF or damage to the I/O-62 and or the connector panel might result. J7 SPARE: Configurable 20 lines of TTL I/O This connector supports 20 lines of TTL each of which can be configured as either input or output via the softplane.conf file. J8 SPARE: Analog Inputs 10 differential analog inputs, up to 20V max multiplexed into a single A/D convertor sampling each at >1000 Hz. This can be used for monitoring environmental systems at the radar site. J9- MISC: RS422 I/O, D/A and A/D 7 additional RS422 lines, each configurable to be either input or output, and 2 each dedicated

(nonmultiplexed) A/D inputs (580V with pot adjust) and D/A outputs (10V). The RS422 lines are convenient for high-speed polarization switch control. J10-11: RS232C I/O These two connectors can be used for serial angle input. The most common format is the RCV01 format, although custom formats from antenna/pedestal manufacturers such as Orbit, Andrew and Scientific Atlanta are also supported. J12: S-D- AZ and EL synchro input For systems that have synchros, the RVP8 can accept a direct synchro input from both AZ and EL. The nominal voltage and frequency are 100V @ 60 Hz. S/D conversion is performed in the I/O-62. J13-14: TP1 & TP2: Programmable test point scope outputs Am exciting feature of the RVP8 is the programmable test points. These are usually used to connect to an oscilloscope. The user can then specify what is output to the test points in the form of an analog voltage for display on the scope. Some examples are:

S LOG receiver power output (an oldtime radar AScope) S Burst pulse S Analog input monitor The advantage of using the test points is that technicians can leave them permanently connected to a rackmount oscilloscope and then select what is displayed. This saves time and reduces cabling errors when test switching cables. 221 RVP8 Users Manual May 2003 Hardware Installation J15-18: TRIG1-4- Output triggers The waveforms appearing on the four trigger outputs are programmed by the user to meet the radars exact timing needs. These correspond to the trigger generators TGEN1, TGEN2, TGEN3 and TGEN4. More triggers can be configured on the SPARE connectors if they are required. All lines may be setup and used independently and can contain, for example, pre-trigger pulses, calibration gates, range strobes, scope triggers, etc. The triggers are driven at

+12V into 75W and can be independently-timed at rates between 50Hz and 20000Hz with better than 0.02% accuracy. For dual-PRF velocity unfolding applications, the RVP8 trigger generator must be used as opposed to an externally supplied pre-trigger (see next section). The timing of the triggers is phase-locked to the sample clock in the IFD, which can be phase locked to the COHO of a coherent system. For coherent systems that do not sample the actual transmit pulse (for phase correction), this is recommended. The trigger waveforms are configurable in software using the mt commands. This sets the trigger timing, trigger sense (active high or active low pulse) and the minimum and maximum PRF for each pulse width. See sections 3.3.4. It is sometimes useful to dedicate one of the TRIG outputs to trigger an oscilloscope. J15: TRIG1- Selectable input pre-trigger Users may supply the RVP8 with their own CMOS-Level pre-trigger for installations in which adequate trigger control already exists. One of the connectors (typically TRIG1) may be configured to accept an input pre-trigger. The trigger input uses CMOS levels (1.5V max low, 2.5V min high) for improved noise immunity. The trigger input may also be driven as high as

+100V or as low as 100V without damage. This makes it easier to connect to existing high-voltage trigger distribution systems. The rising or falling edge of this external TRIGINsignal is interpreted by the RVP8 as the pretrigger point; the actual pulsewidth of the signal does not matter. The delay to range zero is configured via the TTY Setups. The other trigger outputs are then synchronized to the input trigger. The synchronization jitter between the user pretrigger and the other trigger outputs is less than 0.014 microseconds. Trigger jitter can be improved in the case of coherent systems, by phase locking the IFD to the same reference clock used to generate the external triggers (typically the COHO). This provides approximately 10 dB of additional phase stability. The RVP8s response to a missing external trigger is that the processor will insert fake (software) triggers at a rate of 250Hz whenever the trigger input is missing for more than 0.100 seconds. These fake triggers will keep the RVP8s internal code and external outputs running in spite of the missing input (the data values will all be zero, and the no trigger bit will be set in GPARM immediate status word #1). Normal operation automatically resumes as soon as the external trigger is restored. 222 RVP8 Users Manual May 2003 Hardware Installation 2.3.5 Power-Up Details (Alan) Draft WARNING: The Main Chassis redundant power supplies are NOT auto-ranging like the IFD. These are factory configured for the expected voltage, but should be VERIFIED by the customer before power is applied to the system. Ideally, the RVP8 main chassis should be powered-up after or at the same time as the IFD. This allows the diagnostic tests on the main board to run properly and exercise both components of the system. If the main board is switched on first, then all of the IFD diagnostics will fail and the RVP8 will be generally unusable, even if power were subsequently applied to the IFD. Often the power sequencing order can not be controlled in detail, e.g., the IFD may be located in a different cabinet or a different room from the main chassis. To help in these cases, the RVP8 performs a special power sequencing reboot whenever the IFD is turned on after the Main board has already powered up. This special reboot will occur whenever a) the fiber signal was not present at boot time, b) the last boot was not a power sequencing reboot, and c) the fiber signal is detected for five continuous seconds. Thus, you may powerup your equipment in any order. When the RVP8 is first powered up, it will always boot from the on-board ROM (nothing else would be possible). but the ROM is also considered the most trusted source of code, and therefore will also be used for all hard resets:

S External hardware RESET line (parallel interface reset) S SCSI Bus reset sequence S RVP8 RESET command with Pwr option selected When the BOOT command has been used to install a new version of code, that new code will persist across all of the following types of soft resets:

S Autoreset performed by the internal Watchdog S Any type of reset invoked using the * local TTY command S The power sequencing reboot that occurs when the IFD is turned on after the RVP8 board has already powered up. S RVP8 RESET command with Rst or Dig options selected A 32-bit CRC check is included in the RVP8s boot ROM. This allows the entire ROM image to be checked for internal consistency during the startup diagnostics, and during a reboot from the host computer. An error bit is allocated in GPARM Output Word #12 to indicate a checksum failure. The CRC check is designed to accept ROMs that are programmed from either a 0x00 or 0xFF blank state. If you are making your own ROMs from Intel Hex data files, you may use either 0x00 or 0xFF as the default value for ROM locations that are not explicitly defined by the file. Note: SIGMET has support for third party RVP8 software developers who would like to incorporate the BOOT command into their RVP8 driver. 223 RVP8 Users Manual May 2003 Hardware Installation 2.3.6 Socket Interface The RVP8 as shipped is configured to listen on a network port. It is ready to interface to a host computer via the network using a program called DspExport. It is also ready to run some commands on the RVP8 itself. The RVP8 comes with some builtin SIGMET supplied utilities such as setup, dspx and ascope. These utilities are described in the IRIS Utilities Manual. Because the RVP8 can only have one program controlling it at a time, use of a local program like dspx will block network access, and vice versa. How DspExport Works DspExport is a daemon program which is normally configured to run all the time. When it receives a socket connection request it will establish an exclusive connection to the RVP8. If a second connection request come in while the first is still active, it will fail, and return the message Device allocated to another user. To see if it is running on your RVP8, try typing

$ ps aef | grep DspExport During development, it can always be started up manually by typing DspExport at a shell prompt. It can be started with the v option for move detailed logging. It defaults to using port 30740. If you wish to use another port, start it with an option such as port:12345. The command line option help lists these options. Source Examples The source code for DspExport and for the dsp library is supplied on the RVP8 release cdrom. This can be optionally installed as part of the upgrade procedure as discussed in section A.6. You will find DspExport in ${IRIS_ROOT}utils/dsp, and you will find the dsp library in

${IRIS_ROOT}libs/dsp. In the library, you will find example code which talks to DspExport in file OpenSocket.c, dsp_read.c and dsp_write.c. Search for the string SOCKET, and you can see how the code differs between SCSI interface and socket interface. Socket protocol The socket interface basically supports all the Host Computer Commands in chapter 6. There are a few layers of formatting on top of that. All messages going both ways consist at the lowest level of an 8-character decimal ASCII number, followed by a block of data. The decimal number indicates how many bytes follow. Generally, all data transfers are initiated by the host computer by sending a block of data which consists of a command word followed by the |

character, followed by optional data. It will respond to all commands with either an Ack| indicating acknowledgment that the command was OK, or Nak| indicating that there was an error. For Nak, the reply will always include a string indicating what the error was. For Ack there is optional data following. On initial socket connection request DspExport will provide a response of either Nak indicating the connection failed, and why, or Ack followed by some connection information. This Ack string is in the form of name/value pairs, and will look something like:

Ack|CanCompress=1,Model=RVP8,Version=7.32 224 RVP8 Users Manual May 2003 Hardware Installation Your program can choose to evaluate or ignore any of these keywords. CanCompress=1 indicates that the DspExport computer supports compression. The host computer can then choose to use compression if it wants to. DspExport supports only the 5 commands discussed individually below:

Read command (READ) Example: READ|100 means read 100 bytes from the RVP8. Since the RVP8 interface is a 16-bit word interface, these read sizes should always be even. It will always reply with a Ack|

followed by 100 bytes of binary data, or with a Nak|, in other words there can be no partial reads. Write command (WRIT) Example: WRIT|<data> Where <data> is some binary data. This data is written to the RVP8. Again, the data size should be even. Read Status command (STAT) Example: STAT| This reads the status bits back from the RVP8. This is a 1 bit value, set to 1 if the RVP8 has data available in its output buffer. It will return either Ack|0, or Ack|1, or a Nak. This is the equivalent of the dspr_status() call in the dsp library. Set Information command (INFO) Example: INFO|ByteOrder=LittleEndian,WillCompress=1,Version=7.32. This command can be used to inform RVP8s DspExport about the host computer. Current options available are:

ByteOrder to inform DspExport of the byte order of the host computer. This is needed because all the data read or written to/from the RVP8 is in 16-bit words. If the host computer has a different byte order from the RVP8, DspExport will byte swap the data. WillCompress to inform DspExport to use compression or not. Compression is only used if both sides agree to use it. The host computer should only set this to 1 if it received a CanCompress of 1 on initial connection. The only thing compressed is the data from normal READ commands. If it is compressed, it will reply with the acknowledge compressed string of AkC. The compression program is the zlib compress and uncompress. The uncompress function requires that the caller know the expected uncompressed size. This is true for RVP8 reads, because the reader always specifies the read size. Version, send the IRIS version. Read data available command (RDAV) Example: RDAV|100|2 This means read up to 100 bytes of data from the RVP8 in individual DMA transfers of 2 bytes each. Before each read, the status is checked to see if there is more data available. If not, the read stops, and the number of bytes read is returned. This is merely a performance enhancing command since the same feature is available by using the READ command and the STAT command. 225 RVP8 Users Manual May 2003 Hardware Installation Notes on migrating from the SCSI interface Here are suggestions for customers who are converting an existing program which used a SCSI interface to the RVP7 to the socket interface to the RVP8. First take a look at our source code which handles either SCSI or socket. In OpenSocket.c you can see the code which replaces the SCSI device open call. The SCSI inquiry command is replaced by reading the string returned after the socket is opened. The SCSI read command is replaced by the READ|.. command. The SCSI modesense command is replaced by the STAT| command. The SCSI write command is replaced by the WRIT|... command. You should get your code working first without using the RDAV command or using compression. There is a significant difference between the RVP7 and RVP8 in regards to the FIFO reset command. This is the RVP8 command 0x008C (see section 6.11). The RVP8 is unable to read incoming commands if the output FIFO is entirely full. Therefore, if you put the RVP8 into continuous output mode, then issue the FIFO reset command to return to interactive mode, it may hang. To see how we have handled this problem, look in the source file DspResetFifo.c. Basically we write the FIFO reset command, then loop waiting 1/10 of a second, then do a large ReadAvailable command with DMA size 2 bytes. This continues until nothing is read back. 226 RVP8 Users Manual May 2003 Hardware Installation 2.4 Digital AFC Module (DAFC) The DAFC is a small self-contained circuit board which can passively eavesdrop on the RVP8s serial uplink transmissions. Its purpose is to generate a set of digital AFC control lines that could be applied, for example, to a custom STALO frequency synthesizer. A full size

(3x3.75) assembly diagram of the board is shown in Figure 23. It can be installed in the radar system either as a bare board, or packaged into a small metal enclosure. Figure 23: Assembly Diagram of the DAFC SIGMET recommends that the DAFC board be used in new system designs whenever AFC is required, as it offers these advantages over other methods of frequency control:

1) The use of a digital frequency synthesizer is superior to using analog AFC because the stability of a synthesized STALO can be made much greater than that of a tunable cavity oscillator. Also, noise on the AFC control voltage directly contributes to phase noise in the received weather targets in analog AFC systems, so cabling of the control signal can become tricky. 2) The RVP8 Connector Panel can also be made to output 8bit AFC (TTL or RS422). However, this is not in general recommended because of the potential for noise on the cable which is typically run >2m into a radar cabinet. Using the DAFC module is preferable because the board can be physically located very close to the STALO. The length of the control cable and its susceptibility to noise and ground loops are therefore reduced. Also, the DAFC board can supply up to 24 output control lines, rather than just eight. The digital output lines are made available as TTL levels on a 25-pin female D connector

(P1). There are 130W resistors (R1R25) in series with each output line to help protect the board against momentary application of non-TTL voltages on its external pins. However, these resistors do impose a restriction on the input line configuration of the receiving device. To 227 RVP8 Users Manual May 2003 Hardware Installation assure a valid TTL low level of 0.6V max. requires that the STALO inputs be pulled up to +5 with nothing less than (approx.) 1.2KW. Put another way, the low level input current of the receiving device should not exceed 4.5mA. Most STALOs that we have seen use 5-20KW pull-up resistors, so this should not be a problem. All twenty five pins of the D connector are wired identically on the DAFC board, i.e., each pin connects to one end of a 2-pin jumper (2x25 header H1), the other end of which connects to a Programmable Logic Device (PLD) chip. The PLD lines can be configured either as inputs or outputs, and this single chip handles all of the decoding and driving needs for the entire board. For each D connector pin that is to be used as an AFC output or Fault Status input, you should install the corresponding jumper to connect that pin through to the PLD, or use a wirewrap wire if the pin must go to a different PLD line. The D connector pin numbers are printed next to each of the jumper locations. Because of the ordering of the pins in the connector housing, jumpers 1 through 13 are interleaved with jumpers 14 through 25. The uplink protocol that the board should be expecting is selected by jumpers H3 and H4, as summarized in Table 27. The first three table entries describe three fixed mappings of the traditional AFC-16 uplink format onto various pins of the 25-pin D connector. One of these choices must be used whenever the DAFC is interfaced to an RVP8 system whose uplink uses the older style 16-bit AFC uplink format. In this case you will have to make most or all of the pin assignments using wirewrap wire to connect each bit to its corresponding pin. This will be somewhat tedious, but hopefully one of the three formats will be a reasonable starting point for doing the wiring. By far the most preferable solution, however, is to use the Pinmap uplink protocol (available since Rev.19) which allows for complete software mapping of all 25 external pins. Table 27: DAFC Protocol Jumper Selections H4 H3 Function On On On Off Off On Off Off AFC-16 format, Bits<0:15> on Pins<1:16>, Fault input on Pin 25 AFC-16 format, Bits<0:15> on Pins<25:10>, Fault input on Pin 3 AFC-16 format, Bits<0:15> on Pins<18, 19, 6, 7, 21, 22, 23, 11, 10, 9, 20, 8, 12, 25, 13, 24>, Fault input on Pin 4 Pinmap format, software assignment of all pins Ground, +5V, and +24V power supply pins on the D connector should be connected with wirewrap wire to the nearby power and ground posts H6, H7, and H8. The PLD jumpers for these power supply pins must not be installed. Two 3K/6K resistive terminators are also available at H5 for pulling pins up to approximately +3.3V when that is appropriate. Unused D connector pins should remain both unwired and not jumpered. Warning: It is important that the jumpers only be installed for pins that carry TTL inputs or outputs destined for the on-board PLD. The jumpers must be removed for all power supply pins, and for unused and reserved pins of the external device. 228 RVP8 Users Manual May 2003 Hardware Installation The DAFC board runs off of a single +5V power supply which can be applied either from the STALO through the D connector, or externally through the terminal block. There are also provisions for supplying +24V (approx.) between the terminal block and the D connector, which is handy for cabling power to a STALO that requires the second voltage. Two green LEDs indicate the presence of +5V and +24V. Terminal block Pin #1 is +5V, Pin #2 is +24V, and Pin#3 is Ground. Pin #1 is the one nearest the corner of the board. There is an option for having a Fault Status input on the D connector of the DAFC. Since the board is completely passive in its connection to the uplink, the fault status bit will not affect the uplink in any way. Rather, the bit is simply received by the board (with optional polarity reversal) and driven onto the terminal block (P3) from whence it can be wired to some other device, e.g., a BITE input line of an RCP02. A yellow LED is included to indicate the presence of any external fault conditions. The AB position of the 3-pin Alarm jumper (H9) connects the Fault Status signal to Pin #4 of the terminal block, whereas the BC position grounds that terminal block pin. A second ground can be made available at Pin #5 of the terminal block by installing a jumper in the BC position of the Spare 3-pin jumper (H10). This second ground could be used as a ground return when the Fault Status line is driven off of the terminal block. The AB position of the Spare jumper is reserved for some future input or output line on the terminal block. Both the shield and the center conductor of the uplink SMA input connector (P2) are electrically isolated (> 100KW) from the rest of the DAFC board. Moreover, the SMA connector pins themselves are high-impedance and unterminated. What this means is that the board can be TEEd into the uplink cable anywhere in the cable run from the RVP8/Rx board to the IFD. Since the cable is driven by the RVP8/Rx, it must be at one end of the cable; and since termination is provided by the IFD, it must be at the other end. The DAFC can be anywhere in the middle. Be sure, however, that the TEE is located right at the DAFC itself so that an unterminated cable stub is not created. A red LED is included to indicate that a valid uplink data stream is being received. A crystal oscillator is used to supply the operating clock for the on-board logic, and there are two choices of frequency to use. If jumper H2 is Off then the crystal frequency should be equal to the IFDs sampling clock faq, and if H2 is On the frequency should be (0.75 faq) . Additional information about using AFC can be found in Sections 2.2.10, 3.3.6, and 5.1.2. 2.4.1 Example Hookup to a CTI MVSR-xxx STALO Here is a complete example of what would need to be done in hardware and software to interface the DAFC to a Communication Techniques Inc. digital STALO. The electrical interface for the STALO is via a 26-pin ribbon cable which carries both Control and Status, as well as DC power. This cable can be crimped onto a mass-terminated 25-pin D connector (with one wire removed) and plugged directly into the DAFC. The resulting pinout is shown in Table 28. The STALO frequency is controlled by a 14-bit binary integer whose LSB has a weight of 100 KiloHertz. In addition, the Inhb pin must be low for the STALO to function. Power is supplied on the +5V and +24V pins, and two grounds are provided. An alarm output is also available. 229 RVP8 Users Manual May 2003 Hardware Installation Table 28: Pinout for the CTI MVSR-xxx STALO Ribbon Pin D Pin Function Ribbon Pin D Pin Function 1 1 Ground 2 14 3 2 +5V 4 15 5 3 +24V 6 16 7 4 Alarm 8 17 9 5 10 18 Bit0 11 6 Bit2 12 19 Bit1 13 7 Bit3 14 20 Bit10 15 8 Bit11 16 21 Bit4 17 9 Bit9 18 22 Bit5 19 10 Bit8 20 23 Bit6 21 11 Bit7 22 24 Ground 23 12 Bit12 24 25 Bit13 25 13 Inhb 26 First configure the IFD pins themselves. Pins 1 and 24 are power supply grounds, and are connected with wirewrap wire to the nearby ground posts. Pins 2 and 3 supply +5V and +24V to the STALO, and should be wire wrapped to the internal power posts. The STALO power, as well as the DAFC power, is then supplied externally via the terminal block on the DAFC itself. Sixteen jumpers should be installed to connect the Control and Status lines, i.e., pins 4, 613, 1823, and 25. We will use pinmap uplink protocol, so H3 and H4 are removed; and a x1 on-board crystal, so H2 is also removed. The STALO has an output frequency range from 52006020MHz in 100KHz steps. In this example we will assume that we need an AFC frequency span of 55805600MHz. This can be done with the following setups from the Mb section:

AFC span [100%,+100%] maps into [ 3800 , 4000 ]

AFC format 0:Bin, 1:BCD, 2:8B4D: 0, ActLow: NO AFC uplink protocol 0:Off, 1:Normal, 2:PinMap : 2 PinMap Table (Type 31 for GND, 30 for +5) Pin01:GND Pin02:GND Pin03:GND Pin04:GND Pin05:GND Pin06:02 Pin07:03 Pin08:11 Pin09:09 Pin10:08 Pin11:07 Pin12:12 Pin13:GND Pin14:GND Pin15:GND Pin16:GND Pin17:GND Pin18:00 Pin19:01 Pin20:10 Pin21:04 Pin22:05 Pin23:06 Pin24:GND Pin25:13 FAULT status pin (0:None): 4, ActLow: NO We map the AFC interval into the numeric span 38004000, and choose the Bin (simple binary) encoding format. The actual frequency limits therefore match the desired values:

5200MHz + ( 3800 x 100KHz ) = 5580MHz 5200MHz + (4000 x 100KHz ) = 5600MHz The Inhb line is held low, and fault status is input on Pin 4. Note that all pins that are not directly controlled by the software uplink (e.g., power pins, and unused pins) are merely set to GND in the setup table. 230 RVP8 Users Manual May 2003 Hardware Installation 2.4.2 Example Hookup to a MITEQ MFS-xxx STALO The electrical interface for this STALO uses a 25-pin D connector with the following pin assignments S GROUND on pins 1 and 2. S Four BCD digits of 1KHz, 10KHz, 100KHz, and 1MHz frequency steps, using Pins <25:22>, <21:18>, <17:14>, <13:10>. S Seven binary bits of representing 10MHz steps, Bits<0:6> on Pins<9:3>. First configure the IFD pins themselves. Pins 1 and 2 are ground, and are connected with wirewrap wire to the nearby ground posts. Pins 3 through 25 all are signal pins, so we plug in a jumper for each of these 23 pins. We will use pinmap uplink protocol, so H3 and H4 are removed; and a x1 on-board crystal, so H2 is also removed. In this example we will assume that we wish to control the STALO in 20KHz steps from 1.350GHz to 1.365GHz. This can be done with the following setups from the Mb section:

AFC span [100%,+100%] maps into [ 1350000 , 1365000 ]

AFC format 0:Bin, 1:BCD, 2:8B4D: 2, ActLow: NO AFC uplink protocol 0:Off, 1:Normal, 2:PinMap : 2 PinMap Table (Type 31 for GND, 30 for +5) Pin01:GND Pin02:GND Pin03:22 Pin04:21 Pin05:20 Pin06:19 Pin07:18 Pin08:17 Pin09:16 Pin10:15 Pin11:14 Pin12:13 Pin13:12 Pin14:11 Pin15:10 Pin16:09 Pin17:08 Pin18:07 Pin19:06 Pin20:05 Pin21:GND Pin22:GND Pin23:GND Pin24:GND Pin25:GND FAULT status pin (0:None): 0, ActLow: NO We map the AFC interval into a numeric span from 1350000 to 1365000, and choose the 8B4D mixed-radix encoding format. The STALO itself has 1KHz frequency steps, but the AFC servo will be easier to tune if we intentionally degrade this to 20KHz. This is done simply by grounding all four of the 1KHz BCD input lines, plus the LSB of the 10KHz BCD digit. A more creative use for one of these unused pins would be to remove the pin 25 jumper, wirewrap pin 25 to ground (so the STALO sill reads it a logic low), and assign pin 25 as a fault status input. That pin could then be connected to an external fault line, if the STALO has one. 231 RVP8 Users Manual May 2003 Hardware Installation 2.5 RVP8 Custom Interfaces This section describes some additional points of interface to the RVP8. These hookups are less conventional than the standard interfaces described earlier in this chapter, but they sometimes can supply exactly what is needed in exactly the right place. For the most part, these custom interfaces are merely taps into existing internal signals that would not normally be seen by the user. 2.5.1 Using the IFD Coax Uplink The Coax Uplink is the IFDs single line of communication from the RVP8/Rx processor board. All of the information that is needed by the IFD arrives through this uplink; and as such, this signal might contain information that is also useful for other parts of the radar system. In particular, it is a convenient source of digital AFC, along with reset and other status bits, plus limited trigger timing information. The uplink is a single digital transmission line that carries a hybrid serial protocol. The two logic states, zero and one are represented by 0-Volt and +15-Volt (open circuit) electrical levels. The output impedance of the uplink driver is approximately 55. When the cable is terminated in 75 by an internal resistor in the IFD, the overall positive voltage swing will be approximately 8.6-Volts. The electrical characteristics of the uplink have been optimized for balanced groundless reception, so that external noise and ground loop currents will not be introduced into the IFD. The recommended eavesdropping circuit is shown in Figure 24, and consists of a high speed comparator (Maxim MAX913, or equivalent) and input conditioning resistors. Both the shield and the center conductor of the coax uplink feed the comparator through 33K isolation resistors; no direct ground attachment is made to the shield itself. The 500 resistors provide the local ground reference, and the 47K resistor supplies a bias to shift the unipolar uplink signal into a bipolar range for the comparator. Figure 24: Recommended Receiving Circuit for the Coax Uplink 500W GND 33KW 33KW Coax Uplink Input Max913 or equiv. Received TTL Signal 500W 47KW GND

+5V 232 RVP8 Users Manual May 2003 Hardware Installation The uplink signal, shown in Figure 25, is periodic at the radar pulse repetition frequency, and conveys two distinct types of information to the IFD. The signal is normally low most of the time (to minimize driver and termination power), but begins a transition sequence at the beginning of each transmitted pulse. Figure 25: Timing Diagram of the IFD Coax Uplink t burst t s t s t s t s t s 1 2 3 4 5 6 7 8 9 10... The first part of each pulse sequence is a variable length burst window which is centered on the transmitted pulse itself, and which has a duration tburst approximately 800ns greater than the length of the current FIR matched filter. The burst window defines the interval of time during which the IFD transmits digitized burst pulse samples, rather than digitized IF samples, on its fiber downlink. The exact placement and width of the burst window will depend on the trigger timing and digital filter specifications that the user has chosen, usually via the Pb and Ps plotting setup commands. Following the burst window is a fixed-length sequence of 25 serial data bits which convey information from the RVP8/Rx board. The first four data bits form a characteristic (0,1,1,0) marker pattern. The first zero in this pattern effectively marks the end of the variable length burst window, and the other three bits should be checked for added confidence that a valid bit sequence is being received. Table 29 defines the interpretation of the serial data bits. Table 29: Bit Assignments for the IFD Coax Uplink Bit(s) Meaning 14 520 21 22 2324 25 Marker Sequence (0,1,1,0). This fixed 4-bit sequence identifies the start of a valid data sequence following the variable-length burst window. 16-bit multi-purpose data word, MSB is transmitted first (See below) Reset Request. This bit will be set in just one transmitted sequence whenever an RVP8 reset occurs. If set, then interpret the 16-bit data word as 4-bits of command and 12-bits of data, rather than as a single 16-bit quantity (See below) Diagnostic select bits. These are used by the RVP8 power-up diagnostic routines; they will both be zero during normal operation. Green LED Request; 0=Off, 1=On. The state of this bit normally follows the Fiber Detect LED on the RVP8/Rx board. 233 RVP8 Users Manual May 2003 Hardware Installation The period ts of the serial data is (64 faq) , where faq is the acquisition clock frequency given in the Mc section of the RVP8 setup menu. For the default clock frequency of 35.975MHz, the period of the serial data will be 1.779sec. The logic that is receiving the serial data should first locate the center of the first data bit at (0.5 ts) past the falling edge at the end of the burst window. Subsequent data bits are then sampled at uniform ts intervals. The actual data sampling rate can be in error by as much as one part in 75 while still maintaining accurate reception. This is because the data sequence is only 25-bits long, and hence, the last data bit would still be sampled within 1/3 bit time of its center. Having this flexibility makes it easier to design the receiving logic. For example, if a 5MHz or 10MHz clock were available, then sampling at 1.8sec intervals (1:85 error) would be fine. Likewise, one could sample at 1.75sec based on a 4MHz or 8MHz clock (1:61 error), but only if the first sample were moved slightly ahead of center so that the sampling errors were equalized over the 25-bit span. Interpreting the Serial 16-bit Data Word The serial 16-bit data word has several different interpretations according to how the RVP8 has been configured, and whether Bit #22 of the uplink stream is set or clear. The evolution of these different formats has been in response to new features being added to the IFD (Section 2.2), and the production of the DAFC Digital AFC Module (Section 2.4). The original use of the uplink data word was simply to convey a 16-bit AFC level, generally for use with a magnetron system. Bit #22 is clear in this case, and the word is interpreted as a linear signed binary value. The use of this format is discouraged for new hardware designs, but it will always remain available to guarantee compatibility with older equipment. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 16Bit AFC Level | AFC16

Level 0111111111111111 (most positive AFC voltage) 0000000000000000 (center AFC voltage) 1000000000000000 (most negative AFC voltage) When the IFD is jumpered for phase locking to an external reference clock, then Bit #22 will be clear and the data word conveys the PLL clock ratio, and the Positive/Negative deviation sign of the Voltage Controlled Crystal Oscillator (VCXO). This format is commonly used with klystron systems, especially when the RVP8 is locking to an external trigger. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Pos| Numerator 1 | Denominator 1 | PLL16

Note that the AFC-16 and PLL-16 formats can never be interleaved for use at the same time, since there would be no way to distinguish them at the receiving end. Finally, an expanded format has been defined to handle all future requirements of the serial uplink. Bit #22 is set in this case, and the data word is interpreted as a 4-bit command and 12-bit data value. A total of 16x12=192 auxiliary data bits thus become available via sequential transmission of one or more of these words. The CMD/DATA words can also be used along with one of the AFC-16 or PLL-16 formats, since Bit #22 marks them differently. 234 RVP8 Users Manual May 2003 Hardware Installation 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Command | Data | CMD/DATA

Commands #1, #2, and #3 control the 25 output pin levels of the DAFC board. These transmissions may be interspersed with the PLL-16 format in systems that require both clock locking and AFC, e.g., a dual-receiver magnetron system using a digitally synthesized COHO. Note that the entire 25-bits of pin information are transferred synchronously to the output pins only when CMD=3 is received. This assures that momentary invalid patterns will not be produced upon arrival of CMD=1 or CMD=2 when the output bits are changing. CMD=1 Data<0>

Data<6>

Data<11:7>

CMD=2 Data<11:0>

CMD=3 Data<11:0>

DAFC output pin 25 Fault Input is active high Which pin to use for Fault Input (0:None) DAFC output pins 24 through 13 DAFC output pins 12 through 1 These three digital AFC pinmap commands are recommended as a replacement for the original AFC-16 format in all new hardware designs. If you only need 12-bits of linear AFC, then map the AFC range into the 2048 to +2047 numeric span, and select binary coding format (See Section 3.3.6); the 12-bit data with CMD=3 will then hold the required values. To get a full 16-bit value, use a 32768 to +32767 span and extract the full word from both CMD=2 and CMD=3. Of course, other combinations of bit formats and number of bits (up to 25) are also possible. Command #4 is used to control some of the internal features of the IFD. Bits <4:0> configure the on-board noise generator so that it adds a selectable amount of dither power to the A/D converters. This noise is bandlimited using a 10-pole lowpass filter so that most of the energy is within the 150KHz to 900KHz band, with negligible residual power above 1.4MHz. Each of the five bits switch in additional noise power when they are set, with the upper bits making successively greater contributions. Bits <6:5> permit the IF-Input and Burst-Input signals to be reassigned on the fiber downlink. CMD=4 Data<4:0>

Data<6:5>

Built-in noise generator level IF-Input and Burst-Input selection 00 : Normal 10 : Burst Always 01 : Swap IF/Burst 11 : IF Always 2.5.2 Using the (I,Q) Digital Data Stream (Alan) The (I,Q) data stream that is computed by the FIR filter chips is communicated in real time to the central CPU. The IBD<17:0> data bus and IBDCLK clock signals are sourced on the P3 96-pin DIN connector of the RVP8. These TTL signals are normally kept internal to the RVP8, but some users may have a need to tap into them directly, e.g., to feed a separate data processor with the demodulated I and Q. Making the electrical connections to the (I,Q) data stream is especially easy with the RxNet7 packaging of the RVP8, since the complete set of signals are driven onto a dedicated 68-pin connector on its backpanel. Moreover, special PECL drivers on that connector make it possible 235 RVP8 Users Manual May 2003 Hardware Installation to run the cable over distances as great as ten meters. Please see the RxNet7 Users Manual for full details, as this is the recommended approach for driving the (I,Q) data out to an external device. If the RVP8s internal TTL signals are to be used directly, the physical connections must be made in such a way that no more than 12cm of additional wire length is added at the backplane. One way to do this would be to plug a custom driver board into an unused RVP8/AUX slot, from which the IBDxxx signals could be accessed. Another approach would be to mount the RVP8 board(s) in a completely custom backplane enclosure which also includes the users equipment that receives the (I,Q) data stream. The timing of the clock and data lines is shown in Figure 26 for the interval of time after the start of each transmitted pulse. The 18-bit data bus conveys two special code words at the beginning of each pulse, followed by (I,Q) for the Burst/COHO sample, followed by (I,Q) from the receiver. The receiver data continue to flow until the next transmitted pulse restarts the sequence anew, after a brief (approximately one range bin) clearing period. The data bus can be sampled on either the falling or rising edge of the clock, as there is an enforced 28ns data hold time after each rising clock edge. Using the rising clock edge will give the greatest data setup time, and this is usually preferred. Figure 26: Timing diagram of the (I,Q) Data Stream New Pulse Code Trigger Code Burst I Burst Q Bin #1 I Bin #1 Q IBD<17:0> Data Bus Clearing Period

(after last pulse) 28ns 82ns Range Bin Spacing IBDCLK Data Clock The New Pulse code is a unique 18-bit value that signifies the start of each new pulse of data. This is the only code or data word in which the MSB is zero. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 |

The Trigger Code follows immediately after the New Pulse code. It has a 1 in its MSB, and three different bit fields encoded into its low byte. These fields give information about the pulse itself. Codes that are not listed below are reserved, and will never appear on the data bus. 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 0 0 0 0 0 0 0 | Flags | Bank | Waveform |

The 2-bit Flags field tells how this pulse will be used internally by the RVP8. This information is probably irrelevant to the external data processor, if all that it is doing is eavesdropping on the received data. 236 RVP8 Users Manual May 2003 Hardware Installation 01 This is the final pulse of a collection of pulses that will contribute to the next pro-

cessed ray. The 3-bit Bank field tells the major classification of the pulse. 000 001 010 111 Normal pulse Low PRF pulse during Dual-PRF mode Blanked transmitter version of a normal pulse Pulse used for receiver noise measurement (SNOISE Command) The 3-bit Waveform field indicates the minor classification of the pulse. 000 001 000-111 Normal pulse, or first pulse in a multi-part pulse sequence. Indicates that this is an alternate pulse. This is the V channel for a single-

channel polarization radar in which the receive or transmit polarization alternates pulse to pulse from H to V. This is also the longer PRT pulse whenever DPRT (Dual-PRT) mode is running. These incrementing codes will be output for the first eight pulses of any custom trigger pattern that the user has defined (See Section 6.14). If the custom pattern is more than eight pulses long, the 111 code will be held until the end of the se-

quence. The (I,Q) data for the Burst/COHO sample, as well as for the receiver samples, all have the same floating point format consisting of a 2-bit unsigned exponent (Exp) and 15-bit signed mantissa

(Man). 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 | Exp | Floating Point Mantissa (Signed) |

This format does not rely on a hidden bit in the mantissa. Rather, the mantissa is simply a 15-bit (generally unnormalized) value between 16384 and +16383, and the encoded floating point value is:

Value + Man 16Exp Note that the exponent shifts the value not in increments of one bit, but rather, by four bits (by factors of 16). The mantissa will always be the largest integer (i.e., greatest relative precision) that will fit into the fifteen available bits. The overall dynamic range is 90dB while maintaining at least 66dB SNR within each sample. However, the format also gracefully underflows by allowing the mantissa to become small when Exp=0. This greatly extends the dynamic range into weak signals for which high relative precision is not required on each sample. The usable dynamic range of values over the entire receiver span is therefore approximately 125dB. 237

 

 

RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 3. TTY Nonvolatile Setups (draft) The RVP8 provides an interactive setup menu that can be accessed either from a serial TTY, or from the host computer interface. Most of the RVP8s operating parameters can be viewed and modified with this menu, and the settings can be saved in non-volatile RAM so that they take effect immediately on power-up. This permits custom trigger patterns, pulsewidth control, matched FIR filter specs, PRF, etc., to be configured by the user in the field. The TTY menu also gives access to a collection of graphical setup and monitoring procedures that use an ordinary oscilloscope as a synthesized visual display. The burst pulse and receiver waveforms can be examined in detail (both in the time and frequency domain) and the digital FIR filter can be designed interactively to match the characteristics of the transmitted pulse. 3.1 Overview of Setup Procedures This section describes basic operations within the setup menus such as making TTY connections, entering and exiting the menus, and saving and restoring the configurations. The setup TTY should be plugged into the modular 6-pin phone jack located at the top edge of the RVP8 board. The electrical interface may be either RS232 or RS423. If the phone jack connection is inconvenient, the terminal may be wired directly to the TIOXMT and TIORCV signals on the P2 96-pin connector. The TTY should be configured for 7-bit or 8-bit data (the MSB is always zeroed), no parity, and either one or two stop bits. With jumper JP4 in the AB position, the interface runs at 9600 baud; in the BC position the rate is 1200 baud (factory default), or some other rate set via the menu. Thus, the AB setting always makes a reliable 9600 baud connection, even if the the alternate rate is accidently set to a bad or forgotten value. Note: the reliable 9600 baud rate requires that the crystal located at X1 have a frequency of 4.9152MHz. 3.1.1 Initial Entry and Help List The interactive setup menu is invoked by pressing the Escape key on the TTY. If that key can not be found on the keyboard, you can sometimes use Control [ to generate the ESC code. The RVP8 then responds with the following banner and command prompt. SIGMET Incorporated, USA RVP8 Digital IF Signal Processor Rev.A/01 RVP8>

The banner identifies the RVP8 product, and gives the hardware version of the board (e.g., Rev.A) and software version (e.g., 01). This information is important whenever RVP8 support is required, and it is also repeated in the printout of the V command (See below). The Q command is used to exit from the menus and to restart the RVP8 with the (possibly changed) set of current values. It is important to quit from the menus before attempting to resume normal RVP8 operation. Portions of the RVP8 command interpreter remain running while the menus are active (so that the TTYOP command works properly), but the processor as a whole will not function until the menus are exited. 31 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) From the command prompt, typing help or ? gives the following list of available commands. Command List:

F: Use Factory Defaults S: Save Current Settings R: Restore Saved Settings M: Modify/View Current Settings Mb Burst Pulse and AFC Mc Board Configuration Mf Clutter Filters Mp Processing Options Mt<n> Trigger/Timing <for PW n>

Mz Transmitter Phase Control M+ Debug Options P: Plot with Oscilloscope Pb Burst Pulse Timing Ps Burst Spectra and AFC Pr Receiver Waveforms P+ Visual Test Pattern V: View Jumpers and Status

?: Cmd list (?? Settings list)

*: Reboot <Max Slaves> <+>

~: Swap Burst/IF Inputs on IFD Q: Quit 3.1.2 Factory, Saved, and Current Settings The current settings are the collection of setup values with which the RVP8 is presently operating; the saved settings are the collection of values stored in non-volatile RAM. The saved settings are restored (made current) each time the RVP8 is powered up. The S command saves the current settings into the non-volatile RAM, and the R command restores those non-volatile values so that they become the current settings. The F command initializes the current settings with factory default values. Thus, F followed by S saves factory defaults in non-volatile RAM, so that the RVP8 powers up in its original configuration as shipped. The RVP8 retains all of its saved settings when new ROM upgrades are installed; the new version of code will automatically use all of the previous saved values. However, if the RVP8 detects that the new release requires a setup parameter that did not exist in the previous release, then a factory default value will automatically be filled in for that parameter. A warning is printed whenever this occurs (See also, Section 3.1.4). There is also support for intermediate minor releases of RVP8 code. Each ROM has a major version number (the one that it always had), plus a minor version number for intermediate unofficial releases. The minor number starts from zero at the time of each official release, and then increments until the next official release. The RVP8 includes the minor release 32 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) number (if it is not zero) in the printout of the V command. Likewise, the minor release number of the code that last saved the nonvolatile RAM is also shown. This is an improvement over having to check the date of the code to determine which minor release was running. Note that the RVP8 does not actually begin using the current settings until after the Q command is entered, so that the processor exits the TTY setup mode and returns to normal operation. 3.1.3 Processor Reset Command The * command may be used to reset the signal processor from the TTY. This can be handy when the other methods of reset (power-up, parallel interface reset signal, or SCSI bus reset) can not easily be done. The command is robust in that pressing the Escape key followed by *, followed by two Returns, always resets the RVP8. There are certain wait conditions from which a TTY ESC does not immediately enter the setup monitor. However, the above four-key sequence always forces a full reset. The RVP8 diagnostics can run in a continuous loop that is useful during production burnin testing. In this mode the complete set of powerup tests is repeated approximately once per second. The green LEDs on the RVP8/Main and RVP8/AUX boards will blink on each run as a progress indicator. All red LEDs will initially be on, but each will begin to blink if any diagnostic ever fails on that board. A line of text is also printed to the setup TTY to show the progress of the tests and a summary of any errors. The RVP8s Perpetual Diagnostic Loop maintains a histogram of receiver IF-Input noise levels in 1dB steps from 85dBm to 72dBm. You can view the accumulated noise distribution by typing N while the diagnostic loop is running. This feature is intended for use during factory burn-in and testing of RVP8/IFD units. This special test mode can be started in two ways. One is to powerup the processor with the RVP8/Main I/O jumpers JP17JP22 in the (somewhat illegal) pattern: JP17:BC, JP18:BC, JP19:AB, JP20:AB, JP21:AB, JP22:AB. This method has the advantage of not requiring a TTY connection. The second method is to reset the processor from the local TTY monitor using the

*+ command. This is the normal reset command, but with a plus sign (debugging) suffix. 3.1.4 V View Internal Status The V command allows you to view some internal status within the RVP8. This information is available for inspection only, and can not be changed from the TTY. The view listing begins with the banner:

Jumpers and Internal Status and then prints the following lines:

Rev.B board, ROM V14.12 from Mon Jul 12 19:29:07 1999 This line shows the revision level of the RVP8 board, the ROM code version, and the date and time that this release was compiled. This lets you know the age of the release, even if the release notes have been misplaced. The date can also be helpful in keeping track of unofficial interim releases. 33 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Values were last saved using ROM version V14 This line tells which version of RVP8 code was the last to write into the non-volatile RAM. It is printed only if that last version was different from the ROM version that is currently running. The information is included so that a smart upgrade can often be done, i.e., values that did not exist in the prior release can be filled in with a guess that is better than merely taking the factory default. Warning: 3 automatic defaults were inserted. This warning will appear (accompanied by a beep) if one or more automatic factory defaults were required when the non-volatile RAM was last restored. It is likely that these automatic defaults will be acceptable operating values; but it would be wise to check the release notes to see what new parameters were added, and to decide on their proper settings. The warning will disappear once the S command is issued. This is because the missing saved slots are then filled in with valid values. Diagnostics: PASS Slave DSP Count: 3 If errors were detected by the powerup diagnostics then an error bitmask will be shown on the first line. The word PASS indicates that no errors were detected. The slave DSP count is also shown, which is the number of processors that were detected during the powerup sequence (and which will be used during subsequent processing). The RVP8 main board has three slave DSPs, and the each RVP8/AUX board supplies ten more. Up to two RVP8/AUX boards may be attached at the same time (23 slave DSPs total) for extremely intensive processing applications. An itemized list (consisting of bit pattern and text) is printed whenever any of the powerup diagnostics fail. The possible messages that might appear are:

0x00000001 : No fiber downlink signal detected 0x00000002 : 16Bit AFC level read/write 0x00000004 : IF Receiver reset request not sent 0x00000008 : I/O FIFO full before 4096 writes 0x00000010 : I/O FIFO not full after 4096 writes 0x00000020 : Transmit phase latch bits 0x00000040 : Downlink local counter test 0x00000080 : Receiver status bits & switches 0x00000100 : Test byte pattern from receiver 0x00000200 : Test word pattern from receiver 0x00000400 : NonVolatile RAM 0x00 and 0xFF flags 0x00000800 : UART read/write check 0x00001000 : External RAM check 0x00002000 : SCSI controller chip error 0x00004000 : Range mask RAM and addressing 0x00008000 : I&Q FIFO interrupt & trigger flags 0x00010000 : I&Q FIFO data bits 0x00020000 : FIR processing of ramp pattern 0x00040000 : Boot words not accepted by first slave 0x00080000 : No reply slave DSP count 0x00100000 : Invalid count of slave DSPs 0x00200000 : Global communication port tests 34 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 0x00400000 : Internal tests failed on some slave 0x00800000 : Trigger Generator RAM and addressing 0x01000000 : Excessive coax/fiber round trip jitter 0x02000000 : No sync found in round trip test 0x04000000 : Internal error in compile/link Coax/Fiber/Pipeline Delay: 0.624 usec (Stdev: 0.014 usec) During bootup the RVP8 measures the round trip delay along 1) the coax uplink to the receiver module, 2) the pipeline delays within the receiver module, 3) the optical fiber downlink to the main board, and 4) pipeline delays in the data decoding hardware. The time shown is accurate to within 14ns, and is used internally to insure that the absolute calibration of trigger and burst pulse timing remains unaffected by the distance between the main board and the receiver module. You may freely splice any lengths of coax and fiber without affecting the calibrations; the delay time will change, but the trigger and burst calibrations will remain constant. The standard deviation of the measured delay is also shown. If the coax uplink and fiber downlink cables are run properly this variation should be less than the period of the acquisition clock, e.g., 0.028 msec for the standard 35.975MHz rate. Larger errors may indicate a problem in the cabling. A diagnostic error bit is set if the error is greater than two acquisition clock periods. IFD:Okay, Burst Pwr:48.6 dBm, Freq:35.975 MHz RVP8/IFD and connecting cables are all working properly This line summarizes the receiver status and Burst input signal parameters. The status may show:

Okay NoFiber Problem in DownLink fiber cable from RVP8/IFD > RVP8/Main UpErr Problem in UpLink COAX cable from RVP8/Main > RVP8/IFD NoPLL RVP8/IFD PLL is not locked to external user-supplied clock reference DiagSW RVP8/IFD test switches are not in their normal operating position Reset by: Software Uptime: 0days 00:49:22 This line lists the origin of the last processor reset, as well as the total time that has elapsed since that reset occurred. The running time is given in days, followed by hours : minutes : seconds. The timer wraps around after approximately 180-days of continuous operation. The cause of the last reset will be one of the following:

1) Power-Up 3) SCSI Bus Reset 5) RESET OpCode with Rst bit 7) BOOT OpCode 9) TTY * command 11) Burn-In Self Tests 2) External RESET line 4) RESET OpCode with Pwr bit 6) RESET OpCode with Dig bit 8) Internal Watchdog 10) IFD Power Sequencing 3.1.5 Burst-In / IF-In Swap Command The ~ command swaps the Burst and IF inputs at the IFD. Requests to toggle the state are made from the top level as follows:

35 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) RVP8> ~

IFD Burst/IF Inputs are: SWAPPED RVP8> ~

IFD Burst/IF Inputs are: NORMAL The selection remains in effect for the duration of the setup session, but then returns to NORMAL upon exiting the TTY monitor. The ~ command is very handy because it allows the Pb, Pr, and Ps plotting commands to easily run with one input or the other. Here are two examples of how this might be useful. S When checking the range alignment on a Klystron system, the Pb plot can not be used in the usual way to center the Tx burst because a continuous-wave COHO

(rather than a burst pulse) is typically used as the phase reference in these systems. However, if you swap the Burst and IF inputs, you can then use the Pb command to view and center the received leakage of the Tx pulse, and thus locate range zero. S When setting up the AFC loop, you can use your RF signal generator to simulate the transmitters frequency, and then run the loop with swapped RVP8/IFD inputs. The AFC servo will then hunt and follow the siggen frequency supplied via the receiver. You can then make step changes in that frequency to verify that the loop responds properly. Note that the same input swapping function is also available via the RVP8/IFD toggle switches. However, those switches may be located far away from the operators terminal; hence, the command interface is still a valuable addition. The ~ command can only be used with the new Rev.D RVP8/IFD; the command is unimplemented, and will not even show up in the Help list, when earlier receivers are connected. 36 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 3.2 Host Computer I/O Debugging The RVP8 supports two very powerful monitoring functions that are helpful in debugging the I/O interface to the host computer. One examines the physical layer of the interface, i.e., the electrical handshake and data lines themselves. The other examines the application layer, i.e., the 16-bit opcodes and data that define the RVP8s application programming interface. 3.2.1 Physical-Level I/O Examiner The RVP8 has TTY support for debugging the physical level of the host computers SCSI or Parallel interface. The X (eXamine) command allows you to watch all incoming 16-bit words as they arrive from the host computer. In addition, you may also send 16-bit words back the other way. The X command is only available from the RS232 hardware TTY interface; it can not (obviously) be used via chat mode over the same I/O interface that it trying to examine. As such, the X command will not even be listed in the RVP8s top level help menu during a chat mode session. While the X command is running, any words that arrive from the computer will immediately be printed in hex format, along with an address (word counter, starting from zero) at the start of each line. Meanwhile, the W subcommand can be used to write individual words back to the computer, and the Q subcommand will exit the I/O examiner entirely. Note: When the X command is running, the RVP8 does not interpret the incoming 16-bit words as commands and arguments. Data sent to the RVP8 are discarded after being printed; and output from the RVP8 will occur only if the W subcommand is manually used. The X command is intended to debug the physical layer of the computer interface in a very controlled manner. The following dialog was captured in response to the host computer writing 100, 200, 300

(decimal) to the RVP8. The W subcommand was then used twice to output a 0x4000 and 0x8000 from the RVP8, and the computer then sent the values 1, 2, 3, 4, 5. RVP8> X Host Computer I/O Debug Monitor Q: Exit the monitor W: Output a word to the computer 0x0000: 0x0064 0x00C8 0x012C Output Word : 0x4000 Output Word : 0x8000 0x0003: 0x0001 0x0002 0x0003 0x0004 0x0005 3.2.2 Application-Level I/O Examiner The RVP8 has TTY support for debugging the application level of the host computers SCSI or Parallel interface. The Real Time TTY Monitor (RTM, see Section 3.3.7) can be configured to expose the computers complete I/O stream while the RVP8 is running and processing commands in its normal manner. Because of the enormous amount of TTY output that can be 37 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) generated by this option, all other RTM selections are disabled whenever host computer I/O is being monitored. Also, those other RTM selections would interfere with the multi-line formatting of the I/O text. The TTY printout shows incoming opcodes called out by name, and subsequent input and output words formatted into a table. The data are printed in Hex, twelve words per line, and include a word offset (origin zero) at the start of each line. The offset is reset to zero at the start of each new input or output sequence. Lines of data that are repeats of identical values will be skipped with a ... indication. This shortens and simplifies the printout; but more importantly, it reduces TTY overhead so that the processor is less I/O bound. Also for this reason, the 0x Hex prefix is omitted during the possibly lengthy printing of the data word tables. Note: As with all other Real Time TTY Monitor (RTM) functions, the RVP8 remains completely functional while host computer I/O is being monitored. However, unlike all other RTM functions, the I/O monitor will stall the main processor whenever the TTY becomes I/O bound; and the performance of the RVP8 will be degraded, perhaps severely. It is recommended that you configure the TTY for 38.4-KBaud to minimize the serial I/O delays. The following sample transactions were captured in response to starting the IRIS/Open ZAUTO utility. An I/O RESET and diagnostic OTEST are first performed. The pulse width selection bits and maximum trigger rates are then set with PWINFO, and angle sync is disabled with LSYNC. The header words for processed data are decided using CFGHDR, operational parameters are loaded with SOPRM, and final RVP8 parameters are read back with GPARM. Finally, the trigger rate is set using SETPWF, and a dummy range mask consisting of a single bin is setup with LRMSK. Opcode 0x008C (RESET) Opcode 0x0004 (OTEST) Output Words 0: 0001 0002 0004 0008 0010 0020 0040 0080 0100 0200 0400 0800 12: 1000 2000 4000 8000 Opcode 0x000F (PWINFO) Input Words 0: 8421 012C 0BB8 0FA0 1F40 Opcode 0x0011 (LSYNC) Opcode 0x005F (CFGHDR) Input Words 0: 0001 0000 Opcode 0x0002 (SOPRM) Input Words 0: 0019 000F 07AE 0008 FE70 0080 00A0 0000 0003 000A AAAA 8888 12: C0C0 C000 0000 0000 0000 AAAA 0000 2710 Opcode 0x0009 (GPARM) Output Words 0: 1200 0001 0960 FFFF FFFF 0D5B 0000 0000 0000 4284 0000 0000 12: 0019 743D 0007 0000 0000 230B 0032 5DC0 0BB8 1770 1D4C 2EE0 24: 8421 0000 2EE0 2EE0 0960 0960 000F 07AE 0008 FE70 0080 00A0 36: 0000 0000 0000 0000 0000 0000 0001 000E 0000 000E 0000 0D5B 48: 8000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 60: 0000 0000 0000 0000 38 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Opcode 0x0010 (SETPWF) Input Words 0: 2EE0 Opcode 0x0001 (LRMSK) Input Words 0: 0001 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 12: ... 504: 0000 0000 0000 0000 0000 0000 0000 0000 This RTM option to monitor computer I/O is automatically disabled at powerup, and therefore can not be saved permanently. This is to avoid confusing situations in which the monitor is accidently left running the RVP8 would appear to be working, but at a puzzling level of degraded performance. 39 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 3.3 View/Modify Dialogs The M command may be used to view, and optionally to modify, all of the current settings. The current value of each parameter is printed on the screen, and the TTY pauses for input at the end of the line. Pressing Return advances to the next parameter, leaving the present one unchanged. You may also type U to move back up in the list, and Q to exit from the list at any time. Typing a numeric or YES/NO response (as appropriate to the parameter) changes the parameters value, and displays the line again with the new value. All numbers are entered in base ten, and may include a decimal point and minus sign. In some cases, several parameters are displayed on one line, in which case, as many parameters are changed as there are new values entered. In all cases, the numbers are checked to be within reasonable bounds, and an error message (listing those bounds) is printed if the limits are exceeded. Note that changes to the settings (generally) do not take effect until after the Q command is typed, at which point the RVP8 exits the local TTY menu and resumes its normal processing operations. Since the number of setup questions is large, follow the M command with a second letter to select the subcategory, i.e., Mb (Burst Pulse and AFC), Mc (Board Configuration), Mf (Clutter Filters), Mp (Processing Options), Mt (Triggers and Timing), Mz (Transmitter Phase Control), M* (Stand-alone Settings) or M+ (Debug Options). The M command by itself prints the entire set of questions so that you can make a hard copy. The M command always works from the current parameter values, not from the saved values in non-volatile RAM. If the host computer has modified some of the current values, then you will see these changes as you skip through the setup list. However, typing S at that point would save all of the current settings and would, perhaps, make many changes to the original non-volatile settings. In general, to make an incremental change to the saved settings, first type R to restore all of the saved values, then use M to make the changes starting from that point, and S to save the new values. A listing of the parameters that can be viewed and modified with the M command is detailed in the following subsections. In each case, the line of text is shown exactly as it appears on the TTY with the factory default settings. A definition of each parameter is given and, if applicable, the lower and upper numeric bounds are shown. 3.3.1 Mc Board Configuration This set of commands configure general properties of the RVP8/IFD and RVP8/Main boards. Acquisition clock: 35.9751 MHz This is the frequency of the oscillator at U5 in the IF receiver module. Except for custom receivers, this will always be 35.9751 MHz; which gives a fundamental sample spacing of 1/240 km (approximately 4.17 meters). Limits: 33.33 to 41.67 MHz Dual simultaneous receivers are being used: NO Answer this question Yes if the RVP8 will be processing simultaneous signals from two separate receivers. Answering No will revert to normal operation with just a single receiver. 310 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) DualLNA/Rcvr singlechannel switched mode: NO For dual-polarization single-receiver systems, this question decides whether you have a single LNA and IF-Amplifier that switches between H&V (the typical case); or two separate receivers, each hard wired to H and V, with switching performed after the IF amplifiers. The question affects how noise levels are measured and applied to the data. Synthesize LOG video output waveform: YES Upper 100.0 dB will occupy 85.0% of voltage span Force freerunning video mode: NO Plot data from secondary receiver: NO The RVP8 supports the option of sourcing a LOG Video analog output signal from the backpanel of the main chassis. There are two ways that this signal can be configured:

S Self-Triggering, Free-Running Mode This is the default mode that is available on all RVP8 boards. The output signal is periodic at approximately the PRF of the radar, but is free-running, i.e., not actually synchronized with the radar trigger. A synthetic 1.0 msec wide, full scale, trigger pulse is embedded at the zero-range start of each LOG Video waveform. This marker can easily trigger an oscilloscope if the scopes trigger level is set just below the maximum LOG Video voltage level. S Waveform Locked to Radar Trigger This mode requires a (one-wire) hardware modification to the Rev.B RVP8/Main board. The LOG Video waveform then becomes locked to the radar trigger, so that the LOG signal can be displayed on any device that already receives the radar trigger. In either case, the LOG Video output signal is unipolar, ranging from approximately 0.0V to 3.0V. It is active during all data processing modes that the host computer might request, as well as during the idle time between scans. The signal is absent

(zero), however, during the short intervals of time that the RVP8 is being reconfigured by the host computer, or when the RVP8s local TTY setups are being used. The time resolution of the synthesized LOG Video signal is fixed at 1.0 msec per bin. This is independent of the actual range resolution of the FIR matched filter. Whatever (I,Q) data are actually being computed by the FIR front end are selected for a nearest fit to each 1.0 msec synthetic output cell. The maximum number of incoming FIR range bins that can be selected among is 5460. Thus, for example, the maximum range of the LOG Video signal would be 682km when the FIR range resolution is 125meters. Answer the first question Yes if you would like the RVP8/Main board to synthesize and drive the LOG Video output signal. The cost of doing this is that one of the slave DSP chips will be removed from the normal Doppler processing chain, and dedicated to the task of LOG Video generation. On a single-board system, the 311 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) three available slave DSPs would be reduced to two; whereas on a dual-board system, the 13 available DSPs would be reduced to 12. Obviously, the percentage penalty is less in a larger system. The second question decides how the overall dynamic range of the receiver will fit into the 12-bit unipolar output voltage span of the DAC that produces the LOG Video waveform. The default setting calls for the upper 100dB of dynamic range to occupy 85% of the output voltage span. This means that the strongest IF input signal would produce 85% of the maximum DAC voltage (approximately 2.55 Volts); 50dB down would be 42.5%, and 100dB down would be 0%, i.e., zero volts. If you are using a self-triggering LOG Video waveform, then the 15% of headroom provided by the default settings leaves room for the embedded trigger pulse. However, if your RVP8 has the hardware modification required to synchronize the LOG Video to the system trigger, then the full 100% of the DAC voltage span can freely be used. The third setup question can be used to force freerunning mode on an RVP8 that has the hardware modification. This question is included mostly for testing purposes. The last question only appears in dual-receiver mode. Answer Yes if you would like the LOG video analog output signal to be based on the data from the secondary receiver rather than from the primary receiver. Scope plots Holdoff ratio: 0.50, Stroke: 1000.0 usec The oscilloscope plotting commands are described in Chapter 4. This question allows you to vary the amount of holdoff time that is inserted between each drawing stroke, as well as the stroke length itself. Try increasing the holdoff if your scope is not triggering reliably. Longer holdoffs make it easier for the scope to find the initial trigger point, but may introduce visible flicker. To reduce flicker, try decreasing the stroke duration from its default value of 1000 microseconds. Limits: Holdoff 0.05 to 5.00, Stroke 100 to 10000 msec. PWINFO command enabled: No The Pulsewidth Information user interface command can be disabled, thus further protecting the radar against inappropriate combinations of pulsewidth and PRF. This is a more safe setting in general, and is even more important when DPRT triggers are being generated. It can also be useful when running user code that is not yet fully debugged. TRIGWF command enabled: NO The Trigger Waveform user interface command can be disabled if you want to prevent the host computer from overwriting the RVP8s stored trigger specifications. This is the default setting, based on the assumption that the built-in plotting commands would be used to configure the triggers. Answering YES will allow new waveforms to be loaded from the host computer. RVP7 Emulation: No The RVP8 implements a reasonably precise emulation of the RVP7 command set. This mode is useful because it allows an RVP8 to be plugged directly into a software system that used to run with an RVP7. All of the configuration steps that are new and 312 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) unique to the RVP8 can be handled by the local TTY and Scope setups, thus making no demands on the users system code for support. Answer this question YES for maximum compatibility with old driver software. However, if you are running IRIS version 6.11 or higher, then answer NO to enable using new RVP8 features as they are developed. The RVP8 returns a version number of 35 when the processor is running in RVP7 compatibility mode. This fudged value will appear in the SCSI Inquiry Command reply, and in the GPARM parameter packet. Elsewhere, the correct RVP8 ROM version number will always appear. The reason for doing this is so that the RVP8 appears (to the host computer) to be a modern RVP7 with all of the latest opcodes and features. 3.3.2 Mp Processing Options Major Mode- 0:User, 1:PPP, 2:FFT : 0 The top level RVP8 operating modes are described in the documentation of SOPRM command word #9. This question allows you to use the mode that has been selected by that command, or to force the use of a particular mode. Window- 0:User, 1:Rect, 2:Hamming, 3:Blackman : 0 Whenever power spectra are computed by the RVP8, the time series data are multiplied by a (real) window prior to computation of the Fourier Transform. You may use whichever window has been selected via SOPRM word #10, or force a particular window to be used. R2 Processing- 0:Never, 1:User, 2:Always : 1 Controls R0/R1 versus R0/R1/R2 processing. Selecting 0 unconditionally disables the R2 algorithms, regardless of what the host computer requests in the SOPRM command. Likewise, selecting 2 unconditionally enables R2 processing. These choices allow the RVP8 to run one way or the other without having to rewrite the user code. This is useful for compatibility with existing applications. Clutter Microsuppression- 0:Never, 1:User, 2:Always : 1 Controls whether individual cluttery bins are rejected prior to being averaged in range. Same interpretation of cases as for R2 Processing above. 2D Final Speckle/Unfold 0:Never, 1:User, 2:Always : 1 The Doppler parameter modes (PPP, FFT, etc) include an optional 3x3 interpolation and speckle removal filter that is applied to the final output rays. This 2-dimensional filter examines three adjacent range bins from three successive rays in order to assign a value to the center point. Thus, for each output point, its eight neighboring bins in range and time are available to the filter. Only the dBZ, dBT, Vel, and Width data are candidates for this filtering step; all other parameters are processed using the normal 1-dimensional (three bins in range) speckle remover. See Section 5.3.3 for more details. 313 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Unfold Velocity (VhVl) 0:Never, 1:User, 2:Always : 0 This question allows you to choose whether the RVP8 will unfold velocities using a simple (Vhigh Vlow) algorithm, rather than the standard algorithm described in Section 5.6. Bit-11 of SOPPRM word #10 is the host computers interface to this function when the 1:User case is selected (See Section 6.3). Note: This setup question is included for research customers only. The standard unfolding algorithm should still be used in all operational systems because of its lower variance. For this reason, the factory default value of this parameter is 0:Never. Process w/ custom trigs 0:Never, 1:User, 2:Always : 0 This question allows you to choose whether the RVP8 will attempt to run its standard processing algorithms even when a custom trigger pattern has been selected via the SETPWF command. Generally it does not make sense to do this, so the default setting is 0:Never. Bit-12 of OPPRM word #10 is the host computers interface to this function when the 1:User case is selected (See Section 6.3). Minimum freerunning ray holdoff: 100% of dwell This parameter controls the rate at which the RVP8 processes free-running rays in the FFT, DPRT, and Random Phase modes. This prevents rays from being produced at the full CPU limit or I/O limit of the processor (whichever was slower); which could result in highly overlapping data being output at an unusably fast rate. Note that this behavior will only occur when one of these non-PPP modes is chosen, and is then allowed to run without angle syncing. Such is likely the case for IRIS manual scans or during Passive IRIS mode. To make these free-running modes more useful, you may establish a minimum holdoff between successive rays, expressed as a percentage of the number of pulses contributing to each ray. Choosing 100% (the default) will produce rays whose input data do not overlap at all, i.e., whose rate will be exactly the PRF divided by the sample size. Choosing 0% will give the unregulated behavior in which no minimum overlap is enforced and rays may be produced very quickly. Limits: 0 to 100%

Linearized saturation headroom: 4.0 dB The RVP8 uses a statistical saturation algorithm that estimates the real signal power correctly even when the IF receiver is overdriven (i.e., for input power levels above

+4dBm). The algorithm works quite well in extending the headroom above the top end of the A/D converter, although the accuracy decreases as the overdrive becomes more severe. This parameter allows you to place an upper bound on the maximum extrapolation that will ever be applied. Choosing 0dB will disable the algorithm entirely. Limits: 0 to 6dB Apply amplitude correction based on Burst/COHO: YES Time constant of mean amplitude estimator: 70 pulses The RVP8 can perform pulse-to-pulse amplitude correction of the digital (I,Q) data stream based on the amplitude of the Burst/COHO input. Please see Section 5.1.6 for a complete discussion of this feature. 314 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Limits: 10 to 500 pulses IFD builtin noise dither source: 57.0dBm This question will only appear if the processor is attached to a Rev.D RVP8/IFD that includes an out-of-band noise generator to supply dither power for the A/D converters. The available power levels are { Off, 57dBm, 37dBm, 32dBm, 27dBm, 22dBm, 19dBm }. The closest available level to your typed-in value will be used. You can observe the band-limited noise easily in the Pr plot to confirm its amplitude and spectral properties. For standard operation, we recommend running at 57dBm. The problem higher levels of dither level is that, for certain choices of (I,Q) FIR filter, the stopband of the filter may not give enough attenuation to preserve the RVP8/IFDs inherent noise level. For example, the factory default 1MHz bandwidth Hamming filter has a stopband attenuation near DC of approximately 43dB. You can see this graphically at the right edge of the Ps menu. The in-band contribution of dither power is therefore approximately (37dBm) 43dB = 80dBm, which exceeds the A/D converters 1MHz bandwidth noise of 81.5dBm. TAG bits to invert AZ:0000 EL:0000 TAG scale factors AZ:1.0000 EL:1.0000 TAG offsets (degrees) AZ:0.00 EL:0.00 The incoming TAG input bits may be selectively inverted via each of the 16-bit words. The values are displayed in Hex. Setting a bit will cause the corresponding AZ (bits 015) or EL (bits 1631) lines to be inverted. Note that the SOPRM command also specifies TAG bits to invert. Both specifications are XORed together to yield the net inversion for each TAG line. The overall operations are performed in the order listed. Incoming bits are first inverted according to the two 16-bit XOR masks. This yields an unsigned 16-bit integer value which is then multiplied by the signed scale factor. The result is interpreted as a 16-bit binary angle (in the low sixteen bits), to which the offset angle is finally added. As an example, suppose that the elevation angle input to the RVP8 was in an awkward form such as unsigned integer tenths of degrees, i.e., 0x0000 for zero degrees, 0x000a for one degree, 0x0e06 for minus one degree, etc. If we apply a scale factor of 65536/3600 = 18.2044 to these units, we will get 16-bit binary angles in the standard format. If we further suppose that the input angle rotated backwards, we could take care of this too using a multiplier of 18.2044. Interference Filter 0:None, Alg.1, Alg.2, Alg.3: 1 Threshold parameter C1: 10.00 dB Threshold parameter C2: 12.00 dB The RVP8 can optionally apply an interference filter to remove impulsive-type noise from the demodulated (I,Q) data stream. See Section 5.1.4 for a complete description of this family of algorithms. 315 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Polarization Params Filtered:YES NoiseCorrected:YES PhiDP Negate: NO , Offset:0.0 deg KDP Length: 5.00 km T/Z/V/W computed from: HXmt:YES VXmt:YES T/Z/V/W computed from: CoRcv:YES CxRcv:NO The first question decides whether all polarization parameters will be computed from filtered or unfiltered data, and whether noise correction will be applied to the power measurements. The second and third questions define the sign and offset corrections for F and the length scale for KDP. The fourth and fifth questions control how the standard parameters (Total Reflectivity, Corrected Reflectivity, Velocity, and Width) are computed in a multiple polarization system. Answering YES to H-Xmt and/or V-Xmt means that data from those transmit polarizations should be used whenever there is more than one choice available. Thus, these selections only apply to the Alternating and Simultaneous transmit modes. Likewise, answering YES to Co-Rcv and/or Cx-Rcv means to use the received data from the co-channel or cross-channel. The receiver question will only appear when dual simultaneous receivers have been configured. A typical installation might use H-Xmt:YES, V-Xmt:YES, Co-Rcv:YES, Cx-Rcv:NO. This will compute (T/Z/V/W) from the co-polarized receiver using both H&V transmissions. Including both transmissions will decrease the variance of (T/Z/V/W);

although some researchers prefer excluding V-Xmt because that is more standard in the literature. Also, if your polarizations are such that the main power is returned on the cross channel, then you will probably want Co-Rcv:NO and Cx-Rcv:YES. DualRx Sum H+V Time Series: NO In dual-receiver systems, you may choose whether the (H+V) time series data consist of the sum of the H and V samples or the concatenation of half the H samples followed by half the V samples. The later is more useful when custom software is being used to analyze the data from the two separate receive channels. 3.3.3 Mf Clutter Filters Doppler Filter Set- 0:40dB, 1:50dB, 2:Saved : 0 The RVP8 has two built-in IIR Doppler clutter filter sets; one set having 40dB of stopband attenuation, and the other having 50dB. This question chooses which set is loaded on powerup. 316 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Spectral Clutter Filters Filter #1 Type:0(Fixed) Width:1 EdgePts:2 Filter #2 Type:0(Fixed) Width:2 EdgePts:2 Filter #3 Type:0(Fixed) Width:3 EdgePts:3 Filter #4 Type:0(Fixed) Width:4 EdgePts:3 Filter #5 Type:1(Variable) Width:1 EdgePts:2 Hunt:2 Filter #6 Type:1(Variable) Width:2 EdgePts:2 Hunt:2 Filter #7 Type:1(Variable) Width:3 EdgePts:3 Hunt:3 These questions define the heuristic clutter filters that operate on power spectra during the FFT-type major modes. Filter #0 is reserved as all pass, and is not redefinable here. For filters #1 through #7, enter a digit to choose the filter type, followed by however many parameters that type requires. Fixed Width Filters (Type 0) These are defined by two parameters. The Width sets the number of spectral points that are removed around the zero velocity term. A width of one will remove just the DC term; a width of two will remove the DC term plus one point on either side; three will remove DC plus two points on either side, etc. Spectral points are removed by replacing them with a linear interpolating line. The endpoints of this line are determined by taking the minimum of EdgeMinPts past the removed interval on each side. Variable Width, Single Slope (Type 1) The RVP8 supports variable-width frequency-domain clutter filters. These filters perform the same spectral interpolation as the fixed-width filters, except that their notch width automatically adapts to the clutter. The new filters are characterized by the same Width and EdgePts parameters in the Mf menu, except that the Width is now interpreted as a minimum width. An additional parameter Hunt allows you to choose how far to extend the notch beyond Width in order to capture all of the clutter power. Setting Hunt=0 effectively converts a variable-width filter back into a fixed-width filter. The algorithm for extending the notch width is based on the slope of adjacent spectral points. Beginning (Width1) points away from zero, the filter is extended in each direction as long as the power continues to decrease in that direction, up to adding a maximum of Hunt additional points. If you have been running with a fixed Width=3 filter, you might try experimenting with a variable Width=2 and Hunt=1 filter. Perhaps the original fixed width was actually failing at times, but you were reluctant to increase it just to cover those rare cases. In that case, try selecting a variable Width=2 and Hunt=2 filter as an alternative. In general, make your variable filters wider by increasing Hunt rather than increasing Width. This will preserve more flexibility in how they can adapt to whatever clutter is present. Residual clutter LOG noise margin: 0.15 dB/dB Whenever a clutter correction is applied to the reflectivity data, the LOG noise threshold needs to be increased slightly in order to continue to provide reliable qualification of the corrected values. The reason for this is that the uncertainty in the corrected reflectivity becomes greater after the clutter is subtracted away. 317 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) For example, if we observe 20dB of total power above receiver noise, and then apply a clutter correction of 19dB, we are left with an apparent weather signal power of

+1dB above noise. However, the uncertainty of this +1dB residual signal is much greater than that of a pure weather target at the same +1dB signal level. The Residual Clutter LOG Noise Margin allows you to increase the LOG noise threshold in response to increasing clutter power. In the previous example, and with the default setting of 0.15dB/dB, the LOG threshold would be increased by 19x0.15

= 2.85dB. This helps eliminate noisy speckles from the corrected reflectivity data. Whitening Parameters Noise threshold for replacing a point: 1.20 Replacement value multiplier: 0.5000 SNR in tails, for determining width: 0.25 These questions control the adaptive whitening filter that is used by the Random Phase processing algorithms. A spectral point will be whitened if the ratio of its power to the noise power exceeds the Noise threshold for replacing a point. The whitened point will consist of a complex value whose ARG is identical to that of the original point, and whose MAG is the product of the noise level with the Replacement value multiplier term. The nominal spectral width of the whitened region is a function of the power and width of the coherent signal, and the noise level. Assuming a Gaussian model, the SNR in tails... value is the ratio of the coherent power in the tails of the distribution to the noise level. RPhase SQI Threshold Slope:0.50 Offset:0.05 The two values in this question define a secondary SQI threshold that is used to qualify the LOG data during Random Phase processing. The secondary SQI level is computed by multiplying the primary user-supplied SQI threshold by the SLOPE, and adding the OFFSET. See also Section 5.9.3. Limits: SLOPE: 0.0 to 2.0, OFFSET 2.0 to 1.0 3.3.4 Mt General Trigger Setups These questions are accessed by typing Mt with no additional arguments. They configure general properties of the RVP8 trigger generator Pulse Repetition Frequency: 500.00 Hz This is the Pulse Repetition Frequency of the internal trigger generator. Limits: 50 to 6000Hz. Transmit pulse width: 0 Limits: 0 to 3 Use external pretrigger: NO PreTrigger active on rising edge: YES PreTrigger fires the transmitter directly: NO When an external pretrigger is applied to the TRIGIN input of the RVP8, either the rising or falling edge of that signal initiates operation. This decision also affects which signal edge becomes the reference point for the pretrigger delay times given in the Mt<n> section. 318 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Answer the second sub-question according to whether the radar transmitter is directly fired by the the external pretrigger, rather than by one of the RVP8s trigger outputs. In other words, answer YES if the transmitter would continue running fine even if the RVP8 TRIGIN signal were removed. This information is used by the L and R subcommands of the Pb plotting command, i.e., when slewing left and right to find the burst pulse, the pretrigger delay will be affected rather than the start times of the six output triggers. 2way (Tx+Rx) total waveguide length: 0 meters Use this question to compensate for the offset in range that is due to the length of waveguide connecting the transmitter, antenna, and receiver. You should specify the total 2-way length of waveguide, i.e., the span from transmitter to antenna, plus the span from antenna to receiver. The RVP8 range selection will compensate for the additional waveguide length to within plus-or-minus half a bin, and works properly at all range resolutions. POLAR0 is high for vertical polarization : NO POLAR1 is high for vertical polarization : NO These questions define the logical sense of the two polarization control signals POLAR0 and POLAR1. In a dual-polarization radar POLAR0 should be used to select one of two possible states (nominally horizontal and vertical, but any other polarization pair may also be used). The control signal will either remain at a fixed level, or will alternate from pulse to pulse with a selectable transition point (See Section 3.3.5). POLAR1 is identical to POLAR0, but may be configured with a different polarity and switch point. This second signal could be used if the radars polarization switch required more than one control line transition when changing states. Quantize trigger PRT to ((1 x AQ) + 0) clocks It is possible to control the exact quantization of the PRT of the internal trigger generator. Normally the trigger PRT is chosen as the closest multiple of AQ (the acquisition clock period) that approximates the requested period. This question allows the possible PRTs to be constrained to ((N x AQ) + M) clock cycles. This feature can be useful for synchronous receiver systems in which the trigger period must be some exact multiple of the COHO period. Blank output triggers according to TAG#0 : NO Blank when TAG input is high : NO Blank triggers 1:YES 2:YES 3:YES 4:YES 5:YES 6:YES These questions control trigger blanking based on the TAG0 input line. You first select whether the trigger blanking feature is enabled; and then optionally choose the polarity of TAG0 that will result in blanking, and which subset of the six user definable triggers are to be blanked. Blank output triggers during noise measurement : NO The RVP8 can inhibit the subset of blankable trigger lines whenever a noise measurement is taken. This will be forced whenever trigger blanking (based on TAG0) is enabled, but it can also be selected in general via this question. Since noise triggers must be blanked whenever trigger blanking is enabled, this question only appears if trigger blanking is disabled. 319 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) This question permits the state of the triggers during noise measurements to be consistent and known, regardless of whether the antenna happens to be within a blanked sector; and you have the additional flexibility of choosing blanked noise triggers all the time. RxFixed Triggers: #1:N #2:N #3:N #4:N #5:N #6:N P0:N P1:N Z:N You have explicit control over which RVP8 trigger outputs are timed relative to the transmitter pre-fire sequence, versus those which are relative to the actual received target ranges. Triggers in the first category will be moved left/right by the L/R keys in the Pb plot, and will also be slewed in response to Burst Pulse Tracking. Triggers in the second category remain fixed relative to receiver range zero, and are not affected by the L/R keys or by tracking. This question specifies which triggers are Tx-relative and which are Rx-relative. Answer with a sequence of Y or N responses for each of the six trigger lines, for the two polarization control lines, and for the timing of the phase control lines. You should answer No for any trigger that is involved with the pre-fire timing of the transmitter. If you enable the Burst Pulse Tracker (Section 5.1.3) you will probably want to assign a Yes to some of your triggers so that they remain fixed relative to the burst itself. It is very helpful to have these two categories of trigger start times. Triggers that fire the transmitter, either directly or indirectly, should all be moved as a group when hunting for the burst pulse and moving it to the center of the FIR window. However, triggers that function as range strobes should be fixed relative to range zero, i.e., the center of that window, and the center of the burst. This distinction becomes important when the transmitters pre-fire delay drifts with time and temperature. Replace triggers with alternate waveforms: YES Trigger #1 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #2 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #3 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #4 0:Normal, 12:Pol01, 36:PW03 : 1 Trigger #5 0:Normal, 12:Pol01, 36:PW03 : 0 Trigger #6 0:Normal, 12:Pol01, 36:PW03 : 4 These questions make it possible to reassign the waveforms that are driven onto the six user trigger (TRIG16) BNC outputs on the backpanel of the RVP8. This makes it easier to adapt the external cabling of the RVP8 so as to make better use of the available BNC connectors and related 15V drivers. You may substitute either of the two polarization control lines or the four pulsewidth control lines in place of any of the six normal triggers. In the example above, triggers #1, #2, #3, and #5 are all driven with their normal waveforms. However trigger #4 will have a copy of the POLAR0 polarization control line, and trigger #6 will have a copy of the PWBW1 pulsewidth control line. Neither POLAR0 nor PWBW1 themselves are changed by these assignments. Whenever any of the six user trigger lines is reassigned from its normal setting, the plot of that trigger within the Pb command will show a hashed line across the screen. This is a graphical reminder that that trigger has been replaced by some other waveform. 320 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Merge triggers to create composite waveforms: YES Merge Trigger #1 into : #1: #2: #3: #4: #5: #6:

Merge Trigger #2 into : #1: #2: #3: #4: #5: #6:

Merge Trigger #3 into : #1:Y #2: #3: #4: #5: #6:

Merge Trigger #4 into : #1: #2:Y #3: #4: #5: #6:

Merge Trigger #5 into : #1: #2:Y #3: #4: #5: #6:

Merge Trigger #6 into : #1: #2: #3: #4: #5: #6:

These questions allow you to merge the six user triggers together; resulting in trigger patterns that can be much more complex. In this example, Trigger #3 will be merged into Trigger #1; Trigger #3 will be unaltered, and Trigger #1 will be the OR of itself with Trigger #3. Likewise, Triggers #4 and #5 will be merged into Trigger #2 so that the later will contain three distinct pulses within each PRT. Answer each question with a sequence of up to six Y or N responses in order to set the merged destinations for each trigger line. Note that the six triggers are still defined in the usual way in the Mt<n> menu, i.e., start time, width, etc. The only change is that you may now combine these individual pulse definitions into a more complex composite output waveform. 3.3.5 Mt<n> Triggers for Pulsewidth #n These questions are accessed by typing Mt, with an additional argument giving the pulsewidth number. They configure specific trigger and FIR bandpass filter properties for the indicated pulsewidth only. Trigger #1 Start: 0.00 usec

#1 Width: 1.00 usec High:YES Trigger #2 Start: 0.00 usec + ( 0.500000 * PRT )

#2 Width: 10.00 usec High:YES Trigger #3 Start: 3.00 usec

#3 Width: 1.00 usec High:YES Trigger #4 Start: 2.00 usec

#4 Width: 1.00 usec High:YES Trigger #5 Start: 1.00 usec

#5 Width: 1.00 usec High:YES Trigger #6 Start: 5.00 usec + (0.001000 * PRT )

#6 Width: 2.00 usec High:NO These parameters list the starting times (in microseconds relative to range zero), the widths (in microseconds), and the active sense of each of the six triggers generated by the internal trigger generator. Setting a width to zero inhibits the trigger on that line. The Start Time can include an additional term consisting of the pulse period times a fractional multiplier between 1.0 and +1.0. This allows you to produce trigger patterns that would not otherwise be possible, e.g., a trigger that occurs half way 321 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) between every pair of transmitted pulses, and remains correctly positioned regardless of changes in the PRF Enter this multiplier as 0 if you do not wish to use this term, and it will be omitted entirely from the printout.. In the above example, Trigger #2 is a 10.0 msec active-high pulse whose leading edge occurs precisely halfway between the zero-range of every pair of pulses. Likewise, Trigger #6 is a 2.0 msec active-low pulse whose falling edge is nominally 5.0 msec prior to range zero, but which is advanced by 1.0 msec for every millisecond of trigger period. All other triggers behave normally, and have fixed starting times that do not vary with trigger period. Some subtleties of these variable start times are:

S The PRT multipliers can only be used in conjunction with the RVP8s internal trigger generator. The PRT-relative start times are completely disabled whenever an external trigger source is chosen from the Mt menu. S When PRT-relative triggers are plotted by the Pb command, the active portion of the trigger will be drawn cross-hatched and at a location computed according to the current PRF. The cross-hatching serves as a reminder that the actual location of that trigger may vary from its presently plotted position. S The PRT multiplier for a given pulse is applied to the interval of time between that pulse and the next one. This distinction is important whenever the RVP8 is generating multiple-PRT triggers, e.g., during DPRT mode, or during Dual-PRF processing. Multipliers from 0.0 to +1.0 are generally safe to use because they shift the trigger into the same pulse period that originally defined it. For example, a start time of (0.0 msec + (0.98 * PRT)) would position a trigger 98%

of the way up to the next range zero. But, if 0.98 were used, and if the period of the previous pulse was shorter than the current one, then that shorter period would become incorrect (longer) as a result of having to fit in the very early trigger. A small but important detail is built into the algorithm for producing the six user trigger waveforms. It applies whenever a) the trigger period is internally determined, i.e., the external pretrigger input is not being used, and b) the overall span of the six trigger definitions combined does not fit into that period. What happens in this case is that any waveforms that do not fit will be zeroed (not output) so that the desired period is preserved. This means that you can define triggers with large positive start times, and they will pop into existence only when the PRF is low enough to accommodate them. For example, if Trigger #2 is defined as a 200.0msec pulse starting at +400.0msec, then that trigger would be suppressed if the PRF were 2000Hz, but it would be present at a PRF of 1000Hz. Whenever a trigger does not completely fit within the overall period it is suppressed entirely. Thus, even though the +400.0msec start time is still valid at 2000Hz, the entire 200.0msec pulse would not fit, and so the pulse is eliminated altogether. Start limits: 5000 to 5000 msec. Width limits: 0 to 5000 msec. 322 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Maximum number of Pulses/Sec: 2000.0 Maximum instantaneous PRF : 2000.0 (/Sec) These are the PRF protection limits for this pulsewidth. The wording of the Maximum number of Pulses/Sec question serves as a reminder that the number shown is not only an upper bound on the PRF, but also a duty cycle limit when DPRT mode is enabled. The Maximum instantaneous PRF question allows you to configure the maximum instantaneous rate at which triggers are allowed to occur, i.e., the reciprocal of the minimum time between any two adjacent triggers. This parameter is included so that you can limit the maximum DPRT trigger rate individually for each pulsewidth. Note that the maximum instantaneous PRF can not be set lower than the maximum number of pulses per second. PRF limits: 50 to 20000Hz. External pretrigger delay to range zero: 3.00 usec Range Zero is time at which the signal from a target at zero range would appear at the radar receiver outputs. This parameter adjusts the delay from the active edge of the external trigger to range zero. It is important that this delay be correct when the RVP8 is operating with an external trigger, since the zero range point is a fixed time offset from that trigger. When the transmitter is driven from the internal trigger signals, those signals themselves are adjusted (see Burst Pulse alignment procedures) to accomplish the alignment of range zero. Limits: 0.1 to 500 msec. Range resolution: 125.00 meters The range resolution of the RVP8 is determined by the decimation factor of the digital matched FIR filter that computes I and Q. This decimation factor is the ratio of the filters input and output data rates, and can be any integer from six to sixteen. The Acquisition Clock (See Mc Section) sets the input data rate. At its standard frequency of 35.9751MHz, the available range resolutions (in meters) are:

50.0, 58.3, 66.7, 75.0, 83.3, 91.7, 100.0, 108.3, 116.7, 125.0, and 133.3. The ranges that are selected by the bit mask in the LRMSK command are spaced according to the range resolution that is chosen here. Also, the upper limit on the impulse response length of the matched FIR filter (see below) is constrained by the range resolution. If you choose a range resolution that can not be computed at the present filter length, then a message of the form: Warning: Impulse response shortened from 72 to 42 taps will appear. Limits: 50.0 to 133.3 meters. FIR-Filter impulse response length: 1.33 usec The RVP8 computes I and Q using a digital FIR (Finite Impulse Response) matched filter. The length of that filter (in microseconds) is chosen here. At the standard Acquisition Clock rate of 35.9751MHz, a 1.00 microsecond impulse response corresponds to a filter that is 36 taps long. The filter length should be based on several considerations:

323 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) S S S It should be at least as long as the transmitted pulsewidth. If it were shorter, then some of the returned energy would be thrown away when I and Q are computed at each bin. The SNR would be reduced as a result. It should be at least as long as the range bin spacing. The goal here is to choose the longest filter that retains statistical independence among successive bins. If the filter length is less than the bin spacing, then no IF samples would be shared among successive bins, and those bins would certainly not be correlated. It should be slightly longer than either of the above bounds would imply, so that the filter can do a better job of rejecting out-of-band noise and spurious signals. The SNR of weak signals will be improved by doing this. In practice, a small degree of bin-to-bin correlation is acceptable in exchange for the filter improvements that become possible with a longer impulse response. The FIR coefficients taper off to zero on each end; hence, the power contributed by overlapping edge samples is minimal. SIGMET recommends beginning with an impulse response length of 1.21.5 times the pulsewidth or bin spacing, whichever is greater. The maximum possible filter length is bounded according to the range resolution that has been chosen; a finer bin spacing leaves less time for computing a long filter. For the RVP8 Rev.A processor, the filter length must be less than 2.92 msec at 125-meter resolution; for Rev.B and higher this limit increases to 6.67 msec. NOTE: Cascade filter software is being contemplated that will extend the maximum impulse response length to at least 50 msec. This is of interest when very long

(uncoded CW) transmitted pulses are used. FIR-Filter prototype passband width: 0.503 MHz This is the passband width of the ideal lowpass filter that is used to design the matched FIR bandpass filter. The actual bandwidth of the final FIR filter will depend on 1) the filters impulse response length, and 2) the design window used in the process. The actual 3dB bandwidth will be:

S Larger than the ideal bandwidth if that bandwidth is narrow and the FIR length is too short to realize that degree of frequency discrimination. In these cases it may be reasonable to increase the filter length. S Smaller than the ideal bandwidth if the FIR length easily resolves the frequency band. This is because of the interaction within the filters transition band of the ideal filter and the particular design window being used. For example, for a Hamming window and sufficiently long filter length, the ideal bandwidth is an approximation of the 6dB (not 3dB) attenuation point. Hence, the 3dB width is narrower than the ideal prototype width. This parameter should be tuned using the TTY output and interactive visual plot from the Ps command. The actual 3dB bandwidth is shown there, so that it can be compared with the ideal prototype bandwidth. Limits: 0.05 to 10.0 MHz. 324 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Output control 4bit pattern: 0001 These are the hardware control bits for this pulsewidth. The bits are the 4-bit binary pattern that is output on PWBW0:3 Bit Limits: 0 to 15 (input must be typed in decimal) Current noise level: 75.00 dBm Powerup noise level: 75.00 dBm or Current noise levels PriRx: 75.00 dBm, SecRx: 75.00 dBm Powerup noise levels PriRx: 75.00 dBm, SecRx: 75.00 dBm These questions allow you to set the current value and the power-up value of the receiver noise level for either a single or dual receiver system. The noise level(s) are shown in dBm, and you may alter either one from the TTY. The power-up level(s) are assigned by default when the RVP8 first starts up, and whenever the RESET opcode is issued with Bit #8 set. Likewise, the current noise level is revised whenever the SNOISE opcode is issued. These setup questions are intended for applications in which the RVP8 must operate with a reasonable default value, up until the time that an SNOISE command is actually received. They may also be used to compare the receiver noise levels during normal operation, which serves as a check that each FIR filter is behaving as expected when presented with thermal noise. Transmitter phase switch point: 1.00 usec This is the transition time of the RVP8s phase control output lines during random phase processing modes. The switch point should be selected so that there is adequate settling time prior to the burst/COHO phase measurement on each pulse. This question only appears if the PHOUT[0:7] lines are actually configured for phase control (See Section 3.3.1). Limits: 500 to 500 msec. Polarization switch point for POLAR0: 1.00 usec Polarization switch point for POLAR1: 1.00 usec The RVP8s POLAR0 and POLAR1 digital output lines control the polarization switch in a dual-polarization radar. During data processing modes in which the polarization alternates from pulse to pulse, the transition points of these control signals are set by these two questions. The values are in microseconds relative to range zero; the same units used to define the start times of the six user triggers. The logical sense of POLAR0 and POLAR1 is set by questions described in Section 3.3.4. Limits: 500 to 500 msec. 3.3.6 Mb Burst Pulse and AFC These questions are accessed by typing Mb. They set the parameters that influence the phase and frequency analysis of the burst pulse, and the operation of the AFC feedback loop. Receiver Intermediate Frequency: 30.0000 MHz This is the center frequency of the IF receiver and burst pulse waveform. The RVP8 can operate at an intermediate frequency from any of the three alias bands 2232MHz, 4050MHz, and 5868MHz. These bands are delineated by 4MHz 325 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) safety zones on either side of integer multiples of half the RVP8/IFDs 36MHz sampling frequency. The value entered here implicitly defines the band, and hence, the boundaries of the 18MHz window in which the IF is assumed to fall. Limits: 22 to 68 MHz. Primary Receiver Intermediate Frequency: 30.0000 MHz Secondary Receiver Intermediate Frequency: 24.0000 MHz These alternate questions will replace the previous question whenever the RVP8s dual-receiver mode is selected. You should enter the two intermediate frequencies for your primary and secondary (nominally horizontal and vertical polarized) receivers. Note that you can easily swap receiver channels merely by exchanging the two frequency values. IF increases for an approaching target: YES The intermediate frequency is derived at the receivers front end by a microwave mixer and sideband filter. The filter passes either the lower sideband or the upper sideband, and rejects the other. Depending on which sideband is chosen, an increase in microwave frequency may either increase (STALO below transmitter) or decrease

(STALO above transmitter) the receivers intermediate frequency. This question influences the sign of the Doppler velocities that are computed by the RVP8. PhaseLock to the burst pulse: YES This question controls whether the RVP8 locks the phase of its synthesized I and Q data to the measured phase of the burst pulse. For an operational magnetron system this should always be YES, since the transmitters random phase must be known in order to recover Doppler data. The NO option is appropriate for non phase modulated Klystron systems in which the RVP8/IFD sampling clock is locked to the COHO. It is also useful for bench testing in general. In these NO cases the phase of I and Q is determined relative to the stable internal sampling clock in the RVP8/IFD module. Minimum power for valid burst pulse: 15.0 dBm This is the minimum mean power that must be present in the burst pulse for it to be considered valid, i.e., suitable for input into the algorithms for frequency estimation and AFC. The reporting of burst pulse power is described in Section 4.4; the value entered here should be, perhaps, 8 dB less. This insures that burst pulses will still be properly detected even if the transmitter power fades slightly. The mean power level of the burst is computed within the narrowed set of samples that are used for AFC frequency estimation. The narrow subwindow will contain only the active portion of the burst, and thus a mean power measurement is meaningful. The full FIR window would include the leading and trailing pulse edges and would not produce a meaningful average power. Since radar peak power tends to be independent of pulse width, this single threshold value can be applied for all pulsewidths. Limits: 60 to +10 dBm. Design/Analysis Window 0:Rect, 1:Hamming, 2:Blackman : 1 You may choose the window that is used in 1) the design of the FIR matched filter, and 2) the presentation of the power spectra for the various scope plots. Choices are rectangular, Hamming, and Blackman; the Hamming window being the best overall 326 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) choice. The Blackman window is useful if you are trying to see plotted spectral components that are more than 40dB below the strongest signal present. It is especially useful in the Pr plot when a long span of data are available. FIR filters designed with the Blackman window will have greater stopband attenuation than those designed with the Hamming window, but the wider main lobe may be undesirable. The rectangular window is included mostly as a teaching tool, and should never be used in an operational setting. Settling time (to 1%) of burst frequency estimator: 5.0 sec The burst frequency estimator uses a 4th order correlation model to estimate the center frequency of the transmitted pulses. Each burst pulse will typically occupy approximately one microsecond; yet the frequency estimate feeding the AFC loop needs to be accurate to, perhaps, 10KHz. Obviously this accuracy can not be achieved using just one pulse. However, several hundred of the (unbiased) individual estimates can be averaged to produce an accurate mean. This averaging is done with an exponential filter whose time constant is chosen here. Limits: 0.1 to 120 seconds. Lock IFD sampling clock to external reference: NO This question determines the usage of the shared SMA connector that is labeled AFC/(CLK) on the RVP8/IFD. It is generally not necessary to phase lock the IFD sampling clock to the radar system clock, since very good stability is obtained from the burst phase measurements during normal operation. However, two cases that benefit from clock locking are 1) using the RVP8 in a klystron system where an external trigger is provided, and 2) dual-receiver systems in which computation of F is important. The following two questions will appear only if you have requested that the IFD sampling clock be locked to an external clock reference. See Section 2.2.11 for a description of the hardware setups that must accompany this selection. PLL ratio of (1/1) ==> Input reference at 17.9876 MHz The VCXO phase-locked-loop (PLL) in the RVP8/IFD can work with any input reference clock whose frequency is a rational multiple (P/Q) of half the desired sampling frequency, i.e., center frequency of the VCXO. This question allows this ratio to be established. In general, the best PLL performance will be attained when the ratio is reduced to lowest terms, e.g., use a ratio of 6/5 rather than 12/10. Limits: 1 to 128 for both numerator and denominator. VCXO has positive frequency deviation: YES Most VCXOs have positive frequency deviation, i.e., their output frequency increases with increasing input control voltage. This question will generally be answered yes, but is included to accommodate the other case as well. The PLL will not lock, and will be completely unstable, if the wrong choice is made. Enable AFC and MFC functions: YES AFC is required in a magnetron system to maintain the fixed intermediate frequency difference between the transmitter and the STALO. AFC is not required in a klystron system since the transmitted pulse is inherently at the correct frequency. 327 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) The following rather long list of questions will appear only if AFC and MFC functions have been enabled. AFC Servo 0:DC Coupled, 1:Motor/Integrator : 0 The AFC servo loop can be configured to operate with an external Motor/Integrator frequency controller, rather than the usual direct-coupled FM control. This type of servo loop is required for tuned magnetron systems in which the tuning actuator is moved back and forth by a motor, but remains fixed in place when motor drive is removed. These systems require that the AFC output voltage (motor drive) be zero when the loop is locked; and that the voltage be proportional to frequency error while tracking. Please see Section 3.3.6.1 for more details. Wait time before applying AFC: 10.0 sec After a magnetron transmitter is first turned on, it may be several seconds or even minutes until its output frequency becomes stable. It would not make sense for the AFC loop to be running during this time since there is nothing gained by chasing the startup transient. This question allows you to set a holdoff delay from the time that valid burst pulses are detected to the time that the AFC loop actually begins running. Limits: 0 to 300 seconds. AFC hysteresis -- Inner: 5.0 KHz, Outer: 15.0 KHz These are the frequency error tolerances for the AFC loop. The loop will apply active feedback whenever the outer frequency limit is exceeded, but will hold a fixed level once the inner limit has been achieved. The hysteresis zone minimizes the amount of thrashing done by the feedback loop. The AFC control voltage will remain constant most of the time; making small and brief adjustments only occasionally as the need arises. AFC outer tolerance during data processing: 50.0 KHz In general, the AFC feedback loop is active only when the RVP8 is not processing data rays. This is because the Doppler phase measurements are seriously degraded whenever the AFC control voltage makes a change. To avoid this, the AFC loop is only allowed to run in between intervals of sustained data processing. This is fine as long as the host computer allows a few seconds of idle time every few minutes; but if the RVP8 were constantly busy, the AFC loop would never have a chance to run. This question allows you to place an upper bound on the frequency error that is tolerated during sustained data processing. AFC is guaranteed to be applied whenever this limit is exceeded. Limits: 15 to 4000 KHz. AFC feedback slope: 0.0100 D-Units/sec / KHz AFC minimum slew rate: 0.0000 DUnits/sec AFC maximum slew rate: 0.5000 D-Units/sec These questions control the actual feedback computations of the AFC loop. The overall span of the AFC output voltage is set by Gain and Offset potentiometers on the RVP8/IFD module (See Section 2.2.10). The control level that is applied to the AFCs 16-bit Digital-to-Analog converter is specified here in D-Units, i.e., 328 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) arbitrary units ranging from 100 to +100 corresponding to the complete span of the D/A converter. Since the DUnit corresponds in a natural way to a percentage scale, the shorter % symbol is sometimes used. AFC feedback will be applied in proportion to the frequency error that the algorithm is attempting to correct. The feedback slope determines the sensitivity and time constant of the loop by establishing the AFCs rate of change in (D-Units / sec) per thousand Hertz of frequency error. For example, a slope of 0.01 and a frequency error of 30KHz would result in a control voltage slew of 0.3 D-Units per second. At that rate it would take approximately 67 seconds for the output voltage to slew one tenth of its total span (20 D-Units / (0.3 D-Units / sec) = 67 sec). AFC is intended to track very slow drifts in the radar system, so response times of this magnitude are reasonable. Keep in mind that the feedback slew is based on a frequency error which itself is derived from a time averaging process (see Burst Frequency Estimator Settling Time described above) . The AFC loop will become unstable if a large feedback slope is used together with a long settling time constant, due to the phase lag introduced by the averaging process. Keep the loop stable by choosing a small enough slope that the loop easily comes to a stop within the inner hysteresis zone. See Section 3.3.6.1 for more information about these slope and slew rate parameters. AFC span [100%,+100%] maps into [ 32768 , 32767 ]

AFC format 0:Bin, 1:BCD, 2:8B4D: 0, ActLow: NO AFC uplink protocol 0:Off, 1:Normal, 2:PinMap : 1 The RVP8s implementation of AFC has been generalized so that there is no difference between configuring an analog loop and a digital loop. The AFC feedback loop parameters are setup the same way in each case; the only difference being the model for how the AFC information is made available to the outside world. Many types of interfaces and protocols thus become possible according to how these three questions are answered. AFC output follows these three steps:

S The internal feedback loop uses a conceptual [100%,+100%] range of values. However, this range may be mapped into an arbitrary numeric span for eventual output. For example, choosing the span from 32768 to +32767 would result in 16-bit AFC, and 0 to 999 might be appropriate for 3-digit BCD; but any other span could also be selected from the full 32-bit integer range. S Next, an encoding format is chosen for the specified numeric span. The result of the encoding step is another 32-bit pattern which represents the above numeric value. SIGMET will make an effort to include in the list of supported formats all custom encodings that our customers encounter from their vendors. Available formats include straight binary, BCD, and mixed-radix formats that might be required by a specialized piece of equipment. The 8B4D format encodes the low four decimal digits as four BCD digits, and the remaining upper bits in binary. For example, 659999 base-10 would encode into 0x00419999 Hex. S Finally, an output protocol is selected for the bit pattern that was produced by encoding the numeric value. The bits may be written to the eight RVP8/Main 329 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) backpanel RS232 outputs, or sent on the uplink as a value to be received by the RVP8/IFD and converted to an analog voltage. Yet another option is for the bits to be sent on the uplink and received by the RVP8/DAFC board, which supports arbitrary remapping of its output pins. To summarize: the internal AFC feedback level is first mapped into an arbitrary numeric span, then encoded using a choice of formats, and finally mapped into an arbitrary set of pins for digital output. We are hopeful that this degree of flexibility will allow easy hookup to virtually any STALO synthesizer that one might encounter. PinMap Table (Type 31 for GND, 30 for +5) Pin01:00 Pin02:01 Pin03:02 Pin04:03 Pin05:04 Pin06:05 Pin07:06 Pin08:07 Pin09:08 Pin10:09 Pin11:10 Pin12:11 Pin13:12 Pin14:13 Pin15:14 Pin16:15 Pin17:16 Pin18:17 Pin19:18 Pin20:19 Pin21:20 Pin22:21 Pin23:22 Pin24:23 Pin25:24 FAULT status pin (0:None): 0, ActLow: NO These questions only appear when the PinMap uplink protocol has been selected. The table assigns a bit from the encoded numeric word to each of the 25 pins of the RVP8/DAFC module. For example, the default table shown above simply assigns the low 25 bits of the encoded bit pattern to pins 1-25 in that order. You may also pull a pin high or low by assigning it to +5 or GND. Note that such assignments produce a logic-high or logic-low signal level, not an actual power or ground connection. The latter must be done with actual physical wires. One of the RVP8/DAFC pins can optionally be selected as a Fault Status indicator. You may choose which pin to use for this purpose, as well as the polarity of the incoming signal level. Note that the standard RVP8/DAFC module only supports the selection of pins 1, 3, 4, 13, 14, and 25 as inputs. This setup question allows you to choose any pin, however, because it does not know what kind of hardware may be listening on the uplink and what its constraints might be. Burst frequency increases with increasing AFC voltage: NO If the frequency of the transmit burst increases when the AFC control voltage increases, then answer this question Yes; otherwise answer No. When this question is answered correctly, a numerical increase in the AFC drive (DUnits) will result in an increase in the estimated burst frequency. If the AFC loop is completely unstable, try reversing this parameter. Mirror AFC voltage on 0:None, 1:I, 2:Q : 0 AFC/MFC can be mirrored on a backpanel output of the main chassis using this question. When either I or Q is selected, the AFC/MFC voltage will be present on the corresponding BNC output, and the other output will be used for scope plotting. This configuration would be useful, for example, in a dual-receiver magnetron system that needs a phase locked acquisition clock in the RVP8/IFD, but also needs an AFC tuning voltage to control the transmit frequency. When None is selected, scope plotting will revert to its normal Q output. 330 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) The voltage range of the I and Q outputs is approximately 1 Volt, and is not adjustable. When AFC/MFC is mirrored on these lines, you will probably need to add an external Op-Amp circuit to adjust the voltage span and offset to match your RF components. We also recommend that you add significant low-pass filtering

(cutoff at 3Hz) to remove any power line noise or crosstalk that may be originating within the RVP8/Main chassis. Enable Burst Pulse Tracking: YES This question enables the Burst Pulse Tracking algorithm that is described in Section 5.1.3. Remarkably, for such an intricate new feature, there are no additional parameters to configure. The characteristic settling times for the burst are already defined elsewhere in this menu, and the tracking algorithm uses dynamic thresholds to control the feedback. Enable Time/Freq hunt for missing burst: No Number of frequency intervals to search: 5 Settling time for each frequency hop: 0.25 sec Automatically hunt immediately after being reset: YES Repeat the hunt every: 60.00 sec These questions configure the process of hunting for a missing burst pulse. The trigger timing interval that is checked during Hunt Mode is always the maximum

+20msec; hence no further setup questions are needed to define the hunting process in time. The hunt in frequency is a different matter. The overall frequency range will always be the full 100% to +100% AFC span; but the number of subintervals to check must be specified, along with the STALO settling time after making each AFC change. With the default values shown, AFC levels of 66%, 33%, 0%, +33%, and

+66% will be tried, with a one-quarter second wait time before checking for a valid burst at each AFC setting. You should choose the number of AFC intervals so that the hunt procedure can deduce an initial AFC level that is within a few megaHertz of the correct value. The normal AFC loop will then take over from there to keep the radar in tune. For example, if your radar drifts considerably in frequency so that the AFC range had to be as large as 35MHz, then choosing fifteen subintervals might be a good choice. The hunt procedure would then be able to get within 2.3MHz of the correct AFC level. The settling time can usually be fairly short, unless you have a STALO that wobbles for a while after making a frequency change. Note that hunting in frequency is not allowed for Motor/Integrator AFC loops, and the two AFC questions will be suppressed in that case. The RVP8 can optionally begin hunting for a missing burst pulse immediately after being reset, but before any activity has been detected from the host computer. This might be useful in systems that both drift a lot and generally have their transmitter On. However, this option is really included just as a work around; the correct way for a burst pulse hunt to occur is via an explicit request from the host computer which knows when the pulse really should be present. Blindly hunting in the absence of that knowledge can not be done because there are many reasons why the burst pulse may legitimately be missing, e.g., during a radar calibration. 331 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) The automatic hunt for the burst pulse will always run at least once whenever the feature is enabled. The automatic hunting ceases, however, as soon as any activity is detected from the host computer. Only use this feature on radars with a serious drift problem in their burst pulse timing. Simulate burst pulse samples: NO The RVP8 can simulate a one microsecond envelope of burst samples. This is useful only as a testing and teaching aid, and should never be used in an operational system. A two-tone simulation will be produced when the RVP8 is setup in dual-receiver mode. The pulse will be the sum of two transmit pulses at the primary and secondary intermediate frequencies. To make the simulation more realistic, the two signal strengths are unequal; the primary pulse is 3dB stronger than the secondary pulse. Frequency span of simulated burst: 27.00 MHz to 32.00 MHz The simulated burst responds to AFC just as a real radar would. The frequency span from minimum AFC to maximum AFC is given here. 3.3.6.1 AFC Motor/Integrator Option The question AFC Servo 0:DC Coupled, 1:Motor/Integrator selects whether the AFC loop runs in the normal manner (direct control over frequency), or with an external Motor/Integrator type of actuator. The question AFC minimum slew request:... provides additional control when interfacing to mechanical actuators whose starting and sustaining friction needs to be overcome. The DC-Coupled AFC loop questions (changes shown in bold) are:

AFC Servo 0:DC Coupled, 1:Motor/Integrator : 0 Wait time before applying AFC: 10.0 sec AFC hysteresis Inner: 5.0 KHz, Outer: 15.0 KHz AFC outer tolerance during data processing: 50.0 KHz AFC feedback slope: 0.0100 DUnits/sec / KHz AFC minimum slew rate: 0.0000 DUnits/sec AFC maximum slew rate: 0.5000 DUnits/sec and the Motor/Integrator loop questions are:

AFC Servo 0:DC Coupled, 1:Motor/Integrator : 1 Wait time before applying AFC: 10.0 sec AFC hysteresis Inner: 5.0 KHz, Outer: 15.0 KHz AFC outer tolerance during data processing: 50.0 KHz AFC feedback slope: 1.0000 DUnits / KHz AFC minimum slew request: 15.0000 DUnits AFC maximum slew request: 90.0000 DUnits Notice that the physical units for the feedback slope and slew rate limits are different in the two cases. In the DC-Coupled case the AFC output voltage controls the frequency directly, so the units for the feedback and slew parameters use D-Units/Second. In the Motor/Integrator case, the AFC output determines the rate of change of frequency; hence D-Units are used directly. The above example illustrates typical values that might be used with a Motor/Integrator servo loop. The feedback slope of 1.0 D-Units/KHz means that a frequency error of 100KHz would produce the full-scale (100 D-Units) AFC output. But this is modified by the minimum and maximum slew requests as follows:

332 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) S A zero D-Unit output will always be produced whenever AFC is locked. S When AFC is tracking, the output drive will always be at least 15 D-Units. This minimum non-zero drive should be set to the sustaining drive level of the motor actuator, i.e., the minimum drive that actually keeps the motor turning. S When AFC is tracking, the output drive will never exceed 90 D-Units. This parameter can be used to limit the maximum motor speed, even when the frequency error is very large. The AFC Motor/Integrator feedback loop works properly even if the motor has become stuck in a cold start, i.e., after the radar has been turned off for a period of time. The mechanical starting friction can sometimes be larger than normal, and additional motor drive is required to break out of the stuck condition. But once the motor begins to turn at all, then the normal AFC parameters (minimum slew, maximum slew, feedback slope) all resume working properly. The algorithm operates as follows:

S Whenever AFC correction is being applied, the RVP8 calculates how long it would take to reach the desired IF frequency at the present rate of change. For example, if we are 1MHz away from the desired IF frequency, and the measured rate of change of the IF burst frequency is 20KHz/sec, then it will be 50 seconds until the loop reaches equilibrium. S Whenever the AFC loop is in Track-Mode, but the time to equilibrium is greater than two minutes, then the Minimum Slew parameter will be slowly increased. The idea is to gradually increase the starting motor drive whenever it appears that the IF frequency is not actually converging toward the correct value, i.e., the motor is stuck. S As soon as the frequency is observed to begin changing, such that the desired IF would be reached in less than two minutes, then the Minimum Slew parameter is immediately put back to its correct setup value. The loop then continues to run properly using its normal setup values. Manual Frequency Control (MFC) operates unchanged in both of the AFC servo modes. Whenever MFC is enabled in the Ps command, it always has the effect of directly controlling the output voltage of the AFC D/A converter. The MFC mode can be useful when testing the motor response under different drive levels, and when determining the correct value for the minimum slew request. 3.3.7 M+ Debug Options A collection of debugging options has been added to the RVP8 to help users with the development and debugging of their applications code. For the most part, these options should remain disabled during normal radar operation. These questions are included so that the RVP8 can be placed into unusual, and perhaps occasionally useful, operating states. 333 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) Noise level for simulated data: 50.0 dB This is the noise level that is assumed when simulated I and Q data are injected into the RVP8 via the LSIMUL command. The noise level is measured relative to the power of a full-scale complex (I,Q) sinusoid, and matches the levels shown on the slide pots of the ASCOPE digital signal simulator. Limits: 100dB to 0dB Simulate output rays: NO Answering YES to this question causes the RVP8 to output bands of simulated data. The bands can occupy a selectable range interval, and span a selectable interval of data values. Start bin:0, Width:10 bins, Bands:16 This question is only asked if we are simulating output rays. The Start Bin chooses the bin number (origin zero) where the simulated bands will begin. The width of each band (in bins), and the total number of bands are also selected. The upper limit for all parameters is the maximum bin count for the RVP8 (which depends on board configuration, and number of attached RVP8/AUX boards). Limits: Start: 0-Max, Width: 1-Max, Bands: 1-Max Start data value:0, Increment:16 This question is only asked if we are simulating output rays. The data value that will be assigned to the first simulated band, and the data increment from one band to the next, are selected. The permissible values are from 0 to 65535, i.e., the full unsigned 16-bit integer range. This full range is useful when simulating 16-bit output data; for the more typical 8-bit output formats, only the low byte of the start and increment are significant. Limits: 0 to 65535 3.3.8 Mz Transmitter Phase Control These questions are used to configure the 8-Bit phase modulation codes that may be used to control the phase of a coherent transmitter. The RVP8 will output a pseudo-random sequence of phase codes that are chosen from a specified set of available codes, i.e., all 8-bit patterns that are valid for the phase modulation hardware. The random sequence is output only when the RVP8 is in one of its random phase processing modes (time series or parameter). At all other times, a fixed idle phase code pattern is output. See also Sections 3.3.1 and 3.3.5 where related phase control questions are found. 8Bit code to output when idle: 0x00 This is the bit pattern to be output whenever the RVP8 is not in a random phase processing mode. Note that this idle code does not have to be one of the activecodes that are enabled below. Selection of Valid 8-Bit States 000F: Y 334 RVP8 Users Manual April 2003 TTY Nonvolatile Setups (draft) 101F:

202F:

303F:

404F:

505F:

606F:

707F:

808F:

909F:

A0AF:

B0BF:

C0CF:

D0DF:

E0EF:

F0FF:

This set of questions defines the subset of active 8-bit codes that are valid states for the transmit phase modulator. Answer each line with a sequence of Ys or Ns to indicate whether the corresponding 8-bit code is enabled. Only the codes that appear with a Y will be used by the RVP8; the indicates an unused code. The character was used instead of N so that the visual contrast of the printed table would be improved. As an example, if your klystron transmitter has an octant phase modulator that is controlled by three digital lines, you might enable phase codes zero through seven, and then cable the modulator to the low three bits of the 8-bit code. The upper five bits would not need to be used in this case. 335 RVP8 Users Manual April 2003 PlotAssisted Setups 4. Plot-Assisted Setups The RVP8/IFD receiver module replaces virtually all of the IF components in a traditional analog receiver. The alignment procedures for those analog components are usually very tedious, and require continued maintenance even after they are first performed. Subtle drifts in component specifications often go unnoticed until they become so severe that the radars data are compromised. The RVP8 makes a big improvement over this by providing an interactive graphical alignment procedure for burst pulse detection, Tx/Rx phase locking, and calibration of the AFC feedback loop. You may view the actual samples of the burst pulse and receiver waveform, examine their frequency content, design an appropriate matched filter, and observe live operation of the AFC. It is a simple matter to check the spectral purity of the transmitter on a regular basis, and to discover the presence of any unwanted noise or harmonics. Moreover, the RVP8 is able to track and modify the initial settings so that proper operation is maintained even with changes in temperature and aging of the microwave components. The Plot-Assisted Setups are accessed using the various P commands within the normal TTY setup interface. These commands are described later in this chapter. For a standalone RVP8 the graphical output can be viewed as a synthesized image on an ordinary oscilloscope. Section 4.1 describes how to make the oscilloscope connections. The RVP8 also supports new opcodes that allow the host computer to monitor the data being plotted. Users with IRIS/Open software can view the plots directly on their workstation screen, and thus, can carry out the graphical checkup and alignment procedures remotely via a network. 41 RVP8 Users Manual April 2003 PlotAssisted Setups 4.1 Oscilloscope Connections All that is required to view the graphical displays is an oscilloscope with a single vertical input channel. Setup the scope as follows:

Vertical Input Vertical Channel BNC cable to Q output of RVP8, terminated in 50W or 75W according to cable type. Variable gain, approximately 1V fullscale deflection. High frequency rejection enabled (to soften the appearance) Horizontal Time Base 100 msec/division (1ms full sweep), no holdoff. Trigger Source From vertical channel, rising edge, DC coupled. Either 0.3V or +0.3V (approximately) Trigger Level Use Norm rather than Auto, so that the display will be blank when Trigger Mode nothing is being plotted. The RVP8 synthesizes a waveform on its Q channel consisting of a repeating sequence of graphical strokes, each of which is 1ms in duration. A typical plot will have between five and fifteen strokes that blend together to form the complete image. In between each stroke is a 0.5ms idle period in which the output voltage remains at its lowest level (bottom of the screen). The idle period ends with a 2.0msec trigger pulse to the top of the screen, followed by the next 1.0ms drawing stroke. Because the oscilloscope is set to trigger on the rising edge of its input, these brief trigger pulses will initiate the horizontal sweeps that draw each stroke of the image. Thus, the waveform is self triggering, and no external trigger signal is required. This model assumes that the 0.5ms idle period (50% of the full sweep time) is long enough for the scopes horizontal time base to retrace and begin waiting for the next trigger event. Most scopes can easily do this; but if not, try increasing the holdoff ratio (See setup question on page 312) until a clean and stable display is observed. Z-axis (intensity) modulation is not required since the oscilloscope automatically blanks its beam between sweeps. When a plot requires certain strokes to be appear brighter than others, the RVP8 accomplishes this merely by drawing that particular stroke more than once in the overall sequence. The plotting technique relies on the luminance persistence of the oscilloscope phosphor to blend the multiple strokes into a single, flicker free, complex display. This happens automatically on an analog scope, but can be awkward if a digital sampling scope is used. This is because a digital scope is usually intended to capture and hold a single trace of data, rather than to sweep out multiple traces and allow them to blend into a single image. Digital scopes are not recommended here, but if one must be used, try experimenting with its controls that affect persistence and overwriting. 42 RVP8 Users Manual April 2003 PlotAssisted Setups 4.2 P+ Plot Test Pattern The RVP8 can produce a simple test pattern that is useful when the oscilloscope is attached for the first time. From the TTY monitor enter the P+ command. This will print the message Plotting Test Pattern... on the TTY and then produce the plot shown in Figure 41. This display is actually an overlay of six different strokes: 1) bottom line, 2) middle line, 3) top line, 4) line sloping up, 5) line sloping down, and 6) the sine wave pattern. The later changes phase with each plot so that, with a little imagination, it appears to be radiating from the left side of the display. Figure 41: Oscilloscope Display of Test Pattern Verify that the test pattern is stable, and adjust the vertical gain so that the top and bottom lines are exactly the full height of the oscilloscope screen. At the same time, adjust the horizontal and vertical offsets so that the image is exactly centered. When you are satisfied that the plot is being drawn correctly, type Q or ESC to return to the TTY monitor. 43 RVP8 Users Manual April 2003 PlotAssisted Setups 4.3 General Conventions Within the Plot Commands The Pb, Ps, and Pr commands all have a similar structure to their TTY user interface. Each command begins by printing a list of subcommands that are valid in that context. These subcommands are single keystrokes that are executed immediately by the RVP8 as they are typed. The ENTER key is not required. The available subcommands are different for each plot command; but, as much as possible, each key has a similar meaning across all commands. The working and measured parameters for each plot command are printed on the TTY as two lines of information following the subcommand list. The first line contains settings that only change when a subcommand is issued; but the second line is live and reflects the current status of the burst input, the IF input, or the AFC output. The first line is printed just once, but the second line is continually overprinted on top of itself. This makes it appear as a live status line whose values always remain up to date. The Pb, Ps, and Pr commands will report No Trigger on the TTY status line whenever the external trigger is expected but missing. The TTY screen will scroll upward each time a new subcommand is executed, so that a history of information lines and command activity can be seen on the screen. You may also use the Carriage-Return key to scroll the display up at any time. If the initial list of subcommands disappears off the top, you may type ? to force a reprint. To exit the plot command entirely and return to the TTY main menu type Q or ESC. These basic help and exit keystrokes apply everywhere within the RVP8 setup menus. To save space and minimize clutter on the TTY screen, they are not shown in the itemized list of subcommands. Most commands have a lowercase and an uppercase version. If a lowercase command does something, then its uppercase version does the same thing but even more so (or in reverse). For example, if the w subcommand widens something by a little bit, then W would widen it a lot. This simple convention reduces the number of different subcommand keys that are needed, and makes the interface easier to memorize. The oscilloscope display and TTY status lines are continually updated with fresh data several times per second. Occasionally it is useful to freeze a plot so that it can be studied in more detail, or compared with earlier versions. To accomplish this, every plotting command supports a Single Step mode that is accessed by typing the . (period) key. This key causes the oscilloscope display and TTY status lines to freeze in their present state, and the message Paused... will be printed. Subsequently, typing another . will single step to the next data update, but the plot and printout will still remain frozen. Typing Q or ESC will exit the plot command entirely (as they normally do). All other keys return the plot command to its normal live updating, but the key is otherwise discarded (i.e., subcommand keys are not executed while exiting from single step mode). All of the plot commands support subcommands whose only purpose is to alter the appearance of the display, e.g., zoom, stretch, etc. These subcommands make no changes to the actual working RVP8 calibrations. However, the display settings are stored in nonvolatile RAM just like all of the other setup parameters. This means that all previous display settings will be restored whenever you restart each plot command. This is very convenient when alternating among the various plots. 44 RVP8 Users Manual April 2003 PlotAssisted Setups The Pb, Ps, and Pr commands are intended to be used together for the combined purpose of configuring the RVP8s digital front end. You may, of course, run any of the commands at any time; but the following procedure may be used as a guideline for first time setups. The full procedure must be repeated for each individual pulsewidth that the radar supports. 1. Use Mb to set the systems intermediate frequency (See Section 3.3.6). 2. Use Mt to choose the PRF and pulsewidth (See Section 3.3.4). Also, choose the range resolution now, as it may constrain the design of the matched filter later. 3. Use Mt0, Mt1, etc., to set the relative timing of all RVP8 triggers that are used by the the radar. Do not worry about the absolute values of the trigger start times. Just setup their polarity and width, and their start times relative to each other (See Section 3.3.5). Make an initial guess of FIR filter length as 1.5 times the pulsewidth. 4. Use Pb to slew the start times of all triggers so that the burst pulse is properly sampled (See Section 4.4). Refine the impulse response length if necessary so that all samples easily fit within the display window. 5. Use Ps to design the matched FIR filter (See Section 4.5). Further refine the impulse response length and passband width to achieve a filter that matches the spectral width of the burst, and that has strong attenuation at DC. If the FIR length is changed, return to Pb to verify that the burst is still being sampled properly. 6. Continue using Ps and Mb to tune up the AFC feedback loop. The settings that work for one pulsewidth should also work for all others. 7. Use Pr to verify that targets are being detected with good sensitivity (See Section 4.6). Sometimes it is useful to run the Pb and Ps commands with samples from the IF-Input of the RVP8/IFD, rather than from the Burst-Input. Likewise, it is sometimes useful to view the Pr plots on samples of Burst data. The top-level ~ command (See Section 3.1.5) allows you to do this easily. 45 RVP8 Users Manual April 2003 PlotAssisted Setups 4.4 Pb Plot Burst Pulse Timing For magnetron radars the RVP8 relies on samples of the transmit pulse to lock the phase of its synthesized I and Q data, and to run the AFC feedback loop. The Pb command is used to adjust the trigger timing and A/D sampling window so that the burst pulse is correctly measured. 4.4.1 Interpreting the Burst Timing Plot The oscilloscope plot will ultimately resemble Figure 42, which shows a successful capture of the transmitters burst pulse. The horizontal axis of the display represents time, and the overall time span from the left edge to the right edge is listed as PlotSpan on the TTY. Figure 42: Successful Capture of the Transmit Burst The upper portion of the plot shows the sampling window wherein the burst pulse is measured. The duration of this window is determined by the impulse response length of the matched FIR filter. This is because the same FIR coefficients that compute I and Q are also used to compute the reference phase vectors for the burst pulses. The A/D samples of the RVP8/IFDs burst input are plotted (somewhat brighter) within the sample window. The RVP8 computes the power-weighted center-of-mass (COM) of the burst pulse envelope. This allows the processor to determine the location of the middle of the transmitted pulse within the burst analysis window. The Pb plot displays small tick marks on the top and bottom of the burst sample window to indicate the location of the COM. These markers are only displayed when valid burst power is detected. A second error bar is drawn surrounding the tick mark to indicate the uncertainty of the mark itself. This error interval is used by the burst pulse tracking algorithm to decide when a timing change can be made with confidence. It is possible to independently choose a subinterval of burst pulse samples that are used by the AFC frequency estimator. Thus, the AFC feedback loop is not constrained to use the same set of samples that are chosen for the FIR filter window. The FIR window typically is longer than the 46 RVP8 Users Manual April 2003 PlotAssisted Setups actual transmitted pulse, and thus, the samples contributing to the frequency estimate will include the leading and trailing edges of the pulse. These edges tend to have severe chirps and sidebands, compared to the more pure center portion of the pulse. The AFC frequency estimate

(which is power weighted) could be mislead by these edges and might not tune to the optimum center frequency if they were included. The lower portion of the plot shows the six triggers that are output by the RVP8. Trigger #0 is at the top, and Trigger #5 is on the bottom. They are drawn in their correct polarity and timing relative to each other, and relative to the burst sample window. Note that the sample window is always drawn in the center of the overall time span. Thus, depending on the PlotSpan and location of the six triggers edges, triggers that do not vary within the plotted time span will appear simply as flat lines. The RVP8 defines Range Zero to occur at the center of the burst sample window. This also defines the zero reference point for the starting times of the six programmable triggers. For example, a trigger whose starting time is zero will be plotted with its leading edge in the exact horizontal center of the display. Knowing this convention makes the absolute value of the trigger start times more meaningful. 4.4.2 Available Subcommands Within Pb The list of subcommands is printed on the TTY:

Available Subcommands within Pb:

I/i Impulse response length Up/Dn A/a & S/s Aperture & Start of AFC window L/l & R/r Shift triggers left/right T/t Plot time span Up/Dn Z/z Amplitude zoom B/b BP Tracking On/Off (temporary)

+ Hunt for missing burst

. Single Step These subcommands change the matched filters impulse response length, shift the radar triggers, and alter the format of the display. I/i A/a & S/s L/l & R/r The I command increments or decrements the length of the matched filters impulse response. Each keystroke raises or lowers the FIR length by one tap. These commands raise/lower the aperture/start of the subwindow of burst pulse samples for AFC. If you never use these commands, then the full FIR window will be used; however, shortening the AFC interval will result in two sample windows being drawn on the plot. The smaller AFC window should be positioned into the center portion of the transmitted pulse, where the burst amplitude and frequency are fairly stable. These two commands shift the entire group of six RVP8 triggers left or right (earlier or later in time). The lowercase commands shift in 47 RVP8 Users Manual April 2003 PlotAssisted Setups T/t Z/z B/b

0.025 msec steps, and the uppercase commands shift in 1.000 msec steps (approximately). The reason for shifting all six triggers at once is that the relative timing among the triggers remains preserved. However, the absolute timing (relative to range zero) will vary, and this will cause the burst pulse A/D samples to move within the sample window. The T command increments or decrements the overall time span of the plot. The available spans are 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000 and 5000 microseconds. The value is reported on the TTY as PlotSpan. The Z command zooms the amplitude of the burst pulse samples so that they can be seen more easily. The value is reported on the TTY as Zoom. These keys temporarily disable or re-enable the Burst Pulse Tracker. The tracker must be disabled in order for the L/R keys to be used to shift the nominal trigger timing. The b key disables tracking and sets the trigger slew to zero; the B key re-enables tracking starting from that zero value. The + subcommand initiates a hunt for the burst pulse. Progress messages are printed as successive AFC values are tried, and the trigger slew and AFC level are set according to where the pulse was found. If no burst pulse can be found, then the previous trigger slew and AFC are not changed. 4.4.3 TTY Information Lines Within Pb The TTY information lines will resemble:

Zoom:x2, PlotSpan:5 usec, FIR:1.36 usec (49 Taps) Freq:27.817 MHz, Pwr:53.9 dBm, DC:0.14%, Trig#1:5.00, BPT:0.00 Zoom PlotSpan FIR Freq Indicates the magnification (in amplitude) of the plotted samples. A zoom level of x1 means that a full scale A/D waveform exactly fills the height of the sample window. Generally, the signal strength of the burst pulse will not be quite this high. Thus, use larger zoom levels to see the weaker samples more clearly. You may zoom in powers of two up to x128. Indicates the overall time span in microseconds of the complete scope display, from left edge to right edge. Indicates the length of the impulse response of the matched FIR filter, and hence, the duration of the burst pulse sample window. The length is reported both as a number of taps, and as a time duration in microseconds. Indicates the mean frequency of the burst, derived from a 4th order correlation model. The control parameters for this model are set using the Mb command (Section 3.3.6). 48 RVP8 Users Manual April 2003 PlotAssisted Setups Pwr DC Trig#1 BPT Indicates the mean power within the full window of burst samples. DC offsets in the A/D converter do not affect the computation of the power, i.e., the value shown truly represents the waveforms

(Signal+Noise) energy. Indicates the nominal DC offset of the burst pulse A/D converter. This is of interest only as a check on the integrity of the front end analog components. The value should be in the range 2.0%. Indicates the starting time of the first (of six) RVP8 trigger outputs. This number will vary as the L and R subcommands cause the triggers to slew left and right. Note that if the radar transmitter is directly fired by an external pretrigger, then the pretrigger delay (in the form PreDly:6.87) will be printed instead. This shows the present value of timing slew (measured in microseconds) being applied to track the burst. The slew will be zero initially when the RVP8 is first powered up, meaning that the normal trigger start times are all being used. 4.4.4 Recommended Adjustment Procedures The burst pulse timing must be calibrated separately for each individual pulsewidth. Repeat the following procedure for each pulsewidth that you plan to use. Each iteration is independent. It is first necessary to setup the proper relative timing for all RVP8 triggers that are being used. The six trigger output lines are completely interchangeable, and each may be assigned to any function within the radar system. For example, Trigger #0 might be the transmitter pretrigger, Triggers #2 and #3 might synchronize external displays, and Triggers #1, #4, and #5 might be unused. Choose an initial impulse response length of 1.5 times the transmit pulsewidth. This length will be refined later when the matched filter is designed (See Section 4.5). Adjust the plot time span to view a small region around the sample window, and set the initial amplitude zoom to x16. This assures that the plotted waveform will still be noticeable even if the burst signal strength is very weak. Verify that the transmitter is radiating, and observe the burst pulse samples on the display. Use the L and R commands to shift the timing of all six triggers relative to range zero. This has the effect of moving the burst sampling window relative to the transmitted pulse. Depending on whether the triggers are set properly, you may at first see nothing more than a flat line of misplaced A/D samples. However, after a few moments of hunting, the burst pulse should appear on the oscilloscope screen. Fine tune the triggers so that the burst envelope is centered in the window, and adjust the amplitude zoom for a comfortable size display. The clean center portion of the burst pulse should then be isolated to a narrower subwindow of the overall FIR interval. Use theA and S commands to change the aperture and start of the narrowed region from which the AFC frequency estimators data will be derived. Check that the burst pulse signal strength is reasonably matched to the input span of the RVP8/IFDs A/D converter. The maximum analog signal level is +4dBm. Exceeding this level produces distorted samples that would seriously degrade the algorithms for phase locking and 49 RVP8 Users Manual April 2003 PlotAssisted Setups AFC. However, if the signal is too weak, then the upper bits of the A/D converter are wasted and noise is unnecessarily introduced. We recommend a peak signal level between 6dBm and

+1dBm, i.e., a signal that might be viewed at x2 or x4 zoom. Take note of the burst energy level reported on the TTY; it will help decide the minimum energy threshold for a valid burst pulse, which is needed in Section 3.3.6. 410 RVP8 Users Manual April 2003 PlotAssisted Setups 4.5 Ps Plot Burst Spectra and AFC Once the transmit burst pulse has been captured the next step is to analyze its frequency content and to design a bandpass filter that is matched to the pulse. In a traditional analog receiver the matched filters use discrete components that can not be adjusted, and the transmit spectrum can not be viewed unless a spectrum analyzer is on hand. The RVP8 eliminates all of these restrictions via its Ps command, which plots the burst spectrum, designs the bandpass filter, plots its frequency response, and also helps with alignment of the AFC. 4.5.1 Interpreting the Burst Spectra Plots An example of a plot from the Ps command is shown in Figure 43. The oscilloscope screen is divided into two independent areas. The major portion (the lower seven eighths) is devoted to power spectrum plots of the burst pulse and/or the matched filter response. The top portion

(single line) serves as a visual indicator of the present AFC level. Figure 43: Example of a Filter With Excellent DC Rejection The horizontal axis of the spectrum plot represents frequency. The overall span from the left edge to the right edge is always 18MHz, but the exact endpoints depend on which alias band the radars intermediate frequency falls in. For example, a 30MHz IF would imply a horizontal axis range of 18MHz to 36MHz, whereas a 60MHz IF would make the range 54MHz to 72MHz. The frequency span is printed on the TTY when the command is first entered. Since the left edge of the spectral plot always represents an integer multiple of 18MHz, either the left side or the right side will always be a multiple of 36MHz. This is important to remember when designing the matched filter, since fixed DC offsets in the A/D converters will appear aliased at these 36MHz multiples. 411 RVP8 Users Manual April 2003 PlotAssisted Setups The vertical axis of the spectrum plot is logarithmic and is marked with faint horizontal lines in 10-dB increments. An overall dynamic range of 70 dB can be viewed at once. The horizontal lines also contain major and minor tick marks to help calibrate the frequency axis. Major marks are small downward triangles that represent integer multiples of 5MHz; minor marks are in between and represent 1-MHz steps. The power spectrum example in Figure 43 is from a system with an intermediate frequency of 30MHz. Thus, the left edge of the plot begins at 18MHz, and the graph is centered on the third major tick, i.e., 30MHz. Two types of spectra can be plotted on the screen: 1) the frequency response of the FIR filter, and 2) the frequency content of the burst pulse itself. The burst spectrum is computed by first applying a Hamming window to the raw samples. You may choose to view either plot individually, or both at the same time. Figure 43 is an example of a single filter response plot, whereas Figure 44 shows a combined display of both spectra. The combined display makes it easy to compare the filter being designed with the live waveform that it is intended to selectively pass. Note that the filters frequency response is always drawn with its passband peak touching the top of the plot. The vertical height of the burst spectrum, however, will vary with signal strength but can be adjusted using the Z subcommand. The horizontal line at the top of the plotting area is also marked with an upward pointing major and minor tick. These indicate the present value of the burst pulse frequency estimator. The major tick is a triangle whose position along the horizontal axis corresponds directly to the estimated frequency. It should always be positioned directly over the main lobe of spectral power. The minor tick gives finer scale resolution by indicating the fractional part of each 1-MHz multiple. For example, in Figure 43 the burst frequency estimate was 30.027MHz. The major tick thus appears slightly to the right of 30MHz, and the minor tick appears 2.7%

across the screen. Note that when an upward tick happens to overlap a downward tick the two simply add together so that both can still be seen. It is helpful to read the minor tick relative to the ten horizontal division lines that are present on most scopes. Motion of the minor tick is apparent even with very small changes in burst pulse frequency; a change of just 5 KHz can easily be seen. This means that you can observe the frequency drift of the magnetron in great detail, and also watch the AFCs behavior in real time. The horizontal line at the very top of the display (above the spectra plot) serves to indicate the present value of the AFC control voltage. The line contains an upward pointing major and minor tick, similar to the ones used to represent the burst frequency estimate on the line below. However, the horizontal axis now represents voltage rather than frequency, and the overall span is the complete range of the AFCs digital-to-analog converter. The major tick will move from the left edge to the right edge as the AFC varies from its minimum to maximum value. The minor tick will traverse the screen at ten times this rate. 412 RVP8 Users Manual April 2003 PlotAssisted Setups 4.5.2 Available Subcommands Within Ps The list of subcommands is printed on the TTY:

Frequency span of the plot is 18.0 MHz to 36.0 MHz. Available Subcommands within Ps:

I/i Impulse response length Up/Dn N/n & W/w Filter bandwidth Narrower/Wider U/u & D/d MFC Up/Down (On/Off = , Test |) A/a & S/s Aperture & Start of AFC window

# Print filter coefficients

$ Search for an optimal filter V/v Number of spectra averaged Z/z Amplitude zoom

<space> Alternate Plots

% Toggle between dual receivers

. Single Step These subcommands change the design of the matched FIR filter, assist with calibration of the AFC loop, and alter the format of the display. I/i N/n & W/w U/u & D/d

The I command increments or decrements the length of the matched filters impulse response. Each keystroke raises or lowers the FIR length by one tap. Often the matched filters characteristics can be very much improved merely by changing the FIR length by one or two taps. Be sure to experiment with this as you design your filter. The N and W commands change the passband width of the matched filter, making it narrower or wider. The lower case commands make changes in 1KHz steps, and the upper case commands use 100KHz steps. The value is reported on the TTY as BW. Often a small change in passband width will shift the exact locations of the filters zeros, and possibly improve the DC rejection. The U and D commands implement the Manual Frequency Control (MFC) override, and allow the RVP8/IFDs AFC output voltage to be manually set to any fixed level. The lower case commands make changes in 0.05 D-Unit steps, and the upper case commands use 1.0 D-Unit steps. The value is reported on the TTY as AFC. MFC mode is toggled on and off using the = key. A warning will be printed if the Ps command is exited while MFC is enabled, and you will be given a second chance to reenable AFC. The AFC test submode is entered by typing the | key. The following list of keybindings will be shown, and will remain in effect until the test mode is exited by typing Q. AFC Test Mode Subcommands W Use WalkingOnes pattern P Toggle Pin/Bit numbering 09,AO Toggle AFC Bits 024 (Pins 125) 413 RVP8 Users Manual April 2003 PlotAssisted Setups 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 O N M L K J I H G F E D C B A 9 8 7 6 5 4 3 2 1 0 The Ps command continues to run normally during the AFC test mode. The customary AFC information will be replaced with a hexadecimal readout of the present 25-bit value. Your live display may look something like:

Navg:3, FIR:1.33 usec (48 Taps), BW:1.000 MHz, DCGain:ZERO Freq:26.610 MHz, Pwr:64.6 dBm, AFCTest:0000207F (Bits) Initially, a walking-ones bit pattern will be output in lieu of the normal formatted AFC value. This test pattern shifts a single 1 downward through the AFC word, making a transition approximately every 4ms. It is intended to help ring out and test the wiring for digital AFC installations. The walking-ones test is handy as an oscilloscope diagnostic, and you may return to it at any time by typing W. Typing any of the characters 0 through 9 or A through O will enter a new mode in which a static 25-bit digital AFC pattern is controlled directly. Each key toggles its corresponding bit, as summarized in the keybindings printout. Any 25-bit pattern can be made by toggling the appropriate bits (initially all zero) to one. Within any particular pattern, it is also easy to toggle a particular bit On/Off in order to verify its function. The P command lets you decide whether the 25-bit word represents a numeric AFC span that is mapped into pins via the pin-map table in the Mb menu; or whether it represents those pins directly. The printed hex test value will be followed either by (Bits) or (Pins) accordingly. When in Pins mode, the 0 key toggles Pin-1, the 1 key toggles Pin-2, etc. When in Bits mode, the 0 key toggles whatever pin or pins have been designated to be driven from Bit-0 of the numeric AFC. The Pins mode is useful when you are doing the initial electrical tests of the wiring of each pin. After the pin wiring has been verified and the Mb mapping table has been created, then the Bits mode allows you to test the complete digital AFC interface. The # command results in a printout of the coefficients of the current FIR filter. The values are scaled by the coefficient with the largest absolute value, so that they all fall within the 1 to +1 range. This detailed information may be used to model the behavior of the filter for point targets that fall in between discrete range bins, e.g., as will happen when performing a radar sphere calibration. See Section 5.1.1 for the exact definition of these coefficients. The $ command performs an automatic search for optimal (DC gain of zero) filters in the vicinity of the current one. As an example, suppose that we wanted an optimal filter that was approximately 2.2 msec long and 650 KHz wide. We would first use the I/i and 414

RVP8 Users Manual April 2003 PlotAssisted Setups W/wN/n subcommands to manually move to that starting point. Typing $ would then print a dialog line in which the search span length and width are chosen. You may keep the indicated values or type in new ones, just as for all RVP8 setup questions. The search begins when the spans are accepted. The search procedure may require a few seconds to a few minutes, depending on the length and width spans that are being scanned. During this time, a progress message is printed showing the length and width currently under examination. You may type Q to abort the search and retain the original filter settings. When the search completes normally, it will print Done and replace the old filter settings with the best ones that could be found. In dual-receiver mode, the $ command will search for a filter that minimizes the maximum width and DC offset at both receivers intermediate frequencies. The final filter will be the one that has the best simultaneous performance at both IFs. The V command increments or decrements the number of burst pulse spectra that are averaged together to create the plot. The count ranges from one (no averaging) to 25, and is reported on the TTY as Navg. The Z command zooms (i.e. shifts on a logarithmic scale) in 1.0-dB steps the amplitude of the burst pulse spectra. This is useful when the overall 70dB plot span is not sufficient to hold the full range. Zoom can also be used to line up the burst spectrum with the filter response so that the two can be compared. The zoom level is not printed on the TTY because there is nothing useful that could be done with it. The space bar alternates among three choices for the type of spectra that are plotted: 1) FIR frequency response, 2) Burst pulse spectrum, and 3) Both. In dual-receiver mode, the % command toggles between each receiver. The printed status line is prefixed with Rx:Pri or Rx:Sec according to which receiver is selected. Specifically, typing % will toggle the plot of the FIR filters frequency response, and the printout of its DCGain. However, the plotted spectrum and printed power levels are always based on the sum of all input signals, and thus do not change with %. V/v Z/z

<space>

4.5.3 TTY Information Lines Within Ps The TTY information lines will resemble:

Navg:3, FIR:1.33usec (48 Taps), BW:1.000, MHz, DCGain:ZERO Freq:30.027 MHz, Pwr:64.2 dBm, Loss:1.2dB, AFC:23.05% (Manual) Indicates the number of burst spectra that are averaged together prior to plotting. Larger amounts of averaging increase the ability to see subtle spectral components, but the display will update more slowly. Navg 415 RVP8 Users Manual April 2003 PlotAssisted Setups FIR BW DC-Gain Freq Pwr Loss AFC Indicates the length of the impulse response of the matched FIR filter. See description on Page 48. Indicates the actual 3dB bandwidth of the matched filter. This is the complete width of the passband from the lower frequency edge to upper frequency edge. Note that the filters center frequency is fixed at the radars intermediate frequency, as chosen in the Mb setup command. Indicates the filters response to DC (zero frequency) input. The value is a negative number in decibels, or the word ZERO if the filter has a true zero at DC. The filters DC gain should be kept at a minimum so that fixed offsets in the A/D converters will not propagate into the synthesized I and Q values. Indicates the mean frequency of the burst. See description on Page 48. Indicates the average power in the full burst sample window. See description on Page 49. The filter loss is a positive number in deciBels, and is only displayed if the overall burst power exceeds the minimum valid burst threshold set in the Mb command (clearly, it would not be possible to compute the filter loss when the burst waveform is missing). The filter loss is discussed further in Section 4.5.4. Indicates the level and status of the AFC voltage at the RVP8/IFD module. The number is the present output level in D-Units ranging from 100 to +100. The shorter % symbol is used since percentage units correspond in a natural way to the D-Units. An additional number in square brackets will be printed to the right of the AFC level to show the encoded bit pattern which corresponds to that level. This will only appear when the RVP8 deduces that a special digital format is being used, i.e., when the backpanel phase-out lines have been configured for AFC, or when any of the following are not true: a) the low and high numeric AFC span is 32768 to +32767, b) the uplink is enabled, c) the uplink format is binary, and d) pinmap protocol is OFF. Binary format is printed in base-10, BCD format is printed in Hex, and 8B4D format is printed with the low 16-bits (four BCD digits) in Hex and the upper bits in base-10. The AFC mode is shown to the right of the numerical value(s), and can take on the following states.

(Disabled) Indicates that neither AFC nor MFC are enabled. The output voltage remains fixed at 0% (center of its range). Manual Frequency Control (MFC) is overriding AFC. The U and D commands can be used to slew the voltage up and down.

(Manual) Whenever any of the following four states appears, it implies that AFC is enabled and that MFC is disabled. 416 RVP8 Users Manual April 2003 PlotAssisted Setups

(NoBurst)

(Wait)

(Track)

(Locked) The energy in the burst is below the minimum energy threshold for a valid pulse (See Page 326). The AFC loop remains idle. The burst pulse has become valid just recently, but the AFC loop is idle until the transmitter stabilizes (See Page 327) The burst pulse is valid, and the AFC loop is tracking in order to bring the burst frequency within the inner hysteresis limits. The burst pulse is valid and the AFC loop is locked. The burst frequency is now within the outer hysteresis limits and has previously been within the inner limits while tracking. This is the stable operational mode in which data acquisition should take place. 4.5.4 Computation of Filter Loss The Ps printout displays the power loss (calibration error) that results when the given filter is applied to the given transmit burst waveform. This allows you to correct for the difference between what a broad-band power meter measures as the overall transmit power, and what the RVP8 narrow-band receiver will detect within its passband. The filter loss is a subtle quantity that depends on the combined characteristics of both the transmit waveform and the receiver matched filter. The filter loss is zero if the burst waveform consists of a pure sinusoid at the designated intermediate frequency. It is also very near zero as long as most of the burst energy is confined within the passband of the RVP8s filter. The filter loss will increase as the bandwidth of the burst waveform increases and begins to spill out of that passband. Typical losses for a well-matched filter are in the 0.51.8dB range, depending on the FIR length and other design criteria. As an example, consider how the RVP8 filters would respond to a simple rectangular pulse of energy lasting To seconds. For this discussion we can ignore the sinusoidal IF carrier that must also be present within the pulse, and just focus on the rectangular envelope. This is valid because the signal bandwidth, and hence the filter loss, is determined entirely by the shape of the modulation envelope. For a pulse of length To to have unit-energy it must have an amplitude of 1 To real-valued integral:

. By centering this pulse at time zero the power spectrum is easily computed using a S(f) +

To2 To2 2 cos( 2p f t )dt 1 To

+ sin2( p f To ) p2 f2 To where f is the frequency in Hertz. This is the familiar synch function, whose main frequency lobe extends from 1To to 1To Hertz, and whose total power integrated over all frequencies is 1.0. 417 RVP8 Users Manual April 2003 PlotAssisted Setups We can now examine what the filter loss (dBloss ) would be if this pulse were applied to a bandpass filter. The filter loss is simply the ratio of the power that is passed by the filter, divided by the total input power (1.0 in this case). Assume for the moment that the filter is an ideal bandpass filter centered at zero Hertz (corresponding to how S(f) was defined) and having a bandwidth Bw, then:

+ 10 log10 Bw2 Bw2 S(f) df dBloss This integral can be computed for a few interesting filter bandwidths, yielding filter losses of 0.44dB, 1.11dB, and 3.31dB when Bw is 2To , 1To , and 12To respectively. These three example bandwidths correspond to filters that pass the entire main frequency lobe, half of that lobe, and one quarter of it. You can experimentally verify these results using the RVP8 as follows:

S Using the Mt0 command, setup a To + 0.5 msec trigger pulse from the RVP8 in the vicinity of range zero, and use that trigger to gate a signal generator whose output is applied to the RVP8/IFD Burst Input. Also setup 125-meter range resolution, and a rather long 6.0 msec impulse response length. The long length will make the transition edges of the matched filter as steep as possible, so that it becomes a reasonably good approximation to the ideal bandpass filter used in the above analysis. S Use the Pb command to verify that the burst pulse is present, and position the triggers left and right until the pulse is centered exactly at zero. S Use the Ps command to examine the frequency spectrum of the pulse. You should see a main energy lobe that is 4MHz wide and centered at the radars IF. There should also be weaker lobes spaced 2MHz apart on both sides of the main lobe. If the lobe spacing does not look quite right, it may be because the signal generator has slightly shortened or lengthened the trigger gate. S Continue using Ps to examine filters that are 4MHz, 2MHz, and 1MHz wide at their 3dB points. You should see filter losses reported that are very close to the theoretical values for the ideal bandpass filter. In the above analysis we have assumed that S(f) is the idealized power spectrum of a continuous time signal. Of course, the RVP8 filter loss algorithm can only work from an estimate of S(f) that is obtained from a finite number of samples. The filter loss calculation thus becomes more complicated than the above example in which we integrated an idealized filter response over an idealized power spectrum. Let B^(f) denote the estimated power spectrum of the continuous-time Tx burst waveform, for which we have only a finite number of discrete samples {bn}. For purposes of this discussion we can assume that the frequency variable f is continuous. Furthermore, let C^(f) denote a 418 RVP8 Users Manual April 2003 PlotAssisted Setups power spectrum estimate that is derived in an identical manner using the same number of samples, but of a pure sine wave at the radars IF. The RVP8 determines B^(f) according to its sampled measurement of the transmitted waveform; however it can calculate C^(f) internally based on an idealized sinusoid. The reported filter loss is then:

|H(f)|2 B^(f) df B^(f) df B

|H(f)|2 C^(f) df C^(f) df dBloss

+ 10 log10 Where |H(f)|2 is the spectral response of the RVP8 IF filter, and the integrals are performed over the Nyquist frequency band that is implied by the RVP8/IFD sampling rate. Note that the two integrals involving C^(f) will have constant value and need only be computed once. They serve to normalize the B^(f) integrals in such a way that the filter loss evaluates to 0dB whenever the transmit burst is a pure tone at IF. This normalization is necessary for the filter loss values to be meaningful. Regardless of the bandwidth and center frequency of H(f) , the filter loss should be reported as 0dB whenever the Tx waveform appears to have zero spectral width, i.e., is indistinguishable from a pure IF sinusoid. Of course, the real Tx waveform has only finite duration, and thus should never look like a pure tone as long as the RVP8 is able to see the entire Tx envelope. For this reason, it is important that the filters impulse response length be set long enough (using the Pb plot) to insure that all of the details of the Tx waveform are being captured. If the entire Tx envelope does not fit within the FIR filter, then the filter loss will be underestimated because the Tx spectrum will appear to be narrower than it really is. The RVP8s calculation of digital filter loss is very similar to how the loss of an analog filter would be measured on a test bench. Suppose we are given an analog bandpass filter and are asked to determine its spectral loss when a given waveform is presented. We could use a power meter to measure the waveform power before and after the filter is inserted, and compute the ratio of these two numbers. This corresponds to the first integral ratio in the above equation. However, this is not by itself an accurate measure of filter loss because it does not take into account the bandwidth-independent insertion loss. Put another way, a flat 3dB pad would seem to produce a 3dB filter loss in the above measurement, but that is certainly not the result that we desire. The remedy is to make a second pair of power measurements of the filters response to a CW tone at the passband center. This serves to calibrate the gain of the filter, and allows us to compute a filter loss that captures the effects of spectral shape independent of overall gain. This normalization step corresponds to the second integral ratio in the above equation. If your radar calibration was performed using CW waveforms, then the reported filter loss should either be added to the receiver calibration losses, or subtracted from the effective transmit power; the net result being that dBZ0 will increase slightly. In dual-receiver systems the filter loss is computed for the primary and secondary channels using only the portion of bandwidth that is allocated to that channel. For example, if the two IFs are 24MHz and 30MHz, then the filter losses for each channel would use the frequency intervals 419 RVP8 Users Manual April 2003 PlotAssisted Setups 2127MHz and 2733MHz respectively. This is necessary to avoid picking up energy from the other receiver and interpreting it as out-of-band input power. A consequence, however, is that the real out-of-band power is underestimated, i.e., the filter loss itself is underestimated. We recommend temporarily switching dual-receiver systems back to single-receiver mode when the filter loss is being measured. This is easily done by changing the Mc setup question back to single, and disconnecting the secondary burst input to the RVP8/IFD. 4.5.5 Recommended Adjustment Procedures The Ps command should be used only after the burst pulse has been successfully captured by way of the Pb command. Use the <space> key to display the burst spectrum plot by itself, and use the Z key to shift the entire graph into view. You are now looking at the actual frequency content of the transmitted pulse. The plot should show a clean main power lobe centered at the receivers intermediate frequency. Check the spectrum for spurious harmonics, excessive width, and other out-of-band noise. Make any adjustments in the transmitter that might give a sharper main lobe or reduced spurious noise. Once we know the power spectrum of the transmitted pulse we can begin designing the matched FIR filter. Use the <space> key to display both the filter response and the burst spectrum on the same plot. Use the Z key to shift the bursts main lobe up to the top horizontal line of the graph. This makes it level with the filters peak lobe, which is always drawn tangent to the same top line. Figure 44: Example of a Poorly Matched Filter Begin with the FIR length that was chosen previously in the Pb command, and use the N and W keys to set an initial bandwidth equal to the reciprocal of the pulsewidth. The main lobes of the two plots should more-or-less overlap. Experiment with changing the FIR length and bandwidth to achieve a filter with the following properties. 420 RVP8 Users Manual April 2003 PlotAssisted Setups S The filter width should be no greater than the burst spectral width. A wider passband will reduce the SNR of the received signal because out-of-band noise would be allowed to pass. S The DC gain should be as small as possible, preferably less than 64dB (See discussion below). S If there are conspicuous interference spikes at particular frequencies, try to adjust the location of the filters zeros so that the interference is maximally attenuated. The filter should not pass any frequencies that do not actually contain useful information from the original transmitted pulse. If anything, choose a filter whose width is slightly narrower than the bursts spectral width. Figure 44 shows an example of a filter that is poorly matched to the pulse. Although the filter has fairly good DC rejection, it passes frequencies that are outside of the transmitters broadcast range. These frequencies contribute nothing but noise to the synthesized I and Q data stream. There are two procedures for optimizing the performance of the FIR filter:

S Manual Method The process of arriving at a nearly optimal filter will require a few minutes of hunting with the I, W, and N keys. Every time you press any of these keys the RVP8 designs a new FIR filter from scratch, and displays the results. Fortunately, the DSP chips are fast enough that this can be done quickly and interactively. Even though the user must still control two degrees of freedom (length and bandwidth), the RVP8s internal design calculations are actually performing several hundred iterative steps each time, which preferentially select for the best filter. Because the FIR coefficients are quantized in the filter chips themselves, the process of finding an optimal filter becomes quite nonlinear. S Automatic Method Simply type the $ command and let the RVP8 do all of the work (See description in Section 4.5.2). The offset error of the RVP8/IFDs A/D converter is at most 10mV, i.e., 27dBm into its 50W input. If we wish to achieve 85-dB of dynamic range below the converters +4dBm saturation level, then we expect usable I and Q values to be obtainable from a (sub-LSB) input signal at 81dBm. This is 54dB below the interference that would result from the worst-case A/D offset. But a weak input signal at 81dBm would still be damaged by even an equal level of DC interference. Therefore, adding another 10dB safety margin, we get 64dB as the recommended maximum DC gain of the matched filter. This DC gain should be reduced even further if it is known that coherent leakage is present in the receive signal at a level greater than the 27dBm worse-case A/D offset. Figure 45 shows a 30MHz filter with particularly poor (42dB) DC rejection. The frequency range of the plot is 18MHz36MHz; hence, DC appears aliased at the right edge. Not only is there a peak in the filters stopband at DC, but it is the largest stopband peak anywhere in the plot. Contrast this with the filter shown in Figure 43 that has a true zero at DC. In general, a poor filter can be converted into a nearby good filter by making only incremental changes to the impulse response length and/or desired bandwidth. 421 RVP8 Users Manual April 2003 PlotAssisted Setups Figure 45: Example of a Filter With Poor DC Rejection 422 RVP8 Users Manual April 2003 PlotAssisted Setups 4.6 Pr Plot Receiver Waveforms The Pb and Ps commands described in the previous sections have been used to analyze the signal that is applied to the Burst-In connector of the RVP8/IFD receiver module. The task that remains is to checkout the actual received signal that is connected to IF-In. The goal is to verify that the received signal is clean and appropriately scaled, and that nearby targets can be seen clearly. The Pr command is used to make these measurements. 4.6.1 Interpreting the Receiver Waveform Plots An example of a plot from the Pr command is shown in Figure 46. The horizontal axis represents time (range) starting from a selectable offset and spanning a selectable interval. The data are acquired from a single transmitted pulse, are are plotted both as raw IF samples and as the LOG of the detected power using the FIR filter for the current pulsewidth. Figure 46: Example of Combined IF Sample and LOG Plot The IF samples are plotted on a linear scale as signed quantities, with zero appearing at the center line of the scope. Any DC offset that may be present in the A/D converter is not removed, and will be seen as a shift in the baseline at higher zoom levels. For example, the converters worst case DC offset of 10mv would appear as a 91-count offset in the 12-bit range spanning 2048 to +2047. At the x32 or higher zoom scales, this offset would peg the sample plot off scale. Typically the DC offset will be much less than this worst case value; but the RVP8 preserves the DC term in the Pr sample plot so that its presence is not forgotten. The AC amplitude of the IF samples will increase wherever targets are present. On top of these samples is drawn the detected power on a logarithmic scale. Each horizontal line represents a 10dB change in power. The graph is scaled so that the LOG power reaches the top display line when the samples occupy the full amplitude span. Using Figure 46 as an example, 423 RVP8 Users Manual April 2003 PlotAssisted Setups the two equal-power targets just to the left of center are approximately 18dB down from the top. The amplitude of the samples is thus 10(*1820) + 0.13 , i.e., 13% of full scale. This correspondence between the LOG scale and the amplitude scale applies regardless of the plots zoom level. As the IF samples are zoomed up and down by factors of two, the LOG plot will shift up and down in 6dB steps. The LOG plot is obtained by convoluting the FIR filter coefficients with the raw IF data samples, and then plotting log(I2 ) Q2) at each possible offset along the sampling interval. This convolution produces only (1 + N I) output points, where N is the number of sample points and I is the length of the FIR filter. For this reason the LOG plot begins approximately I/2 samples from left side and ends approximately I/2 samples from the right. The LOG points are computed at each possible offset within the raw IF samples. At the nominal 35.975MHz sampling rate the spacing between LOG samples will be a mere 8.33 meters. Thus, the LOG plot gives a very detailed view of received power versus range. Of course, successive LOG points will be highly correlated because successive input data intervals differ by only one sample point. This is why the LOG plots appear smooth compared to the instantaneous variation of the raw IF samples. As the starting offset of the Pr plot is decreased to range zero you will begin to see part of the burst pulse (the second half of it) appear at the left edge of the plot. This is because the burst data samples are multiplexed onto the same fiber cable that carries the IF data samples. Zero range is defined to occur at the center of the burst window; hence, the later half of the burst pulse will be visible when the plot begins at range zero. A second type of Pr display is shown in Figure 47. This plot shows a frequency spectrum of the received data samples in a format that is nearly identical to the Ps display. The horizontal axis represents the same band of frequencies (half the sampling rate), and the vertical axis represents power in 10dB steps. The entire vertical axis is used so that an overall span of 80dB is visible. This particular plot was made with the time span set to 50 msec, and with a 1-meter antenna attached to the IF input so that a broad range of signals (radio stations, electrical noise, etc.) would be detected. The purpose of the Pr power spectrum is to check for spurious interference in the IF signal from the radar receiver. The spectrum should be viewed with the transmitter turned off, and with the starting range moved out so that the burst samples are not mixed in with the receiver data. The power spectrum is computed using the complete interval of raw IF samples which, depending on the chosen time span, may contain many hundreds of points. The frequency resolution of the Pr spectrum can therefore be quite fine; making it possible to discern any interfering frequencies with some detail. The Pr spectrum plot will properly show a 0-Hz peak from any DC offset in the A/D converter, and is thus consistent with how the DC offset is presented in the Pr sample plot. Both of these plots preserve the DC component of the IF samples so that it can be monitored as part of the routine maintenance of the receiver system. This is one of the few places in the RVP8 menus and processing algorithms where the DC term deliberately remains intact. 424 RVP8 Users Manual April 2003 PlotAssisted Setups Figure 47: Example of a Noisy High Resolution Pr Spectrum 4.6.2 Available Subcommands Within Pr The list of subcommands is printed on the TTY:

Available Subcommands within Pr:

L/l & R/r Start range Left/Right T/t Plot time span Up/Dn V/v Number of spectra averaged Z/z Amplitude zoom

<space> Alternate Plots

% Toggle between dual receivers

. Single Step These subcommands change the start time and span of the IF sampling window, and alter the format of the display. L/l & R/r T/t The L and R commands shift left and right the starting point of the window of IF samples. The lower case commands shift in 0.25 msec steps, and the upper case commands use 10 msec steps. The starting point is displayed both in microseconds and kilometers on the TTY, and is not allowed to be set earlier than range zero. The T command increments or decrements the time duration of the window of IF samples. The window is not allowed to become shorter than the impulse response length of the FIR filter, since that would preclude calculating even a single LOG power point. The value is reported in microseconds on the TTY, and the largest permitted span is 50 msec. 425 RVP8 Users Manual April 2003 PlotAssisted Setups V/v Z/z

<space>

The V command increments or decrements the number of power spectra that are averaged together to create the plot. The count ranges from one (no averaging) to 25, and is reported on the TTY as Navg. The Z command zooms the amplitude of the IF samples by factors of two from one to 128. The LOG plots are shifted in corresponding 6dB increments as the amplitude is zoomed up and down. The zoom level is reported on the TTY so that absolute power levels and A/D usage can be assessed. The space bar alternates among three choices for the type of data that are plotted: 1) Received Samples, 2) Received Samples and LOG Power, and 3) Received Power Spectrum. In dual-receiver mode, the % command toggles between each receiver. The printed status line is prefixed with Rx:Pri or Rx:Sec according to which receiver is selected. Specifically, typing % will toggle the LOG plot of the received power, and the printout of the Total, Filtered, and Midpoint powers. However, the plots of power spectra and raw IF data samples are always based on the sum of all input signals, and thus do not change with %. 4.6.3 TTY Information Lines Within Pr The TTY information lines will resemble:

Zoom:x1, Navg:4, Start:0.00 usec (0.00 km), Span:5 usec Total:63.3 dBm, Filtered:77.6 dBm, MidSamp:77.4 dBm Zoom Navg Start Span Total Filtered Indicates the magnification (in amplitude) of the plotted samples. A zoom level of x1 means that a full scale A/D waveform exactly fills the vertical height of the plot. Generally, the IF signal strength will not be quite this high. Thus, use larger zoom levels to see the weaker samples more clearly. You may zoom in powers of two up to x128. Indicates the number of spectra and/or LOG powers that are averaged together prior to plotting. Larger amounts of averaging increase the ability to observe subtleties of the signals, but the display will update more slowly. Indicates the starting time of the IF sample window relative to range zero. The time is shown both in microseconds and in kilometers. Indicates the time span of the IF sample window in microseconds. Indicates the total RMS power that is being detected by the IF-Input A/D converters. This total is computed using all of the raw IF samples in the chosen interval, and is the sum of power at all frequencies other than 0 Hz (and its aliases). Indicates the RMS power that falls only within the passband of the FIR filter for the current pulsewidth. This is computed using all of the raw IF samples in the chosen interval. 426 RVP8 Users Manual April 2003 MidSamp PlotAssisted Setups Also indicates the RMS power within the passband of the FIR filter, but using only the raw IF samples in the exact center of the chosen interval. The computation of Total Power is performed using the same subset of central IF samples that are used to compute Filtered Power. This smaller subset of IF samples comes about because filtering the data requires a convolution with the current FIR filter, and this computation does not produce results all the way to the edges of the input data. This is the same reason that the LOG plots do not extend across the full screen. Because of this definition, it is valid to intercompare the Total Power and Filtered Power. The two numbers will match exactly as long as all of the incoming power falls within the passband of the FIR filter. The difference between the two powers can be used as a measure of the filter loss for a given pulse shape, i.e., the portion of signal that is lost outside of the filters passband. Note: The Total, Filtered, and MidSamp values represent true RMS power (i.e., variance), and not merely a sum-of-squares. Thus, any DC offset present in the A/D converter will not affect these power levels. 427 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5. Processing Algorithms (draft) This draft chapter is based on the legacy RVP7 algorithms. The RVP8 will have some additional features and may not contain some of the legacy features. This chapter describes the real-time data processing algorithms implemented within the RVP8 signal processor. The discussion is confined to the mathematical description of these algorithms. Figure 51 shows the overall process by which the RVP8 converts the IF signal into corrected reflectivity, velocity, and width. Table 51 summarizes the quantities that are measured and computed by the RVP8. The type of the quantity (i.e., real or complex) is also given. Subscripts are sometimes used to denote successive samples in time from a given range bin. For example, sn denotes the I and Q video sample from the nth pulse from a given range bin. In cases where it is obvious, the subscripts denoting the pulse (time) are dropped. The descriptions of all the data processing algorithms are phrased in terms of the operations performed on data from a single range bin identical processing then being applied at all of the selected ranges. Thus, there is no need to include a range subscript in this data notation. It is frequently convenient to combine two simultaneous samples of I and Q into a single complex number (called a phaser) of the form:

s + I ) jQ where j is the square root of 1. Most of the algorithms presented in this chapter are defined in terms of the operations performed on the ss, rather than the is and qs. The use of the complex terms leads to a more concise mathematical expression of the signal processing techniques being used. In actual operation, the complex arithmetic is simply broken down into its real-valued component parts in order to be computed by the RVP8 hardware. For example, the complex product:

is computed as s + W Y Real{s} + Real{W} Real{Y} * Imag{W} Imag{Y}

Imag{s} + Real{W} Imag{Y} ) Imag{W} Real{Y}

where Real{} and Imag{} represent the real and imaginary parts of their complex-valued argument. Note that all of the expanded computations are themselves real-valued. In addition to the usual operations of addition, subtraction, division, and multiplication of complex numbers, we employ three additional unary operators: ||, Arg and *. Given a number s in the complex plane, the magnitude (or modulus) of s is equal to the length of the vector joining the origin with s, i.e.

| s | + Real{s}2 ) Imag{s}212 51 RVP8 Users Manual April 2003 Processing Algorithms (draft) The signed (CCW positive) angle made between the positive real axis and the above vector is:

+ Arg{s} + arctanImag{s}

Real{s}

where this angle lies between * p and ) p and the signs of Real{s} and Imag {s} determine the proper quadrant. Note that this angle is real, and is uniquely defined as long as |s| is non-zero. When |s| is equal to zero, Arg{s} is undefined. Finally, the complex conjugate of s is that value obtained by negating the imaginary part of the number, i.e., Note that Arg{s*} = Arg{s}. The reader is referred to any introductory text on complex numbers for clarification of these points. s* + Real{s} * j Imag{s}. Table 51: Algebraic Quantities Within the RVP8 Processor p b I, Q s s T0 R0 R1 R2 SQI V W CCOR LOG SIG C N Z T Instantaneous IF-receiver data sample Instantaneous Burst-pulse data sample Instantaneous quadrature receiver components Instantaneous time series phaser value Time series after clutter filter Zeroth lag autocorrelation of A values Zeroth lag autocorrelation of A values First lag autocorrelation of A values Second lag autocorrelation of A values Signal Quality Index Mean velocity Spectrum Width Clutter correction Signal to noise ratio for thresholding Signal power of weather Clutter power Noise power Corrected Reflectivity factor UnCorrected Reflectivity factor Real Real Real Complex Complex Real Real Complex Complex Real Real Real Real Real Real Real Real Real Real 52 RVP8 Users Manual April 2003 Processing Algorithms (draft) Figure 51: Flow Diagram of RVP8 Processing dBZ dBT V W Speckle Remover Thresholding SIGTH LOGTH SQITH CCORTH FLAGS dBZ dBT V W SQI SIG CCOR N l dBZ0 a Calibrate Calculate Output Data Moments Range Averaging Kbins Micro Clutter Suppression CCORTH R0 R1 (R2) T0 M Correlate Correlate M This step dif fers for FFT and Pulse Pair Modes Filter si FIR Decimate in Time AFC D/A FFT Compute Frequency A/D 36 MHz A/D 36 MHz Burst IF 53 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.1 IF Signal Processing The starting point for all computations within the RVP8 are the instantaneous IF-receiver samples pn and, the instantaneous burst-pulse or COHO reference samples bn. These data are available at a very high sampling rate (typically 36MHz), which makes possible the digital implementation of functions that are traditionally performed by discrete components in an analog receiver. The RVP8s all-digital approach replaces a great deal of analog hardware, avoids problems of aging and maintenance, and makes it easy to tune-up the receiver and alter its parameters. This section describes these IF signal processing steps. 5.1.1 FIR (Matched) Filter The RVP8 implements a digital version of the matched filter that is found in the traditional analog radar receiver. The equivalent Finite-Impulse-Response (FIR) filter is designed using an interactive graphical procedure described in Section 4.5. The filter length (number of taps), center frequency, and bandwidth are all adjustable. The design procedure computes two sets of filter coefficients f i n such that the instantaneous quadrature samples at a given bin are:

I + N*1 Q + N*1 n and f q f q f i pn, pn n n+0 n n+0 where N is the length of the filter. The input samples pn are centered on the range bin to which the (I, Q) pair is assigned. Note that some of the pn are likely to overlap among adjacent bins, i.e., the filter length may be chosen to be greater than the bin spacing. Such an overlap introduces a slight correlation between successive bins, but the longer length allows a better filter to be designed. The convolution sums for I and Q are computed on the RVP8/Main board using dedicated FIR chips that can perform up to 576 million sums of products per second. The pn are represented as 16-bit signed integers, and the f i numerical optimization procedure is used to quantize the ideal filter coefficients into their 10-bit hardware values. The overall spectral purity of the FIR filter will typically be greater than 66dBc. n are represented as 10-bit signed integers. A n and f q The reference phase for each transmitted pulse is computed using the same two FIR sums, except with bn substituted for the pn. For a magnetron system the N bn samples are centered on the transmitted burst; for a klystron system they are obtained from the CW COHO. If the klystron is phase modulated, then the samples should be from the modulated COHO. The f i n coefficients are computed as:

+ ln sinp f i n

) 2p fIF fSAMP 4 n * N * 1 2

, n + 0 AAA N * 1 54 RVP8 Users Manual April 2003 Processing Algorithms (draft) where fIF is the radar intermediate frequency, fSAMP is the RVP8/IFD crystal sampling frequency, and ln are the coefficients of an N-point symmetric low-pass FIR filter that is matched to the bandwidth of the transmitted pulse. The multiplication of the ln terms by the sin() terms effectively converts to the low-pass filter to a band-pass filter centered at the radar IF. The formula for the f q The phase of the sinusoid terms, and the symmetry of the ln terms, has been carefully chosen to have a valuable overall symmetry property when n is replaced with (N1)n, i.e., the sequence is reversed:

n coefficients is identical except that sin() is replaced with cos(). f i

(N*1)*n

+ l(N*1)*n f i

(N*1)*n sinp

+ ln cosp 4

) 2p fIF fSAMP

) 2p fIF fSAMP 4

((N * 1) * n) * N * 1 2 n * N * 1 2 f i

(N*1)*n

+ f q n Thus, the coefficients needed to compute I are merely the reversal of the coefficients needed to compute Q; if you know f i n. This is why it is sufficient to print only one set of FIR coefficients during the filter design process described in Section 4.5. n , then you also know f q 5.1.2 Automatic Frequency Control (AFC) AFC is used on magnetron systems to tune the STALO to compensate for magnetron frequency drift. The STALO is typically tuned 30 MHz away from the magnetron frequency. The maximum tuning range of the AFC feedback is approximately 7MHz on each side of the center frequency. This assumes that the systems IF frequency is at least 4MHz away from any multiple of half the digital sampling frequency, i.e., 18, 36, 54, or 72MHz. The RVP8 analyzes the burst pulse samples from each pulse, and produces a running estimate of the power-weighted center frequency of the transmitted waveform. This frequency estimate is the basis of the RVP8s AFC feedback loop, whose purpose is to maintain a fixed intermediate frequency from the radar receiver. The instantaneous frequency estimate is computed using four autocorrelation lags from each set of N bn samples. This estimate is valid over the entire Nyquist interval (e.g., 18MHz to 36MHz), but becomes noisy within 10% of each end. Since the span of the burst pulse samples is only approximately a microsecond, several hundred estimates must be averaged together to get an estimate that is accurate to several kiloHertz. Thus, the AFC feedback loop will typically have a time constant of several seconds or more. Most of the burst pulse analysis routines, including the AFC feedback loop, are inhibited from running immediately after making a pulsewidth change. The center-of-mass calculations are held off according to the value of Settling time (to 1%) of burst frequency estimator, and the AFC loop is held off by the Wait time before applying AFC. This prevents introducing transients into the burst analysis algorithms each time the pulsewidth changes. Additional information about using AFC can be found in Sections 2.2.10, 2.4, and 3.3.6. 55 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.1.3 Burst Pulse Tracking The RVP8 has the ability to track the power-weighted center-of-mass of the burst pulse, and to automatically shift the trigger timing so that the pulse remains in the center of the burst analysis window of the Pb plot. This means that external sources of drift in the timing of the transmitted pulse (temperature, aging, etc.) will be tracked and nulled out during normal operation; so that fixed targets will remain fixed in range, and clean Tx phase measurements will always be available on every pulse. The Burst Pulse Tracker feedback loop makes changes to the trigger timing in response to the measured position of the burst. Timing changes will generally be made only when the RVP8 is not actively acquiring data, in the same way that AFC feedback is held off for similar quiet times. However, if the center-of-mass has drifted more than 1/3 the width of the burst analysis window, then the timing adjustment will be made right away. Also, there will be an approximately 5ms interruption in the normal trigger sequence whenever any timing changes are made. The Burst Pulse Tracker and AFC feedback loop are each fine-tuning servos that keep the burst pulse centered in time and frequency. These servos have been expanded to include a combined Hunt Mode that will track down a missing burst pulse when we are uncertain of both its time and frequency. This coarse-tuning mode is especially valuable for initializing the two fine-tuning servos in radar systems that drift significantly with time and temperature. When the radar transmitter is On but the burst pulse is missing, it may be because either of the following have happened:

S S It is misplaced in time, i.e., the Tx pulse is outside of the window displayed in the Pb plotting command. In this case, the trigger timing needs to be changed in order to bring the center of the pulse back to the center of the window. It is mistuned in frequency, i.e., the AFC feedback is incorrect and has caused the burst frequency to fall outside of the passband of the RVP8 anti-alias filters. In this case the AFC (or DAFC) needs to be changed so that proper tuning is restored. The Hunt Mode performs a 2-dimensional search in time and frequency to locate the burst;

searching across a +20msec time window, and across the entire AFC span. If a valid Tx pulse

(i.e., meeting the minimum power requirement) can be found anywhere within those intervals then the Burst Pulse Tracker and AFC loops will be initialized with the time and frequency values that were discovered. The fine servos then commence running with a good burst signal starting from those initial points. Depending on how the hunting process has been configured in the Mb menu, the whole procedure may take several seconds to complete. The RVP8s host computer interface remains completely functional during this time, but any acquired data would certainly be questionable. GPARM status bits in word #55 indicate when the hunt procedure is running, and whether it has completed successfully. The BPHUNT (Section 6.25) opcode allows the host computer to initiate Hunt Mode when it knows or can sense that a burst pulse should be present 56 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.1.4 Interference Filter The interference filter is an optional processing step that can be applied to the raw (I,Q) samples that emerge from the FIR filter chips. The intention of the filter is to remove strong but sporadic interfering signals that are occasionally received from nearby man-made sources. The technique relies on the statistics of such interference being noticeably different from that of weather. For each range bin at which (I,Q) data are available, the interference filter algorithm uses the received power (in deciBels) from the three most recent pulses:

where:

Pn*2 , Pn*1 , and Pn Pn + 10 log10 I2 n ) Q2 n

. If the three pulse powers have the property that:

Pn*1

* Pn*2 t C1 and Pn * Pn*1 u C2 (Alg.1)

+ C2; but the RVP8 does not force that restriction. then (In, Qn) is replaced by (In*1, Qn*1) . Here C1 and C2 are constants that can be tuned by the user to match the type of interference that is anticipated, and the error rates that can be tolerated. For certain environments it may be the case that good results can be obtained with C1 This 3-pulse algorithm is only intended to remove interference that arrives on isolated pulses, and for which there are at least two clear pulses in between. Interference that tends to arrive in bursts will not be rejected. Two variations on the fundamental algorithm are also defined. The CFGINTF command

(Section 6.22) allows you to choose which of these algorithms to use, and to tune the two threshold constants. You may also do this directly from the Mp setup menu (Section 3.3.2). Pn*1 Pn*1

* Pn*2

* Pn*2 t C1 and Pn * Pn*1 u C2 (Alg.2) t C1 and Pn * LinAvg( Pn*1, Pn*2 ) u C2 (Alg.3) Where LinAvg() denotes the deciBel value of the linear average of the two deciBel powers. The Alg.2 and Alg.3 algorithms also include the receiver noise level(s) as part of their decision criteria. Whenever power levels are intercompared in the algorithms, any power that is less than the noise level is first set equal to that noise level. This makes the filters much more robust and properly tunable, so that interference is more successfully rejected on top of blank receiver noise. Optimum values for C1 and C2 will vary from site to site, but some guidance can be obtained using numerical simulations. The results shown below were obtained when the algorithms were applied to realistic weather time series having a spectrum width = 0.1 (Nyquist), SNR = +10dB, and an intermittent additive interference signal that was 16dB stronger than the weather. The interference arrived in isolated single pulses with a probability of 2%. Performance of the three algorithms is summarized in the first three columns of Table 52, for which C1 and C2 have the common value shown. The fourth column also uses Algorithm #3, but with the value of C1 raised by 2dB. The Missed rate is defined as the percentage of 57 RVP8 Users Manual April 2003 Processing Algorithms (draft) interference points that manage to get through the filtering process without being removed. The False (false alarm) rate is the percentage of non-interference points that are incorrectly modified when they should have been left alone. Table 52: Algorithm Results for +16dB Interference Alg.1 Alg.2 Alg.3 Alg.3, C1+=2dB C1,C2 Missed/False Missed/False Missed/False Missed/False 6.0dB 17.8% 10.91% 17.8% 4.06% 17.8% 3.48% 10.3% 4.15%

8.0dB 10.5% 6.57% 10.5% 2.42% 10.4% 1.71% 6.1% 1.92%

9.0dB 8.5% 5.09% 8.5% 1.81% 8.3% 1.16% 5.4% 1.28%

10.0dB 7.3% 4.01% 7.3% 1.42% 7.5% 0.79% 5.4% 0.85%

11.0dB 8.9% 3.14% 8.9% 1.06% 8.3% 0.51% 6.5% 0.54%

12.0dB 11.6% 2.53% 11.6% 0.85% 11.3% 0.33% 9.9% 0.35%

13.0dB 17.0% 2.07% 17.0% 0.67% 16.3% 0.22% 15.3% 0.23%

14.0dB 23.5% 1.70% 23.5% 0.54% 22.4% 0.14% 21.6% 0.15%

16.0dB 39.2% 1.21% 39.2% 0.35% 39.6% 0.06% 38.9% 0.06%

20.0dB 67.3% 0.65% 67.3% 0.14% 72.5% 0.01% 72.4% 0.01%

It is important to minimize both types of errors. If too much interference is missed, then the filter is not doing an adequate job of cleaning up the received signal. If the false alarm rate is too high, then background damage is done at all times and the overall signal quality (especially sub-clutter visibility) may be compromised. We suggest that you try to keep the false alarm rate fairly low, perhaps below 1%; and then let the missed percentage fall where it may. To summarize the numerical results in Table 52:

S The Missed rates of Alg.1 and Alg.2 are identical, but the False rate of Alg.1 is much higher. Alg.1 clearly does not perform as well for additive interference, but it is included in the suite for historical reasons. S The Missed error rate for Alg.3 is nearly identical to that of Alg.2, but Alg.3 has a significantly lower false alarm rate. This is because of the somewhat improved statistics that result when the linear mean of Pn*2 and Pn*1 is used in the second comparison, rather than just Pn*1 by itself. We recommend that Alg.3 generally be chosen in preference to the other two. S Alg.3 can be further tuned by allowing the two constants to differ. For example, by raising C1 slightly above C2 (fourth column), we can trade off a decrease in the Missed rate for an increase in the False rate. Lowering C1 would have the opposite effect. Keep in mind that optimum tuning will depend on the type of interference you are trying to remove. In the previous example, where the interfering signal is only 16dB stronger than the weather, there was a close tradeoff between the Missed and False error rates. However, Table 53 shows the results that would be obtained if the interference dominates by 26db. 58 RVP8 Users Manual April 2003 Processing Algorithms (draft) Table 53: Algorithm Results for +26dB Interference Alg.1 Alg.2 Alg.3 Alg.3, C2+=5dB C1,C2 Missed/False Missed/False Missed/False Missed/False 6.0dB 17.8% 10.75% 17.8% 3.95% 17.8% 3.44% 17.8% 0.34%

8.0dB 9.9% 6.48% 9.9% 2.31% 9.9% 1.68% 9.9% 0.15%

9.0dB 7.4% 4.99% 7.4% 1.75% 7.4% 1.14% 7.4% 0.10%

10.0dB 5.9% 3.91% 5.9% 1.36% 5.9% 0.76% 5.9% 0.06%

11.0dB 4.8% 3.06% 4.8% 1.06% 4.8% 0.50% 4.8% 0.04%

12.0dB 3.2% 2.37% 3.2% 0.83% 3.2% 0.33% 3.2% 0.03%

13.0dB 2.6% 1.83% 2.6% 0.62% 2.6% 0.20% 2.8% 0.01%

14.0dB 1.9% 1.45% 1.9% 0.50% 1.9% 0.12% 2.6% 0.01%

16.0dB 1.3% 0.90% 1.3% 0.30% 1.3% 0.05% 5.8% 0.00%

20.0dB 3.1% 0.39% 3.1% 0.12% 2.0% 0.01% 31.5% 0.00%

+ 18dB Notice that we can now re-tune the constants and operate with C1

(fourth column); which yields a low 2.8% Missed rate, and an extremely low 0.01% false alarm rate. Since the false alarm rate is (approximately) independent of the interference power, these filter settings would leave all clean weather virtually untouched, i.e., we would have a very safe filter that is intended only to remove fairly strong interference. Such a filter could be left running at all times without too much worry about side effects.

+ 13dB and C2 5.1.5 Large-Signal Linearization The RVP8 is able to recover the signal power of targets that saturate the IF-Input A/D converter by as much as 46 deciBels. This is possible because an overdriven IF waveform still spends some of its time in the valid range of the converter, and thus, it is still possible to deduce information about the signal. Figure 52 shows actual signal generator test measurements with normal A/D saturation (lower line), and with the extrapolation algorithms turned on (upper line). The high-end linear range begins to roll off at approximately +10dBm versus +5dBm, and thus has been extended by 5dB. 5.1.6 Correction for Tx Power Fluctuations The RVP8 can perform pulse-to-pulse amplitude correction of the digital (I,Q) data stream based on the amplitude of the Burst/COHO input. The technique computes a (real valued) correction factor at each pulse by dividing the mean amplitude of the burst by the instantaneous amplitude of the burst. The (I,Q) data for that pulse are then multiplied by this scale factor to obtain corrected time series. The amplitude correction is applied after the Linearized Saturation Headroom correction. The mean burst amplitude is computed by an exponential average whose (1/e) time constant is selected as a number of pulses (See Section 3.3.2). A short time constant will settle faster, but will not be as thorough in removing amplitude variations (since the mean itself will be varying). Longer time constants do a better job, but will require a second or two before valid data is available when the transmitter is first turned on. The default value of 70 will give excellent results in almost all cases. Whenever the RVP8 enters a new internal processing mode (time series, FFT, PPP, etc.), the burst power estimator is reinitialized from the level of the first pulse encountered, and an additional pipeline delay is introduced to allow the estimator to completely settle. Thus, valid 59 RVP8 Users Manual April 2003 Processing Algorithms (draft) 12 11 10 9 8 7 6 5 4 3 2 1 0 1 2 3 4 4 3 2 1 0 1 2 3 4 5 6 7 8 9 10 11 12 Figure 52: Linearization of Saturated Signals Above +4dBm corrected data are produced even when the RVP8 is alternating rapidly between different data acquisition tasks, e.g., in a multi-function ASCOPE display. The additional pipeline delay will not affect the high-speed performance when the RVP8 runs continuously in any single mode. For amplitude correction to be applied, the instantaneous Burst/COHO signal level must exceed the minimum valid burst power specified in the Mb setup section. If that level is not met, e.g., if the transmitter is turned off, then no correction is performed. Thus, the amplitude correction feature conveniently gets out of the way when receiver-only tests are being performed. The maximum correction that will ever be applied is 5dB. If the burst power in a given pulse is more than 5dB above the mean, or less than 5dB below it, then the correction is clamped at those limits. The power variation of a typical transmitter will easily be contained within this interval (it is typically less than 0.3dB). Instantaneous amplitude correction is a unique feature of the RVP8 digital receiver. Bench tests with a signal generator reveal that an amplitude modulated waveform having 2.0dB of pulse-to-pulse variation is reduced to less than 0.02dB RMS of (I,Q) variation after applying the amplitude correction. 510 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.2 Video (I and Q) Signal Processing This section describes the processing of the video (I and Q) data to obtain the reduced parameters: reflectivity, total power, velocity, width, signal quality index, clutter power correction, and sometimes ZDR. The RVP8 employs two methods (selectable) for processing the I and Q signals: pulse-pair and FFT. The methods are similar except in regard to the procedures for clutter filtering. The pulse pair methods are described below; the FFT clutter filtering algorithms are described in Section 5.8. 5.2.1 Time Series Recall that the time series synthesized by the FIR filter consist of an array of complex numbers:

sn + [In ) jQn]

for n + 1, 2, 3, AAA, M where j is * 112 . These data samples are analogous to the I and Q samples in a traditional analog receiver. They are sampled at a selectable resolution in the range 50133 meters. The time series are the starting point for all calculations performed within the RVP8. 5.2.2 IIR Clutter Filter for PPP-Mode The RVP8s pulse-pair-processing mode employs a 4th order Infinite Impulse Response (IIR) digital high pass filter to remove low frequency signals due to ground clutter from the time series. Since the width of the clutter can change with the antenna rotation rate, eight different filters (seven high-pass, plus one all-pass) are provided. The filter stop-bandwidths vary from approximately 2% to 14% of the Nyquist interval, and stop band attenuation is at least 40 dB. A setup question allows selection of either 40 dB or 50 dB filters. The 50 dB filters are intended for Klystron systems. Any of the eight filters can be selected independently at each individual range bin. This permits range-dependent clutter removal. The filter algorithm is outlined below. The input time series sn is processed to form a filtered output time series sn as follows:

sn + B0sn ) B1sn*1

) B2sn*2

) B3sn*3

) B4sn*4

* C1s n*1

* C2s n*2

* C3s n*3

* C4s n*4 where the Bs and Cs are the filter coefficients. Appendix C gives the magnitude response plots for the set of filters supplied with the RVP8. 511 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.2.3 Autocorrelations for PPP-Mode The autocorrelations are computed during pulse-pair-processing mode according to the following algorithms (corresponding physical models are also given):

M M n+1 n+1 Parameter and Definition To + 1 M sn * sn Ro + 1 M R1 R2

+ 1 M * 1

+ 1 M * 2 s*

n sn M*1 M*2 n+1 n+1 s*

n s s*

n s Physical Model grgt (S ) C) ) N grgt S ) N n)1 n)2 grgt S e j p V * p2 W22 grgt S e j 2p V * 2p2 W2 where M is the number of pulses in the time average. Here, s denotes the filtered time series, s denotes the original unfiltered time series and the * denotes a complex conjugate. gr and gt represent the transmitter and receiver gains, i.e., their product represents the total system gain. Since the RVP8 is a linear receiver, there is a single gain number that relates the measured autocorrelation magnitude to the absolute received power. However, since many of the algorithms do not require absolute calibration of the power, the gain terms will be ignored in the discussion of these. To for the unfiltered time series is proportional to the sum of the meteorological signal S, the clutter power C and the noise power N. R0 is equal to the sum of the meteorological signal S and noise power N which is measured directly on the RVP8 by periodic noise sampling. To and R0 are used for calculating the dBZ values- the equivalent radar reflectivity factor which is a calibrated measurement. The physical models for R0 , R1 and R2 correspond to a Gaussian weather signal and white noise. W is the spectrum width and V the mean velocity, both for the normalized Nyquist interval [1 to 1]. The exact value of M that is used for each time average will generally be the Sample Size that is selected by the SOPRM command (See Section 6.3). However, when the RVP8 is in PPP mode and antenna angle synchronization is enabled, the actual number of pulses used may be limited by the number that fit within each rays angular limits at the current antenna scan rate. The value of M will never be greater than the SOPRM Sample Size, but it may sometimes be less. For example, at 1KHz PRF, 20_/sec scan rate, 1_ ray synchronization, and a Sample Size of 80, there will be 50 pulses used for each ray (not 80). Note, however, that the number of pulses used in the batched (non-PPP) modes will always be exactly equal to the Sample Size, since those modes are allowed to use overlapping pulses. 512 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.2.4 Range averaging and Clutter Microsuppression The next step (optional) is to perform range averaging. Range averaging can be performed over 2, 3, ..., 16 bins. This is accomplished by simply averaging the T0, R0 , R1 and R2 values. This reduces the number of bins in the final output to save processing both in the RVP8 and in the host computer. At the users option, the range averaged data can be restricted to include only those bins which have an estimated clutter-to-signal ratio that falls within the CCOR threshold interval. By excluding isolated point clutter targets from the range average the sub-clutter visibility of the averaged data is increased. Specifically, the Doppler test that is applied to each bin in order that it contribute to the overall sum is:

10 log R0

* 10 log T0 u CCORthresh . 5.2.5 Reflectivity The corrected reflectivity Z is output using a log scale based on the following equation:

dBZ + 10 logT0

* N N

) dBZo ) 20 log r ) ar ) CCOR This equation is simply a dB version of the familiar radar equation for distributed targets. The relationship between the measured autocorrelation function, the received signal and the noise can be expressed as:

To + gtgrS ) N where gt and gr represent the transmitter and receiver gains, S is the average backscattered power from the targets and N is the measured average noise power. Neglecting attenuation and the contribution of ground clutter (for the moment), the radar equation can be written as. Z + CSr2 +Cr2 0N grgt r2 r2 o To * N N where C is the radar constant and ro is a reference range which we will later set to 1 km. This is identical to the first three terms of the dB version of the equation with the definition that:

Zo + Cr2 oN grgt

+ Cr2 oIo where Io + N grgt Zo is called the calibration reflectivity factor. It is the equivalent radar reflectivity factor at the reference range when the return signal power is equal to the noise power (SNR=0 dB). It is sometimes called the minimum detectable dBZ at 1 km. The parameter Io is the measured noise power at IF with appropriate calibration for the system gain. Calibration of the RVP8 involves defining the radar constant C and measuring the value of Io. This is discussed in detail in Section 5.4. Essentially, the measurement of Io is based on the measurement of the system noise at the time of calibration. However, if the receiver gain were to change after calibration, the use of periodic noise sampling properly corrects for this. For example, if the receiver gain were to change by a factor k, then we would measure a noise value of kN and an autocorrelation value of kTo, i.e., 513 RVP8 Users Manual April 2003 Processing Algorithms (draft) Z + CSr2 +Cr2 0N grgt r2 r2 o k To * k N k N Thus the ks cancel to give us the same result for Z. This makes the approach robust to system gain fluctuations. Another way of saying this is that as long as the system sensitivity (noise figure) does not change, then the system does not require re-calibration. The individual terms in the dB form of the equation are summarized below. 1st Term : 10 logT0

: Signal to Noise Ratio

* N N The effect of this term is to subtract the measured noise. It is also used for LOG thresholding. If this number is above the user input value LOGthresh the dBZ is passed. 2rd Term: dBZo : Calibration Reflectivity (see discussion above) dBZo is the minimum detectable dBZ at a reference range ro=1 km, 3th Term: 20 log r : Range Normalization This term is the r 2 ro range normalization expressed in dB form. 4th Term: ar : Gaseous Attenuation Correction This term accounts for gaseous attenuation. The constant a is set in the RVP8 EEROM since it is a function of wavelength. For a C-band system the default value is 0.016 dB per km (for two-way path attenuation). 5th Term: CCOR: Clutter Correction This term corrects for the measured ground clutter. Its derivation is discussed in section 5.2.9. 514 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.2.6 Velocity For a Doppler power spectrum that is symmetric about its mean velocity, the velocity is obtained directly from the argument of the autocorrelation at the first lag, i.e.,

+ arg R1 1 where q

. q 1 V + l 4pts l is the radar wavelength, ts is the sampling time (1/PRF). q interval [* p, p]. When q

+" p , then V +" Vu where the unambiguous velocity is , 1 is constrained to be on the 1 Vu + l 4ts

. If the absolute value of the true velocity of the scatterers is greater than Vu , then the velocity calculated by the RVP8 is folded into the interval * Vu , Vu

, which is called the Nyquist interval. Folding is usually easily recognized on a color display by a discontinuous jump in velocities. For example, if the true velocity is Vu ) DV, then the velocity calculated by the RVP8 is * Vu ) DV, which is 2Vu away from the true mean velocity. For 8-bit outputs, rather than calculating the absolute velocity in scientific units, the RVP8 calculates the mean velocity for the normalized Nyquist interval [1,1], i.e., the output values are, V + q 1 p . For example, an output value of 0.5 corresponds to a mean velocity of * Vu2. The normalized velocity V is more efficient use of the limited number of bits. 5.2.7 Spectrum Width Algorithms The spectrum width is a measure of the combined effects of shear and turbulence. To a lesser extent, the antenna rotation rate can also effect the spectrum width. At high elevation angles, the fall speed dispersion of the scatterers also effects spectrum width. There are two choices for the spectrum width algorithm used in the RVP8, depending on the speed and accuracy that are required for the application:

R0, R1 fast algorithm valid when SNR >> 10 dB R0, R1, R2 accurate algorithm for SNR >> 0 to 5 dB The approach used is selected in the SOPRM command. The two approaches are described below:

R0, R1 Width Algorithm Given samples of the Doppler autocorrelation function, numerous estimates of spectral vari-

ance can be computed (Passarelli & Siggia, 1983). The particular estimator used by the RVP8 employs the magnitudes of R0 and R1 and assumes that the Doppler spectrum is Gaussian (usually an acceptable assumption) and that the signal-to-noise ratio is large. Spe-

cifically we have (similar to Srivastava, et al 1979):

Variance + 2 ln Ro

+ * 2 ln[SQI]

| R1 |

515 RVP8 Users Manual April 2003 Processing Algorithms (draft) where ln represents the natural logarithm. This can be compared to the expression in the preceding section for SQI to illustrate that this expression for the variance is only valid when:

SNR SNR ) 1

[ 1 which occurs when the SNR is large. This variance estimator is normalized to the Nyquist interval in units of [* p, p]. Thus, for example, a variance of p225 would be obtained from a Gaussian spectrum having a stan-

dard deviation equal to one fifth of the total width of the plotted spectral distribution. For scientific purposes, the spectrum width (standard deviation) is more physically meaningful than the variance, since it scales linearly with the severity of wind shear and turbulence. For these reasons, the width W is output by the RVP8:

W + Variance p Again, for efficient packing in 8-bits, width is normalized to the Nyquist interval [1, 1 ]. For the example given above, the output width W would be (1/5). To obtain the width in me-

ters per second, one multiplies the output width by Vu . R0, R1, R2 Width Algorithm The width algorithm in this case is similar except that the addition of R2 extends the validity of the width estimates to weak signals. In this case the variance is:

Variance + 2 3 ln| R1 |

| R2 |

The output width W is then defined as in the previous section. 5.2.8 Signal Quality Index (SQI threshold) An important feature of the RVP8 is its ability to eliminate signals which are either too weak to be useful, or which have widths too large to justify further analysis. This is done via the signal quality index (SQI) which is defined as:

SQI + | R1 |

R0 The SQI is the normalized magnitude of the autocorrelation at lag 1 and varies between 0 for an uncorrelated signal (white noise) to 1 for a noise-free zero-width signal (pure tone). Mean velocity estimates are degraded when the spectrum, width is large or when the signal-to-noise ratio is weak. The SQI is a good measure of the uncertainty in the velocity estimates and is a convenient screening parameter to compute. In terms of the Gaussian model, the SQI is :

SQI + SNR SNR ) 1

*p2W2 2 e where the SNR is the signal-to-noise ratio. For very large SNRs the SQI is a function of the spectrum width only. For a zero-width pure tone (W=0), the SQI is a function of the SNR only

(e.g., for W=0, an SNR of 1 corresponds to SQI=0.5). The SQI threshold is typically set to a value of 0.4 to 0.5. 516 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.2.9 Clutter Correction (CCOR threshold) In addition to calculating the R0 , R1 and optional R2 autocorrelation terms, which are based on filtered time series data, the RVP8 also computes T0 which is the total unfiltered power. By comparing the total filtered and unfiltered powers at each range bin, a clutter power, and hence a clutter correction, for that bin can be derived. The clutter correction is defined as, CCOR + 10 log S C ) S

+ 10 log 1 CSR ) 1 where S is the weather signal power, C is the clutter power and CSR is the clutter-to-signal ratio. The algorithm for calculating CCOR depends on whether the optional R2 autocorrelation lag is computed as described below. R0, R1 Clutter Correction In this case CCOR is estimated from, CCORest + 10 logR0

+ 10 log S ) N T0 C ) S ) N 1 ) 1 SNR CSR ) 1 ) 1 SNR

+ 10 log Here, the expression is strictly valid only when the signal-to-noise ratio

(SNR=S/N) is large. Thus when the 2-lag approach is used, the clutter corrections are not as accurate for weak weather signals. However, the error is typically less than 3 dB. R0, R1, R2 Clutter Correction In this case there is enough information to compute the clutter signal and noise power inde-

pendently. The algorithm for CCOR is:

CCORest + 10 log The clutter power is computed from:

S C ) S

+ 10 log 1 CSR ) 1 C + To * Ro + [C ) S ) N] * [S ) N]

The signal power S is then computed from:

S + | R1 | exp p2W2 2 W is the width that has been previously calculated. This approach yields more accurate re-

sults for the clutter correction in the case of a low SNR. 517 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.2.10 Weather Signal Power (SIG threshold) A parameter called SIG is also calculated to provide an estimate of the weather signal-to-noise ratio in dB for thresholding. The SIG calculation is different depending on the whether the optional R2 autocorrelation is computed. R0, R1 Calculation In this case the SIG is computed as follows:

SIG + 10 log T0

) CCOR

* N N This term represents the SNR after the removal of clutter. The CCOR value is the one de-

scribed for R0, R1 in the previous section. R0, R1, R2 Calculation In this case the SIG is computed based on the SNR which is:

SIG + 10 log 2pS

* 2pS R0 where the signal power S is determined as described in the preceding section. 5.2.11 Signal to Noise Ratio (LOG threshold) A parameter called LOG is also calculated to provide an estimate of the total signal-to-noise ratio in dB useful for reflectivity thresholding. The formula is below:

LOG + 10 logT0

* N N 518 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.3 Thresholding An important feature of the RVP8 is its ability to accept or reject incoming data based on derived properties of the signals themselves. Typically, rejected data are not displayed by the users software, thus making for very clean weather presentations. 5.3.1 Threshold Qualifiers For data quality control, each RVP8 output parameter can be qualified, i.e., either accepted or rejected for output, based on four threshold criteria:

ID LOG SQI CCOR SIG Criterion Name Signal-to-Noise Ratio Signal Quality Index Clutter Correction Weather Signal Power Pass Criterion LOG > threshold SQI > threshold CCOR > threshold SIG > threshold The calculation of the measured levels (e.g., SQI) for each of these qualifications has been described in previous sections of this chapter. All four qualification criteria can be switched on and off independently, and the threshold levels (e.g., SQIthresh) can each be set independently. Further, each qualifier test can be ANDd and ORd with any other. This allows very complex thresholds criteria to be constructed as required. The four threshold qualifiers are summarized below. LOG SQI CCOR SIG It is essentially a measure of the total power SNR. This is usually used for thresholding of the reflectivity data. The default LOG threshold value is 0.5 dB. The SQI threshold is typically used for velocity and width thresholding since it is a measure of the coherency. It is a number between 0 and 1 (dimensionless) where 0 is perfect white noise and 1 is a pure tone (perfect Doppler signal). The default SQI threshold value is 0.5. The clutter correction threshold is typically used to reject measurements when the clutter in a range bin is very strong (i.e., when the calculated CCOR is a large negative number in dB). The appropriate value depends on the coherency of the radar system. The default threshold is set to 25 dB. Threshold values less than this (more negative) reject fewer clutter bins. Threshold values closer to zero reject more clutter bins. This is typically used only for thresholding the spectrum width to assure that the signal power is strong enough for an accurate width measurement. The default threshold value is 10 dB. If R2 processing is used, this can usually be reduced to 5 dB for width thresholding. The following are the default threshold combinations for each of the parameters that can be selected for output from the RVP8:

519 RVP8 Users Manual April 2003 Processing Algorithms (draft) Parameter Description Threshold dBZ dBT V W ZDR Reflectivity with clutter correction Reflectivity without clutter correction Mean velocity Spectrum width Differential reflectivity LOG and CCOR LOG SQI and CCOR SQI and CCOR and SIG LOG 5.3.2 Adjusting Threshold Qualifiers The effect of the various threshold qualifiers for each output parameter are discussed in this section. In optimizing thresholds for your application, it is recommended that you change only one parameter (level or criterion) at a time so that you can verify the effect. Some hints for optimizing the levels for the default criteria are provided below:

LOG SQI CCOR SIG To optimize the LOG level, display dBT or dBZ and select the lowest value of the threshold that eliminates the display noise. If the LOG level is set too high you lose sensitivity. Note that if you average more pulses or ranges, then the threshold level can usually be reduced. To optimize the SQI level, display velocity and select the lowest value of the threshold that eliminates the display noise. If the SQI level is set too high you lose sensitivity. In general, you should see a greater area covered by velocity than reflectivity since the velocity is more sensitive. If you do not, you should reduce your SQI threshold. Note that if you average more pulses or ranges, then the threshold level can usually be reduced. This is used to eliminate clutter targets that are very strong. It should not be set to eliminate all clutter targets on a clear day since this means that you are losing sensitivity. To optimize the CCOR threshold it is best to know your system coherency in terms of dB of clutter cancelation. Start at a value of 10 dB greater (closer to 0) than this. Now display a PPI of dBZ at an antenna elevation of ~1 degree. The display should be relatively clean of any clutter targets since most will be rejected. Now reduce the CCOR (more negative) to increase the number of clutter targets on the display until the number of clutter targets does not increase. The optimum value of the CCOR is approximately 5 dB more (closer to zero) than this point. For example, if the number of clutter targets is a maximum at 35 dB, then set the CCOR to ~30 dB. Note that your clutter filter selection will effect the result. This should be done last. To optimize the SIG level, display the width W and select the lowest value of the threshold that eliminates the display noise. If the SIG level is set too high you lose sensitivity. Note that if you average more pulses or ranges, then the threshold level can usually be reduced. When thresholding dBZ and dBT reflectivity data with SQI, the comparison value for accepting those data is the secondary SQI threshold that is defined via a slope and offset from the primary user value (see Mf command). This secondary threshold is more permissive (lower valued), and 520 RVP8 Users Manual April 2003 Processing Algorithms (draft) is traditionally used to qualify LOG data only in the Random Phase processing mode. But the secondary SQI threshold is applied uniformly in all processing modes whenever reflectivity data are specified as being thresholded by SQI. This gives you more freedom in applying an SQI threshold to your LOG data, because the cutoff value for reflectivity can be chosen independently from the cutoff value for the other Doppler parameters. The full SQI test would not normally be applied to LOG data because of the so-called black hole problem, i.e., loss of LOG data within regions of high shear, even though the reflectivity itself was strong. You may experiment with applying a secondary SQI threshold to help cleanup the LOG data, but without introducing any significant black holes. 5.3.3 Speckle Filters A speckle filter is a final pass over each output ray, wherein isolated bins are removed. There are two speckle removers in the RVP8. S S 1D single-ray speckle filter. This can be used for any output parameter. 2D 3x3 speckle filter. If enabled, this is applied only to T, V, Z and W. The 1D speckle filter is the default technique. The 2D 3x3 filter is enabled by selection in the mp TTY setups:

2D Final Speckle/Unfold User or Always Both of these speckle filters remove isolated data points that are likely to be noise, interference, aircraft, birds or other point targets. Meteorological targets typically occupy multiple range bins so are not effected by the speckle filter. There are two primary benefits derived from using a speckle filter:

S Displays look cleaner to observers. S Thresholds can be set slightly more sensitive without increasing the number of noise pixels. The 2D 3x3 filter actually performs data filling of missing speckles as well as eliminating isolated speckle bins. The two algorithms are discussed below. 521 RVP8 Users Manual April 2003 1D Speckle Filter Processing Algorithms (draft) A ray is the basic azimuth unit of the RVP8 (e.g., 1 degree) over which the samples are averaged to obtain the output base data (T, Z, V, W). For this filter, a speckle is defined as any single, valid bin (not thresholded), having thresholded bins on either side of it in range. Any such isolated bin in a ray is set to threshold. The algorithm is shown schematically below. Input Ray Output Ray X 1D Speckle Filtering Range X Indicates Thresholded Bin Indicates Valid Bin X Indicates Speckle Note that there are two independent 1D speckle removers one for the reflectivity data (dBT, dBZ and ZDR) and one for the Doppler data (V and W). Each one should be switched on or off, depending on the specific nature of the targets being observed. For example, when making a clutter map of the area, one would certainly want to switch both speckle filters off. 2D 3x3 Speckle Filter The 2D filter examines three adjacent range bins from three successive rays in order to assign a value to the center point. Thus, for each output point, its eight neighboring bins in range and time are available to the filter. Only the dBZ, dBT, Vel , and Width data are candidates for this filtering step; all other parameters are processed using the default 1D speckle filter. The rules for the filter are as follows:

Valid Center Point Thresholded Center Point Center Point Action Assign Threshold If there are no or only one other valid point in the 3x3. If there are 5 or fewer valid neighbors in the 3x3. Else Do Nothing. Pass the center point value as-is. If there are 6 or more valid neighbors in the 3x3, average to fill the center point. Thus the 2D 3x3 filter performs 2 functions:

S Filling by interpolation. S Thresholding of isolated noise bins. Some examples are shown graphically in the figure below. For dBZ, dBT, and Width, the interpolated value for filling is computed as the arithmetic average of all available neighbors. For Vel , it is not possible to define a meaningful average in a simple way; so the nearest valid neighbor is simply filled in. 522 RVP8 Users Manual April 2003 Processing Algorithms (draft) 2D 3x3 Filtering Concepts Threshold if center point is valid but there are no or only one valid neighbor. Azimuth 1 0

-1 Range

-1

+ Threshold 1 Z00 Z0*1 0 Z output 00 Fill thresholded center point with average if there 6 or more valid neighbors. Azimuth 1 0

-1 Range Z*11 Z01 Z11 Z*1*1 Z0*1 Z10

-1 0 1 2D Velocity Unfolding Step 1: Search pattern for valid second velocity Azimuth 0

-1 V11*1 3

-1 Range V200 2 1 0 1 PRF2 PRF1 Indicates Thresholded Bin Z output 00

+ [Z*11 ) Z01 ) Z11 ) Z10 ) Z*1*1)Z0*1]

6 The filter has some interesting properties when combined with other algorithms. Dual PRF Unfolding DualPRF velocity unfolding is computed within the 3x3 filter whenever both are enabled. There are two steps to the process:

S Step 1: The most recent and the previous ray are used. For every valid point in the most recent ray, the algorithm performs a search among the three nearest neighbors in the previous ray to find a valid velocity. The search pattern is shown at the bottom of the previous figure. This larger selection of alternatePRF bins 523 RVP8 Users Manual April 2003 Processing Algorithms (draft) makes it more likely that the algorithm will find the pairs of Low/High PRF data that are required for unfolding. S Step 2: The unfolded velocities are then subjected to the standard 3x3 filtering. Dual PRF, Random Phase Processing In random phase processing, the seam at the start of the second trip is always problematic since the transmitter main bang and nearby clutter will virtually always wipeout the first few 2nd trip range bins. At a constant PRF the 2nd trip seam is always at the same range, but in dual PRF random phase mode, the seam is different each ray. Thus thresholded bins at the seam of the high PRF can be surrounded on either side by valid bins taken at the low PRF. The 3x3 filter has the effect of interpolating the reflectivity and width data over the bins at the 2nd trip seam. Velocity data will also be filledin using the nearest neighbor. Thus the 2D filter mitigates much of the damage that is caused at the 2nd trip seam to make a nearly seamless display. The maximum speed of the RVP8 is reduced to approximately 85000 bins/second when the 3x3 filter is ON approximately 60% of its maximum throughput when the filter is OFF. This is still a rather large value, and should not affect most customers. For example, there would be no problem running a scan having 2048 bins at 1degree resolution and a 40 deg/sec scan rate. However, if you really need to operate at the absolute upper limit of the RVP8 s throughput, then the 3x3 filter should be disabled in the Mp menu. 524 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.4 Reflectivity Calibration The calculation of reflectivity described in section 5.2.5 required the calibration reflectivity dBZo . This section describes its derivation. Note that customers with the SIGMET IRIS system can use the zauto utility to perform the calibration. (See the IRIS Utilities Manual.) Figure 53: Model Intensity Curve

) m B d

, e l a c s g o l

r e w o P d e r u s a e M 7 P V R N 10 log Io Power at Antenna Feed

(log scale, dBm) Plot Method for Calibration of Io This approach generates the curve shown above to determine the value of Io. The general procedure is to connect a calibrated signal generator to the radar receiver and inject known dBm power levels to generate a calibration plot of measured power vs the inserted power at the antenna feed, similar to that in Figure 53. The calibration reflectivity dBZo is computed from the radar constant and the value of Io which is the intercept of the straight line fit with the Noise level. Io is the signal level for 0 dB SNR, i.e., signal power equals noise power. Typically a CW test signal is used for this. Follow the instructions provided by the radar manufacturer for injecting a test signal. During calibration, the radar should be fully operational, so that all sources of noise are present. Ideally the transmitter should be turned on during calibration. Important: Verify with the radar manufacturer that no damage will occur to the signal generator if the transmitter is running during the calibration. To perform the calibration, insert signals at steps of 5 or 10 dB over the entire range of the system. Draw the plot shown in figure 53. You can utilize fine resolution steps at the ends of the scale to observer the details of the roll off. Be sure to raise the antenna up a few degrees to 525 RVP8 Users Manual April 2003 Processing Algorithms (draft) avoid ground thermal noise. Also tune the frequency of the signal generator using the setup command pr, and displaying the received signal spectrum. Be sure to check the tuning at the end of the calibration to make sure the signal generator and IFD have not drifted apart. Each time that a new signal level is injected, the measured power values are obtained by first invoking the SNOISE command and then reading-back the results using the GPARM command. The Log of Measured Noise Level (Word 6) from GPARM should be used. This procedure averages many samples together. For IRIS users, this is all handled by the zauto utility. Finally turn it all the way down and make one more sample to measure the noise level N. Io is obtained from the intercept of the horizontal line at N and the straight line fit to the linear portion of the curve. This value must be corrected for losses as discussed in the section below. Single-Point Direct Method for Calibration of Io This calibration method requires no support software. The approach uses the TTY setups commands. Again the signal generator output must be calibrated in absolute dBm. Use a power meter to check the calibration. S Turn the radiate off and connect the signal generator to the test signal injection point. S Raise the antenna to at least 20 degrees, and set the azimuth to point away from any known RF sources including the sun. S Select the pulse width using the mt command. S Select the pr command and use the commands to set the following:

Plotting Received Power Spectrum... Rx:Pri, Zoom:x1x8, Navg:25, Start:100.01 usec (14.99 km), Span:50 usec S Set the signal generator to the approximate radar RF frequency with a power level corresponding to a strong signal (30 dB above the noise). Use a DC test signal

(not pulsed). This signal should be visible as a peak in the spectrum display. Adjust the siggen RF signal frequency so that produces the precise IF frequency

(e.g., IF frequency of 30 MHz). S Turn the signal generator off and record the Filtered power level. Note that because of the large averaging it will require several seconds for the average to stabilize. S Turn the signal generator on, verify that the peak is still at the IF frequency and adjust the power level to obtain precisely 3 dB more Filtered power than was observed with the noise only. Again, allow several seconds for the averaging to stabilize after you make each amplitude adjustment. This is the value of Io, i.e., the test signal signal power equals the noise power. The next step is to correct the value of Io for losses as discussed in the section below. 526 RVP8 Users Manual April 2003 Processing Algorithms (draft) Treatment of Losses in the Calibration In the calibration of the dBm level of the test signal, be sure to account for any losses that may occur between the antenna feed and the injection point, and in the cable and coupler that is used to connect the signal generator to the injection point. Figure 54 illustrates the nomenclature of the various losses that are involved in the calibration. The relationship between the injected test signal and the value of the received power relative to the feed is:

dBmFeed dBmFeed

+ dBmInjected

+ dBmSiggen

) dBLFeed:Coupler

* dBLCoupler

* dBLCable

) dBLFeed:Coupler For example, assume the following:

Loss between the feed and the coupler dBLFeed:Coupler Loss caused by the coupler Loss in the cable from siggen to coupler dBLCoupler dBLCable 3 dB 30 dB 2 dB Then if the test signal generator output is 50 dBm, the injected power is The equivalent power at the feed is then 3 dB more than this dBmInjected = 50[30+2]= 82 dBm. dBmFeed = 82+3 = 79 dBm. During the calibration, there are several ways to handle the losses using these equations. Two examples are:

S Each signal generator value can be corrected for losses so that the calibration plot shows IFD measured power vs received power at the feed. This is recommended for manual calibration. S The signal generator values can be plotted directly and the intercept power Io can be corrected for losses so that it is properly referenced to power at the feed. This is the approach used by the IRIS zauto utility. 527 RVP8 Users Manual April 2003 Processing Algorithms (draft) Figure 54: Illustration of Losses that Affect LOG Calibration dBmFeed Feed Pt Feed Receive Path LFeed:Coupler Transmit Path Lt Transmitter Pt Coupler Receiver RVP7 IFD LCoupler LCable Sig Gen dBmsiggen Determination of dBZo The calibration reflectivity is determined from the radar equation as follows:

dBZo + 10 log Cr2 oIo where Io is in mW (corrected for receive losses), the reference range ro is 1 km, and the radar constant C is:

where, C + 2.69 1016l2 t q f G2 Pt Lt l Pt Lt t q f G Radar wavelength in cm. Transmitted peak power in kW. Transmit loss (e.g., 3 dB corresponds to Lt + 2 ) Pulse width in microseconds. Horizontal half-power full beamwidth. Vertical half-power full beamwidth. Antenna gain (dimensionless) on beam axis. 528 RVP8 Users Manual April 2003 Processing Algorithms (draft) The radar constant is determined from the characteristics of your radar (check with the manufacturer if you are unsure of the values). Note that transmit losses are accounted for in the radar constant, while receiver loss is usually included in the calculation of Io. Finally, if the value of Io calculated above was not based on loss-corrected dBm values, correct Io as follows:

dBIo corrected

+ dBIo * dBLCoupler

* dBLCable

) dBLFeed:Coupler Example Calculation of dBZo:

This sample calculation is provided so that programmers can check their arithmetic. The radar parameters:

l Pt Lt t q f G Radar wavelength in cm. Transmitted power in kW. Transmit Loss Pulse width in microseconds Horizontal half-power beamwidth in degrees Vertical half-power beamwidth in degrees Antenna gain (dimensionless) on beam axis 5 cm. 500 kW 2 (3 dB) 1 microsecond 1 degree 1 degree 19,953 (43.0 dB) The radar constant for this example is, C + 2.69 1016l2 Pt t q f G2 Lt + (2.69 1016)(5)2

+ 6.76 106 mm6 m*3 km*2 mW*1

(500)(1)(1)(19, 953)2 (2.0) Assume that Io with loss correction is calculated to be 105 dBm (3.16 10*11 mW), then dBZo is, dBZo + 10 logCr2 oIo

+ 10 log (6.76 106) (1)2 (3.16 10*11)

+ * 36.7dB (mm6 m*3) This value would be down-loaded to the signal processor using the SOPRM command. 529 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.5 Dual PRT Processing Mode The RVP8 supports two major modes for Dual PRT processing, i.e., algorithms using triggers that consist of alternate short and long periods. Most of the Doppler parameters are available in each of these modes. You may also request time series data in both cases; the samples will be organized so that the first pulse of a short PRT pair always comes first. 5.5.1 DPRT-1 Mode The DPRT-1 trigger consists of a very short PRT from which Doppler data are obtained, followed by a much longer PRT whose purpose is to limit the average duty cycle of the transmitter. No information is extracted from the long PRT pair, but Dual-PRF techniques can still be used by varying the short period from ray to ray. The -1 suffix in the name for this mode is a reminder that Doppler parameters are computed from the short PRT only. The DPRT-1 mode is intended for millimeter wavelength radars that must run at a very high effective PRF (up to 20KHz) to get an acceptable unambiguous velocity, but which also have a much lower duty cycle constraint on the average number of pulses transmitted each second. In DPRT-1 mode the requested PRF from the host computer will generally be quite large (up to 20KHz); and the reciprocal of this effective instantaneous PRF will determine the triggers short PRT interval. In this way, all subsequent physical calculations will be scaled correctly, e.g., unambiguous velocity, maximum first trip range, etc., are all supposed to be based on the short PRT interval. The host computer must therefore be configured so that it can ask for these very high trigger rates. The duration of the long PRT interval is not specified directly by the host computer. Rather, the RVP8s Maximum number of Pulses/Second setup parameter is used to compute how much delay to insert in order to insure that the transmitters duty cycle is not exceeded. This special treatment applies only in DPRT mode; all other modes that have uniform triggers continue to interpret the RVP8s trigger bound as a simple Maximum PRF. Since DPRT-1 mode uses only the short pairs of pulses, it is not possible to run the R2 moment estimation algorithms. The RVP8 will return the GPARM Invalid Processor Configuration bit if R2 is requested in DPRT mode. The error bit will also be returned if the number of pulses requested (sample size) is not even. All other error conditions are the same as FFT mode. Warning: Since the RVP8s Maximum number of Pulses/Sec is used to enforce the duty cycle limit, it is essential that it not be overwritten by the host computers upper PRF limit, which typically will be much higher. To insure this, you must make sure that the PWINFO command is disabled in the RVP8 Mc setup menu. You will have no duty cycle protection if you do not do this. Note: You may still choose to run Dual-PRF velocity unfolding within the DPRT-1 mode. What will happen is that the short PRT will vary in the selected 3:2, 4:3, or 5:4 ratio, but the overall duty cycle will remain constant. The combination of DualPRF and DPRT-1 is tremendously effective in extending the radars unambiguous velocity interval. 530 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.5.2 DPRT-2 Mode The trigger consists of alternating short and long period pulses, where the ratio of the periods is determined by the velocity unfolding ratio that has been selected. Doppler data are extracted from both the short and long pulse pairs (hence the -2 suffix), and unfolded velocities are made available on each ray based on the combined PRT data from that ray alone. DPRT-2 mode is intended for rapidly scanning radars where the ray-to-ray spatial continuity assumptions of the traditional Dual-PRF algorithms do not apply. The DPRT-2 velocity unfolding algorithm uses a modified version of the standard Dual-PRF algorithm. Both start by computing a simple velocity difference as a first approximation of the unfolded result. The standard algorithm uses that difference to unfold the velocity from the most recent ray, which yields a lower variance estimate than the difference itself. The DPRT-2 algorithm is similar, except that the folded velocity from both PRTs are unfolded independently and then averaged together. In addition to the above, the RVP8 also computes the DC average of the (I,Q) data within each bin. This is used as a simple estimate of clutter power, so that corrected reflectivities are available in DPRT-2 mode whenever a non-zero clutter filter is selected. DPRT-1 mode is the same in this respect. However, the DPRT-2 widths use an improved algorithm based on the two different PRTs, and which avoids the SNR sensitivity of the DPRT-1 width estimator. 531 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.6 Dual PRF Velocity Unfolding For a radar of wavelength l operating at a fixed sampling period ts + 1PRF , the unambiguous velocity and range intervals are given by:

Vu + l 4ts and Ru + c ts 2 where c is the speed of light. Often these intervals do not fully cover the span of velocity and range that one would like to measure. The problem is generally worse for short wavelength radars, since that unambiguous velocity span is directly proportional to l for a given ts. If the unambiguous range interval is made sufficiently large by increasing ts , then the resulting velocity span may be unacceptably small. The RVP8 provides a built-in mechanism for extending the unambiguous velocity span by a factor of two, three, or four beyond that given above. The technique, called Dual PRF velocity unfolding, uses two pulse periods rather than one, and relies on the extra information thus obtained to correct (i.e. unfold) the mean velocity measurement from each individual period. The Dual PRF trigger pattern consists of alternating (N+k)-pulse intervals where the period in each interval is either t h (for the high-PRF). Here N is the sample size, and k represents a delay that permits the clutter filter to equilibrate to the new PRF after each change. The clutter filter impulse response lengths vary according to which filter is selected. l (for the low-PRF) or t l and t The two trigger periods t give factors of two, three, and four times velocity expansion over the t unfolding algorithm makes use of the following results. Suppose that the radar observes a target with mean velocity V at each of the two trigger periods. The measured phase angles for the R1 autocorrelations at the two PRFs are:

h must be chosen in either a 3:2, 4:3, or 5:4 ratio. These ratios h period alone. The

+ 4p V t l q l l and q h

+ 4p V t l h where angles outside the basic [* p, p] interval are returned to that interval by appropriate additions of " 2p. These angles correspond to the ordinary single-PRF Doppler velocity measurements, and the " 2p uncertainties reflects the fact that each measurement is folded into its own unambiguous interval:

Vul

+ l 4t l and Vuh

+ l 4t h If we define f to be the difference between the two measured phases then:

which can be interpreted as a phase angle within the unfolded interval:

f + q

* q h l

+ 4p l t l

* t h Vu unfold

l

* t h) 4(t l 532 RVP8 Users Manual April 2003 Processing Algorithms (draft) Now if t l and t h are in a 3:2 ratio, then:

* t h t l

+ t l 3

+ t h 2 and thus Vu unfold

+ 3Vul

+ 2Vuh The angle f represents a velocity phase angle in [* p, p] , but with respect to an enlarged unambiguous interval. Thus, by simply differencing the folded angles from the high and low PRFs, we obtain an angle that is unfolded to a larger velocity span. Similar reasoning shows that the 4:3 ratio gives a factor of three improvement over Vuh . In practice, the unfolded angle f is not in itself a suitable velocity estimator. The reason is that the variance of f is equal to the sum of the variances of each of its components, i.e., twice that of the individual measurements alone. If the target is at all noisy, then this increase in variance can be severe. Rather than use f directly, the RVP8 uses it only as a rough estimate in determining how to unfold the individual velocity measured from each PRF. Figure 55: Dual PRF Concepts ql * qh Region I Result ql3 Region III ql * qh Region I Result Region II qh2 Region II Low PRF Case High PRF Case This technique is illustrated in Figure 55. The figure shows how the low-PRF and high-PRF angles are unfolded based on the difference angle. The diagrams show phase planes representing the large unfolded velocity interval, and the locations of various vectors on those planes. Referring first to the right figure, the difference angle is plotted, and the plane is divided into two equal size regions, one of which is centered on the difference vector. The high-PRF angle is then divided by two and plotted. The resultant unfolded velocity angle must either be this vector, or this vector plus p . Since adding p places the vector into acceptance Region 1 where it is 533 RVP8 Users Manual April 2003 Processing Algorithms (draft) nearest the difference angle, we conclude that this is the correct unfolding. Likewise, on the left diagram we unfold the low-PRF angle by dividing the plane into thirds centered on the difference angle. The result angle is either q l 3

, q l 3

) 2p 3 or q l 3

) 4p 3 depending on which one falls into the acceptance Region 1. Note that the resultant angle is the same in each case. The RVP8 makes efficient use of the incoming data by unfolding velocities from both the low and the high-PRF data, making use each time of information in the previous ray. When low-PRF data are taken the derived velocities are unfolded by combining information from the previous high-PRF interval. Likewise, when high-PRF data are acquired the velocities are unfolded based on the previous low-PRF interval. Thus, when operating in the Dual PRF mode, the RVP8 outputs one data ray for each (N+k)-pulse interval. However, the velocity data in the Dual PRF rays are unfolded, so that the [1,+1] interval now represents either two or three times the prior velocity range. Put another way, the data are still interpreted as described in the section on mean velocity estimation, except that Vu is now larger. The width data are also modified somewhat during Dual PRF unfolding. Although valid widths are obtained independently on all rays, those measured at low-PRF are larger than those at high-PRF. This is simply because the dimensionless width units are with respect to a larger velocity interval in the latter case. To compensate for this, low-PRF widths are multiplied by either 2/3 or 3/4 before being output. This puts them in the same scale as the high-PRF values, and thus, the widths do not vary on alternate pulses. A useful consequence of this is that width data can be sent directly to a color display generator without having to plot every other ray in a different scale. There are a few words of caution that should be kept in mind when using the RVP8 in the Dual PRF processing modes. The unfolding algorithms make the assumption that targets are more-or-less continuous from ray to ray. Otherwise, it would not make sense to use data from a previous ray to unfold velocities in the current ray. Users must therefore assure that their antenna scan rate and beamwidth are such that each target is illuminated, at least partially, over each full 2(N+k)-pulse interval. In practice, a certain amount of decorrelation from ray to ray is acceptable, since the previous rays are used only to decide into which unfolded interval the current ray should be placed. Small errors in the previous ray data, therefore, cause no error in the output. However, large previous-ray errors would lead to incorrect unfolding. A more subtle side effect of Dual PRF processing arises from clutter filtering because clutter notches now appear at several locations in the unfolded velocity span, rather than just at zero velocity. These additional rejection points come about because the original velocity intervals are mapped some integer number of times to create the unfolded interval. Since each original interval has a clutter notch at DC, it follows that the final expanded velocity interval will have several such notches. For example, in the 3:2 case, in addition to removing DC the clutter filter removes velocities at * 2Vu3 , ) 2Vu3 , and Vu . Unfortunately, these clutter filter images are a fundamental consequence of the Dual PRF processing technique and are not easily removed. They can cause trouble not only for the velocity unfolding itself, but because the computed clutter corrections to be wrong at the image 534 RVP8 Users Manual April 2003 Processing Algorithms (draft) points. However, there is a useful work-around in the RVP8 to minimize their impact turning the clutter filter off at far ranges where little clutter is expected and using a narrow clutter filter minimizes the effects of the clutter filter on weather targets. The 4:3 PRF unfolding ratio is more susceptible to unfolding errors in cases where the spectrum width is large and/or the SNR is low. The user should experiment with the two ratios to determine which provides the best results for their particular application. Although the RVP8 trigger generator can produce any trigger frequency, only the 3:2 and 4:3 ratios can be used with the built-in unfolding algorithms. The RVP8 still permits other PRT ratios to be explored, but the unfolding technique must then be manually programmed on the users host computer. Oscilloscope observations of Dual PRF triggers can sometimes be confusing. Figure 56 shows seven possible scope traces (and their associated probabilities) for the RVP8 trigger during Dual PRF operation. The PRF ratio is 4:3, and the sample size is 50 pulses at the high PRF, and 37 pulses at the low PRF. The signal labelled SCOPE is the composite of these traces, and is what would actually be seen on an oscilloscope. Notice that there are a number of low probability pulses. The exact details of the sample sizes and the trigger hold off time can make the low probability pulses appear to come and go randomly. This is normal, and is no cause for alarm. Figure 56: Example of Dual PRF Trigger Waveforms 47.0%

47.3%

1.0%

1.0%

1.0%

1.3%

1.3%

SCOPE 100%

50% 50%

49% 2.3% 48.6% 48% 2.3% 2.3% 94.3% 2.3% 2.3%

535 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7 Optional Dual Polarization- ZDR, PHIDP, KDP, LDR, ... 5.7.1 Overview of Dual Polarization Polarization measurements can provide additional information that can be used to determine more accurate measurements of rainfall or, in some cases, infer particle type such as hail or graupel. The fundamental basis for polarization is that raindrops, particularly larger ones, are not spherical they are oblate (flattened) such that the horizontal axis is longer than the vertical axis. This means that raindrops will respond differently, for example, to vertical and horizontal polarization of the electric field vector. Because of this, and for technical reasons, most polarization radars use horizontal and vertical polarization. For a review of polarization techniques and variables, please refer to Doviak and Zrnic (1993) section 8.5. Fundamentally a polarization radar measures amplitude and phase in the same manner as a conventional radar. The new information is that the amplitude and phase can be measured at more than one polarization. The differences in amplitudes and phases measured at different polarizations contain information on the presence or absence of non-spherical scatterers such as large flattened drops. For convenience, some of the basic polarization variables are described below:

ZDR: Differential Reflectivity In the case of amplitude (power) measurements, the larger horizontal axis of drops causes the power measured at horizontal polarization (of the electric field) to be larger than the pow-

er measured at vertical polarization. The ratio of the reflectivity factors ZH/ZV expressed in dB is given the name ZDR or differential reflectivity. It is generally positive in rain (i.e., >1) and is usually less than about 5 dB. When the rainfall rate is large, there are typically more large drops so that ZDR is larger. Low ZDR and high dBZ indicates the presence of hail which is perhaps tumbling with no preferred orientation. ZDR, because it is a ratio of powers, is not sensitive to the radar calibration as long as the overall gain of the H and V channels is the same (or calibrated). PhiDP and KDP: Differential Phase and Specific Differential Phase In the case of phase measurement, the speed of propagation is also affected by the asymmetry of the larger drops. Because of the longer dimension of the horizontal axis of drops, the me-

dium is effectively more dense for horizontal than for vertical polarization so that the speed of light is reduced for horizontal polarization. This causes the horizontal wavelength to be slightly compressed (more phase cycles per unit distance) in comparison with the vertical wavelength which leads to a phase difference between horizontal and vertical. The phase difference HV is called DP differential phase shift. DP increases with range since the phase shifts faster (more frequency cycles per unit distance) for the compressed horizontal microwaves as compared to the faster vertical microwaves. The range derivative of the dif-

ferential phase, i.e., the change of phase per unit distance, is called KDP or the specific differ-

ential phase. KDP is almost directly proportional to the rainfall rate so that it has the potential for improving precipitation rate measurements as compared to traditional ZR relationship measurements which can be highly inaccurate. 536 RVP8 Users Manual April 2003 Processing Algorithms (draft) LDR: Linear Depolarization Ratio Some advanced polarization radars can transmit at one polarization and receive simulta-

neously in two channels, usually the copolarized and crosspolarized components. For ex-

ample, when transmitting horizontal, both horizontal (copolarized) and vertical (crosspo-

larized) are received by two separate channels. In the case of vertical or horizontal, the ratio of the power Zcross / Zco is called the linear depolarization ratio or LDR. The amount of inci-

dent radiation that is depolarized by a particle depends on the particle shape and orientation

(e.g., canting angle with respect to horizontal). Perfectly spherical particles do not depolarize either horizontal or vertical polarization so that LDR is zero. Particles that are wet, tumbling and irregularly shaped will give larger LDR values. Therefore, LDR values in rain tend to be small, e.g., less than 25dB. Larger values of LDR can occur in the bright band or in the presence of hail. A radar and antenna system must be optimized to measure LDR by assuring that the antenna, feed and supporting struts and radome are not themselves depolarizing the transmitted and received radiation. This is called crosspol isolation. The integrated crosspol isolation of the antenna pattern must be better than about 30 dB for LDR measurement since 20 dB is a large LDR.

[RHOHV, PHIDP] [RHOH, PHIH] [RHOV, PHIV]: Correlation Variables There are several correlation functions that can be calculated depending on the capabilities of the radar. These are generally complex having both an amplitude and phase. These are all normalized so that a perfect correlation magnitude is 1 and perfectly decorrelated is 0. RHOHV and PHIDP are the magnitude and phase of the correlation between the horizontal and vertical co-polarized channels. These are available on H/V switching systems or on sys-

tems that transmit simultaneous H and V. As discussed in a preceding paragraph, PHIDP can be used to infer precipitation rate. RHOHV in rain is typically very close to 1 (0.98). RHOHV values can be reduced in the case of irregularly shaped, randomly oriented, wet tumbling particles. Thus RHOHV has information on the particle type. RHOH and PHIH are the magnitude and phase of the correlation between the co-polarized and cross-polar channels for H transmission and simultaneous H and V reception. RHOV and PHIV denote the crosschannel correlation magnitude and phase for vertical transmis-

sion. These are available on dual-channel receiver with transmit either fixed or alternating. The information content of the cross-pol correlations is the topic of current research. 537 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.2 Radar System Considerations A polarization radar is characterized by how it transmits and how it receives. For simplicity we will assume that the radar uses horizontal and/or vertical polarization. However, other polarization pairs could be used (e.g., right and left circular polarization). Transmit Modes S Fixed (horizontal or vertical)- this can be controlled by a switch or the radar can be simply fixed to transmit a single polarization. If a switch is used, it can be a simple slow waveguide switch rather than a fast switch (pulse-to-pulse). S Alternating (horizontal and vertical)- in this case the radar alternates pulse-to-pulse between horizontal and vertical. A high-power fast switch is used to switch the polarization between the two channels. S Simultaneous (horizontal and vertical)- horizontal and vertical are transmitted simultaneously. Receive Modes S Single-channel receiver- used only for alternating transmission. The receiver typically receives the copolarized radiation (transmit H and receive H then transmit V and receive V). S Dual-channel receiver- receives two channels (H and V) simultaneously. The table below summarizes the various transmit and receive cases and the polarization variables that are available for each. Note that standard parameters are available for all cases (dBT, dBZ, V and W). The RVP8 supports all of these cases. Transmitter Type Receiver Type Fixed H Fixed V Single-Channel Conventional Radar Conventional Radar Dual-Channel LDRH RHOH PHIH LDRV RHOV PHIV Alternating H&V ZDR RHOHV PHIDP and KDP LDRH LDRV RHOH RHOV PHIH PHIV ZDR RHOHV PHIDP and KDP Simultaneous H+V Not applicable ZDR RHOHV PHIDP and KDP

(STAR mode) The fixed single -channel cases are conventional radars rather than polarization radars. The case of simultaneous H+V transmission and a single radar does not make physical sense. The other cases provide various polarization measurements. The fixed dual-channel cases allow the cross-polarization LDR and the co-pol/cross-pol correlation amplitude and phase to be measured 538 RVP8 Users Manual April 2003 Processing Algorithms (draft)

(e.g., RHOH and PHIH). The simultaneous H+V transmission and dual-channel reception is sometimes called the STAR mode (simultaneous transmit and receive). This allows the copol measurements to be made (ZDR, RHOHV, PHIDP and KDP). The alternating transmission dual-channel receiver allows both the copol and the cross-pol measurements to be made, i.e., it is the most complete. Summary of Radar System Characteristics The RVP8 supports all of these modes, but most polarization radar systems do not. As mentioned before, the measurement of cross-pol parameters such as LDR (fixed or alternating transmission and dual-channel reception) requires a radar system that has been optimized for crosspol isolation, e.g., an offset feed antenna and no radome. By removing the feed, support struts and radome from the path of the radiation, the crosspol isolation can be improved. The single-channel alternating method has been used in several polarization radars for ZDR measurement. The advantage of this approach is that it is relatively easy to modify a conventional radar by simply adding a dual port feed and a high-power fast switch above the antenna rotary joints. The disadvantage is that the switch is costly and will eventually fail. For these reasons, the STAR mode has come into recent use. No switch is required and the components are fairly reliable. The disadvantage of the approach (as it is usually implemented) is that a dual rotary joint and dual waveguides are required to duct both the H and the V through the antenna pedestal up to the antenna feed. In spite of this, the STAR mode offers perhaps the best approach for upgrading an existing radar or for factory installation on a new radar of conventional design. 539 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.3 RVP8 Dual-Channel Receiver Approach Dual-Channel Multiplexing for the IFD The RVP8 uses an innovative technique for implementing the dual-channel receiver approach, i.e., dual-channel multiplexing. Just as a single wire can carry multiple telephone conversations, two polarization channels can be put on the same wire at different IF frequencies, digitized by the IF Digitizer and then separated by digital filtering. This means that the exact same hardware that is used for a single-channel digital receiver is used for the dual-channel application. The typical IF separation is 6 MHz and the channel isolation is about 50 dB which is more than adequate for even sensitive LDR measurements. The figure below shows a block diagram of the approach for the magnetron case. Figure 57: Dual Receiver Magnetron Case Horizontal RF RF +30 MHz Vertical RF Horizontal IF @ 30 MHz 30 BPF 24 RF +24 MHz Vertical IF @ 24 MHz Down IF In IFD Horz Burst @ 30 MHz Burst/COHO Uplink Transmit Burst RF RF +30 MHz 30 BPF 24 CLK RF +24 MHz Vert Burst @ 24 MHz DAFC RF +30 MHz RF +24 MHz Dual STALO Reference clock of synthesized STALO (e.g. 10 MHz) Digital AFC Control for Magnetron Systems 24 Magnetron Approach The approach for the magnetron case requires a dual output STALO to obtain the two IFs for horizontal and vertical (H and V). The H and V RF channels are mixed to obtain the H and V IF signals at 30 and 24 MHz in the example. In addition, the transmit sample (also know as the burst pulse is split and mixed with the two IFs so that there is a version at 30 and 24 MHz. This is important for the determination of the transmit phase corresponding to each IF. Both the H and V IF signals are combined and then digitized in the usual way by a standard RVP8 IFD. The same is done with the 24 and 30 MHz versions of the transmit burst sample. The 540 RVP8 Users Manual April 2003 Processing Algorithms (draft) antialiasing filters usually installed on the IFD are removed and replaced by separate filters that are placed ahead of the point where the signals are combined. Note that these filters are centered at the appropriate IF frequency and are typically 6 MHz wide for a 6 MHz IF separation. The two composite signals are then digitized by the IFD identically to the case of a single-channel receiver and later separated during the digital band pass filtering/mixing step to obtain the I and Q of the burst sample and range bin values of I and Q values. Klystron Approach In the case of a Klystron system, the approach is the same, except that the COHO must generate two frequencies which are mixed with the STALO to provide the two reference frequencies. These are used in place of the STALO1 and STALO2 frequencies in the diagram. The same two COHO signals (e.g., at 24 and 30 MHz) are then treated identically to the transmit burst pulse in the magnetron case. In this case there is no burst pulse so the two burst pulse mixers are not required. Reference Clock to IFD In either case, it is critical that the oscillators (both STALOs in the case of a magnetron and the STALO and both COHOs in the case of a Klystron) be phase locked to a common reference clock. This clock, or a derivative frequency of the clock such as a COHO frequency, is input into the IFD to provide an absolute phase reference. Another alternative is two supply the difference frequency between the two IFs as the reference clock. To do this, the outputs of the two STALOs can be mixed by an additional mixer and filtered to obtain (for example) a 6 MHz reference frequency. The RVP8 IFD phase locks its sampling crystal to the reference clock input. Trigger generation by the RVP8 will also be phase locked to the reference clock. The reference clock must be in the range 2 to 60 MHz at 0 to 10 dBm and stable in phase to 107. The RVP8 IFD must be specially configured with a locking crystal to enable this feature. SIGMET will either factory install the modification or assist the customer in performing the modification and supply the necessary components. 541 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.4 Overview of Processing Algorithms Polarization Modes and Outputs Supported by RVP8 The RVP8 supports four polarization modes summarized in the table below. For each case, the standard moments (T, Z, V and W) are calculated as well. The notation for the outputs used here is similar to that in standard usage (e.g., Doviak and Zrnic). However, for LDR we use the notation LDRH to indicate that this is the LDR for horizontal transmission. The notation RHOH and PHIH is used to indicate the magnitude and phase of the covariance between the co- and crosspolarized channels for H transmit. Case Transmit Receive Processing Mode PPP only Dual-Channel Fixed Horizontal or Fixed Vertical Simultaneous H+V

(STAR Mode) Alternating H/V Dual-Channel PPP or ZDR for FFT, Ran-

dom Phase and DPRT1&2 Single-Channel PPP only Alternating H/V Dual-Channel PPP only 1 2 3 4 Polarization Outputs LDRH RHOH PHIH or LDRV RHOV PHIV ZDR PHIDP KDP RHOHV ZDR PHIDP KDP RHOHV LDRH RHOH PHIH LDRV RHOV PHIV ZDR PHIDP KDP RHOHV Input Receiver Sample Notation For the discussion of polarization, we will adopt the notation used by Doviak and Zrnic. The received signal for pulse n from a single range bin shall be denoted as:

s n hh s n vh s n vv s n hv Receive h: Transmit h Receive v: Transmit h Receive v: Transmit v Receive h: Transmit v Horizontal co-polar signal Horizontal crosspolar signal Vertical copolar signal Vertical crosspolar signal The pulse index is now indicated by the superscript as opposed to the subscript. The first subscript indicates the received polarization while the second subscript indicates the transmit polarization. If the transmit is the same as the received polarization, then this is called the copolarized signal. If the transmit and receive are different then this is called the crosspolarized signal. These variables are complex and are the same is the sn notation used earlier, for example we can write:

hh + In s n hh ) jQn hh to show the relationship to the received I and Q values. Either filtered and unfiltered versions of the samples can be selected for processing. However, for convenience we will drop the s notation for filtered samples. 542 RVP8 Users Manual April 2003 Processing Algorithms (draft) Notation and Model for Correlations The pulse pair processing mode is used for all of the polarization calculations, except that ZDR-only processing for the STAR case can be done in either FFT or random phase as well as pulse pair. As with the standard moments, the autocorrelations form the basis for the processing of the polarization variables. The autocorrelations are computed in a manner identical to the standard moments, e.g., in pulse pair mode, the autocorrelations for the horizontal transmit co-polar channel are:

Tohh Rohh

+ 1 M

+ 1 M M M n+1 n+1 R1hh

+ 1 M * 1 R2hh

+ 1 M * 2 sn hh * sn hh hh sn hh * sn M*1 M*2 n+1 n+1 hh * sn)1 sn hh hh * sn)2 sn hh What is different is that for polarization systems, this processing can be applied in up to four separate channels (shh, svh, svv and shv). The physical model for the channel powers is identical to the model used for the standard moment cases, i.e., Co-Channel Power

) Nh o + gr hgt Rhh h Shh v Svv ) Nv o + gr vgt Rvv Cross-Channel Power o + gr vgt Rvh o + gr Rhv

) Nv

) Nh h Svh v Shv hgt Here S is used to denote the actual backscatter average power to the radar which, when multiplied by the appropriate transmitter and receiver gains, yields the actual measured power. Sometimes in comparing powers in two channels (e.g., ZDR and LDR) we will need to know the relative gains of the two channels. However, in many calculations, the relative gains cancel-out and in these cases the algorithms are implemented assuming all the gains are equal to 1. In the algorithm descriptions, we will often use the notation common in the literature that (for example):

Rohh

+ 1 M M n+1 sn hh * sn hh

+ t |s hh|2 u 543 RVP8 Users Manual April 2003 Processing Algorithms (draft) Noise Bias of Channel Power and Optional Correction The average noise powers Nv and Nh are assumed to be receiver noise only. These bias the autocorrelations at lag zero, i.e., the channel power measurements. Autocorrelations at lags 1 and 2 are not biased by noise. Cross channel correlations are also not biased by noise, assuming that the noise in the two channels is independent (a good assumption). The channel noise values are measured directly by the RVP8 during noise sampling. Whether to use these measured values to correct for the noise power when computing a channel power is optionally configured in the TTY setups. The choice is made in the mp TTY setup question Polarization Parameters NoiseCorrected:YES/NO. If enabled, every time that a channel power is calculated, the noise power is subtracted. This has some interesting effects. With no noise correction, ZDR values in weak signal regions will be biased by noise toward 0 dB (equal power), while if noise correction is enabled the values will be unbiased but will show substantial deviation over the region. The choice is up to the user. Clutter Filtering Clutter filtering is available for all four cases. The use of clutter filters should be carefully considered since many polarization parameters such as ZDR and LDR require highly accurate bintobin consistency. The clutter filters will attenuate some small amount of weather near zero velocity and the amount could be slightly different at the two polarizations. When using the clutter filters, users should verify that the functioning is acceptable for their application. The standard moments (T, Z, V, W) are filtered in the usual manner by selecting a clutter filter

(other than Filter #0 which is the All Pass filter). To enable clutter filtering of the polarization variables, the mp TTY setup question Polarization Parameters Filtered should be set to YES. The polarization algorithms will then be calculated with filtered time series. Note that filtering can be effectively disabled for the polarization variables by selecting Filter #0 even if the mp setup is set to enable filtering. This allows users to make easy comparison of the filtered vs unfiltered results using their application software without having to change the RVP8 setup. The s notation for filtered samples shall be dropped in the algorithm discussions. It is understood that the input samples in all cases may be either filtered or unfiltered according to the users choice in the TTY setups. 544 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.5 Case 1: Fixed Transmit: Dual-Channel Receiver Input Receiver Samples In fixed mode the radar is configured (either permanently or by means of a switch) to transmit either vertical or horizontal polarization with dual-channel reception of both the co- and crosschannel polarizations, e.g., transmit horizontal and receive both horizontal (co) and vertical (cross) polarizations. The received samples in the two transmit cases are:

Transmit Horizontal s 1 hh : s1

...sM hh : s M hh : s 2 hh : s 3 s 2 s3 or vh vh vh vh Transmit Vertical s3 s 1 vv : s1 s 2 vv : s 2 hv hv vv : s 3 hv

...sM vv : s M hv Calculation of the Polarization Measurands The processing in this mode is done by pulse pair algorithm. The user may select a clutter filter, but in general this is not recommended for polarization studies since the clutter filter might interfere with the accuracy of sensitive parameters such as LDR. The polarization measurands for the two transmit cases are as follows:

Transmit Horizontal LDRH + 10LOGSvh Shh

+ 10LOGt |s vh|2 u * Nv

* XDR t |s hh|2 u * Nh RHOH + |h|

PHIH + arg[h]

or or or or or Transmit Vertical LDRV + 10LOGShv

+ 10LOGt |s hv|2 u * Nh Svv t |s vv|2 u * Nv

) XDR RHOV + |v|

PHIV + arg[v]

Here, the H and V average channel powers are computed as follows with optional noise correction, i.e., Co-

hShh +t |s hh|2 u * Nh hgt gr hSvh +t |s vh|2 u * Nv vgt gr Cross-

The complex covariance (used above) is:

or or gr vgt gr hgt vSvv +t |s vv|2 u * Nv vShv +t |s hv|2 u * Nh for H transmit h +

hh u t s vhs*

SvhShh or for V transmit v +

vv u t s hvs*

ShvSvv Fortunately, the algorithms do not require us to know all of the individual gain terms. They cancel in the calculation of so are taken as =1 in the implementation. However, the differential receiver gain XDR must be known from calibration to calculate LDR:

dBValueisXDR + 10LOGxdrwherethelinearvalueisxdr +

gr v gr h 545 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.6 Case 2: Simultaneous Dual Transmit and Receive (STAR mode) Input Receiver Samples In this mode there is simultaneous transmit and receive of both vertical and horizontal polarization. For each pulse there is a measurement of the complex amplitude in each channel, i.e., s 1 hh : s1 vv s 2 hh : s 2 vv s3 hh : s 3 vv

...sM hh : s M vv We will assume that M samples are collected for processing, i.e., Note that even though there is crosspolarized radiation received in each channel, this crosspolar contribution can be neglected since the co-polarized received signal is much stronger. Calculation of the Polarization Measurands The processing in this case is done by pulse pair mode. However both FFT and random phase processing can be performed if only ZDR and standard moments are requested for ouput. In any mode, the user may select a clutter filter, but in general this is not recommended for polarization measurements since the clutter filter might interfere with the accuracy of sensitive parameters such as ZDR. The RVP8 calculates the following polarization parameters:

ZDR + 10LOGShh ZDR + 10LOGt |shh|2 u * Nh Svv t |svv|2 u * Nv

) GDR RHOHV + |hv(0)|

PHIDP + arg[hv(0)]

KDP based on least squares fit to PHIDP (see Section 5.7.10). where the following definitions are used:

gr hgt hShh +t |s hh|2 u * Nh gr vgt vSvv +t |s vv|2 u * Nv The noise powers the two channels are denoted as Nh and Nv . The noise corrections to Shh and Svv are optionally configured in the TTY setups. GDR is the total (transmit and receive) differential channel gain. It must be calibrated for the system. dBValueisGDR + 10LOGxdrwherethelinearvalueisgdr +

vgt gr v gr gt h h The correlation function is computed from:

hv(0) +

hh u t s vvs*

ShhSvv The gain terms cancel in the calculation of so in the implementation they are simply assumed to be =1. 546 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.7 Case 3: Alternating H/V Transmit: Single-Channel Receiver Input Receiver Samples This is the traditional ZDR radar with a high-power fast switch that alternates between horizontal and vertical on each pulse. The switch is made just prior to the transmit pulse so that the transmitter radiates and then receives at a single polarization for each pulse. Thus the samples are:

s 1 hh s 2 vv hh . s 3 s M)1 vv For the discussion below we will assume that there are M+1 total samples with M/2 horizontal pulses indexed by (1, 2, 3...M1) and M/2+1 vertical pulses indexed at (2, 4, 6, ...M). Note that the processor does not assume that the first pulse in a sequence is horizontal. Calculation of the Polarization Measurands The processing is done in pulse pair with optional clutter filter. Again, for accurate ZDR measurements, the clutter filter may interfere. The RVP8 calculates the following:

ZDR + 10LOGShh ZDR + 10LOGt |shh|2 u * Nh Svv t |svv|2 u * Nv

) GDR PHIDP + 1 2 argRaR*

b RHOHV + |hv(Ts)|

hv(2Ts)0.25 KDP based on least squares fit to PHIDP (see Section 5.7.10). where the following definitions are used:

|hv(Ts)| + |Ra| ) |Rb|

2 ShhSvv M2*1

(s*

hh[2n * 1]shh[2n ) 1] ) s *

vv[2n]s vv[2n ) 2])

(2Ts) +

n+1 Ra + 1 M2 M2 n+1

(M2 * 1)(Shh ) Svv) s2n*1 hh

* s2n vv and Rb

+ 1 M2 M2 n+1 vv * s2n)1 s2n hh The calculation of the channel powers (t |shh|2 u and t |svv|2 u ) is done using alternating pulses in this case. Note that in the calculation of Rb, the RVP8 uses the extra M+1 sample. The gain terms cancel in the calculation of so in the implementation they are simply assumed to be

=1. 547 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.8 Case 4: Alternating H/V Transmit: Dual-Channel Receiver Input Receiver Samples This is the most comprehensive case of polarization operation since it permits calculation of all of the polarization measurands. In this case the transmitter alternates pulse-to-pulse between horizontal and vertical polarization and the dual-channel receiver provides measurement of both the co- and the cross-polarized return, i.e., s 1 hh : s1 vh s 2 vv : s 2 hv s3 hh : s 3 vh s3 vv : s 3 hv

...s M)1 vv

: sM)1 hv We will assume that M+1 samples are collected for processing (an extra sample is required for the calculation Rb per section 5.7.7). Calculation of the Polarization Measurands The RVP8 calculates the following:

Co-polar channel measurements ZDR, PHIDP, RHOHV Identical to alternating case Section 5.7.7. Cross-polar channel measurements LDRH, LDRV, RHOH, RHOV, PHIH, PHIV Identical to fixed case Section 5.7.9 The co-polar channel measurements are exactly as they are for the alternating single-receiver case. The crosspolar measurements are calculated using fixed case algorithms except they are calculated for BOTH H and V polarizations. 548 RVP8 Users Manual April 2003 5.7.10 KDP Calculation Processing Algorithms (draft) In all modes that compute PHIDP, the signal processor can also be configured to compute KDP-

the specific differential phase in units of degrees per km. This is the range derivative of PHIDP. There are two techniques that have been used to obtain this:

S The smoothed range derivative. S The slope from a least squares fit. The RVP8 uses the least squares approach which is shown schematically in the figure below. Length L DP KDP(one way)= slope/2 Range R The graph shows the thresholded differential phase vs range. This is the starting point for the algorithm. The length scale L is selectable by the user in the TTY setups (mp section, KDP Length in km, default 5.00 km). The KDP value for a bin at range R is computed from a least squares fit that includes points that are within +L/2 as indicated in the figure. PHIDP is output by the processor on the unambiguous interval of 0 to 180 degrees. Before fitting, the points are first unfolded to a common interval by starting at the left-most point and then moving right assuming that a difference of more than 1/2 the unambiguous interval is the result of folding. Since it is the slope that is of interest, the absolute interval is not critical, as long as the points are in a common interval. After fitting, the slope is obtained which corresponds to the 2-way KDP since it is based on the 2-way measurement of PHIDP . To be consistent with most values in the literature, the slope value is divided by 2 so that the final output is the one-way KDP in degrees per km (with a wavelength scaling in the data format). This procedure is repeated for each bin. Thus if the bin spacing is 250 m, the output bin spacing of KDP will be 250 m. It is required that there be at least 50% of the possible number of bins present in the interval L to calculate a valid KDP, else the KDP is set to the threshold value. Since the input PHIDP values are already thresholded, the only additional threshold on KDP is this 50% rule. 549 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.11 Standard Moment Calculations (T, Z, V, W) Overview Standard moments are available for all four of the polarization cases. Since there can be up to four different channels of time series input, there are several choices for computing the standard moments. For example, in the STAR mode (Case 2), the standard moments can be computed from:

S S shh samples svv samples S Average of the results from the shh and svv samples The third case is handled by averaging the individual channel correlations, and then using the average correlations in the standard moment processing. The averaging must take into account the differential gain of the channels. The selection of which method to use is made in setup. There are four questions posed in the mp section:

T/Z/V/W computed from: HXmt:YES VXmt:YES T/Z/V/W computed from: CoRcv:YES CxRcv:NO The first two questions are used to specify that given a choice between vertical and horizontal transmit, which transmit polarization to use. Thus for the fixed H or V case where there is only one transmit polarization, this question does not apply. The processor will simply use samples for the polarization is transmitted. The second two questions are used to specify that given a choice between using the co- or cross-polar receivers which one shall be used. This question applies only to systems that can measure LDR, i.e., fixed or alternating transmit, dual-channel receiver systems). The tables in the sections below summarize the standard moment calculations for each of the four modes and how to configure the four TTY setup responses. Note that these are the only supported modes. Some combinations of responses are unsupported. For example, it is not supported to answer both Co-Rcv: NO and Cx-Rcv: NO. The top of each table identifies the transmitter/receiver case and what samples are available. The notation HH signifies that the shh samples are available. The tables use to indicate that either a YES or NO response will cause the same result, i.e., the RVP does not care what response is made. In cases where averaging is performed, the type of weighting used is indicated

(either GDR or XDR weighting). 550 RVP8 Users Manual April 2003 Processing Algorithms (draft) Model for standard moment autocorrelations The model for the moment autocorrelation calculations is as follows (using Ro as an example):

0 + gr Rhh hgt hShh ) Nh 0 + gr Rvv vgt vSvv ) Nv 0 + gr Rvh vgt hSvh ) Nv 0 + gr Rhv hgt vShv ) Nh where:

Rhh 0 , Rvh 0 , Rvv 0 , Rhv 0 Are the autocorrelations if the samples at lag zero. Shh, Svh, Svv, Shv The average power returned from the scatterers. h, gr gr v h, gt gt v Nh, Nv Receiver gains for horizontal and vertical receive. Transmitter gains for horizontal and vertical transmit. Measured noise power of the samples. In other words, the power that is measured in a channel has two components:

S Backscattered power from the targets that is effected by the transmitter and receiver channel gains. S Receiver noise which is measured by the RVP8 during noise sampling. In the case of R1 and R2 autocorrelations, the model is similar except that there is no noise bias. Calibration Parameters For dBZ calculations, a calibration constant is required, i.e., the dBZo value in Section 5.4. Depending on the polarization case and the technique selected for standard moment calculation, it may also be required to have GDR and XDR, i.e., S GDR- The ratio of the total gains (transmit/receive) of the two coreceive channels. S XDR- The ratio of the receiver gains in a dual receiver system. This is not required for the Case 2: STAR or the Case 3: Alternating SingleChannel. The RVP8 supports a single calibration reflectivity dBZo. In all cases it is assumed that the dBZo is for the horizontal coreceive (HH) channel. The only exception is for fixed vertical polarization, in which the algorithm assumes that the calibration is for the vertical co-receive

(VV) channel. XDR and GDR are also downloaded and used to adjust the dBZo as required depending on the users selection for the standard moments. For example, in STAR mode, if the user selects dBZ to be computed from the VV channel, the dBZo for the HH and a GDR adjustment are used to calculate the dBZ in the VV channel. The remainder of this section discusses the standard moment calculation options for the each polarization case. For a discussion of how to calibrate XDR and GDR see Section 5.7.13. 551 RVP8 Users Manual April 2003 Processing Algorithms (draft) Case 1H: Fixed Horizontal Transmit, Dual Channel Receive (HH, VH) dBZo from HH Channel Calculate T, Z, V, W from:

HH (co) (Recommended) VH (xdr1 weighting) HH+VH (xdr1 weighting) HH Channel (copol) TTY Setup Question Responses HXmt VXmt CoRcv YES NO YES CxRcv NO YES YES This is the recommended channel for the case of linear polarization. The reason is that for linear polarization, the copolar channel will have the strongest signal. Processing is identical to a conventional radar. VH Channel (crosspol) This choice would be used for circular or elliptic transmit polarization. Since the algorithm assumes that dBZo is from the copolar channel, xdr is used to adjust the autocorrelations as follows:

o o T0 + xdr*1Tvh R0 + xdr*1Rvh R1 + xdr*1Rvh R2 + xdr*1Rvh N + xdr*1Nv 1 2 These adjusted autocorrelations are then used as per the standard moment processing for a conventional radar. To illustrate this, consider the example of reflectivity processing. The radar equation can be written as (see section 5.2.5):

Zvh + C Svh r2 +Cr2 r2

+Cr2 gr 0Nv gr vgt h r2 Tvh r2 o o 0Nh gr hgt h h gr v r2 o o Tvh

* Nv Nh

, where Tvh 0

* Nv Nv

+ gr vgt hSvh

* Nv The third term is simply 1/XDR so that we can write:

Zvh +Cr2 0Nh gr hgt h r2 xdr*1Tvh o r2 o

* xdr*1Nv Nh In this case, the first term is the dBZo for the HH channel. Thus we can use the dBZo for the HH channel to calibrate the cross-channel, if we first adjust the crosschannel noise and power by 1/XDR and then normalize by Nh. The reflectivity calculation assumes that the calibrated XDR value compensates for any differences in the radar constant between the two channels, i.e., we do not need to have separate radar constants for the two channels. 552 RVP8 Users Manual April 2003 HH+VH Channels Processing Algorithms (draft) This choice would be used for elliptic transmit polarizations that give comparable return signal in both the co- and cross-channels. The approach is to obtain average autocorrelation functions as follows:

T0 +

R0 +

R1 +

R2 +

N +

o ) xdr*1Tvh Thh o 2 o ) xdr*1Rvh Rhh o 2 Rhh 1

) xdr*1Rvh 1 2 Rhh 2

) xdr*1Rvh 2 2 Nh ) xdr*1Nv 2 These adjusted autocorrelations are then used as per the standard moment processing for calibration with respect to the HH channel. 553 RVP8 Users Manual April 2003 Processing Algorithms (draft) Case 1V: Fixed Vertical Transmit and Dual Channel Receive (VV, HV) dBZo from VV Channel Calculate T, Z, V, W from:

VV (co) HV (xdr weighting) VV+HV (xdr weighting) TTY Setup Question Responses HXmt VXmt CoRcv YES NO YES CxRcv NO YES YES This is the only case for which the calibration constant dBZo for the VV channel should be downloaded to the signal processor. VV Channel (copol) This is the recommended channel for the case of linear polarization. The reason is that for linear polarization, the co-polar channel will have the strongest signal. Processing is identical to a conventional radar. HV Channel (crosspol) This choice would be used for circular or elliptic transmit polarization when most of the return is in the cross-pol channel. Since the algorithm assumes that dBZo is from the co-polar channel, xdr is used to adjust the autocorrelations as follows:

T0 + xdrThv o R0 + xdrRhv o R1 + xdrRhv 1 R2 + xdrRhv 2 N + xdrNh These adjusted autocorrelations are then used as per the standard moment processing with dBZo calibrated with respect to the VV channel. 554 RVP8 Users Manual April 2003 VV+HV Channels Processing Algorithms (draft) This choice would be used for elliptic transmit polarizations that give comparable return signal in both the co- and cross-channels. The approach is to obtain average autocorrelation functions as follows:

T0 +

R0 +

R1 +

R2 +

o ) xdrThv Tvv o 2 o ) xdrRhv Rvv o 2 Rvv 1

) xdrRhv 1 2 Rvv 2

) xdrRhv 2 2 N +

Nv ) xdrNh 2 These adjusted autocorrelations are then used as input to the standard moment processing algorithms with dBZo calibrated with respect to the VV channel. 555 RVP8 Users Manual April 2003 Processing Algorithms (draft) Case 2: Simultaneous Transmit and Receive STAR (HH, VV) Case 3: Alternating Transmit SingleChannel Receive (HH, VV) dBZo from HH Channel Calculate T, Z, V, W from:

HH VV (gdr1 weighting) HH+VV (gdr1 weighting) TTY Setup Question Responses HXmt YES NO YES VXmt NO YES YES CoRcv CxRcv A fundamental difference between these two cases is that for all standard moment processing choices, the STAR case has double the number of samples as compared to the single-channel alternating case. However, the processing is otherwise identical. HH Channel Since the HH channel is directly calibrated this is the recommended choice. Processing is identical to a conventional radar. VV Channel In this case, GDR is used to adjust the autocorrelations as follows:

T0 + gdr*1Tvv o R0 + gdr*1Rvv o R1 + gdr*1Rvv 1 R2 + gdr*1Rvv 2 N + gdr*1Nv These adjusted autocorrelations are then used as input to the standard moment processing algorithms with dBZo calibrated with respect to the HH channel. 556 RVP8 Users Manual April 2003 HH+VV Channels Processing Algorithms (draft) This approach gives the benefit of doubling the number of samples used for the reflectivity calculation. T0 +

R0 +

R1 +

R2 +

N +

o ) gdr*1Tvv Thh o 2 o ) gdr*1Rvv Rhh o 2 Rhh 1

) gdr*1Rvv 1 2 Rhh 2

) gdr*1Rvv 2 2 Nh ) gdr*1Nv 2 These adjusted autocorrelations are then used as input to the standard moment processing algorithms with dBZo calibrated with respect to the HH channel. 557 RVP8 Users Manual April 2003 Processing Algorithms (draft) Case 4: Alternating DualChannel (HH, VH, VV, HV) dBZo from HH Channel Calculate T, Z, V, W from:

HH VH (xdr1 weighting) VV (gdr1 weighting) HV (xdr/gdr weighting) HH+VV (gdr1 weighting) HV+VH (xdr & gdr weighting) HH Channel TTY Setup Question Responses HXmt YES YES NO NO YES YES VXmt NO NO YES YES YES YES CoRcv YES NO YES NO YES NO CxRcv NO YES NO YES NO YES Since the HH channel is directly calibrated this is the recommended choice. Processing is identical to a conventional radar. VH Channel Processing is identical to Case 1H: Horizontal Transmit HV Processing. VV Channel Processing is identical to Cases 2&3:STAR and Single Channel Alternating VV Processing. HV Channel The weighting in this case uses both xdr and GDR. T0 + xdr gdr Thv o R0 + xdr gdr Rhv o R1 + xdr gdr Rhv 1 R2 + xdr gdr Rhv 2 N + xdr gdr Nh These adjusted autocorrelations are then used as input to the standard moment processing algorithms with dBZo calibrated with respect to the HH channel. 558 RVP8 Users Manual April 2003 HH + VV Channels Processing Algorithms (draft) Processing is identical to Cases 2&3: STAR and Single Channel Alternating HH+VV Processing. HV + VH Processing The weighting here has to correct for both transmitter and receiver effects in order to use the HH channel dBZo. T0 +

R0 +

R1 +

R2 +

N +

o ) xdr*1Tvh Thv o xdr gdr 2 o ) xdr*1Rvh Rhv o xdr gdr 2 xdr gdr Rhv 1

) xdr*1Rvh 1 2 xdr gdr Rhv 2

) xdr*1Rvh 2 2 Nh ) xdr*1Nv xdr gdr 2 These adjusted autocorrelations are then used as input to the standard moment processing algorithms with dBZo calibrated with respect to the HH channel. An example of how this weighted averaging works is given here. Suppose that we want to compute the average of the reflectivities for the VH and HV channels, Zhv)vh + Cr2 Shv

) Svh 2

+ Cr2

*Nh Thv 0 gr hgt v

*Nv

) Tvh o gr vgt h 2

+ Cr2 gr hgt h

(Thv 0

* Nh) gt h gt v

* Nv) gr h gr v

) (Tvh o 2 but since xdr + gr v gh v and Zvh)hv + Cr2 gr hgt h vgt gdr + gr v gr hgt h xdr gdr Thv 0

) xdr*1Tvh 0 2 xdr gdr Nh

) xdr*1Nv 2

* N + Cr2 r2 r2 o T0

* N Nh oNh gr hgt h Zvh)hv + Cr2 gr hgt h T0 The first term in brackets is precisely dBZo for the HH channel. Thus if we average the correlations using the appropriate GDR and xdr weighting as shown above, then the average reflectivity is obtained by using conventional processing with the HH channel dBZo. 559 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.12 Thresholding of Polarization Parameters The thresholding of polarization parameters by the processor eliminates bins with weak or uncertain signals. Note that the thresholding can be disabled if it is desired to see all of the data regardless of the data quality. All of the polarization parameters are based on power ratios. The RVP8 requires that each power term in a ratio pass a signal-to-noise test similar to the log power test. For example, there are up to four different powers that can be calculated (alternating dual-channel case) so the tests for each of these are:

t |shh|2 u u Nthresh Nh t |shv|2 u Nh u Nthresh t |svv|2 u Nv u Nthresh t |svh|2 u Nh u Nthresh where the linearized threshold that is input as the dB LOG threshold, i.e., Nthresh + 10LOGthresh10 For example, a valid LDRH requires both a valid Shh and a valid Svh. The parameters RHOH and PHIH have the same requirement since they are the magnitude and phase of the cross-correlation function which is based on Shh and Svh. There are two exceptions:

ZDR ZDR requires that both Shh and Svv pass the signal-to-noise tests noted above. However, ZDR can be additionally thresholded by any of the other threshold parameters (LOG, SIG, SQI, CSR) similar to a standard moment. See section 5.3 for a description of the standard moment thresholding. PHIDP for single channel alternating case PHIDP requires that both Shh and Svv pass the signal-to-noise tests noted above. In the single channel alternating case, PHIDP must also satisfy the additional test that the Doppler veloc-

ity at the range bin must be valid, i.e., not thresholded by its own criteria. This is because the algorithm for PHIDP in this case essentially subtracts the phase change due to the Dop-

pler velocity. If the Doppler velocity is uncertain, the algorithm cannot produce reliable re-

sults. 560 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.7.13 Calibration Considerations Polarization systems require additional calibration as compared to conventional systems. There are three aspects to the calibration:

S dBZo measurement in both channels for dBZ and dBT calibration. S GDR measurement for ZDR calibration. S xdr measurement for LDR calibration. These are discussed below. dBZo Calibration for dBZ The RVP8 supports separate calibration of both polarization channels. Measurement of dBZo for each channel of a dual polarization system is identical to the conventional radar case described in Section 5.4. Note that for a single-channel switching system, the only difference between the horizontal and vertical signal paths occurs after the high power switch, i.e., differential insertion loss of the switch itself and any differential insertion loss of the waveguides and feed after the switch. This means that for single-channel switching systems it may be sufficient to calibrate at one polarization and then adjust the calibration of the other channel by the differential gain GDR

(see below). GDR Calibration for ZDR GDR is the relative between the co-polarized channels including both transmitter and receiver gain, i.e., GDR + 10LOG gr vgt v gr gt h h and gdr +

gr vgt v gr gt h h GDR is input into the processor as a dB value. However, for analyses in this chapter, the linear gdr value is sometimes more convenient. In principle, if dBZo could be calibrated perfectly in both channels, measurement of GDR would not be required. In practice, this is not possible because dBZo cannot be calibrated to an absolute accuracy sufficient for ZDR, i.e., to 1/16th of a dB. Therefore, the RVP8 uses the GDR approach. Since GDR includes both transmitter and receiver differential gains, accurate calibration requires that an actual target be observed. One way to do this is as follows:

S Set the GDR to be 0 dB using your application software (e.g., for SIGMET IRIS systems in the setup utility RVP section). Disable clutter filtering for ZDR in either your application software (by selecting filter 0) or explicitly in the RVP8 TTY setups mp section. S Place the antenna at 90 degrees elevation (vertical incidence) during moderate to heavy rain. The melting layer should be at a height that is well above the recovery zone of the T/R and in the antenna far zone. A melting layer higher than 2 km is suggested, but the specific characteristics of the radar should be considered. 561 RVP8 Users Manual April 2003 Processing Algorithms (draft) S Collect ZDR data at vertical incidence while the antenna is rotating in azimuth. S Use a separate application program to average the ZDR values around a full 360 degrees at each range bin (height). Generate a plot of 360-average ZDR vs height. S You should observe that the average ZDR values in regions of strong signal (>20 dB SNR) below the bright band are approximately constant with height. This is the value that should be used in your application software for GDR. S Enter the value and repeat the calibration to verify that the average ZDR is now 0 dB. The rationale for this approach is as follows. When viewed at vertical incidence, rain should have a ZDR of 0 dB since the drops will all appear circular. The reason for averaging over 360 degrees is to cancel-out effects from sidelobe contamination from nearby ground targets and other artifacts of the antenna/feed/radome system. For example the radome may have an obstruction light on the top. Some of these artifacts can be minimized by assuring the the weather targets are strong, i.e., heavy rain is preferred for this calibration. XDR Calibration for LDR XDR is the relative gain in dB between the co- and cross-receiver channels for LDR measurements. Analogous to GDR, it is defined as the dB value of the ratio of the vertical to horizontal receiver gains, i.e., gr v gr h XDR + 10LOG xdr +

and gr v gr h S Three techniques for calibration of XDR are discussed. It is recommended for the transmitter to be off for all of these methods. 1. Solar method Use the sun to measure LDR. The measured value of LDR is then the XDR offset. LDR should be measured in fixed mode for both LDRH and LDRV. The values should be reciprocal (e.g., +1 dB and 1 dB). Use the average of the absolute value if they are not precisely reciprocal (e.g., for +1.4 and 1.2 use 1.3). Finally after inputting the XDR value, retest to verify that the sun has been properly corrected to have zero LDR. 2. Signal generator method with connection to waveguide Connect a signal generator with a splitter to both channels and measure XDR directly. This does not account for any effects that are before the coupler (e.g., waveguide, feed, radome, antenna gain). 3. Linear feed horn remote radiator method Use a calibrated linear feed horn with an RF source located several hundred meters from the radar. Maximize the H channel return and measure the response using the RVP8 pr command Filtered power in the Primary Channel. Now rotate the feed horn to vertical and maximize the power in the Secondary Channel. The difference in dB is XDR. Note that signal multipath effects could bias the results from this technique. S S 562 RVP8 Users Manual April 2003 Processing Algorithms (draft) In all cases it is recommended that for the calibration, XDR be set to 0 dB in the application user software and that the RVP8 TTY setups be configured as follows:

S Noise correction enabled for LDR and noise sample taken prior to the measurements (with care not to sample with a test signal turnedon or while looking at the sun). S Clutter correction disabled for LDR. 563 RVP8 Users Manual April 2003 5.8 FFT Mode 5.8.1 Overview Processing Algorithms (draft) The RVP8 can perform FFT processing of the I and Q time series. This is indicated by the inset box in Figure 51. The major difference between FFT and pulse pair processing is the way in which clutter filtering is performed. The pulse pair mode uses a time domain IIR filter while the FFT mode uses a frequency domain filter. The advantage of the FFT approach is that it is less destructive to overlapped weather (near zero velocity) than the IIR filter since the clutter filter algorithm attempts to interpolate over the weather (see Figure 58). This results in more accurate estimates of velocity, width and clutter correction. Because the clutter correction is more accurate, the resulting reflectivity estimates are more accurate. Figure 58: Comparison of Pulse Pair and FFT Clutter Filters Unfiltered Doppler Spectrum Pulse Pair Mode Spectrum after IIR filter r e w o P

-Vu FFT Mode Spectrum after frequency domain filtering with interpolation

+Vu 0 Velocity 564 RVP8 Users Manual April 2003 5.8.2 FFT Implementation Processing Algorithms (draft) Figure 59 shows a data flow diagram for the FFT processing. In the example, 50 pulses of I and Q are processed. Recall that the I and Q samples refer to a single range bin with an I and Q sample generated for each pulse. Sampling Division The first step of processing is to split the I and Q values into two groups. The FFT algorithm requires the number of samples to be a power of two. This is not very convenient for radar sampling since it effectively quantizes the scan rates to be powers of two. The processing by the RVP8 allows an arbitrary number of pulses to be handled by splitting the samples into two groups the first 2N and last 2N pulses. An FFT is performed on each group and then the results are averaged. This allows an arbitrary number of samples to be processed. The maximum number of samples is 255 which corresponds to performing FFTs on two groups of 128 pulses with 1 sample of overlap. If the requested number of pulses is exactly a power of 2, then the samples are not split and only a single FFT is done. Window and FFT After splitting the samples, a weighting function, or window, is applied. The FFT algorithm is then applied and the magnitude squared of each component is calculated to yield the Doppler power spectrum. Figure 510 shows the response of the Doppler power spectrum to a ground clutter target for each of the three available FFT windows. The schematic Doppler spectra in the example do not show the details of the side lobe structure of the impulse response (see Oppenheim and Schafer, 1975 p. 243245). S Rectangular Window This is really the no-window case since it is equivalent to multiplying each sample by 1. This window has a sinx/x type impulse response, i.e., the impulse response is very narrow which is good, but the side lobes of the Doppler spectrum are rather high ~20 dB near the peak. Thus it is not the best choice for high performance clutter cancelation since the high sidelobes will mask weak weather targets. S Hamming Window This common window is well matched to magnetron systems. The peak of the impulse response is broader than that for the rectangular window, but it has 40 dB peak-to-noise sidelobes. Weak weather targets above this level will not be obscured by these sidelobes. The phase noise of a magnetron system (~1 degree) will typically be slightly larger than the sidelobes caused by the window which means that the window is well matched to the magnetron performance. 565 RVP8 Users Manual April 2003 Processing Algorithms (draft) Figure 59: FFT Processing 50 pulse example Example of 50 pulse input time series where An = In + j Qn A1 A2 A3 A4 A5

. A45 A46 A47 A48 A49 A50 1st. 32 samples Last 32 samples Window and FFT Window and FFT point 32 FFT point 32 FFT Average 32point Spectrum Clutter Cancelation Inverse Transform R0 R1 R2 T0 Standard Processing 566 RVP8 Users Manual April 2003 Processing Algorithms (draft) Figure 510: Effect of Windowing on FFT Response to Ground Clutter r e w o P B d r e w o P B d r e w o P B d 0

-20

-40

-60

-80 0

-20

-40

-60

-80 0

-20

-40

-60

-80 Rectangular Window Hamming Window Blackman Window

-Vu 0 Velocity

+Vu S Blackman Window This is the most aggressive window for clutter cancelation and is appropriate only for Klystron systems that can achieve very low phase noise (~0.1 degree). The peak is the broadest of all the windows, but the side lobes are the lowest. It is not recommended for magnetron systems except for performance testing. 567 RVP8 Users Manual April 2003 FFT Averaging Processing Algorithms (draft) The power spectrum from the first group of samples is averaged with the power spectrum from the last group of samples. Note that if the total number of samples is exactly a power of two, then this step is skipped. Averaging the two power spectra from the overlapping sample groups effectively captures the information from all of the samples. The result is a smoother power spectrum than weather of the individual spectra. Clutter Cancellation The clutter cancelation is done by an interpolation technique shown in Figure 511. In general, the technique discards a selectable number of center points. The algorithm then takes the minimum value of a selectable number of edge points next to the discarded points. The minimum value on each side is used to interpolate across the points that were removed. Figure 511: Example of FFT Clutter Filter in Frequency Domain 0

-20

-40

-60 0

-20

-40

-60 0

-20

-40

-60 r e w o P B d r e w o P B d r e w o P B d

-Vu Spectrum with ground clutter Remove 5 interior points Find minimum of 2 edge points Interpolate across 5 center points

+Vu 0 Velocity 568 RVP8 Users Manual April 2003 Processing Algorithms (draft) This procedure preserves the noise level and/or overlapped weather targets. The result is that more accurate estimates of dBZ are obtained. In extreme cases when the weather spectrum is very narrow, there can still be some attenuation of weather of a broad filter is selected. Inverse Transform After clutter removal, an inverse DFT (Discrete Fourier Transform) is performed to obtain the autocorrelations R0, R1 and R2 (optional). The total power T0 in the unfiltered power spectrum is also computed by summing the spectrum components. Thus the final output of the FFT approach is identical to the pulse pair approach except that the clutter filtering is performed in the frequency domain. 569 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.9 Random Phase 2nd Trip Processing 5.9.1 Overview Second trip echoes can be a serious problem for applications when the radar is operated at high PRF (e.g., >500 Hz). Second trip echoes are caused by the range aliasing of targets. They appear as false echoes on the display, usually elongated in the radial direction. On Klystron systems they will have valid Doppler velocities. On magnetron systems, the Doppler velocities are not valid, but the noise from the 2nd trip echoes can obscure valid first trip velocity information. The RVP8 has optional random phase processing for the filtering and recovery of second trip echoes. Details of the technique are proprietary to SIGMET, Inc. However, the general principle is described here, along with a discussion of the various configuration options to optimize the algorithm performance. The information that is used to separate the first and second trip echoes is the phase. For a magnetron radar, the phase of each pulse is different. This means that when 1st. and 2nd trip echoes are received simultaneously, the phase of the first trip return is different from the phase of the second trip return. For a magnetron radar, the RVP8 measures the phase of the transmitted pulse and the phase locking is done digitally as opposed to the traditionally locking COHO. For a Klystron radar, the phase is controlled by the RVP8 via a digital phase shifter that is precisely calibrated. Typically the Klystron COHO is phase shifted so that each transmit pulse has a different phase. The sequencing is controlled by the RVP8. 5.9.2 Algorithm Figure 512 shows a schematic of the data processing for random phase. The figure shows the Doppler spectra for the 1st. and 2nd trip in the various processing stages. The vertical scale is in dB and the horizontal scale is velocity. In this example, the second trip echo is shown as being stronger than the first trip echo (usually the reverse is true). Ideal 1st and 2nd Trip Echoes The ideal 1st and 2nd trip echoes represent the echoes as they would appear individually. The ideal 1st trip echo is the echo that would be measured if there were no 2nd trip echo interference. The ideal 2nd trip echo represents what would be measured if there were no 1st trip echo interference. If there is no interference from the other trip, a standard Klystron system can measure the ideal spectra, but there is no way to know whether the echoes are in the 1st or 2nd trip. Raw 1st and 2nd Trip Echoes This figure shows how the echoes from the first trip and second trip interfere with each other. For the case of a standard magnetron system, the first trip echo is coherent, while the second trip echo is incoherent (white noise) since the phase of the second trip echo is random. This is because the receiver is phase locked only to the first trip. 570 RVP8 Users Manual April 2003 Processing Algorithms (draft) Another way to implement a magnetron system is to let the COHO free-run (rather than phase locking to the transmit pulse), measure the phase of each transmit pulse and digitally correcting for the transmit phase. Using this digital phase locking technique, the RVP8 can phase lock or cohere to either the first or the second trip. Using this technique alone, it is possible to distinguish between 1st and 2nd trip echoes for the case when the echoes are not overlapped. In other words, the echoes will appear as the idealized 1st and 2nd trip echoes. This range de-aliasing effectively doubles the range of the radar. The problem is that when echoes are overlapped, the noise contamination from the stronger echo will make it impossible to measure the weaker echo. This is illustrated in the figure. Thus if the first trip echo has a good signal-to-noise ratio of 10 dB, then the 2nd trip echo will have a signal-to noise-ratio no better than 10 dB. This is the fundamental problem with using phase alone to separate the 1st and 2nd trip echoes. Filtered 1st and 2nd Trip Echoes Since the strong echo generates noise that obscures the weaker echo, the approach used in the RVP8 is to filter the echo from the other trip the whitening filter. This is shown in the figure. The adaptive whitening filter removes both the clutter and the weather. All of the phase information for the other trip is then contained in the white noise portion of the spectrum. Note that the phase information under the coherent echo that is removed will be dominated by the coherent echo, i.e., the other trip phase information will be contaminated. For this reason, the filtering should effect as small a region of the spectrum as possible. 5.9.3 Tuning for Optimal Performance The Random Phase algorithms are controlled by the same collection of setup and operational parameters that apply to all of the other processing modes, e.g., choice of sample size, clutter filter, angle sync, calibration, etc. However, a few parameters are special to Random Phase mode, and these are described below. Secondary SQI Threshold In standard Doppler processing, an SQI threshold is normally not applied to Reflectivity data because it would cause those data to be rejected in regions of high spectral width. In Random Phase mode we need to relax this convention because reflected power can only be assigned to a particular trip when it is coherent within that trip. Incoherent echoes, regardless of their strength, can not be placed into either trip. Thus, an SQI threshold is required to qualify Reflectivity data in Random Phase mode. The RVP8 defines a secondary SQI threshold SQI2 which is computed from the standard threshold value simply as:

SQI2

+ Offset ) (Slope SQI) Where Slope and Offset are the Random Phase SQI threshold parameters defined in the Mf setup section. The factory default values are (Slope + 0.50) and (Offset + * 0.05) , i.e., the secondary threshold is a little less than half of the standard value. The Random Phase 571 RVP8 Users Manual April 2003 Processing Algorithms (draft) algorithms check whether the SQI of each recovered trip is less than the secondary SQI threshold, and if so, the LOG portion of the data are rejected. This SQI test is necessary for a clean LOG picture, but we need to use a more permissive (lower) threshold value than would usually be applied to the Doppler data alone. The Slope and Offset values should be adjusted so that the density of speckles in Random Phase LOG data is approximately the same as the density of speckles in FFT velocity data for a given primary SQI value. You may then adjust the primary SQI threshold to achieve the appropriate tradeoff of speckles vs. sensitivity for your system in all modes of operation. Even with proper adjustment, it is normal for Random Phase dBZ and dBT data to show holes in regions of weather that have high turbulence or shear. These dropouts will usually match up with similar gaps in the velocity and width data, both of which are traditionally thresholded by SQI. Maximum Power Ratio Between Trips The adaptive filtering that is performed on the data for each trip greatly extends the visibility of a weak echo that is overlapped with a much stronger one. In practice, the filtering process is often able to remove 25-35dB of dominant power in order to reveal a much weaker echo in the other trip. The performance depends on many factors, primarily the spectral width of the dominant echo, and the overall stability of the radar system. The difficulties of removing a dominant other trip echo from a weather signal are analogous to the challenge of removing a dominant clutter target from that same signal. In both cases we are trying to extract a weak weather signature using a filtering procedure that relies on the spectral confinement of the stronger signal. The RVP8 already has a parameter that can be adjusted to control sub-clutter visibility, i.e., the Clutter-to-Signal Ratio (CSR). Just as the CSR applies to the clutter filters, it can likewise be used to place similar limits on the depth of visibility of the adaptive filters. As an example, suppose that the RVP8 is operating in Random Phase mode at a PRF of 1500Hz, and is observing widespread weather having uniform intensity in both the first 100Km trip and the second 100Km trip. If the CSR were set too conservatively at only 15dB, then the algorithm would generally be blind to second-trip weather in the range interval from 100km to 117.8km. The explanation for this can be found in the 1r2 geometric correction for weather echo intensity. At ranges less than 17.8km, the first trip weather would generally dominate the second trip weather by more than 15dB. Thus, the initial 17.8km ring of second trip data would be rejected by the CSR criteria. However, if the CSR were increased to 30dB, then the size of this missing ring would be reduced to only 3.2km. If the CSR is set too low you will notice an abrupt ring of missing data in the beginning of the second trip. If set too high, there will be speckles and other spurious effects within this same interval. The optimum setting should strike a balance between these two effects. R1 vs. R2 Algorithms The Random Phase algorithms for adaptive filtering and separation of trips relies on having the best possible information about the weathers SNR and spectral width. Thus, the R2 Doppler algorithms are always used, regardless of the setting of the R1/R2 flag in the users operational parameters. 572 RVP8 Users Manual April 2003 Processing Algorithms (draft) Random Phase and Dual PRF The random phase processing works seamlessly with the dual PRF processing to provide advanced range and velocity ambiguity resolution. Both the first and 2nd trip echoes can be recovered and displayed to a maximum range of 2X the unambiguous range corresponding to the high PRF. For optimum performance, the 2D 3x3 speckle filter should be used to smooth the 2nd trip seams that occur for each ray. In fact, this smoothing of the 2nd trip seam makes the dual PRF random phase mode work even better than the single PRF random phase. 573 RVP8 Users Manual April 2003 Processing Algorithms (draft) Figure 512: Random Phase Processing Algorithm Ideal 1st Trip Ideal 2nd Trip Raw 1st Trip with 2nd Trip Noise Contamination Raw 2nd Trip with 1st Trip Noise Contamination Filtered 1st Trip Filtered 2nd Trip Inverse Transfrom and ReCohere Recovered 1st Trip Recovered 2nd Trip 574 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.10 Signal Generator Testing of the Algorithms This section describes a variety of IF signal generator tests that can be used to verify correctness of the RVP8 processing algorithms. These tests are routinely performed at SIGMET whenever new algorithms and/or major modes are added to the processor. We have include a few of the test descriptions here so that they can be used by customers who need to debug their systems, or who want to better understand how they work. Additional tests for receiver sensitivity and dynamic range can be found in Appendix E. 5.10.1 Linear Ramp of Velocity with Range Suppose that a continuous-wave IF waveform has an instantaneous frequency f (t) in Hertz

(cycles/sec). Consider a range bin located at time tbin within a set of pulses that are separated by ts + 1PRF. The phase measured at that bin on the nth pulse will be the integral of the frequency within that pulse starting from range zero (since the RVP8 is phase locked to range zero):

Fn + nts)tbin f (t)dt nts If we assume that the input frequency is a linear Frequency Modulation (FM) at the rate of M cycles/sec/sec on top of a base frequency To, then:

F n)1

* Fn +

(n)1)ts)tbin

(To ) Mt)dt * nts)tbin

(To ) Mt)dt + ( M ts ) t bin

(n)1)ts nts which, remarkably, is independent of both To and n. Thus, a linear FM input signal produces a fixed (I,Q) phase difference from pulse-to-pulse at any given range. The magnitude of the phase difference is proportional to the range, and the slope is (Mts) cycles for each second of delay in range. For example, if the test signal generator is sweeping 100KHz every two seconds, then the velocity observed at a range of 300km at 250Hz PRF will be:

* Fn + 100 KHz 2 sec 1 250 F n)1 sec ( 300 km ) 6.6 m sec

+ 0.40 cycles 1 km We would thus observe a velocity of (0.8 Vu) at 300km, where Vu is the unambiguous Doppler velocity in meters/sec. Note that these phase difference calculations have made no assumptions about the RVP8 processing mode, and thus are valid in all major modes (PPP, FFT, DPRT, RPH), as well as in all Dual-PRF unfolding modes. Interestingly, this simple FM signal generator will also produce valid second trip velocities that can be seen during Random Phase processing. This follows from the above analysis because weve never assumed that tbin was smaller than ts, i.e., it is fine for the range bin to be located in any higher-order trip. 575 RVP8 Users Manual April 2003 Processing Algorithms (draft) 5.10.2 Verifying PHIDP and KDP The PHIDP and KDP processing algorithms can be tested using CW signal sources at IF. In the alternating-transmitter single-receiver case, a single FM signal generator is modulated with an RVP8 polarization select line so that slightly different frequencies are generated for the H and V pulses. A maximum FM depth of several kilohertz is all that is required. In the dual-receiver case, two (unmodulated) signal generators are used for each of the H and V intermediate frequencies, and one or the other is detuned slightly from its correct center frequency. In either case the frequency difference that produces a KDP value of 1.0 degree/km will be:

cycles second

) ( 1 360

) ( 299792

) + 833 cycles degree second degree

( 1.0 km km 5.10.3 Verifying RHOH, RHOV, and RHOHV These three terms measure the normalized cross-channel covariance in a polarization radar. They all are computed in essentially the same way having the form:

RHOAB +

t sn t s2 A B *u A sn ut s2 B u A and s n Where the s n B are complex (I,Q) vectors from two receiver channels A and B, and <>

denotes expected value. This suggests that some form of amplitude modulation (AM) of the input signal might be helpful. Suppose that the s n dual-receiver system, and that only the B-Channel is AM modulated so that:

B | + { SB, 0 , SB, 0 , SB B samples are coming from two signal generators installed on a A | + { SA, SA, SA, SA, Sa AAA } , A and s n AAA }

| sn

| sn Then the above estimator reduces to:

RHOAB + ( 1 2 ) SA SB

( 1 S2 A 2 ) S2 B

+ + 0.707 A simple way to create these data is to set the A-Channel siggen for 95% AM depth, and use a sinusoidal modulation source of, perhaps, 400Hz. The reason for not choosing 100% depth is that we would loose the Burst phase reference when the amplitude became smallest. The 26dB reduction in SB is a close enough approximation to zero in the above formula. If we now observe the two receive channels with the RVP8 at a PRF of 800Hz, we will see the various RHOAB terms varying with range; reaching a high value of 1.00, and a low value of 0.707. The plots will be nearly stationary on the ascope screen because the PRF is almost precisely twice the modulation rate (though they are free-running relative to each other). Adjusting the amplitude of either signal generator will not affect the terms, but it will have an interesting effect on SQI. If (T,Z,V,W) are being computed from both channels combined, then the SQI is:

SQI +

S2 A

) ( 1 2 ) S2 B S2 A 576 RVP8 Users Manual April 2003 Processing Algorithms (draft) If we solve this equation for SQI=0.5 we find that the individual SA terms must have twice the power of the individual SB terms. This can be checked by adjusting either signal generator until the minimum plotted SQI is 0.5, and then verifying that the average H and V powers are identical; or, equivalently, that ZDR, LDRH and LDRV are zero. The linear FM ramp described in Section 5.10.1 can also be used as a test of RHOAB in a dual-receiver system. With one siggen modulated and the other fixed, one receive channel will appear to be rotating relative to the other. If the FM modulation is such that 1/N of a full revolution occurs per pulse at a given range, then if the sample size is N pulses we will observe RHOAB + 0 at that range. In fact, the plot of RHOAB will show a characteristic sin(x)x behavior as a function of range. 577 RVP8 Users Manual May 2003 Host Computer Commands 6. Host Computer Commands This chapter describes the digital commands that the host computer must use to set up and control the RVP8 processor for recording data. Each command is described in detailed in a separate section of this chapter. Note that a command mnemonic, or shorthand reference name, is given in each section heading. These names are frequently used to refer to particular commands. The writeup for each command includes a description of what the command does and a pictorial layout of the bits in the 16-bit command word. Commands consist of an initial command word containing an opcode in the low five bits. If additional arguments are required, they are listed as Input 1, Input 2, etc. Finally, if the command produces output, those words are listed as Output 1, Output 2, etc. Often each word is broken down into several independent fields, each consisting of one or more bits. In such cases, the pictorial layouts show the placement of the bit fields within the word, and each field is described individually. All data transferred to or from the RVP8 are in the form of 16-bit words. Before attempting to program the RVP8, it is a good idea to at least skim through the descriptions of every command. The instruction set has been designed to be as concise and orthogonal as possible. User programs should always execute the IOTEST command on power-up to ensure that the interface connections are all intact. The diagnostic result registers from GPARM should also be checked initially to verify that the RVP8 passed all internal checks. Since all internal RVP8 tables and parameters are set to reasonable values on power-up, it is conceivable that PROC commands could be issued immediately to acquire and process radar data. More realistically, however, the default information is first modified to meet the users needs. To set up for data acquisition and processing the following sequence of commands might be executed. Trigger and pulse width are first established using the SETPWF commands. Range bin placement and processor options are then chosen using LRMSK, and SOPRM, and receiver noise samples are taken with SNOISE. The noise levels are not automatically sampled on power-up, so SNOISE must be issued at least once by the user. LFILT is executed if clutter filters are needed. If data rays are to be synchronized with antenna motion, then LSYNC is used to specify a table of antenna angles. After all setups are complete, PROC commands are issued to actually collect, process, and output the data. Errors detected during the execution of commands are noted by the RVP8 and can be monitored using GPARM. The RVP8 contains a 4096-word first-in-first-out (FIFO) buffer through which all output data flow. This buffer is included to simplify the requirements of the users interface hardware. The FIFO holds each sequential word generated by the RVP8 until such time as the user is ready to accept it. Thus, when reading from the processor, it is permissible to fall behind by as many as 4096 words before any slowdown in performance occurs. The RVP8 writes to the FIFO at full speed as long as it is not full, and the internal processing is not affected by the exact speed at which user I/O actually occurs. This continues as long as the average I/O rate on, perhaps 10ms intervals, matches the average rate at which data are being produced. 61 RVP8 Users Manual May 2003 Host Computer Commands The sequence of events described above is altered when the FIFO becomes completely full. Then, when the processor generates the next output word, it waits in an idle loop until the user makes room in the FIFO by reading out one or more words. Until this space becomes available, the RVP8 simply waits and does not proceed any further with its internal processing. This, of course, leads to a slowdown in performance, but it is not a disastrous one. The user always obtains correct data no matter how long it takes to read it. One could take advantage of this fact to synchronize the acquisition of data by the RVP8 with the post-processing and display of that data by the user. In this case, RVP8 would be instructed to output data at the maximum rate, the user would read these words at the users maximum rate, and the overall system would automatically run at the slower of those two speeds. When the output FIFO is full and the RVP8 has the next word ready for output, there is another way that the idle wait loop can be exited, that is, if the processor detects that the user is performing a write I/O cycle. Since the user should have been reading data by now, the presence of a write cycle is taken to mean that some more important condition has arisen. As such, the wait loop is terminated and the RVP8 accepts the write data soon afterward. If the new data are commands, they are executed right away, but any output they try to produce may be lost in a similar manner. The net effect is that the processor continues to execute all commands correctly, but that their output is discarded. The discarded output data are not in fact lost. Rather, the data are eventually replaced with an equal number of zeros. Each time the RVP8 discards an output word, it also increments an internal 24-bit count. When FIFO space becomes available in the future, the processor replaces all of the missing data with zero-valued placeholders. Writing when the FIFO is full can be particularly useful if the new command is a RESET which calls for clearing of the output FIFO. When the RESET is processed, all past and present output data are discarded, leaving the RVP8 output section completely empty. This is useful whenever the processor has pending output data which the user wants to truly throw away. 6.1 No-Operation (NOP) This single-word instruction is simply ignored by the the Signal Processor. The NOP is useful when a number of words are to be flushed through the RVP8 with no side effects. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 0 0 0 | Command

6.2 Load Range Mask (LRMSK) This command informs the signal processor of the ranges at which data are to be collected. An arbitrary set of range bins are selected via an 8192-bit mask. The Nth bit in the mask determines whether data are acquired and processed at a range equal to RES x (N-1). The Range resolution is specified by a TTY setup question (see section 3.3.5), in the range 50 through 133 meters. Any collection of ranges may be chosen from integer multiples of that distance. The example below is given for the default resolution of 125 meters. The range mask is passed to the RVP8 62 RVP8 Users Manual May 2003 Host Computer Commands packed into 512 16-bit words. The least significant bit of each packed word represents the nearest range, and the most significant bit represents the furthest range in each group of 16. Because of memory constraints, the RVP8 uses only the first 5600 bits in the mask. According to the range bins that are selected in the mask, the signal processor computes and stores internally a range normalization table which is later used to convert receiver intensity levels into reflectivity levels in dBZ. Note that the LRMSK command implicitly specifies the number of bins to be processed and output. The maximum bin count is 2048, though depending on the computational intensity of the configuration, the RVP8 may be able to compute fewer bins. If the number of bins selected in the bit mask exceeds this maximum, the trailing bins are truncated. If the new mask does not specify any active bins, then a single bin at range zero is forced on. The default power-up mask selects 256 bins equally spaced by 1.0km starting from zero range. Range averaging is also determined by LRMSK. The upper byte of the command controls how many consecutive bins are grouped together. A value of zero means no averaging; one means that pairs of samples are averaged; 255 means that 256 terms are summed, etc. The individual samples that go into each average are still taken according to the bits that are set in the mask, except that they are now grouped together so that only one net bin results from the several data samples. Note that the limitation of 2048 sampled ranges applies to the bin count prior to averaging. For example, suppose 100 bits are selected in the range mask and no averaging is elected. Then parameters are computed at those 100 ranges, and 100 bins of data are output. If the averaging were set to one, rather than zero, samples would still be taken at the same ranges, but pairs of bins would be averaged together and only 50 ranges would result. Note that the parameters are averaged by summing the autocorrelations for each bin. The range normalization value associated with the averaged bin is computed according to the midpoint of the first and last sample. Incompletely averaged bins are discarded by the LRMSK command. In the above example, if the averaging were set to two so that triples of samples were summed, then only 33 bins would be output. This is because the 100-bit mask left a dangling 100th sample. In the extreme case where there are not enough mask bits to result in even one complete bin, the RVP8 forces the averaging to zero and turns on a single bin at zero range. When the RVP8 is operating in fast-switching dual-polarization mode (See SOPPRM Command, word #2), the maximum number of bins that can be processed is half the usual maximum. This is because duplicate internal memory is needed to hold the states of the clutter filters separately for each polarization. If polarization switching is on and a range mask is loaded having more than 1024 bins, then an error bit is set (GPARM Command, word 9) and only the first 1024 bins are used. Conversely, if a range mask has already been loaded having more than 1024 bins and the user attempts to enter the switching polarization mode, then that request is denied and the RVP8 continues to operate in its prior fixed polarization manner. Whenever the number of range bins is less than 1024, then none of the above interactions ever arises. 63 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Range Avg. (See Text) | | 0 0 0 0 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Bits for ranges 0.000km to 1.875km | Input 1

\_1.875 . \_0.000

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Bits for ranges 1022.000 km to 1023.875 km | Input 512

\_1023.875 \_1022.000 6.3 Setup Operating Parameters (SOPRM) This command is used to configure the Signal Processor. The command should be issued whenever any of the parameters in the list change. The default parameter list consists of twenty 16-bit input words. These can be followed by optional XARG parameters as needed. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 0 1 0 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Sample Size | Input 1

The sample size is continually adjustable from 1 to 256 pulses. However, during the alternating polarization mode, the sample size must be even. If an odd value is entered it is rounded up by one in that case. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Polar |NHD| |16B|CMS| R2| |3x3| |End|Lsr|Dsr|Rnv| Input 2

Each of the single-bit fields selects whether the given processing or threshold option is enabled

(1) or disabled (0). Polar NHD Configures transmit polarization and Zdr processing:

00 Fixed polarization, Horizontal 01 Fixed polarization, Vertical 10 Alternating polarization pulse-to-pulse 11 Dual simultaneous transmission Disables inclusion of header words in the processed data that are output by the PROC command (See also, CFGHDR command). 64 RVP8 Users Manual May 2003 Host Computer Commands 16B CMS R2 3x3 End Lsr Dsr Rnv Configures for 16-bit (rather than 8-bit) data output from the PROC command. This bit affects the single-parameter versions of Reflectivity, Velocity, Width, and Zdr data. However, the PROC commands archive format always holds 8-bit data, regardless of the setting of 16B. This gives the option of extracting both 8-bit and 16-bit data simultaneously from each ray. Enables Clutter Microsuppression, in which individual range bins are rejected

(based on excessive clutter) prior to being averaged together in range. Use three lag (R0/R1/R2) algorithms for width, signal power, and clutter correc-

tion. Switches on the 3x3 output filter (See Section 5.3.3). The RVP8 automatically handles all of the pipelining overhead associated with running the 3x3 filter, i.e., valid output data are always obtained in response to every PROC command. Causes ENDRAY_ to pulse at the end of each ray. Reflectivity speckle remover. When set, range speckles in the corrected and un-

corrected reflectivity data are removed. Doppler speckle remover. When set, range speckles in the velocity and width data are removed. Range normalization of reflectivity data. This bit also enables intervening gas at-

tenuation correction. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Log Slope 65536 * dB / (LSB) | Input 3

This number defines the multiplicative constant that converts the signal power in dB to the units of the 12bit Log of power in sample time series outputs. One fourth of this slope is used to generate the Log of Measured Noise Level output from GPARM (word 6). The recommended value to use here is 0.03 (1966). This gives a dynamic range of 122 dB in 12 bits. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| LOG Threshold in 1/16 of dB | Input 4

Reflectivity values below this level can result in thresholding of data, if the threshold control flags (see below) include LOG Noise bits. The threshold value is always non-negative, and the comparison test is described in Section 5.3. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Clutter Correction (CCOR) Threshold in 1/16 of dB | Input 5

The clutter correction threshold is a bound on the computed log receiver adjustment for clutter. These corrections (in dB) are always negative. Any clutter correction which is more negative than the above value can result in thresholding of data. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | SQI Threshold | Input 6

65 RVP8 Users Manual May 2003 Host Computer Commands The Signal Quality Index (SQI) threshold is an unsigned binary fraction in the range 0 to 255/256. When the SQI for a range bin falls below the stated value it may result in thresholding of data. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Weather Signal Power Threshold in 1/16 of dB | Input 7

Weather Signal Power (SIG) is an estimate of the SNR of the weather component of the received signal. When the SIG (see Section 5.2.10) falls below this comparison value it may result in thresholding of data. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Calibration Reflectivity in 1/16 of dB | Input 8

The calibration reflectivity is referenced to 1.0 kilometers. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | TopMode | | Input 9

The TopMode bits select the overall data acquisition and processing mode for the RVP8. Although the processing algorithms that are used in each top level mode are quite different, the RVP8 command set works in a uniform way in all modes. 0000 0001 0010 0100 0101 Pulse Pair Processing Mode. Doppler clutter filters are 4th-order IIR high pass;

data are processed one pulse at a time as each pulse arrives (see Section 5.2.3). FFT Processing Mode. Doppler clutter filters use nonlinear frequency-domain approach; data are processed in batches of pulses (see Section 5.8). Random Phase Processing Mode. Data from first and second trips are dealiased in range based on knowledge of the radar transmitter phase (see Section 5.9). DPRT-1 Processing Mode. The trigger generator produces alternate short and long pulses, and Doppler autocorrelations are computed using only the short pairs (see Section 5.5). DPRT-2 Processing Mode. The trigger generator produces alternate short and long pulses, and Doppler autocorrelations are computed using both pairs (see Section 5.5). 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |PCT|UVD|Window |ZER| Filter Stabilization Delay | Input 10

The RVP8 clutter filters are controlled by this word. Delay This delay is introduced prior to processing the next ray of data whenever Dual-

PRF velocity unfolding is enabled or the RVP8 has been reconfigured by user commands. The delay permits the clutter filter transients to settle down following PRF and gain switches. The value is specified as the number of pulses, and hence, the number of filter iterations, to wait. 66 RVP8 Users Manual May 2003 Host Computer Commands ZER If set, then the clutter filters internal state variables are zeroed prior to waiting the delay time. For some signal conditions, this may give better results than allowing the filter to naturally flow into the new data. UVD Window Selects the type of window that is applied to time series data prior to computing power spectra via a DFT. Choices are: 0:Rectangular, 1:Hamming, 2:Blackman. Unfold velocities using a simple (Vhigh Vlow) algorithm, rather than the standard algorithm described in Section 5.6. If set, the RVP8 will attempt to run its standard processing algorithms even when a custom trigger pattern has been selected via the SETPWF command. PCT 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Threshold Control Flags for UnCorrected Reflectivity | Input 11

These flags select which threshold comparisons result in unCorrected reflectivity being accepted or rejected at each bin. There are four test comparisons that are made at each range, as described above for input words 4, 5, 6, and 7. Each test either passes and produces a code of 1, 2, 4, and 8 respectively, or fails and produces a code of zero. The sum of the codes for each of the four tests is a number between 0 and 15, which can also be interpreted as the following four-bit binary number:

3 2 1 0

| 8 | 4 | 2 | 1 |

\ \ \ \___ LOG Threshold Passes

\ \ \______ CCOR Threshold Passes

\ \_________ SQI Threshold Passes

\____________ SIG Threshold Passes The individual bits of the Threshold Control Flag word each specify whether data are to be accepted (1) or rejected (0) in each of the sixteen possible combinations of threshold outcomes. Thus, the pattern of bits in the flag word actually represents a truth table for a given logical function of the four threshold outcomes. The following examples show actual values of the Flag word for the stated combinations of acceptance criteria:

Value Criteria FFFF 0000 AAAA 8888 A0A0 8080 F0F0 FAFA C0C0 F000 C000 FFF0 CCC0 All Pass (Thresholds disabled) All Fail (No data are passed) LOG LOG and CSR LOG and SQI LOG and CSR and SQI SQI SQI or LOG SQI and CSR SQI and SIG SQI and SIG and CSR SQI or SIG

(SQI or SIG) and CSR 67 RVP8 Users Manual May 2003 Host Computer Commands A simple way to generate these values is to imagine four 16-bit quantities having the following names and values: LOG=AAAA, CSR=CCCC, SQI=F0F0, SIG=FF00. The flag value needed to represent a given logical combination of threshold outcomes is obtained as the result when that same logical combination is applied to these special numbers. For example:

(SQI or SIG) and CSR = (F0F0 or FF00 ) and CCCC

= (FFF0) and CCCC

= CCC0 which corresponds with one of the examples given above. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Threshold Control Flags for Corrected Reflectivity | Input 12

See Description for Input #11. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Threshold Control Flags for Velocity | Input 13

See Description for Input #11. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Threshold Control Flags for Width | Input 14

See Description for Input #11. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Bits to Invert in TAG Inputs 0 through 15 | Input 15

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Bits to Invert in TAG Inputs 16 through 31 | Input 16

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Intervening Gas Attenuation Correction (dB/km) | Input 17

Gas attenuation correction attempts to compensate for overall (two-way) beam losses due to absorption by atmospheric gasses. The correction is linear with range, and is added to the data along with range normalization. Therefore, clearing the RNV bit in Word #2 above disables the correction. Of course, gas attenuation compensation can still be turned off even when RNV is on, simply by setting a slope of 0.0 dB/km. An attenuation of G db/km is encoded into the unsigned 16-bit word N as follows:

0 N 10000 else G = N / 100000 G = 0.1 + (N 10000)/10000 68 RVP8 Users Manual May 2003 Host Computer Commands This format is backward compatible with the previous linear format for all values between 0.0 and 0.1dB/km; but it extends the upper range of values from 0.65535 up to 5.6535. These larger attenuation corrections are needed for very short wavelength radars. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Threshold Control Flags for Differential Reflectivity (Zdr) | Input 18

See Description for Input #11. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed Zdr Calibration Offset in 1/16 dB (GDR) | Input 19

When differential reflectivity is computed there is a possibility that radar asymmetries will introduce a bias in the Zdr values, i.e., that Zdr will be non-zero even when observing purely spherical targets. This calibration offset permits nulling out this effect. The GDR offset accounts for the overall Tx/Rx gain imbalance between the two channels of the radar. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Radar Wavelength in Thousandths of Centimeters | Input 20

The radar wavelength is used in the calculation of 16-bit velocity and width data, to convert from Nyquist units to absolute physical units. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed LDR Calibration Offset in 1/100 dB (XDR) | XARG 1

The XDR offset is used in the Linear Depolarization Ratio equations, and is the differential receiver gain between the two channels. Note that unlike the GDR offset (used for ZDR), the gain difference does not depend on differential transmit power. The default (power-up) values for the above parameters are listed below. Both the scientific units and the integer-input required by the command to set up that value are given. Most of these defaults will likely be reasonable for a wide variety of radars. Scientific Units 25 pulses Table 61: Default Values For Operating Parameters Parameter Sample Size Flag Word Log Slope LOG Threshold CCOR Threshold Signal Quality Index Threshold SIG Threshold 0.03 dB/LSB 0.5 dB 25.0 dB 0.5 (dimensionless) 10.0 dB Input 25 0017 Hex 1966 8 400 128 160 69 RVP8 Users Manual May 2003 Host Computer Commands Table 61: Default Values For Operating Parameters (cont.) Parameter Calibration Reflectivity Gas Attenuation Zdr Offset (GDR) LDR Offset (XDR) AGC Integration Period Radar Wavelength Dual PRF Filter Stabilization UnCor Refl. Thresh. Control Flag Cor Refl. Thresh. Control Flag Velocity Thresh. Control Flag Width Thresh. Control Flag Zdr Refl. Thresh. Control Flag TAG Bits to Invert Scientific Units 22.0 dBZ 0.016 dB/km 0.0 dB 0.0 dB 8 pulses 5.3 cm. 10 pulses LOG LOG & CSR SQI & CSR SQI & CSR & SIG LOG No Inversions Input 352 1600 0 0 8 5300 10 AAAA Hex 8888 Hex C0C0 Hex C000 Hex AAAA Hex 0000 Hex 6.4 Interface Input/Output Test (IOTEST) This command is used to test both the input and output data busses of the signal processor interface. When issued, the command causes sixteen words to be read from the host controller, after which those same sixteen words are written back out. Typically, the controller supplies a barber pole input sequence consisting, for example, of successive powers of two. If all of the output words are correct, one may conclude that there are no malfunctioning bits in the interface hardware. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 0 1 1 | Command

610 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Arbitrary Data Word #1 Supplied by Host Controller | Input 1

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Arbitrary Data Word #16 Supplied by Host Controller | Input 16

Note: The IOTEST command can also process and echo up to 128 additional XARGS data words (See Section 6.20). 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Copy of Data Word #1 as supplied by Host Controller | Output 1

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Copy of Data Word #16 as supplied by Host Controller | Output 16

6.5 Interface Output Test (OTEST) This command is used to test the integrity of the data being output by the signal processor. The command causes sixteen words to be output consisting of successive powers of two starting from one. By verifying whether each output word is correct, malfunctioning bits in the interface data bus can easily be isolated. This test is less stringent than the input/output test IOTEST, since the input data paths to the processor are not being checked. Typically, the OTEST is performed only when the IOTEST fails, and then to determine whether the fault was on input or output. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 1 0 0 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 | Output 1

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 | Output 16

6.6 Sample Noise Level (SNOISE) This command is used to estimate the current noise level from the receiver, so that the noise can be subtracted from subsequent measurements. Data are sampled for 256 pulses at 256 bins, beginning at a selectable range and spaced by 0.125 meters. The internal trigger generator is 611 RVP8 Users Manual May 2003 Host Computer Commands temporarily set to a special noise rate (usually much lower than the operating rate) during the process. It is ultimately the users responsibility to insure that no returned power is present within the 32km sampling interval. In some cases it may be necessary to raise the antenna during the noise measurement to avoid thermal noise pickup from the ground, or from weather targets. SNOISE has the option of setting up a new sampling range and trigger generator rate each time it is called. Two bits in the command word determine which (if any) of the new values overrides the current values stored in the RVP8. The power-up sampling range is 250km (input value of 250), and the power-up trigger rate is 200Hz (input value of 30000). These initial values persist until such time as they are altered here. Note that both input words must always be supplied after the command, even if the command calls for ignoring one or both of them. The range is supplied directly in kilometers up to a maximum of 992km. The trigger rate resulting from a given input is 6MHz divided by the input value, i.e. the input value is the trigger period in 0.1667 microsecond increments. Keep in mind that the given rate is bounded against the minimum PRT allowed for the current radar pulse width. The SNOISE command bounds the requested starting range of the noise sampling interval. This is to insure that the noise samples will fit within the specified PRT, and within the range mask hardware RAM. The RVP8 sets an error bit when an improper range is requested. The noise sampling procedure also bounds the PRF to 1250Hz before making its measurements. This allows sufficient time for the algorithm to run properly on the 256 bins taken from 256 pulses. Note that the PRF bound is equally well imposed for external triggers too, i.e., external triggers will be ignored for 800sec following each one that is actually used. The SNOISE command should be re-issued now and then to compensate for drift in the RF and A/D systems. However, because DC offsets do not propagate into the I and Q values, reissuing the command is much less critical than with the RVP6. SNOISE must be executed at least once after power-up, before beginning to acquire and process data. The RVP8 does not automatically take a noise sample as part of its initialization procedure. The measured offsets are stored internally for all subsequent uses inside the RVP8. The offset values may be inspected via the GPARM command, as may the current range and rate values themselves. Of course, whenever the range or rate are changed the user must ensure that the new trigger rate allows at least 32km following the new noise range. If this requirement is not met, or if other failures are detected during the noise measurement, appropriate bits are set in the GPARM latched status word. This word should generally be checked after SNOISE to make sure that everything worked properly. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Rat|Rng| | 0 0 1 0 1 | Command

Rng Rat If 1, then the range in input word 1 is taken as the starting noise range for this and all subsequent SNOISE calls. If 1, then the trigger rate in input word 2 is taken as the noise rate for this and all subsequent SNOISE calls. 612 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Starting Range in km (Max 992km) of 32km Sampling Interval | Input 1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Internal Trigger Rate (6Mhz/N) to use During Noise Sampling | Input 2

6.7 Initiate Processing (PROC) The PROC command controls the actual processing and output of radar data. The operating modes and types of data available from the RVP8 are described in detail in Chapter 1. That section also describes the proper use and application of the RVP8 to different radar environments. PROC is a single-word command that specifies the type of processing to be performed, and the type of output to be generated. The two mode bits in the command word select either

Synchronous mode The processor acquires, processes, and outputs one ray in response to each PROC command. Processing is begun only after each command is actually received.

Free running mode A single PROC command is issued and rays are continually output as fast as they can be produced and consumed. This continues until any other command is written, e.g., a NOP could be used to terminate the free running mode with no other consequences.

Time Series mode Always produced in a synchronous manner, this mode require a new PROC command to initiate each new set of samples. Data are output as 8-bit time series, 16-bit time series, or 16-bit power spectra. Optional Dual-PRF velocity unfolding is chosen by command bits eight and nine. For Doppler data either a 2:3, 3:4, or 4:5 PRF unfolding ratio may be selected. The RVP8 carries out all of the unfolding steps internally, so that mean velocity is now output with respect to the larger unambiguous interval. There is no additional velocity processing needed by the user, except of course, to change the velocity scale on any displays being generated. Furthermore, spectral widths are scaled consistently with respect to the higher PRF, and require no user modification before being plotted. When unfolding is selected, the internal trigger generator automatically switches rates on alternate rays. The switch over occurs immediately after the last pulse of the current ray has been acquired; thus overlapping the internal post-processing and output time, with transmitter stabilization and data acquisition at the new rate. Output data are selected by the upper six bits of the PROC command. Packed archive output is selected by setting the ARC bit. Individual byte or word display output is selected by setting any or all of the Z, T, V, W, Zdr, and KDP command word bits. When more than one of these bits is set, the output array consists of all of the bins for the leftmost selected parameter, followed by all of the bins for the next selected parameter, etc. Bits selected in XARG #1 behave the same way, except that the output order is right-to-left. Both archive and display formats can be selected 613 RVP8 Users Manual May 2003 Host Computer Commands simultaneously, in which case the archive format is output first, followed by whichever individual display format values were also selected. The archive format is not recommended for use with new drivers because it can only handle four of the many possible output parameter types. When time series mode is selected there are three output data formats available. For backwards compatibility, there is an 8-bit integer format in which the eight most significant bits from the I, Q, and LOG signals are represented in a byte. This format is not recommended because it will generally miss weak signals. We recommend the floating-point format that uses 16-bits per A/D sample. There is also a 16-bit power spectrum output that is accurate to 0.01dB. (See also GPARM output word #10). In addition to the above output data, the first words of each ray optionally contain additional information about the ray itself. These header words are configured by the CFGHDR opcode, and are included only if the NHD (No-Headers) bit in SOPRM Input #2 is clear. For example, if TAG angle headers are requested, if the ARC, Z and V bits are all set, and if there are 100 bins selected in the current range mask, then each RVP8 output ray consists of the following:

1] TAG15 TAG0 \ From Start of Acquisition 2] TAG31 TAG16 / Interval 3] TAG15 TAG0 \ From End of Acquisition 4] TAG31 TAG16 / Interval

* 200 words of packed archive data,

* 100 words of Corrected Reflectivity data in low byte only.

* 100 words of Velocity data in low byte only, The Command word format for Synchronous Doppler Mode is:

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

|ARC| Z | T | V | W |ZDR|Unfold |KDP| 0 1 | 0 0 1 1 0 | Command

The Command word format for Free Running Doppler Mode is:

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

|ARC| Z | T | V | W |ZDR|Unfold |KDP| 1 0 | 0 0 1 1 0 | Command

Either of these may be augmented by an optional XARG word (See Section 6.20) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | | | | | | | (Tx Vert) | (Tx Horz) | | | |

| |Flg|Phi Rho Ldr|Phi Rho Ldr|SQI|RHV|PDP| XARG 1

Unfold ARC Selects DualPRF unfolding scheme:

00 : No Unfolding 10 : Ratio of 3:4 Selects archive output format in which four data bytes (see 8-Bit descriptions be-

low) are packed into two output words per bin as follows:

01 : Ratio of 2:3 11 : Ratio of 4:5 614 RVP8 Users Manual May 2003 Host Computer Commands High Byte Low Byte

| V | Z | First Word

| W | T | Second Word

The remaining data parameters are available in both 8-Bit and 16-bit formats, according to SOPRM Command input word #2 (See Section 6.3). The same SOPRM word configures the RVP8 for Single or Dual polarization. The later is required for KDP, PDP, and RHV to be computed properly. V Selects radial velocity data. 8-Bit Velocity Format Mean velocity, expressed as a fraction of the unambig-

uous velocity interval, is computed from the unsigned byte N as:

Vm/sec = VNyquist x (N128) / 127.5 0 : Indicates velocity data is not available at this range 1 : Maximum velocity towards the radar 128 : Zero velocity 255 : Maximum velocity away from the radar When velocity unfolding is selected, the output is still interpreted as above, ex-

cept that the unambiguous interval is increased by factors of 2, 3, and 4 for for 2:3, 3:4, and 4:5 unfolding. 16-Bit Velocity Format Mean velocity in meters/second is computed from the unsigned word N as:

Vm/sec = (N32768) / 100 The overall range is from 327.67m/sec to +327.66m/sec in one centimeter/sec-

ond steps as follows:

327.67 m/sec (towards the radar) 0 : Indicates velocity data is not available at this range 1 :

32768 :

65534 :

65535 : Reserved Code

+327.66 m/sec (away from the radar) 0.00 m/sec W Selects spectral width data. 8-Bit Width Format Spectral width is computed from the unsigned byte N as:

WNyquist = N / 256 The overall range is a fraction between 1/256 to 255/256 of the unambiguous in-

terval. The code of zero indicates that width data was not available at this range. 16-Bit Width Format Spectral width in meters/second is computed from the unsigned word N as:

Wm/sec = N / 100 615 RVP8 Users Manual May 2003 Host Computer Commands The overall range is from 0.01m/sec to 655.34m/sec in one centimeter/second steps as follows:

0 : Indicates width data is not available at this range 1 :

65534 :

65535 : Reserved Code 0.01 m/sec 655.34 m/sec Z Selects clutter corrected reflectivity data. 8-Bit deciBel Format The level in decibels is computed from the unsigned byte N as:

dBZ = (N64)/2. The overall range is therefore from 31.5 dBZ to +95.5 dBZ in half-dB steps as follows:

0 : Indicates no reflectivity data available at this range 1 :

64 :

128 :

255 :

31.5 dBZ 0.0 dBZ 32.0 dBZ

+95.5 dBZ 16-Bit deciBel Format The level in decibels is computed from the unsigned word N as:

dBZ = (N32768) / 100 The overall range is from 327.67dB to +327.66dB in 1/100dB steps as follows:

0 : Indicates no reflectivity data available at this range 1 :

32768 :

65534 :

65535 : Reserved Code 327.67 dBZ 0.00 dBZ

+327.66 dBZ T ZDR Selects total reflectivity. Same 8-bit and 16-bit coding formats as for clutter cor-

rected reflectivity above. Selects differential reflectivity data. 8-Bit ZDR Format The level in decibels is computed from the unsigned byte N as:

dB = (N128) / 16 The overall range is from 7.935dB to +7.935dB in one-sixteenth dB steps as fol-

lows:

0 : Indicates no reflectivity data available at this range 1 :

128 :

255 :

7.9375 dB 0.0000 dB

+7.9375 dB 616 RVP8 Users Manual May 2003 Host Computer Commands 16-Bit ZDR Format Same as 16-bit deciBel format. KDP Selects dual polarization specific differential phase data. 8-Bit KDP Format Values are coded into an unsigned byte using a logarith-

mic scale. The KDP angles are multiplied by the wavelength in cm. (to reduce dynamic range) and then converted to a log scale separately for both signs. The minimum value is 0.25 deg*cm/km, and the maximum value is 150.0 deg*cm/

km. A code of zero represents no data, and a code of 128 represents 0 deg*cm/

km. The conversion equation for positive values (codes from 129 to 255) is:

The conversion equation for negative values (codes from 1 to 127) is:

KDP 0.25 600 KDP 0.25 600

N129 126

127N

126 16-Bit KDP Format Same as 16-bit deciBel format, except that the units are hundredths of degrees per kilometer. No weighting by wavelength is introduced. PDP Selects dual polarization differential phase DP data. 8-Bit DP Format The phase angle in degrees is computed on a 180-degree interval from the unsigned byte N as:

DP(mod180) = 180 (N 1) / 254 0 : Indicates no DP data available at this range 1 :

254 :

255 : Reserved Code 0.00 deg 179.29 deg 16-Bit DP Format The phase angle in degrees is computed on a 360-degree interval from the unsigned word N as:

DP(mod360) = 360 (N 1) / 65534 0 : Indicates no DP data available at this range 1 :

65534 :

65535 : Reserved Code 0.000 deg 359.995 deg RHV Selects dual polarization correlation coefficient HV data. 8-Bit HV Format The correlation coefficient is computed on the interval 0.0 to 1.0 using a square root weighting of the unsigned byte N as:

(N 1) 253

HV 0 : Indicates no HV data available at this range 1 :

2 :

253 :

0.0000 (dimensionless) 0.0629 0.9980 617 RVP8 Users Manual May 2003 Host Computer Commands 254 :

255 : Reserved Code 1.0000 16-Bit HV Format The correlation coefficient is computed on the interval 0.0 to 1.0 linearly from the unsigned word N as:

HV = (N 1) / 65533 0 : Indicates no HV data available at this range 1 :

65534 :

65535 : Reserved Code 0.0 (dimensionless) 1.0 Selects Signal Quality Index data. This dimensionless parameter uses the same 8-bit and 16-bit data formats as RHV ( HV). Selects Linear Depolarization Ratio, measured either on the horizontal receive channel while transmitting vertically, or on the vertical receive channel while transmitting horizontally. 8-Bit LDR Format The level in decibels is computed from the unsigned byte N as:

dB = 45.0 + (N1) / 5 This spans an asymmetric interval around zero decibels, and allows for cross channel isolation as large as 45dB. The overall range is from 45.0dB to +5.6dB in 0.2dB steps as follows:

0 : Indicates no LDR data available at this range 45.0 dB 1 :

0.0 dB 226 :

254 :

+5.6 dB 255 : Reserved Code 16-Bit LDR Format Same as 16-bit deciBel format. Selects the cross channel correlation coefficient. This dimensionless parameter uses the same 8-bit and 16-bit data formats as RHV ( HV). Selects the cross channel differential phase. This parameter uses the same 8-bit and 16-bit angular data formats as PDP ( DP). Selects flag word output, bits defined as follows:

0 Range unfolding error 1 LOG threshold passed 2 CCOR threshold passed 3 SQI threshold passed 4 SIG threshold passed 5 Bin was speckle filtered 618 SQI LDR RHO PHI Flg RVP8 Users Manual May 2003 Host Computer Commands The Command word format for Time Series Mode is:

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| TSOUT | Spec Type |Unfold | | 1 1 | 0 0 1 1 0 | Command

TSOUT Selects type of data to be output. 00 : 8-bit Time Series 10 : 16-bit Time Series 01 : Power Spectrum 11 : Unused When the TSOUT bits select Power Spectrum then, depending on the current major mode, a further choice may be needed to select one of several spectral view points. For the Random Phase major mode the possible values of Spec Type are:

0: Raw First Trip 1: Whitened First Trip 2: Cleaned First Trip 3: Final First Trip 4: Raw Second Trip 5: Whitened Second Trip 6: Cleaned Second Trip 7: Final Second Trip When time series output is selected the output data consist either of (3xBxN) or (2xBxN) words, depending on the output format, where B is the number of bins in the current range mask, and N is the number of pulses per ray. Data samples for each bin of pulse #1 are output first, followed by those for each bin of pulse #2, etc. up to pulse #N. In other words, the data are output in the same time-order that they were acquired. In the floating point format, three words are used for each bin:

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Exponent | S | Mantissa | (I)

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Exponent | S | Mantissa | (Q)

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 0 0 | Log of Power in Sample | (LOG)

To convert the floating I and Q samples to voltages: First create a 12-bit signed integer in which bits zero through 9 are copied from the Mantissa field, and bits ten and eleven are either 01 or 10 depending on whether S is 0 or 1. Then, multiply this number by 2**(exponent40), where the exponent field is interpreted as an unsigned 5-bit integer. Finally multiply by the maximum voltage. The resulting value has 12-bits of precision and a dynamic range of approximately 190dB. The large dynamic range is necessary to cover the full range of data. In summary:

Voltage VMAX

(Sign, Mantissa) 2

Exponent40 Note that the resulting voltage span is actually 4 VMAX. The extra factor of four is built into the format so that transient excursions above the full scale input voltage can still be encoded properly. These may arise for time series data that have been processed by an IIR clutter filter. 619 RVP8 Users Manual May 2003 Host Computer Commands The Log of Power in Sample is provided mainly for backwards compatibility. It can be calculated from the I and Q numbers. To convert to dBm it requires a slope and offset as follows:

dBm PMAX

Slope [Value 3584]

Where:

PMAX = +4.5dBm for 12-bit IFD, +6.0dBm for 14-bit IFD VMAX = 0.5309 Volts for 12-bit IFD, 0.6310 Volts for 14-bit IFD Slope = Log Power Slope word 3 of SOPRM command. 0.03 recommended. For backwards compatibility the RVP8 produces a 8-bit fixed point time series format. Because of the limited dynamic range available, this will only show strong signals, and is not recommended for use. The I, Q, and Log power triplets are packed into two 16-bit output words as follows:

High Byte Low Byte

| Q Sample | I Sample | First Word

| Zero | Log Power | Second Word

The Log Power value is the upper 8 bits of the long format. The other numbers are produced by the equation:

Voltage VMAX

Sample

128 When Power Spectrum output is selected, the spectrum size is chosen as the largest power of two

(N2) that is less than or equal to the current sample size (N). When the sample size is not a power of two, a smaller spectrum is computed that by averaging the spectra from the first N2 and the last N2 points. The data format is one word/bin/pulse, in the same order as for time series output. Each word gives the spectral power in hundredths of dB, with zero representing the level that would result from the strongest possible input signal. Thus, the spectral output terms are almost always negative. The time series that are output by the RVP8 are the filtered versions of the raw data, when available. If a non-zero time-domain clutter filter is selected at a bin, then the I and Q data for that bin show the effects of the filter. Whenever you need to observe the raw samples, make sure that no clutter filters are being applied. In pulse pair time series mode with dual receivers, selecting (H+V) will produce data in one of two formats according to the Sum H+V Time Series question in the Mp setup section:

Answering Yes will result in summed time series from both channels, but spectra from the DSP will be the averaged spectra from each channel individually. This allows the IRIS ascope utility to display either the 620 RVP8 Users Manual May 2003 Host Computer Commands spectrum-of-sum or sum-of-spectra according to whether the Spectra from DSP button is pressed in the Processing/Gen-Setup window.

Answering No will still produce the usual (BxN) time series output samples, except that the first half of these samples will be the first half of the H data in their normal order. This will be followed by a zero sample if (BxN) is odd;

followed by the first half of the V data, also in their normal order. In other words, only the first halves of the individual H and V sample arrays are output by the RVP8. As an example, if you select 25 bins and 100 pulses, then the output data will consist of 1250 H samples (from all bins in the first 50 pulses), followed by 1250 V samples from the exact same set of bins and pulses. This is the more useful option when custom algorithms are being run on the data from the two separate receivers. When the number of output words is large there is a possibility that the internal buffering within the RVP8 may overflow and data may be lost. Due to internal memory limitations, the product

(BxN) must be less than 12000. A bit in the latched status word (See GPARM) indicates when time series overflows occur. In such cases, the correct number of words are still output, but they are all zero after the point at which overflow was detected. 6.8 Load Clutter Filter Flags (LFILT) A special feature of the RVP8 processor is that any of the eight available clutter filters may be chosen independently at each selected range. This range-dependent clutter removal is useful when the clutter characteristics vary with increasing range. Typically, clutter interference is most severe in the immediate vicinity of the radar. Thus, a highly rejective filter might be chosen for near ranges, and a less rejective or perhaps no filter could be used at far ranges. The input words following the LFILT command specify the choice of filter to be applied at each of the (up to 2048) selected range bins. A fixed size filter table is always loaded, regardless of whether the range mask (See LRMSK) is using the full number of bins. In such cases, the later filter codes are simply be ignored for the current range mask. However, if a longer range mask is loaded in the future, then those later codes would apply to the appropriately numbered bins. Put another way, each filter code is associated with a particular bin number, not with a particular range. The correspondence between bin numbers and actual ranges is made only through the range mask. Only the low three bits are used in each word to specify the filter number. The correspondence between filter codes and filter characteristics is given in Appendix C. If the ALL bit is set in the Command, then 2048 words are loaded, corresponding to the maximum number of range bins that are allowed. Otherwise only 512 words are loaded, and the 512th filter choice is replicated for all bins further in range. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |ALL| 0 1 0 0 0 | Command

621 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | IQ #1 | Input 1

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | IQ #512 | Input 512

6.9 Get Processor Parameters (GPARM) This command is used to access status information from the RVP8 processor. Sixty-four words are always transferred, some later words are reserved for future compatibility and are read as zeros. For convenience, a shorthand table of the output words is given in Table 62. Table 62: RVP8 Status Output Words Word Description Word Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Revision / Serial number Number of Range Bins Current trigger period Current TAG00 TAG15 Current TAG16 TAG31 Log of Measured Noise Level I Channel DC Offset Q Channel DC Offset Latched Processor Status Immediate Status Word #1 Diagnostic Register A Diagnostic Register B Number of Pulses / Ray Trigger count (Low 16-bits) Trigger Count (High 8-bits) No. of Properly Acquired Bins No. of Properly Processed Bins Immediate Status Word #2 Noise Range in Km Noise Trigger Period Pulse Width 0 min. Trig. Period Pulse Width 1 min. Trig. Period 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 LOG Threshold CCOR Threshold SQI threshold SIG Threshold for Width Calibration Reflectivity Reserved Reserved Range Averaging Choice Reserved Reserved Header configuration of PROC data I-Squared Noise (Low 16-bits) I-Squared Noise (High 16-bits) Q-Squared Noise (Low 16-bits) Q-Squared Noise (High 16-bits) Log of Measured Noise Level LOG-Exponential Noise Std. Dev. Horizontal/Vertical Noise Ratio AFC/MFC Control Value Interference Filter Select Interference Filter C1 Constant Interference Filter C2 Constant 622 RVP8 Users Manual May 2003 Host Computer Commands Table 62: RVP8 Status Output Words (cont.) Word 23 24 25 26 27 28 29 30 31 32 Description Pulse Width 2 min. Trig. Period Pulse Width 3 min. Trig. Period Pulse Width Bit Patterns Current /Pulse Width Current Trigger Gen. Period Desired Trigger Gen. Period PRT at Start of Last Ray PRT at End of Last Ray Processing/Threshold Flags Log Slope Word 55 56 57 58 59 60 61 62 63 64 Description Immediate Status Word #3 Burst Tracking Slew Polarization Algorithm Choices Reserved Reserved Reserved Reserved Reserved Reserved Reserved 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 1 0 0 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Rev Bits 30 | Rev 64 | Serial Number | Output 1

The revision and serial numbers of the particular RVP8 board are accessible here. This information is useful when computer software is being designed to handle a variety of signal processor revisions. The revision number is seven bits total; four of which are still in the high four bits of the word for compatibility with an older format. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Number of Bins Currently Selected in Range Mask | Output 2

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| TRIGIN Current Trigger Period in 1/8km (0.83333 usec) Steps | Output 3

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Current Sample of TAG bits 150 | Output 4

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Current Sample of TAG bits 3116 | Output 5

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 | (MSB) Log of Measured Noise Level (LSB) | Output 6

623 RVP8 Users Manual May 2003 Host Computer Commands This value is scaled 4 times higher than the time series format. See the discussion in Section 6.7. To convert to dBm, use the equation:

dBm PMAX

Slope (Value4) 3584 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| (MSB (Sign)) I Channel Measured DC Offset (LSB) | Output 7

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| (MSB (Sign)) Q Channel Measured DC Offset (LSB) | Output 8

The I and Q values are stored in a linear format, similar to the short form time series. See the discussion in Section 6.7. These numbers should always be very close to zero, because the FIR filter that creates them is designed to reject DC. To convert to voltage, use the equation:

Voltage VMAX

Value

32767 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Latched Status Word (Bits Cleared After Each Access) | Output 9

Bit 0 Bit 1 Bit 2 Bit 3 Bit 5 Bit 6 Bit 7 Bit 9 Bit 10 Bit 11 Bit 15 No Trigger during noise measurement. Trigger too fast during noise measurement, i.e., some of the noise sample bins were positioned past the trigger range. No trigger during PROC command. PRF varied by more than 10 microseconds from the beginning to the end of a processing interval. FIFO overflow during last PROC command. Command received while waiting for output FIFO space. The command was pro-

cessed but some output data has been lost (zeroed). Error detected during last SNOISE command. Error in last Load Range Mask (LRMSK) Command. This generally means that too many range bins were selected. Error in LSIMUL command protocol. Measured phase sequence is incorrect. Invalid processor configuration. This bit is set if the last PROC command called for an illegal combination of parameters. The possible causes are:

Spectrum size greater than 128 or less than 4

More than 342 bins/slave in FFT modes

(bins/slave) x (4 + sample size) exceeds 26200 in FFT modes

(bins/slave) x (sample size) exceeds 3000 for Time Series or Spectra output

Odd number of bins selected during fast polarization switching

Bad combination of polarization parameters 624 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Immediate Status Word #1 (Current State of Affairs) | Output 10

No trigger, or, more than 50ms. since last trigger. Error in loading trigger angle table (See LSYNC Command). PWINFO command is disabled. Angle sync input is BCD (Else binary angle). Angle sync is on elevation axis (Else azimuth axis). Angle sync is enabled. Angle sync is not interruptible. Angle sync is dynamic (else rays begin on sync angles). DSP has full IAGC hardware and firmware configuration. DSP supports 16-bit floating time series. Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 9 Bits 11,10 Current unfolding mode. Bits 13,12 Number of AUX boards attached. Bit 14 DSP supports Power Spectrum output 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Diagnostic Result Register A | Output 11

Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 RVP8/Rx card #1 failure RVP8/Rx card #2 failure RVP8/Tx card #1 failure RVP8/Tx card #2 failure IO62 card #1 failure IO62 card #2 failure Error loading config/setup files Error attaching to antenna library Problem when forking compute processes 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Diagnostic Result Register B | Output 12

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Number of Pulses Being Integrated | Output 13

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Trigger Count (Low 16-bits) | Output 14

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Trigger Count (high 8-bits) | Output 15

625 RVP8 Users Manual May 2003 Host Computer Commands The trigger count is a running tally of the number of triggers received by the RVP8 on the TRIGIN line. It is a full 24-bit counter. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Number of Properly Acquired Bins for Current Range Mask & PRT | Output 16

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| No. of Valid Bins in Initial Part of Ray From Last PROC Cmd | Output 17

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Immediate Status Word #2 (Current State of Affairs) | Output 18

Processor supports FFT algorithms Processor supports Random Phase algorithms Processor supports DPRT (Dual-PRT) algorithms Problem in UpLink COAX cable from RVP8/Main > RVP8/IFD Problem in DownLink fiber cable from RVP8/IFD > RVP8/Main IFD PLL is not locked to external user-supplied clock reference Bit 0 Bit 1 Bit 3 Bit 4 Bit 5 Bit 7 Bits 810 Status of burst pulse and AFC feedback Bit 11 Bit 12 Bit 13 Bit 14 Bit 15 2: Manual Frequency Control 4: AFC is waiting for warm-up 6: AFC is tracking 1: AFC Disabled 3: No burst pulse detected 5: AFC is locked IFD test switches are not in their normal operating position Set according to whether the RVP8 is performing trigger blanking. This allows the host computer to decide whether to interpret the End-TAG-0 bit in the output ray header as a blanking flag, or as a normal TAG line. Missing signal at IFD Burst Input Slave DSP count may be less than the number of available chips Set when valid burst power is detected but the center-of-mass lies outside of the aperture sub-window that defines the portion of the pulse used for AFC analysis. This error bit effectively flags when the burst pulse has drifted out of its optimal placement within the sampling window. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Starting Range in Km at Which Noise Sample Data are Taken | Output 19

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Trigger Period (0.16667usec Increments) During Noise Sampling | Output 20

626 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 0 | Output 21

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 1 | Output 22

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 2 | Output 23

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 3 | Output 24

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Four 4-bit Control Bit Patterns for Each Pulse Width | Output 25

See PWINFO command, input word #1, for definition of these bits. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Window | TopMode | | P.W. | Output 26

P.W. Currently selected radar pulse width TopMode Major Mode (See SOPRM Input #9) Window Spectral Window Choice (See SOPRM Input #10) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Current Trigger Generator Period (0.16667usec Increments) | Output 27

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Desired Trigger Generator Period (0.16667usec Increments) | Output 28

The desired trigger generator rate is that which was selected in the most recently issued SETPWF command (or power-up rate if SETPWF was never issued). The current rate may be different from the desired rate due to bounding against limits for the current pulse width, or being in an odd ray cycle during dual-PRT processing. The measured PRTs are forced to 0xFFFF (the maximum unsigned value) whenever the external trigger is expected but missing. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| TRIGIN Period at Start of Last PROC Acquisition Time | Output 29

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| TRIGIN Period at End of Last PROC Acquisition Time | Output 30

627 RVP8 Users Manual May 2003 Host Computer Commands The PRTs from the start and end of the last ray are the actual measured values whenever possible, i.e., when non-simulated data are being processed, and we either have an external trigger, or an internal trigger that is not in any of the Dual-PRT modes. The units are the same as for the measured current trigger period in Output #3. Outputs 31 through 37 are the current processing and threshold parameters set by SOPRM. See Section 6.3 for additional notes on each of these parameters. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Polar |NHD| |16B|CMS| R2| |End|Lsr|Dsr|Rnv| Output 31

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Log Slope 65536 * dB / LSB | Output 32

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| LOG Noise Threshold in 1/16 of dB | Output 33

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Clutter Correction (CCOR) Threshold in 1/16 of dB | Output 34

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | SQI Threshold | Output 35

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| SIG Threshold in 1/16 of dB | Output 36

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Calibration Reflectivity in 1/16 of dB | Output 37

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved (Zero) | Output 38

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved (Zero) | Output 39

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Range Avg (From LRMSK Command)| Output 40

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved (Zero) | Output 41

628 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved (Zero) | Output 42

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Header Configuration of PROC data (Copy of CFGHDR Input #1) | Output 43

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Noise Sum of I Squared MSB=2**16 LSB=2**31 | Output 44

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Noise Sum of I Squared MSB=1 LSB=2**15 | Output 45

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Noise Sum of Q Squared MSB=2**16 LSB=2**31 | Output 46

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Noise Sum of Q Squared MSB=1 LSB=2**15 | Output 47

To compute the noise power in dBm from Words 44-47, first calculate:

(Word 45) 215 (Word 44) 231

(Word 47) 215 (Word 46) 231 NI NQ From which we obtain:

dBm PMAX

10 log10 NI

3dB

NQ Note that the four integer values become rather small and severely quantized when the noise power drops to low values. Historically, these four words were used to balance the individual gain of the I and Q channels in the RVP6 in the presence of a strong test signal. Since I and Q are inherently balanced in the RVP8, these output words are no longer of much value. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Log of Measured Noise Level (same as word 6) | Output 48

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Exponential-LOG Noise Standard Deviation (8000hex) | Output 49

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Ratio of Horizontal/Vertical Noise Power in Hundredths of dB | Output 50

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 16Bit AFC/MFC Value (32768 through +32767) | Output 51

629 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | IFD Sat.Power | MinRev | Inter.F | Output 52

Inter.F Specifies which interference filter is running. Zero means none; see Section 5.1.4 for a description of the interference filter algorithms. MinRev Minor revision level of the RVP8 code that is currently running. IFD Sat.Power (PMAX) Input power required to saturate the IF-Input A/D converter for the RVP8/IFD re-

ceiver that is currently attached. 0: +4.5dBm 1: +6.0dBm 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Interference Filter Parameter C1 in Hundredths of deciBels | Output 53

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Interference Filter Parameter C2 in Hundredths of deciBels | Output 54

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Immediate Status Word #3 (Current State of Affairs) | Output 55

Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bits 8-11 User-defined Major Modes 1-4 are supported Burst pulse timing adjustments can be made Burst pulse frequency adjustments can be made Burst pulse hunting is enabled Burst pulse hunt is running right now Last burst pulse hunt was unsuccessful Dual PRT Type 2 is supported Could not generate the requested phase sequence Problem with digital transmitter clock 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed trigger slew in hundredths of microseconds | Output 56

This is the same format that is used by the SETSLEW command to set the current trigger slew

(See Section 6.24) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Polarization Algorithm Choices | Output 57

Bit 0 Bit 1 Bit 2 Use H transmissions for (T,Z,V,W) Use V transmissions for (T,Z,V,W) Use CoPol reception for (T,Z,V,W) 630 RVP8 Users Manual May 2003 Host Computer Commands Bit 3 Bit 4 Bit 5 Bit 6 Use CrossPol reception for (T,Z,V,W) Correct all polar params for noise Use filtered data for all polar params Sign convention for PHIdp 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved (Zero) | Output 58

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved (Zero) | Output 64

6.10 Load Simulated Time Series Data (LSIMUL) This command is provided as a diagnostic for proper functioning of the RVP8 algorithms. It permits arbitrary simulated data samples to be input to the processing routines, rather than sampled data from the A/D converters as is ordinarily the case. Since the properties of the simulated data are known exactly, it is possible to verify that the calculations within the RVP8 are proceeding correctly. The LSIMUL command (with operation=1) should be issued prior to the PROC command which is being tested. This enables the simulated data mode. The next PROC command will then wait for N (N = sample size) LSIMUL commands (with operation=2) prior to outputting each ray. The arrival of any other command during that time will cause the simulated data mode to be exited, and error bit #10 will be set in the GPARM latched status word. The error bit is also set if an LSIMUL command with operation=2 is received while simulated data mode is disabled. You may specify a single simulated data sample for every range bin, or a pattern or simulated samples to be replicated over the range of bins. Most RVP8 algorithms are independent of range, and can be tested with identical data at every bin. Notable exceptions, however, are the pop clutter filter, and range bin averaging procedures. In its full generality, the LSIMUL command permits independent I and Q samples to be simulated at every bin of every pulse. If this results in more host computer I/O than is practical, then specify fewer simulated bins and allow the RVP8 to replicate them internally. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Operation | | 0 1 0 1 0 | Command

The available operations are:

0 1 Disable the use of simulated data. RVP8 returns to acquisition and processing of live data from the A/D converters. Enable processing of simulated data. Subsequent PROC commands will use the data supplied in the next N (N = sample size) LSIMUL commands with Opera-

tion=2. 631 RVP8 Users Manual May 2003 Host Computer Commands 2 The receiver noise and offset levels which are internally maintained by the RVP8 are zeroed by this command. This is because the measured offsets are not relevant to the simulated data, and must not be used in the subsequent computations. Thus, it is important to issue the SNOISE command before resuming the acquisition and processing of live radar data. Load one pulse of data samples. Each bin within the pulse is represented by four 16-bit words which represent a single instantaneous sample. You may specify one or more bins to be loaded; the RVP8 will replicate these data as necessary in order to fill out the entire count of acquired bins. Thus, the total number of words loaded is (4+4B), where B is the bin count specified in Word #1. This takes ac-

count of the four header words, plus four words for every bin being defined. If B is zero, then a zero-valued sample is applied for all channels. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Number of Bins of Simulated Data Which Follow | Input 1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Transmit Phase of This Pulse (16-bit Binary Angle) | Input 2

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Transmit Power in Hundredths of dB (Zero dB Nominal) | Input 3

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved | Input 4

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved | Input 5

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed I A/D Sample (F16.12 Format) | Input 6

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed Q A/D Sample (F16.12 Format) | Input 7

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Reserved | Input 8

. 632 RVP8 Users Manual May 2003 Host Computer Commands 6.11 Reset (RESET) The RESET command permits resetting either the entire RVP8 processor, or selected portions thereof. Flags within the command word determine the action to be taken. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Nv |Nse|Fif|Nv |Nv | 0 1 1 0 0 | Command

Nv Nse Fif Reloads configuration from the saved nonvolatile settings. For compatibility with RPV6 and RVP7, any of 3 bits will trigger this response. Reset the receiver noise levels to the power-up default value for all pulsewidths as defined in the Mt setup questions (See Section 3.3.5). Remove any data currently in the output FIFOs. This permits flushing output data that was left from a previous command, so that new output can be read from scratch. See notes in the Introduction to this chapter concerning actions taken by the RVP8 when the output FIFO becomes full. 6.12 Define Trigger Generator Output Waveforms (TRIGWF) Note: This opcode is obsolete, and is included only for backward compatibility with the RVP6. The opcode is disabled by default (See Section 3.3.1), because the interactive trigger setup procedure described in Section 4.4 is the preferred method of defining all RVP8 triggers and timing. TRIGWF should not be used in any new code applications that drive the RVP8. The RVP8 has a built-in trigger generator that can synthesize six independent digital output waveforms, each having arbitrary shape and being active anywhere in a window centered around zero-range. The six trigger outputs can be defined by a 2048-word by 6-bit table which is loaded from the user computer. The patterns are automatically read from the table and output to the six trigger lines during each radar pulse. The six outputs can be used for transmitter triggers, scope triggers, range strobes, PLL gates, etc. The writable waveform table makes the RVP8 unique, in that the detailed timing of trigger and related control signals can be easily adjusted in software, without having to resort to reprogramming PROMs. This makes it possible for user software to edit the trigger timing in a convenient interactive manner. Trigger waveforms are loaded using the TRIGWF command. Four bits in the command word

(PW0 through PW3) select which pulsewidths will receive the new waveforms. On power-up, all four pulsewidths are initialized to user-selected waveforms. The first word following the TRIGWF command specifies the transition point of the POLAR0 polarization control signal. This control signal is either held low or high for the cases of fixed horizontal or vertical polarization, or it alternates from pulse to pulse for fast-switching polarization measurements such as Zdr. The transition point is specified as a value between 0 and 2047, where 1024 represents range zero. These units are the same as the time units for the waveforms which follow, i.e., a 2048-word array holding 6-bit trigger patterns. Bit 0 in each of these words affects the TGEN0 digital output line, bit 1 affects TGEN1, etc. The bits are output at a 7.195MHz rate, and the beginning of the 1024th array word (1025th word following the 633 RVP8 Users Manual May 2003 Host Computer Commands command) corresponds exactly to the instant at which data at range zero are sampled by the RVP8. Note that the output rate can also be interpreted as a new bit coming every 1/48 km. In some cases this is a more useful view. As an example, suppose we wish to make the TGEN0 output be a 0.42 microsecond pretrigger pulse, with a rising edge exactly five microseconds prior to range zero. This would be done by setting bit 0 in input words 988, 989, and 990 following the TRIGWF command, and leaving all other bit 0s clear. Further, if TGEN1 was to be a 0.14 microsecond marker strobe at 20km, we would simply set bit 1 of input word 1984. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |PW3|PW2|PW1|PW0| | 0 1 1 0 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| H | | Transition Point of POLAR0 Control Line | Input 1

H This bit defines the sense of the control line when horizontal polarization is se-

lected. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Bits for 142.22 usec | Input 2

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Bits for zero range | Input 1025

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Bits for +142.08 usec | Input 2049

6.13 Define Pulse Width Control Bits and PRT Limits

(PWINFO) The RVP8 is equipped to control the radar transmitters pulse width and corresponding receiver bandwidth. There are four pulse/bandwidth codes, numbered simply 0 through 3. The association between codes and pulse widths is completely determined by the needs and capabilities of the particular radar on hand. In some cases, the zero code might represent 0.25 microsecond pulse width, and in other cases it may represent 2.0 microseconds. Likewise, some radars may use all four codes, whereas others have fewer options from which to choose. The PWINFO command defines what happens for each of the four possible codes, but does not actually select which code is being used. The later function is performed by SETPWF. The RVP8 drives four TTL output lines (PWBW0 3) which are intended to control the radar pulse/bandwidth hardware. Typically this control is via relays or solid-state switches in the transmitter and receiver. The user decides what state the four lines assume for each pulse width 634 RVP8 Users Manual May 2003 Host Computer Commands code. This is done using word #1 following the command, which contains four codes packed into one 16-bit word. The power-up default is to drive output line N low for a code of N, keeping all other lines high (Input of 7BDE Hex). The flexibility in defining the output bits usually makes the radar hardware connections very simple. For example, if pulsewidth selection relied on choosing one of four relays, then each PWBWn line could serve directly as a relay driver using the default pattern. For each pulse width there is a corresponding minimum trigger PRT permitted. This bound is intended to limit the transmitter duty cycle to a safe value under all conditions. PWINFO sets up these minimum PRTs using words 2 through 5 following the command. The maximum frequency of the internal trigger generator is then constrained at each pulse width to the indicated rate. This protection applies at all times, i.e., during noise sampling, during ray processing, and during the standby time between rays. The default PRT bounds are 2000, 1000, 750, and 500 Hertz (Inputs of 3000, 6000, 8000, and 12000). If your radar does not use all four pulse width codes, it is still a good idea to set the unused PRT limits to reasonable values. This way protection is still provided in the event that SETPWF accidently selects one of the unused states. If the internal trigger generator is not being used, then the PRT limits no longer affect the actual trigger rate and transmitter protection becomes the responsibility of the the user hardware. Finally, note that the entire pulse/bandwidth mechanism can be effectively turned off by setting the four bit patterns and the four PRT limits all to the same value. The PWINFO command can be disabled (for transmitter safety), so that PRT limits cannot accidently be changed by the host computer. When this is one, the RVP8 still reads the five input words, but no changes are made to the pulse width and PRT information. Thus, the command I/O behaves the same way, whether enabled or disabled. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 1 1 1 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Bits for PW 3 | Bits for PW 2 | Bits for PW 1 | Bits for PW 0 | Input 1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 0 | Input 2

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 1 | Input 3

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 2 | Input 4

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Min Trig Period (0.16667usec Increments) for Pulse Width 3 | Input 5

635 RVP8 Users Manual May 2003 Host Computer Commands 6.14 Set Pulse Width and PRF (SETPWF) This command selects the pulsewidth and trigger rate. A 2-bit pulse width code is passed in bits 8 and 9 of the command word, and selects one of four pulse widths as described under PWINFO. The new radar PRT is passed in word #1. For all processing modes that use a fixed trigger rate, this value defines the trigger period that is output at all times except during noise measurements. For Dual-PRF applications, this word defines the short period (high PRF) rate. The long period is internally computed as either 3/2, 4/3, or 5/4 the short period, and the trigger generator alternates between the short and long rates on each successive ray. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | (Rsv) | P.W. | | 1 0 0 0 0 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Desired Trigger Generator Period (0.16667usec Increments) | Input 1

When Input #1 is zero, then the arguments take on an alternate form that allows an array of N

(up to 64) trigger periods to be specified, and also gives much finer time resolution in the choice of each period. The XARGS command is first used to load an array of N 32-bit words that define the trigger period(s) in nanoseconds. The RVP8 will then generate triggers whose shapes

(relative starts and widths) are identical for each pulse, but whose periods follow the selected sequence. Trigger patterns such as these are intended to support research customers who use the realtime (I,Q) data stream directly. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Lower 16Bits of 32Bit Trigger Period in Nanoseconds | XARG 1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Upper 16Bits of 32Bit Trigger Period in Nanoseconds | XARG 2

. 6.15 Load Antenna Synchronization Table (LSYNC) The RVP8 can operate in a mode wherein radar data are acquired in synchronization with the antenna motion along either the azimuth or elevation axis. This special feature frees the user computer from having to separately monitor the antenna angles and request each data ray individually. To use this mode, it is assumed that TAG0-15 are wired to receive azimuth angles, and that TAG15-31 are wired to receive elevation. Angle input may be in the form of either 16-bit binary angles, or four-digit BCD. This synchronization mode is the only one which ascribes any meaning to the TAG inputs; ordinarily they are merely passed on to the user computer as ancillary information. Antenna synchronization is accomplished by way of a table of trigger angles. This table, which contains between three and 1024 angles, is used to define the angle boundaries for each processed ray. The trigger angles need not be uniformly spaced, nor must they span the full 636 RVP8 Users Manual May 2003 Host Computer Commands 360-degrees of rotation. This gives considerable flexibility in the choice of angles. For example, if local obstructions cause shadows in the radar image, then those regions can be skipped merely by omitting table entries in their vicinity. Likewise, as the antenna rotates data can be acquired within one or more sectors by simply specifying the appropriate sets of contiguous bearings at whatever angular resolution is desired. Note that on power-up the angle table is initialized to 360 values corresponding to integer-valued degrees from zero to 359. The synchronization algorithm works automatically with either clockwise or counterclockwise antenna rotation, and can tolerate any sequence of changes in direction, e.g., if the antenna itself is scanning a sector, or if it is turning erratically. Moreover, the trigger angles do not have to be hit exactly in order to start each new ray the antenna need only move across them. This minimizes the possibility of losing data due to missing codes in the angle encoders. The RVP8 will automatically produce an output ray after one second of waiting, even if no trigger angles have been crossed. This is to avoid timeouts with the host computer when the antenna is not moving at all. To use the synchronization mode, the trigger angle table is first loaded using the LSYNC command. The user chooses the number of table entries and then writes the required number of words to the RVP8. The angles must be supplied in a clockwise strictly increasing order, and they must neither reach nor pass zero degrees by the tables end. The first value, however, may be zero. Binary angle representation is used wherein Bit 15 represents 180 degrees, Bit 14 represents 90 degrees, etc. The Ld bit must be set in the command word to indicate that a new table size and set of angles are being loaded. A flag bit is to be set (See GPARM) if errors are detected when loading the table of angles. To actually enable synchronized operation the Ena command bit must eventually be set, and EL and BCD should be either set or cleared according to the users needs. These bits may be used independent of reloading the actual table values. Thus, antenna synchronization may be turned on and off without having to reload the table each time. However, if there were errors when the table was last loaded, the processor ignores the Ena bit and synchronization is forced off. Once enabled, PROC commands are then issued in the usual manner to acquire and process the radar data. Either the single-cycle or free-run PROC mode may be used. Data collection proceeds as usual, except that the rays are now automatically aligned with the trigger angles. The angle sync algorithm is dynamic and works as follows. Each ray begins immediately upon the users request, or upon completion of the previous ray when in continuous processing mode. At the start of the ray, the RVP8 finds the pair of sync angles that enclose the previous trigger angle. The current ray then runs until the antenna passes outside of either limit, at which point processing for that ray is terminated. Once this happens, a new trigger angle is assigned based on which limit was crossed. The maximum number of pulses that will be present in each ray during angle syncing is still given the by the Sample Size field of the SOPRM command. The actual number of pulses will be less only if a trigger angle is crossed before the full pulse count is reached. In general, you should set the Sample Size somewhat larger than the expected pulse count so that the trigger angle crossings make the best use of every available pulse when the antenna is scanning at the expected rate. 637 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |NoI|Ena|El |BCD|Ld | | 1 0 0 0 1 | Command

NoI Ena El BCD Ld Ordinarily, the potentially lengthy sync wait loop is terminated if the user writes additional words to the RVP8. Setting this bit prevents such interrupts. Beware that the processor loop can not be broken in this case except by moving the anten-

na across a trigger angle, or cycling the RESET_ line. Enables antenna synchronization. Synchronization is based on TAG1531 (Elevation) inputs, else TAG015 (Azi-

muth) is used. Specifies that TAG angle input is in the form of 4-digit Binary Coded Decimal;

otherwise, a 16-bit binary angle is assumed. Indicates that a new table size and array of values follow the command. If Ld = 0, then LSYNC is a one-word command only. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Number of Trigger Angles that Follow (3 1024) | Input 1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| (Ignored) | Input 2

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| First Trigger Angle (16-Bit Binary Angle) | Input 3

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Last Trigger Angle (16-Bit Binary Angle) |

6.16 Set/Clear User LED (SLED) This command simply turns the red user LED on and off under program control. The LED is on during the initial running of internal diagnostics, and then remains off unless changed by this command. Note that the red LED can be configured to serve as an internal activity indicator

(see TTY setups), in which case this command has no effect. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |LED| | 1 0 0 1 0 | Command

6.17 TTY Operation (TTYOP) This command controls the TTY chat mode interface to the host computer. The command can simulate the typing of characters on the RVP8s setup TTY. Characters entered in this manner are indistinguishable from those typed on the actual TTY; hence, whatever one can do via the 638 RVP8 Users Manual May 2003 Host Computer Commands TTY, one can also do via this command. The RVP8 sends all TTY output to whichever stream

(TTY, or host computer) provided the most recent input character. This command is also used to monitor the graphical data from the special scope plotting modes. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Operation | 1 0 0 1 1 | Command

The operation codes are as follows:

0 1 2 Sends the ASCII character in the upper byte of the word to the RVP8 as if it had been typed on the setup TTYs keyboard. Allow scope plotting data to be output whenever a plot is being drawn. All rele-

vant status and data words are output once upon each receipt of this command. Subsequently, status and data will be output only when a change has taken place. Disable the scope plotting output data. Any of the following types of data may be output by the RVP8 while the TTY monitor is running. The order of arrival of each data type is indeterminate, but all multi-word sequences will always be output as contiguous words. Individual TTY characters generated by the RVP8 are output in the low byte of the word, with the upper byte set to zeros. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 0 0 0 0 0 0 0 0 | ASCII Character | TTY Char

The status of the plotting modes is given in the following word. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 0 | |PLT| Status

PLT Indicates that a scope plot is being drawn now. The 2-bit intensities of each of 16 possible strokes of data is given in the following 4-word sequence. An intensity of zero represents OFF; one, two and three are successively brighter. 639 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 1 | 0 0 0 0 | Int 3 | Int 2 | Int 1 | Int 0 |

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 1 | 0 0 0 1 | Int 7 | Int 6 | Int 5 | Int 4 |

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 1 | 0 0 1 0 | Int 11| Int 10| Int 9 | Int 8 |

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 0 1 | 0 0 1 1 | Int 15| Int14 | Int 13| Int 12|

The data for each stroke of the plot is given by the following sequence of 501 words. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 1 0 | | Stroke Number | Plot Data

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 1 1 | Value to Plot (0 4095) | Word #1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 1 0 1 1 | Value to Plot (0 4095) | Word #500

. 6.18 Load Custom Range Normalization (LDRNV) Reflectivities computed by the RVP8 are ordinarily corrected for range effects by adding an offset in deciBels equal to 20 log(R / 1km), where R is the range in kilometers. This correction is based on a simple filled beam geometry, and is sufficiently accurate for most meteorological observations. The LDRNV command is provided for applications in which an alternate custom range correction is required, for example, if the radar receivers LNA were to be driven by an external user-supplied STC waveform. LDRNV loads a 251-word custom correction table holding values in hundredths of deciBels over five decades of log(range) from 0.01km to 1000km. There are 50 table entries per decade of range. Thus, the range in kilometers corresponding to an input word #N is 10

, and the default correction table (automatically used on power-up) is simply 40(N 101) . The table values are stored and interpolated whenever the RVP8 loads a new range mask (See LRMSK), at which point custom values for the actual user ranges are computed. The LDRNV command need be issued only once, but it must be done prior to choosing the working set of range bins.

2

N1 50 640 RVP8 Users Manual May 2003 Host Computer Commands The linear intervening gas attenuation correction (See SOPRM) is always added to the reflectivity data, regardless of whether default or custom range normalization is in effect. If this is undesirable, the intervening gas slope should be set to zero. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 1 0 1 0 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed Hundredths dB of Range Normalization for Range 0.01 km | Input 1

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed Hundredths dB of Range Normalization for Range 1000 km | Input 251

6.19 Read Back Internal Tables and Parameters (RBACK) This command permits some of the RVP8 internal tables to be read back for confirmation and diagnostic purposes. This command would not generally be used during normal data acquisition and processing. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Data to Show | | 1 0 1 1 0 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Number of words to output | Input 1

The data that can be returned are:

0 1 2 4 6 7 Full operational parameter table from last SOPRM command. Ray history array consisting of six words per ray for the last 40 rays (in reverse time order) that were processed. Each six-word group holds a. Actual number of samples that went into the ray b. Time since the last ray (in tenths of ms) c. Ending azimuth TAG bits d. Ending elevation TAG bits e. Starting azimuth TAG bits f. Starting elevation TAG bits Angle sync table from last LDSYNC command. Filter selection array from the last LFILT command. Custom range normalization from last LDRNV command. Samples of the TAG input lines at 4ms intervals. The sampling begins at the mo-

ment the RBACK command is received, and continues until the output count is reached. Each 32-bit sample is output as a pair of 16-bit words:

641 RVP8 Users Manual May 2003 Host Computer Commands a. Azimuth b. Elevation

(TAG bits 0 15)

(TAG bits 16 31) 8 10 Doppler clutter filter coefficients (Same format as for LFCOEFS command) Range mask spacing in cm for each pulsewidth 6.20 Pass Auxiliary Arguments to Opcodes (XARGS) This command provides a backward compatible mechanism for supplying additional (optional) arguments to other opcodes. The command may be used freely in the RVP8s instruction stream, even if the opcode being modified does not expect any optional arguments. XARGS will be a NOP in that case. To supply optional arguments to another opcode OP, the XARGS command is first executed with the additional argument count encoded in its upper 11-bits. This is followed by the array of between 0 and 2047 additional arguments. At this point the XARGS command is finished and the OP command is fetched as the next instruction. OP will execute normally, except that the additional arguments from XARGS can be picked up after its own input list has been read to completion. XARGS affects only the opcode that immediately follows it. The entire list of optional arguments is discarded after OP executes, even if OP did not use some or all of the list. However, if OP is yet another XARGS command, then the additional arguments that it supplies will be appended to the first set. In this way, XARGS can supply an arbitrarily large number of additional arguments. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Number of Additional Arguments N | 1 1 0 0 0 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| First Additional Argument | Input 1

. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Last Additional Argument | Input N

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| OP Command that accepts optional arguments | Command

. 6.21 Configure Ray Header Words (CFGHDR) The processed data that are output by the PROC command may contain optional header words that give additional information about each ray. This command configures the set of words that makeup each header. There are (up to) thirty two different choices of words or groups of words 642 RVP8 Users Manual May 2003 Host Computer Commands to include, as indicated by the bit mask following the command. Setting a bit requests that those words be included in the header, and be placed in the order implied by the sequence of the bits. Leaving all bits clear will suppress the header entirely; though this can also be done without changing the configuration via the NHD (No-Headers) bit in SOPRM Input #2. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 0 0 0 1 0 1 1 1 1 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Gpm|Tim|Pul|PRT|Tag| Input 1

Tag Four words containing two 32-Bit TAG samples, one from the beginning and one from the end of the ray:

Word #1 Word #2 Word #3 Word #4 TAG150 TAG3116 TAG150 TAG3116 Start of Ray Start of Ray End of Ray End of Ray

When the RVP8 is operating in dual PRF mode, bit zero of the start TAG word is replaced with a flag indicating that the rays PRF was low (0) or high (1).

When trigger blanking is enabled, bit zero of the end TAG word is replaced with a flag indicating that the trigger was blanked (0) or normal (1). Note that the data within a ray are considered to be invalid if any of the pulses that were used to compute the ray were blanked. Also, the RVP8 will output all zeroed data whenever a ray contains any blanked pulses. PRT Pul Tim Gpm PRT (Pulse Repetition Time) measured at the end of the ray. Same format as GPARM Word #30. The measured PRTs are forced to 0xFFFF (the maximum unsigned value) whenever the external trigger is expected but missing. Number of pulses that were used to compute the ray. Time stamp. Sixteen-bit counter incrementing at a rate of 1000 counts/sec, and sampled at the end of the ray. GPARM. Sends a copy of the 64-word GPARM output with each ray. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | Input 2

6.22 Configure Interference Filter (CFGINTF) The RVP8 can optionally apply an interference filter to its incoming (I,Q) data stream, with the goal of rejecting occasional and sparse interference from other (usually man-made) signal sources. The CFGINTF command is used to choose which filtering algorithm will be applied, and to configure its operation via additional XARGS parameters (See Section 6.20). 643 RVP8 Users Manual May 2003 Host Computer Commands If the XARGS are not supplied, then the filter parameters will simply retain their previous values. Thus, CFGINTF with no XARGS can be used to turn the interference filters On/Off without making any other changes to their threshold constants. Likewise, if only XARG 1 is supplied, then that single threshold value will be used for both C1 and C2. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Filter | 0 0 0 0 0 1 1 1 1 1 1 1 | Command

Filter Chooses which interference algorithm should be run. See Section 5.1.4 for a de-

scription of the available algorithms. 0: None (Interference filtering is disabled) 1: Alg.1 (Traditional JMA Algorithm) 2: Alg.2 (Alg.1 optimized for additive interference) 3: Alg.3 (Alg.2 with better statistics) We recommend that you choose Alg.3 for general operational use. The other algo-

rithms are included mostly for historical reasons. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Threshold Parameter C1 in Hundredths of deciBels | XARG 1

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Threshold Parameter C2 in Hundredths of deciBels | XARG 2

6.23 Set AFC level (SETAFC) This command sets the AFC level to a given value. The signed 16-bit span is identical to GPARM Output #51 which shows the present AFC level, i.e., corresponding to the 100% to

+100% AFC range that is defined in the Mb menu. The RVP8 will automatically convert the new level into whatever analog or digital AFC output format has been configured. The only exception is for the Motor/Integrator type of AFC loop, in which case this command does nothing. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 0 0 1 0 1 1 1 1 1 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 16Bit AFC/MFC Value (32768 through +32767) | Input 1

6.24 Set Trigger Timing Slew (SETSLEW) The Mt menu allows you to select a subset of triggers that can be slewed left and right in order to place the burst pulse accurately at range zero. This command allows you to manually set the present amount of slew. The input argument is in hundredths of microseconds, i.e., ranging from 327.68sec to +327.67sec. The actual span permitted by the RVP8 is +20sec. This is the same format used in GPARM Output #56 which shows the present slew value. 644 RVP8 Users Manual May 2003 Host Computer Commands 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 0 0 1 1 0 1 1 1 1 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Signed trigger slew in hundredths of microseconds | Input 1

6.25 Hunt for Burst Pulse (BPHUNT) This command starts up the internal procedure to hunt for a missing burst pulse when we are uncertain of both its time and frequency. Depending on how the hunting process has been configured in the Mb menu, the whole procedure may take several seconds to complete. The RVP8s host computer interface remains completely functional during this time, but any acquired data would certainly be questionable. GPARM status bits in word #55 indicate when the hunt procedure is running, and whether it has completed successfully. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| |Now| 0 0 0 0 1 1 1 1 1 1 1 1 | Command

Now Forces the hunt procedure to be started even if the burst pulse is already present. Normally the procedure will only be started when the burst pulse is missing at the time BPHUNT is given. 6.26 Configure Phase Modulation (CFGPHZ) This command configures the RVP8 phase control output lines, which determine the relative phase of each transmitted pulse. In some cases the phase sequence that is chosen will also have side effects elsewhere in the processor, e.g., different algorithms may be used in Random Phase mode according to the transmit sequence that is requested. Some of the phase sequences chosen by CFGPHZ also expect additional arguments to have been supplied by the XARGS command. Phase sequences are expressed as a list of N 16-bit binary angles representing the desired phase sequence. The sequence is assumed to be periodic with period N. The Mz command defines the correspondence between phase codes and phase angles, and is described in Section 3.3.8. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | PhSeq | 0 0 0 1 0 0 0 1 1 1 1 1 | Command

PhSeq=0 Selects No Modulation. The RVP8 outputs a constant default phase request as defined in the Mz menu. PhSeq=1 Selects a Random Phase sequence. This is also the default phase modulation that will be output following power-up. From the set of valid phase codes that are de-

fined in the Mz setup section, a random code is automatically chosen for each pulse. Each code has an equal probability of being chosen each time, and the 645 RVP8 Users Manual May 2003 Host Computer Commands choice is independent of any previous state. No XARG words accompany this command. PhSeq=2 Selects a User Defined sequence. If no XARGS have been supplied, then the RVP8 outputs the default idle phase that is defined in Mz. If XARGS are sup-

plied, then they are interpreted as a sequence of 16-bit binary angles. The RVP8 will make the best match between each desired angle and the closest realizable angle that the phase modulation hardware can produce. The maximum length of the sequence is 1024 pulses. PhSeq=3 Selects the SZ(8/64) sequence. This is a systematic code due to Sachidananda and Zrnic, which does a nice job separating and recovering first and second trip echoes in Random Phase mode. It will usually perform better than a truly random transmit sequence, especially when the processing interval is fairly short (as little as 32-pulses). With no XARGS, the RVP8 automatically generates the phase se-

quence using the closest realizable angles that the phase modulation hardware can produce. This is the recommended way to invoke SZ(8/64) coding. However, you may also supply your own 32-pulse angle sequence. 6.27 Set User IQ Bits (UIQBITS) Load user-specified bits that will be included with the pulse headers in the live (I,Q) data stream. The current permanent bits are stored right in the shared (I,Q) data segment, and a FIFO history is also maintained so that the bits can be associated with the data being acquired right now as the UIQBITS opcode is executed. Each 16-bit command arg specifies bits to Set/Clr in successive bytes of the structure. This allows user code to safely change some bits without affecting others. The permanent Set/Clr bits are updated in the signal processor and retain their value from the last time they were defined. The bits are repeated into all pulse headers. The ONCE bits, however, are transitory and will appear in only one pulse header each time they are set. The user bits from separate calls will never be collapsed into a single pulse header, even if the header and bit times indicate that they could. This means that each UIQBITS opcode will always result in at least one pulse header being tagged with exactly those data. This is generally what you want, since no other exact outcome could be guaranteed based on time-of-arrival alone. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| | 0 0 0 1 0 0 1 1 1 1 1 1 | Command

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 64 Permanent User Bits to SET | Inputs 14

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 64 Permanent User Bits to CLEAR | Inputs 58

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| 64 Transitory ONCE Bits | Inputs 912

646 RVP8 Users Manual May 2003 Host Computer Commands 6.28 Custom User Opcode (USRINTR and USRCONT) These opcodes are part of the open software extensions to the RVP8, which allow custom opcodes to be defined for each major mode of operation. Arguments may be passed into a custom opcode handler as an XARG list. Likewise, an optional array of words returned from that handler will appear after the command executes. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| User Bits | 1 1 1 1 1 0 |CON| 1 1 1 1 1 | Command

UserBits Four additional bits defined by the user to help subdivide the opcode functions if CON desired. If set, then the RVP8s IQ data acquisition thread proceeds continuously while the opcode is executed. If clear, then the IQ stream is interrupted prior to handling the call. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Optional Input Words | XARG List

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

| Optional Output Words | User Output

647

 

 

RVP8 Users Manual April 2003 Software Installation A. Software: Basics, Installation and Backup A.1 Overview The RVP8 and RCP8 are implemented using standard PCI components with some custom cards supplied by SIGMET. While seemingly very different products, these actually have very similar hardware and software. The software installation, configuration and backup/recovery procedures are nearly identical. For this reason, this appendix is written to cover both the RVP8 and RCP8. This appendix covers the following topics:

Login, logout and shutdown Software installation Software configuration System backup/recovery Software upgrade Network basics Section A.2 Section A.3 Section A.4 Section A.5 Section A.6 Section A.7 Your system is shipped with all software installed so you are really ready to start using the unit immediately after opening the box. You should read this appendix to become familiar with the general operating procedures, especially the system backup procedures which will help you if you ever need to re-install the software after a disaster or install an upgrade provided by SIGMET. Other references related to the software are:

RVP8 Programmers Manual: Describes the development environment, public source and APIs provided by SIGMET.

IRIS Utilities Manual: Describes utilities for radar calibration, test and maintenance that are shipped with the RVP8 and RCP8 A1 RVP8 Users Manual April 2003 Software Installation A.2 Basics of Login, Logout and Shutdown The RVP8 and RCP8 both use the Linux operating system and XWindows. When logging into the RVP8 either locally or over the network via telnet you will need to supply a user name and password. The system is tolerant of the AC power being suddenly turned-off, but in general it is recommended to follow a power-off shutdown procedure. These procedures are described in this section. Important: For network security reasons, both the RVP8 and RCP8 are shipped with remote access disabled. To learn how to enable telnet, refer to the end of Section A.7.2. A.2.1 Power up procedure The power switch is located on the lower right front of the unit. When you power the unit on, the RVP8 goes through an automatic startup of the operating system at the end of which the RVP8 software and performs powerup self tests. This is described in detail in Section 2.3.5. If you are not doing any diagnostic or software maintenance work on the system, there is no need to log-in after power-up; simply turn the unit on and your application software will take over. No operator intervention is required. However, to perform maintenance functions such as software upgrades, testing and backup/recovery, you will need to log-in. A.2.2 Local and remote login There are two ways to login to the RVP8:

Local login: The local keyboard, mouse and monitor can be used. Note these often are not connected on operational systems. SIGMET provides a keyboard and mouse with each system. The monitor is optional and may be provided by the customer, to SIGMET specification. Most VGA monitors will work.

Remote login: If telnet is enabled you can use this for remote access. Check with your network administrator. For the remainder of this discussion it is assumed that local login is used. A.2.3 Default operator and root login passwords There are two default users defined in the standard software installation:

root with password xxxxxxxx (8 lower case xs). This is for Operating System maintenance functions. operatorwith password xxxxxx (6 lower case xs). This is for RVP8 application software maintenance functions. For a complete list of supported utilities see Section 1.6. These are all described in detail in the IRIS Utilities Manual. A2 RVP8 Users Manual April 2003 Software Installation Your system administrator can change either of these passwords by using standard Linux password support. A.2.4 Login procedure Local login as operator after power-up

Connect keyboard, mouse and monitor and then cycle power on the system to force a reboot. This causes Linux to recognize these devices on power-up.

At the power-up login prompt type operator and press Enter. When prompted, provide the appropriate password (factory default is xxxxxx, 6 lower case xs). Logging-in as operator you will be taken to an X-Window screen.

Right-click the mouse and select New Window to get a terminal window. The top of the terminal window shows, for example:

operator on rvp81 : /home/operator i.e., your user name, the node name of the system and the current directory path. If you would like to have a terminal with a bigger font, you can type sigterm. Switching from operator to root login using su"

The easiest way to switch to a root login for system administration work is to type the super user command su and then give the root password. The prompt will change from $ to # indicating that you are root. Exiting su" root login to return to operator In an Xterminal where you have become the super user (su), simply type exit to return to operator. The prompt will change from # to $. Local root login after powerup To login as root after a powerup or after exiting XWindows, simply type root and press Enter at the login prompt, then give the appropriate password (factory default is xxxxxxxx, 8 lower case xs). You will be in a full screen terminal. This is not as convenient as XWindows since only one terminal can be displayed on the screen. If you need a second full screen terminal type Alt-F2. You can return to your original terminal by typing Alt-F1. The other function keys can provide additional terminals. A3 RVP8 Users Manual April 2003 A.2.5 Logout procedure Logout from XWindows Software Installation

Method 1: Right-click the mouse and select Exit.

Method 2: Simultaneously click Ctrl-Alt-Backspace. You will be logged out and the screen will show the initial login prompt. on the full screen terminal. Root Logout from full screen terminal If you loggedin as root from the power-up full screen terminal, A.2.6 Poweroff shutdown procedure If you need to swap PCI cards in the chassis, you must first do a poweroff shutdown as described here.. As either operator or root type poweroff. The system will go through a shutdown sequence. When it is done Power down will be displayed. At this point you can press the power switch located on the right lower front of the chassis. A4 RVP8 Users Manual April 2003 Software Installation A.3 Software Installation A.3.1 When to perform software installation When your unit arrives, it is shipped with all software installed. Therefore, software installation is usually not necessary at the initial installation. There are two occasions when you might want to re-install the software:

Installation of a new CDROM release from SIGMET.

Recovery in the event of disk corruption or failure. A.3.2 Preparing for the installation The following should be done before you perform the software installation:

Either locate or, if possible, make a backup of your custom configuration files per Section A.5. If you have made a backup in advance, then you will make the reinstallation much easier.

Locate your software installation CDROM that was originally supplied by SIGMET or perhaps you will perform an installation of an upgraded version supplied by SIGMET. In the event that you need a software installation CDROM, contact SIGMET (support@sigmet.com). These are provided free of charge by SIGMET. However, the specific version that was originally shipped with your system may no longer be available. In this case you will install an updated version.

Make sure that all PCI cards are properly installed.

From the as-Built documentation that is supplied with your system, verify the type of motherboard or SBC that is installed. If you cannot locate this, then you can check directly on the board itself by removing the top cover of the unit. For example, the Super Micro G2 motherboard is labeled in the rear left part of the board (relative to the front of the chassis). You may need a flashlight to read:

Super P4DPEG2

Connect the connector panel to the I/O-62 via the cable that is provided.

Connect the keyboard, mouse and monitor. Note that the VGA monitor is typically supplied by the customer.

For the RVP8, the IFD should be installed and powered so that it can pass its self tests later in the procedure. If an external reference clock is used for the IFD, then this should be active so that the unit can pass self tests. For complete information on hardware installation see Section 2. Once you have completed these steps, go to Section A.3.3 below. A5 RVP8 Users Manual April 2003 Software Installation A.3.3 Installing the system software After you have prepared for the installation, as described in the previous section, you are ready to install the software. Initial software installation steps

Ready the unit with keyboard, mouse, monitor, etc. as described in the previous section.

Switch the power on using the switch on the lower right front of the unit.

Press the eject button on the CDROM drive and when it opens, insert the RDA CDROM into the drive.

When prompted, press Del to enter the setup (lower right of number pad). Hint: If you get too busy inserting the CDROM and miss the BIOS setup prompt, simply power the unit off and on to start again, this time with the CDROM already in the drive. Setting the BIOS If the BIOS has been configured already during a previous installation or at the factory, then you should skip this step. Note that specific BIOS keystrokes and menus often change. Use this section as a general guide.

Reset to Defaults: In the BIOS setup, reset BIOS to default parameters. This is typically done by pressing F9 or in the Exit section and then confirming the YES/NO question.

Set Time: In the Main section, set the system time and date to UTC. This is a 24 hour clock (8:00 pm = 20:00).

Enable Floppy: In the Main section, set Legacy Diskette A: 1.44MB 3.5.

Set Device Boot Order: In the Boot section, select the boot order to be:

CDROM Floppy Hard Drive

(sometimes listed under Removable Devices)

Select SAVE and EXIT. The unit will reboot automatically from the CDROM. A6 RVP8 Users Manual April 2003 Software Installation Booting from the RDA Installation CDROM

When the BOOT: prompt is presented, type the following command, depending on the version of CPU that is in your system:

For Supermicro G2 board type:

linux ks=cdrom:/ks/ksgbhda.cfg For Supermicro Q board type:

linux ks=cdrom:/ks/ks100.had.cfg4.8 After typing the appropriate command press ENTER.

The software is installed automatically at this point. If prompted with:

Would you like to initialize this drive?, select YES (using the TAB key) and then select ENTER.

After about 10 minutes, the CDROM ejects. Remove it. The PC reboots automatically. Continue to next section. Installation steps to enable automatic startup of the RDA software

At login prompt, login as: root and password xxxxxxxx (8 xs)

If you are installing an RVP8, type:

chkconfig level 2345 dspexport_init on chkconfig level 016 dspexport_init off chkconfig level 2345 rvp8_init on If you are installing an RCP8, type:

chkconfig level 2345 rcp8_init on

Logout of root by typing exit. A7 RVP8 Users Manual April 2003 Software Installation Installation steps to flash FPGAs in SIGMET devices In this section you will be installing FPGA software into each of the SIGMET components. You will need to make an inventory of what is in your system and then issue an rdaflash command to each one as described below:

Login as operator with password xxxxxx (6 xs)

You will enter XWindows. Right click the mouse and start a terminal window.

For each SIGMET component (italic) type the appropriate command (bold):

SIGMET Component Unit ID If RVP8, type:

Standard RVP8/Rx Card Standard I/O62 Card 0 0 rdaflash program rvp8rx0 rdaflash program io620 Standard Connector Panel 0 rdaflash program io62cp0 Optional RVP8/Tx Card Optional 2nd RVP8/Rx 0 1 rdaflash program rvp8tx0 rdaflash program rvp8rx1 Standard I/O62 Card 0 If RCP8, type:

rdaflash program io620 Standard Connector Panel 0 rdaflash program io62cp0

Do a system shutdown by typing poweroff

When Power down is displayed, turn power off with power switch on lower right of front panel. This completes the FPGA software installation. A8 RVP8 Users Manual April 2003 Software Installation Reboot power-up check and RDA diagnostics After you have completed the installation steps above, you should reboot the unit. You can observe the progress of the reboot on the monitor. In addition, the front panel LED display will show the time of the reboot and display diagnostic messages. Typically about 1 minute is required for the system to complete reboot. After the reboot is completed:

Verify that the front panel LED display does not indicate any faults.

Log-in as operator, run dspx and issue the v command. Check the results against the example in Section 3.1.4. Note that both the IFD and connector panel should be installed and connected. An example session is shown below:

$ dspx Digital Signal Processor Chat Mode Checking for code upgrades... Okay

(Type ^C to exit Chat Mode)

(hit Esc to start) SIGMET Incorporated, USA RVP8 Digital IF Signal Processor V1.10(Pol) RVP8> v Important: When you are done, type quit and then Ctrl-C to exit dspx.

Stop the rvp8 (or rcp8) process by typing:

$ killall rvp8 (or rcp8)

Run the following diagnostics and observe the results:

(for RVP8 and RCP8 systems)

$ rdadiags io620

$ rdadiags io62cp0 tests I/O62 tests connector panel

(for RVP8 systems only)

$ rdadiags rvp8rx0 Run these also for any optional RVP8 cards such as:

$ rdadiags rvp8tx0

$ rdadiags rvp8rx1 tests RVP8/Tx tests 2nd RVP8/Rx

Restart the RVP8 or RCP8 process by typing (for the RVP8 example):

$ rvp8 &

Verify that the restart messages show no faults. A9 RVP8 Users Manual April 2003 Software Installation A.4 System Software Configuration After the receiving your unit from the factory, or after software reinstallation, there are several configuration steps required to customize your system for your particular environment and application. The configuration tools available for this are summarized in the table below. Configuration Tool RDA Device setup utility RVP8 setup_dsp.conf setup_ant.conf RCP8 TTY setups RVP8 rvp8.conf rcp8.conf RCP8 Description of Configuration Features Configures the local environment required to run RVP8 the support utilities such as ascope and dspx. Examples include radar equation parameters that are required for calibration, pulse width definitions and PRF request limits. Configures the local environment required to run the RCP8 support utilities that such as antenna or bitex. Examples include, max allowed AZ/EL ve locity request, MIN and MAX elevation angles that can be requested and LAT/LON of radar for sun tracking. Defines the details of the sampling and processing algorithms as well as the operational configuration of the system. Examples include, IF filter de sign and selection, PRF limits, relative trigger timing, dual polarization fea tures. Used to configure which status and control bits are available and define the antenna servo control parameters. Examples include, physical or virtual tachometer selection, shutdown safety criteria and internal antenna simula tor on/off. softplane.conf RVP8 RCP8 File that is edited which defines the various I/O signals on the I/O62 con nector panel, pin by pin. For example, whether a line is an input or output, nector panel, pinbypin. For example, whether a line is an input or output, electrical spec such as RS422 or TTL, what local variable name is associat ed with each line. Important: Both the setup utility and the TTY setups must be configured to customize your system. This is part of the installation procedure. All of the configuration results are stored as ASCII text .conf files, typically in a directory called /usr/sigmet/ (factory default). The file names are indicated in the table above. Each file has a factory default configuration file that is stored in the template directory (the default is

/usr/sigmet/config_template/init/). An advantage of this approach is that for a radar network with identical hardware, configuration maintenance can be performed by copying pre-tested files over the network. The following serve as references and are not repeated here:

setup utility IRIS Utilities Manual RVP8 TTY setups RVP8 Users Manual RCP8 TTY setups RCP8 Users Manual The configuration of the softplane.conf file is described below. A10 RVP8 Users Manual April 2003 Software Installation A.4.1 Configuring the softplane.conf file What is the softplane.conf file ?

The softplane.conf file is used to define pinbypin assignment of I/O functions to various connectors on the I/O-62 connector panel. It is a plain text ASCII file that is self-documented. Since the RVP8 and RCP8 have virtually no jumpers, or wirewrap, all I/O configuration on the I/O-62 connector panel is done by software approach according to this file. Where is softplane.conf ?

The file resides in the IRIS_CONFIG directory. Typically this is /usr/sigmet/config (this is the default directory that is factory installed). The factory configurations are also available in the

/usr/sigmet/template/init directory so that you can always return to the factory defaults if you need to. When do I need to change softplane.conf ?

The softplane.conf file that is shipped with your system is configured for a standard connector panel with I/O as described in Appendix B. As long as you use the standard I/O pin assignments, then you do not need to change softplane.conf. If you need to redefine some of the I/O pins on the connector panel, or add additional SIGMET cards such as a second I/O-62 then you must change softplane.conf. Editing softplane.conf You will need to use a text editor to modify the softplane.conf file. There are two editors included in the system:

vi The generic UNIX editor that is available on every UNIX system. It is really arcane to use, but many people know how to use it out of necessity or they are simply used to it now. emacs:

support when you are in XWindows so it a little easier to learn than vi. This is more user friendly with keyboard commands and mouse If you are not familiar with either of these, then you will need to either find someone who is or learn how to use these tools. To start an editing session you would do the following as operator:

$ cd /usr/sigmet/config

$ vi softplane.conf or emacs softplane.conf A11 RVP8 Users Manual April 2003 softplane.conf file example Software Installation An example from the beginning and some excerpts from the softplane.conf file are shown below

(note that the command cat causes the file to be listed on a terminal):

$ cat /usr/sigmet/config/softplane.conf

# * Softplane Configuration File *

# The following general purpose control and status signals

# can be routed to/from any available hardware pin. The ~

# prefix character may be used for signal inversion.

# Control Outputs Status Inputs

# cPedAZ[15:0] sPedAZ[15:0]

# cPedEL[15:0] sPedEL[15:0]

# cEarthAZ[15:0] sServoPwr

# cEarthEL[15:0] sLocal

# cServoPwr sStandby

# cCabinetRelay sLowerEL

# cTransmitPwr sUpperEL

# cPWidth[3:0] sTransmitPwr

# cTrigBlank sTransmitLocal

# cRadiateOn sPWidth[3:0]

# cRadiateOff sTrigBlank

# cReset sRadiate

# cIrisMode[2:0] sAirflowFlt

# cAux[63:0] sWavegpFlt

# true sInterlockFlt

# false sMagCurrentFlt

# sReset

# sIrisMode[2:0]

# sAux[319:0]

splConfig.sVersion = 7.32

# IO62 Slot #0

splConfig.Io62[0].lInUse = 1

# The remote backpanel type should be one of the following:

# Direct : Direct I/O with IO62 connector itself

# IO62CP : Standard IO62CP connector panel

# RVP88D : RVP8 portion of WSR88D panel

# RCP88D : RCP8 portion of WSR88D panel

splConfig.Io62[1].sExtPanel = IO62CP

# TTL/CMOS on J1

splConfig.Io62[0].Opt.Cp.J1.pin01 = sPedAZ[0]

splConfig.Io62[0].Opt.Cp.J1.pin02 = sPedAZ[1]

splConfig.Io62[0].Opt.Cp.J1.pin03 = sPedAZ[2]

... A12 RVP8 Users Manual April 2003 Software Installation

# Relays and relay drivers on J6

splConfig.Io62[0].Opt.Cp.J6_IntRelay1 =

splConfig.Io62[0].Opt.Cp.J6_IntRelay2 =

splConfig.Io62[0].Opt.Cp.J6_IntRelay3 =

splConfig.Io62[0].Opt.Cp.J6_ExtRelay1 =

splConfig.Io62[0].Opt.Cp.J6_ExtRelay2 =

splConfig.Io62[0].Opt.Cp.J6_ExtRelay3 =

splConfig.Io62[0].Opt.Cp.J6_ExtRelay4 =

# BNC testpoint monitors

splConfig.Io62[0].Opt.Cp.J13_BNC =

splConfig.Io62[0].Opt.Cp.J16_BNC =

# BNC trigger drivers direct from IO62 PCI card.

# Special signals trigger[8:1] may also be used here.

splConfig.Io62[0].Opt.Cp.J14_BNC =

splConfig.Io62[0].Opt.Cp.J15_BNC =

splConfig.Io62[0].Opt.Cp.J17_BNC =

splConfig.Io62[0].Opt.Cp.J18_BNC =

# RS232 TTY transmitters from IO62

splConfig.Io62[0].Opt.Cp.TTY0_Tx =

splConfig.Io62[0].Opt.Cp.TTY1_Tx =

# IO62 Slot #1

splConfig.Io62[1].lInUse = 0

# IO62 Slot #2

splConfig.Io62[2].lInUse = 0

# <End of softplane definitions>

A13 RVP8 Users Manual April 2003 Software Installation softplane. conf organization and syntax The softplane.conf file is used to define every I/O pin on every connector, on the PCI cards themselves and on the connector panel. There are two primary definitions that are made for each pin:

Physical interface- the electrical properties (RS422 output, analog input, TTL output, etc.).

Logical interface- The internal variable name that is associated with each pin. With this in mind, we can describe the syntax of the file.

# at the beginning of a line indicates a comment. These are used for internal documentation and if you make changes you should comment them, for example

# TTL I/O on J7

# Modification by REP on 2 Apr 03

# Added new interlock input on connector panel J7 pin07

The top part of the file provides a list of internal variables names that are used to define the logical interface to the softplane. These are divided into status inputs

(also called indicators) and control outputs (also called requests). For example, sPedAZ0 corresponds to the LSB of a digital azimuth angle relative to the antenna pedestal. The tables on the next page provide a summary of the available status and control variable names. Important: This table is subject to change

Each definition line in the file starts with the keyword text:

# splConfig...

The first un-commented line of the file indicates the version of the IRIS support software that was last used to machinegenerate the file. This is an information only field for traceability purposes and is thus not edited. In the example we have this shown as:

# splConfig.sVersion = 7.32 A14 RVP8 Users Manual April 2003 Software Installation Summary of softplane.conf Status and Control Bits Control Output Meaning/Interpretation cPedAZ[15:0]

cPedEL[15:0]

cEarthAZ[15:0]

cEarthEL[15:0]

16 bits of antenna azimuth angle relative to the pedestal (fixed base system) 16 bits of antenna elevation angle relative to the pedestal (fixed base system) 16 bits of antenna azimuth angle relative to the earth (moving platform) 16 bits of antenna elevation angle relative to the earth (moving platform) cServoPwr To control servo power on cCabinetRelay To control a relay signal cTransmitPwr cPWidth[3:0]

cTrigBlank cRadiateOn cRadiateOff cReset cIrisMode[2:0]

cAux[63:0]

true false Request transmit power on Request one of four pulse widths Trigger blanking signal Request radiate on Request for radiate off Request a reset of external equipment Request the application software (e.g., IRIS) to switch to 1 of 8 operating modes. Arbitrarily assigned output requests Internal logic variable Internal logic variable Status Input Meaning/Interpretation sPedAZ[15:0]

sPedEL[15:0]

sServoPwr sLocal sStandby sLowerEL sUpperEL sTransmitPwr sTransmitLocal sPWidth[3:0]

sTrigBlank sRadiate sAirflowFlt sWavegpFlt 16 bits of antenna azimuth angle relative to the pedestal (fixed base system) 16 bits of antenna elevation angle relative to the pedestal (fixed base system) Servo power on indicator Antenna local mode indicator, usually tied to an external local/remote switch. Radar ready to radiate indicator Lower limit switch indicator Upper limit switch indicator Transmitter cabinet power on indicator Transmitter local mode indicator, usually tied to an external local/remote switch. Indicator of the current pulse width Indicator that trigger blanking is requested, usually from an external source. Radiate on indicator Cooling airflow fault indicator Wave guide pressure fault indicator sInterlockFlt Master interlock fault indicator sMagCurrentFlt Transmitter overload fault indicator sReset Request for reset coming from external source sIrisMode[2:0]

Information on which operating mode is active in the application software sAux[319:0]

Arbitrary status indicators A15 RVP8 Users Manual April 2003 Software Installation

Next, each piece of hardware is identified as being either in use or not in use. splConfig.Io62[0].InUse = 1 if in use splConfig.Io62[0].InUse = 0 if unused or not installed Currently, the I/O-62 is the only I/O device supported by the softplane.

The method of connecting to the I/O-62 is specified next, for example:

splConfig.Io62[0].sExtPanel = DIRECT Currently, the options are:

Type of Connection softplane Descriptor Direct connect to I/O-62 via 62 pin connector I/O-62 Connector Panel (used for RVP8 and RCP8) WSR88D connector panel, RVP8 portion WSR88D connector panel, RCP8 portion DIRECT IO62CP RVP88D RCP88D

The assignments for each connector and each pin are then made. For convenience, these are usually grouped together by connector. For example lets say that , Pin 1 of connector J1 on the I/O-62 connector panel is assigned to be the LSB of the input azimuth angle, i.e.,

# TTL/CMOS on J1

splConfig.Io62[0].Opt.Cp.J1.pin01 = sPedAZ[0]

The notation indicates that no assignment is made.

# BNC testpoint monitors

splConfig.Io62[0].Opt.Cp.J13_BNC =

In the example above the pin name is J13_BNC.

Putting a ~ in front of a logic variable inverts the variable. splConfig.Io62[0].Opt.Cp.J1.pin03 = ~sPedAZ[2]

Check in the /usr/sigmet/config_template/init directory for other examples of softplane configurations. A16 RVP8 Users Manual April 2003 Software Installation A.5 System Backup and Recovery Because both the operating system and the RDA software are contained on the RDA CDROM, in the event of a serious failure, the complete software is simply re-installed from scratch. There are however, a few files that contain your custom configurations. In general these are files in the

/usr/sigmet/config directory and the /etc directory. In fact, since they are all simple text files, they will, in most cases, fit onto a 1.44 MB 3.5 floppy diskette. SIGMET provides two utilities for backup/restore:

rda_backup- finds all files modified after the original installation (or reinstallation), puts them into a compressed UNIX tar file and copies the result to either a floppy disk or a directory on the hard disk. System created files in directories such as /tmp and /var are excluded from the backup. rda_restore- restores the contents of a backup tar file from floppy disk to the hard disk to the RVP8. In the case where the backup tar file is written to a directory on the hard disk, the user can then use ftp to put it on another computer on the network, or alternatively, put the file on CDROM via the CDRW device. This section describes the use of the rda_backup and rda_restore utilities. A.5.1 System Backup When to make a backup You should make a backup whenever you have made a change to the configuration of your system: Examples include:

Changing softplane.conf or other .conf files in /usr/sigmet/config.

Changing files related to networking or security in /etc. SIGMET does not recommend that you attempt to backup individual files. Instead you should use the backup procedure described here since it will make the restore much easier, plus you might miss something important that rda_backup will find. Backup Media There are two primary media for backup:

1.44 MB floppy disk drive (FDD)

A directory on the local hard disk drive (HDD) In most cases you will use the 1.44 MB FDD approach. You would backup to an HDD directory in the event that a backup, because it is too large, fails on the floppy . If you use the HDD approach you must either transfer the backup to a CDROM via the CDRW, or use ftp to copy files to another machine. See Section A.5.3 for the procedure. The next two sections describe how to prepare these two media. A17 RVP8 Users Manual April 2003 Software Installation Preparing the floppy backup media Every time you backup, you should use a freshly formatted floppy. It is possible to have several backups on a single floppy, but this is a bit risky if that diskette fails. Indeed some system managers even make two backups for added security. This is a smart thing to do. There are three ways to format a floppy:

Purchase formatted floppies. This is the easy way.

Format the floppy on a Windows machine. Simply select the floppy drive

(usually A:) under My Computer and then right click the mouse to select Format

Use Linux to format the floppy. The command (as root) is:

# mkfs.msdos v n RVPBACKUP /dev/fd0 Here the text RVPBACKUP serves as the DOS volume label for the floppy. For and RCP8 use the text RCPBACKUP. You can use other text if you want, but do it in upper case with no spaces or special characters. It is also assumed that the floppy drive is /dev/fd0. After you have a formatted floppy, the next thing to do is to LABEL IT, for example, write on the label RVP Date e.g.,YYMMDD A18 RVP8 Users Manual April 2003 Software Installation Mounting the floppy backup media Insert the floppy disk into the drive and then mount it (first use the su command to become root):

$ su Password:

# mount /dev/fd0 /mnt/floppy If there is a problem with this, check that there is a directory called /mnt/floppy. If not, create it as root with:

# mkdir /mnt/floppy It is a good idea to make sure that the floppy does not contain anything from a previous backup that you want so after you mount it check it with:

# cd /mnt/floppy

# ls als If the floppy disk contains files from a previous backup that you want to keep, select another disk. Preparing a hard disk backup directory In the case that you are using a directory on the hard disk, as operator create a directory such as

/tmp/backup.

$ cd /tmp

$ mkdir backup Backup files will be written to this directory with unique, machine generated file names that contain the YYMMDDHHMMSS time code. A19 RVP8 Users Manual April 2003 Running rda_backup Software Installation After the media has been prepared and mounted (in the case of an FDD), then simply type the command:

$ rda_backup v /mnt/floppy up for floppy disk back-

In the case of a hard disk backup to a directory such as /tmp/backup you would type:

$ rda_backup v /tmp/backup for hard disk backup The rda_backup utility will then check all of the directories where you have likely made configuration file changes. Any files that were modified since the original installation will be included in the backup. If you use the v option when starting rda_backup, then a listing of files will be displayed on the terminal. When the backup is complete, the terminal will show:

... Backup Complete: <File name>

0.9 MB 20 Files

Un-mounting and removing the floppy To unmount the floppy, become root via the su command and type:

$ su Password:

# cd /

# umount /dev/fd0 You may now push the eject button on the front of the drive to remove the floppy. Double check that it is labeled with the proper date. The most common problem encountered when un-mounting is that the FDD is in use. This means that a terminal is in the /mnt/floppy directory. Typing cd / will take a terminal out of the FDD directory. A20 RVP8 Users Manual April 2003 A.5.2 System Recovery Recovering an entire system Software Installation In the event that your system becomes unbootable perhaps because of a disk failure or corruption, you will simply reinstall the entire system per Section A.3.3, and then use your rda_backup floppy disk and the rda_restore utility to recover your custom configuration files. Recovering the configuration files is described below:

In the event of a hard disk failure, you will first need to replace the standard IDE hard disk before attempting to recover your system. Most computer stores will carry such a disk or you can contact support@sigmet.com to purchase a new one. Mounting the floppy or CDROM If you are recovering from a floppy drive or CDROM, then you must first mount these devices.

Mounting the floppy is described in Section A.5.1.

Mounting the CDROM is described in Section A.6.5. You must be root to mount devices. Use the su command to switch from operator to root. Type exit to switch back to operator. After the floppy is mounted, you should check to verify that the backup file that you want is indeed on the disk. Do this as follows:

$ cd /mnt/floppy

$ ls als This will give you a listing of files on the floppy. The procedure for a CDROM is the same except the device is /mnt/cdrom. Running rda_restore After the media has been mounted, run the rda_restore utility as operator. In the example below, it is assumed that the device is /mnt/floppy.

$ rda_restore v /mnt/floppy Other possible devices are a CDROM (e.g., /mnt/cdrom) or a hard disk drive directory (e.g.,

/tmp/backup). The v command will provide a list of all files that were restored. At the end of the restore you will get a message:

... Restore Complete <filename>

0.9 MB 20 Files

All that remains is to unmount and remove the floppy (this is done as root) as described below. A21 RVP8 Users Manual April 2003 Software Installation Un-mounting and removing the floppy or CDROM In the case of a floppy, become root and then issue the umount command:

$ su Password:

# cd /

# umount /dev/fd0 (Note: spelling is indeed umount) You may now push the button to eject the floppy. For a CDROM, you can use the eject command (instead of umount):

# eject This completes the restoration of your custom configuration files. A.5.3 Transferring a backup file from the RVP8 hard disk If you used rda_backup to make a backup file on the hard disk (e.g., in the /tmp/backup directory), then you need to transfer this file to another medium for safety in case the hard disk fails. There are three options:

ftp to another networked computer

Copy to the floppy

Copy to the CDROM These are described below. ftp to another computer This assumes that there is another computer on the network, that you know its IP address or it is configured in your /etc/hosts file and that the security settings on the other computer permit ftp. Check with your network manager to verify these criteria. For this example, it is assumed that you made your backup to a directory called /tmp/backup and that you are going to send it to another computer in the /tmp directory. To copy the backup file login as operator and in an X-Terminal type:

$ cd /tmp/backup (or use the actual directory if different)

$ la als

(to view the files in the directory) Identify the file that you want to transfer via ftp and write down its name, then:

$ ftp <hostname or IP address>

ftp> cd /tmp ftp> put <filename of backup in /tmp/backup>

ftp> quit

The backup file is now on the other computer in the directory /tmp A22 RVP8 Users Manual April 2003 Copy to a floppy Software Installation First check the size of the backup file to determine if it will fit on a floppy. To do this for backup files stored in /tmp/backup:

$ cd /tmp/backup

$ ls als The file size in bytes is shown just to the left of the date column. To fit on a floppy the backup file that you want to copy it must be less than 1,440,000 bytes (1.44 MB). If it is larger than this you cannot use the floppy approach. Note backup filename that you want to copy from the /tmp/backup to the floppy. Then:

Mount the floppy as described in Section A.5.1.

Copy the file to the floppy using the cp command:

# cp /tmp/backup/<filename> /mnt/floppy where the filename corresponds to the backup file that you want to copy.

Verify that the file was properly copied by typing:

$ cd /mnt/floppy

$ ls als

Un-mount the floppy as root with the commands:

# cd /

# umount /dev/fd0 Copy to a CDROM For large backup files that exceed 1.44 MB, then you can use the CDRW to write a CDROM. To do this cd to the root of the directory you want to make into a cdrom. Using the example of backups stored in /tmp/backup, as operator type,

# cd /tmp/backup

# mkisofs v V RVP8 SETUP o /tmp/rvp8.iso /tmp/backup Where the volume label is arbitrary text specified in the quotes (e.g., RVP8 SETUP), file

/tmp/rvp8.iso is the the temporary iso image file you are building. You can call this anything. To actually burn the cdrom, place a blank write-once or rewriteable disk into the CDRW and then type:

# cdrecord v speed=8 dev=0,0,0 eject /tmp/rvp8.iso

(Note the comma delimiters in 0,0,0) The specific options might be a bit different based on hardware. For example the max speed, or the device if there are more than one scsi devices. You can type cdrecord scanbus to see all the scsi devices. If the CDROM drive is not in the list then you cannot use this procedure. However, for a standard SIGMET installation it will show in the list. A23 RVP8 Users Manual April 2003 Software Installation A.6 Software Upgrade and Support A.6.1 Where to get software upgrades The RVP8 and RCP8 (collectively the RDA) are active products. New features and bug repairs are provided in the form of software upgrades. Software upgrades from SIGMET can be obtained from two sources:

RDA Network Upgrades- These are available from ftp.sigmet.com. For example, to obtain the release RDA 8.00 you would go to:

ftp.sigmet.com/outgoing/releases/rda8.00 Section A.6.4 shows a typical ftp session. These public releases are FREE of charge but do not include support services unless you are under warranty or have purchased a support contract from SIGMET. Contact support@sigmet.com if you need to arrange a support contract.

CDROM Upgrades- these are provided as part of a support contract and contain manuals and source code as well as the operational software. A.6.2 When should I upgrade If your system is working fine and you do not require the new features of a release, then often the best thing is to NOT upgrade. Check the release notes available at www.sigmet.com in the customer support section to see what changes have been made since your current release was installed. Be sure to check the release notes for all intervening releases. To check the release that you have currently installed, you can type the command:

$ show_machine_code version IRIS Version 8.00 (indicates version 8.00) A.6.3 How should I upgrade There are two basic upgrade techniques:

CDROM Full Re-Install- Backup your configuration files and network files and then do an install from scratch as described in Section A.3.3. This is not the preferred technique since it is possible that the backup of configuration files will be incomplete.

Upgrade using install utility- This is the preferred technique since it leaves all configuration files intact. This is described in Section A.6.5. Once you have decided on either a network or CDROM upgrade, then proceed with the upgrade installation as described in the sections below. A24 RVP8 Users Manual April 2003 Software Installation A.6.4 Getting the network upgrade files There are two ways to get the network upgrade files. Both techniques use ftp to get the files from ftp.sigmet.com. The ftp client service is enabled on the RVP8 allowing you to run an ftp session on the RVP8 and get files from another networked computer:

Use the RVP8 to get the files- a one-step procedure that requires that you have internet access from the RVP8.

Use another machine on the network a two-step procedure to first ftp the files from SIGMET to another computer, and then get them from this machine by running ftp on RVP8. Note that an alternative is to copy the files to a CDROM and then mount the CDROM on the RVP8 and copy the files. No matter what technique you use, you will need some basic familiarity with ftp. Here we will assume that the RVP8 has direct internet access (the one-step procedure). The two-step procedure is analogous. Important: The default security configuration allows the ftp client to run locally on the RVP8, but does not allow ftp access from other systems to the RVP8. Therefore, you must always run ftp from the RVP8 to get the files there. The one-step approach: Direct download to RVP8

On the RVP8, create a directory called /tmp/rdaX.XX. Here the X.XX is the version number of the RDA software that you want to install. This naming convention makes it easy to identify the version of the install files. As operator type (assuming version 8.00 for all examples here):

$ cd /

$ mkdir /tmp/rda8.00

Position yourself in the /temp directory by typing:

$ cd /tmp/rda8.00 Note that on a windows machine, all of the commands below can be typed in the MSDOS prompt window (remember to use the \ backslash for DOS).

Start ftp and follow the sample session below (your responses are indicated by bold)

$ ftp ftp.sigmet.com Connected to ftp.sigmet.com 220 Welcome to SIGMET Name: anonymous 331 Guest login ok, send your complete email address as password. Password: <Use your email address>

230 Guest login ok, access restrictions apply. ftp> cd outgoing/releases/

A25 RVP8 Users Manual April 2003 ftp> dir Software Installation

You will see a directory listing of available releases. You are looking for an rda release. Assume it is rda8.00, then:

ftp> cd rda8.00 ftp> dir

Now you will see a list of files with file sizes. If you have a low-speed link, then you will want to download only a minimal installation which consists of:

app.gz install install.gz install.rf instiris

Make a list of the files that you want to download including at least the five files in the list above, and then prepare to download by selecting BINARY file transfer:

ftp> bin 200 Type set to I. Important: If you do not specify BINARY transfer, the download will not work.

Now get the files, for example:

ftp> get app.z 200 PORT command successful. 150 Opening BINARY mode data connection for app.gz (4897560 bytes) 226 Transfer complete. You will get a confirmation that BINARY transfer is being used and the size of the file in bytes is displayed. Depending on the size of the file and the speed of your connection, the download could take many minutes. When the file transfer is completed, you will get a confirmation message. You can also use the multiple get command mget to get all of the files:

ftp> mget *

You will be prompted for each file download so you can still pick- and-choose by typing y or n to select (yes or no).

After you have downloaded all of the files, then end your session by typing:

ftp> quit 221 Goodbye

$ (back to UNIX prompt) For the one-step approach, you have all of the files that you need in the directory /tmp/rda8.00 on the RVP8. A26 RVP8 Users Manual April 2003 Software Installation Completing the two-step approach using another computer The two step approach is to use another computer to get the upgrade files and then get these files on the RVP8. The first step of getting the files from SIGMET is done analogus to the one-step approach described above. The second step is to ftp the files from the other computer to the RVP8. This is also analogous to the procedure described above. An alternative is to put the files on a CDROM, mount the CDROM on the RVP8 and then copy the files to the RVP8. The end result of all these various procedures is that the upgrade files are on the RVP8 in a directory called /tmp/rdaX.XX. N Set the modes on the files Become root using the su command and password. Go to the RVP8 directory where the files were downloaded and change the mode on two of the files that require execute privilege, i.e.,

# cd /tmp/rda8.00

# chmod +x install

# chmod +x instiris You are now ready to move on to the next section. Alternative download technique using a browser An alternative, but somewhat less reliable approach to using the manual ftp commands is to use a browser such as Netscape. To connect to the SIGMET ftp site, simply typein the address ftp://ftp.sigmet.com You can then click on outgoing/releases/rdaXX.X to get a list of files to download. While holding the Shift key, click the file that you want to download. You will be prompted to select a destination directory and file name:

Warning: Use this technique with caution only if you are sure that you know how your browser is functioning. Each browser is different. Some may performASCII rather than BINARY transfers. Also, some may re-name the files when they are copied. If this is the case, then be sure to re-name them back to the original name, with lower-case letters. A27 RVP8 Users Manual April 2003 Software Installation A.6.5 Starting the install utility The install utility is a graphical user interface that allows you to install SIGMET-supplied software either as a new installation or as an upgrade. In the case of the RDA, install is used to perform software upgrades only. New RDA installations use the procedure described in Section A.3.3 since this also conveniently installs the proper Linux operating system in one step. install can be used to upgrade from either of two sources:

From a release CDROM provided by SIGMET.

From files placed in a local directory (e.g., /tmp/rdaX.XX). These files are obtained via an ftp download as described in the previous sections. Login as operator to start XWindows Install uses XWindows, so must be run from an Xterminal rather than the full scree text display. Login initially as operator to start XWindows. Start a terminal and become root by issuing the su command and password (default is 8xs- xxxxxxxx). Stop all SIGMET applications and processes Before you can actually do the upgrade, you must make certain that all SIGMET applications are stopped. You can do this by exiting any utilities and then typing (as root) killall rvp8 (or rcp8). Then type ps_iris to verify that all SIGMET processes are stopped. If there are remaining processes, you can stop them as root with the kill <process ID number> command. The process ID number is the first column of numbers displayed in the ps_iris result. Running install from a SIGMET RDA release CDROM If you have a SIGMET release CDROM, install can be run directly from it. First either login as root or become root using the su command. Then mount the CDROM:

$ su password:

# mount /dev/scd0 /mnt/cdrom OR if this does not work because of the specifics of your hardware type:

# mount /dev/hdb /mnt/cdrom After you have successfully mounted the CDROM, run install as follows:

# cd /mnt/cdrom/linux

# ./install When you have finished running install, you need to unmount the CDROM and eject it:

# cd /

# eject /mnt/cdrom Running install from a local directory The procedure is identical to the CDROM procedure described above, except you invoke install in the local directory (e.g., first cd /tmp/rda8.00). A28 RVP8 Users Manual April 2003 Software Installation A.6.6 Using the install utility The install utility is shown below. The utility allows you to select the source for the files and the system on which you want to do the installation. You can also select which files you want to install. The menu fields are described in the following sections. rvp8 rvp8 Install from/to, Read from- select whether you are installing from a temporary directory or a CDROM. Type-in the directory that contains your install files. In the example, this is

/tmp/rda8.00 Install from/to, Install to- Type-in the network node name of your RVP8 or RCP8. If you are unsure, look at the very top of the menu. In the example, the nodename is rvp8. Enter the directory anchor point for the install typically this is /usr/sigmet (the factory default). What to install- click the Upgrade button and any special packages that you may want to install. In the case of an installation from a local directory, be sure that you have downloaded the corresponding files from SIGMET. For a minimal installation you would select only the Upgrade option. If you are installing from CDROM then you have the manuals there so also select Manuals to get the most up to date documentation. A29 RVP8 Users Manual April 2003 Software Installation Keep old files- should be clicked-in, unless the release notes specify otherwise. When you have finished making your selections, then click Start to do the install. A text status screen will show you the progress of the install. If you had clicked Verbose, then this status screen would show more detail. install error message that applications are still running The most common problem in running install is that SIGMET application processes are still running on the system. You will get a message complaining that there are processes still running. Perhaps you forgot to do a killall rvp8 or have other utilities running. Check Section A.6.5 for instructions on stopping SIGMET processes. After all processes are stopped (a clean ps_iris), then click Start again. A30 RVP8 Users Manual April 2003 Software Installation A.7 Network Basics The RVP8 and RCP8 are generally delivered from SIGMET packaged as fully integrated Linux based computers running the SIGMET RDA application software. Being Linux computers, they have the ability to interface to a computer network- in fact, for normal operation in communicating with host software running on a different computer, they must be connected to a network. This chapter gives some helpful information for:

The default RVP8 or RCP8 configuration as delivered

How to change this default configuration

How to use the RVP8 and RCP8 in conjunction with other hosts on the network A.7.1 Default Out Of The Box Configuration When delivered as fully integrated Linux computers, the RVP8/RCP8 has two LAN interfaces. These are designated as ETH0 and ETH1. The ETH0 interface is the only one that is enabled by default. The ETH1 interface is available, but no enabled. Both of the LAN interfaces are RJ45 style ports that accept a standard LAN twisted pair style cable. SIGMET recommends that CAT 5e or better cable be used for this connection. On most systems there are two network connectors. Usually ETH0 is the left one (looking at the back of the unit) next to the VGA connector. Depending on the version of the motherboard, the LAN interfaces are both either 10/100 Mbps, or 100/1000 Mbps. In both cases the interfaces will negociate to the highest speed allowed by the device (often a hub or a switch) that they are connected to. To determine the style of motherboard, look at the Model Number in the back corner of the motherboard. If it has a Q suffix, the LAN speeds are 10/100. If it has a G2 suffix, the LAN speeds are 100/1000. The IP address of the RVP8/RCP8 out of the box is 192.168.76.90 with subnet mask of 255.255.255.0. There is no default route nor DNS server configured. Thus the RVP8/RCP8 could be used immediately on network identified as 192.168.76.0. The RVP8/RCP8 is configured with only a minimum number of network services running. This implies a very conservative (safe) network security profile. The only service that is running is the portmapper as this service is required by the SIGMET RDA application software. With a very safe and conservative security policy such as this out of the box configuration, the RVP8 and RCP8 will be able to exist on the network and have no security concerns. A31 RVP8 Users Manual April 2003 Software Installation A.7.2 Making Changes to Default Configuration The one change that probably will be needed to the RVP8/RCP8 in almost every instance is to change the default IP address of ETH0. This will of course allow you to use the RVP8/RCP8 on a preexisting computer network. IP Address Configuration To change the IP address, you must edit the file /etc/sysconfig/network_scripts/ifcfgeth0. The default version of this file will have about 10 lines and two of them of the format:

IPADDR=192.168.76.90 NETMASK=255.255.255.0 You may change the IPADDR to any valid address and if necessary, you should also change the NETMASK. You should contact your network administrator for assistance in identifying appropriate values for these lines. The other lines in the file require no change. It should be noted that the RVP8/RCP8 requires the same IP address all the time, thus dynamic IP addressing

(such as DHCP) is not appropriate. After making the above changes to the ifcfgeth0 file, you should reboot to make the changes take effect. If you wish to use the second LAN interface (ETH1), to configure this, you should create the file ifcfgeth1 in the /etc/sysconfig/networkscripts directory. The easiest say to do this is to just copy the ifcfgeth0 file to ifcfgeth1. Then edit the ifcfgeth1 file and change the DEVICE=eth0 line to read DEVICE=eth1, and change the IPADDR and NETMASK lines as appropriate. Again, contact your network administrator for assistance in identifying the appropriate values. In addition, you must edit the file /etc/modules.conf and for Q series motherboards, add to the end a line reading alias eth1 eepro100. For G2 series motherboards, add a line reading alias eth1 e1000. Then reboot to make these changes take effect. Default Routes and Hostname In the default configuration, the RVP8/RCP8 can communicate with any other computer on the local network, but is not configured to communicate with computers on other networks. To allow such communication, edit the file /etc/sysconfig/network and add the line GATEWAY=192.168.76.1. Of course substitute the IP address of your default gateway for the 192.168.76.1 value in this example. You system administrator can provide you with the correct value. Also in the same file a line such as HOSTNAME= localhost.localdomain exists in this file. You can substitute a new hostname for the localhost.localdomain. You must also edit the file /etc/hosts and add to this a line that first lists the IP address of your ETH0, then lists your hostname exactly as it appears in the /etc/sysconfig/network file. After making any changes to default routes and/or hostnames, you must reboot your computer before they will take effect. A32 RVP8 Users Manual April 2003 Software Installation Hosts and DNS In the out of the box configuration, the RVP8/RCP8 can communicate with other computers on the network, but only by using IP Addresses. If you want to communicate with other computers using Hostnames, you must configure either a hosts table or DNS. Generally, a small network of only a few computers uses a hosts table, while large networks generally use DNS. It is up to you to decide which method is appropriate and again, your network administrator can provide advice. To configure hostnames using a host table, this is done by editing the /etc/hosts files and adding lines that default the IP address of a host and its hostname. For example, a line such as:

met_server would allow you to communicate with the host met_server using its hostname rather than its IP address. For DNS, you do not need to enter individual hostnames into a local host file, but it is assumed that all of the hostnames and IP addresses are stored on a central DNS server. All you need to do is to install a pointer to this server computer and then you can communicate using hostnames to any of the computers in the list on the DNS server. To enable DNS, edit the file /etc/resolv.conf and add a line such as:

nameserver 192.168.76.99 Of course substitute the IP address of your DNS server for the 192.168.76.99 listed above, and again, your network administrator can provide you with the appropriate information. Time Zones Configuration By default, the system clock and time zone of your RVP8/RCP8 are set to UTC (Universal Time also called Greenwich time). If you wish to change your time to be reported as local time rather than UTC, you can use the timeconfig utility to do this. When using timeconfig, you need to select your local time zone from the list provided. And also you need to select if the BIOS stores time in UTC. SIGMET recommends using BIOS time in UTC because this is more standard. But you are free to choose any timezone (or UTC) from the list provided. You should reboot your computer after making any change using timeconfig. Time Synchronization using NTP Because the data generated by the RVP8/RCP8 is time stamped, it is often useful to have an automated way of keeping the system clock accurate. Using the Network Time Protocol (NTP) is an effective and easy way of doing this. To use NTP, you must have an NTP server on your network. Often this is a single system where your network administrator oversees keeping the clock accurate so other computers can sync their clocks to it. There are also automatic NTP servers that sync their clock to GPS (satellite based time) and then other computers can sync to this. Assuming you have such an NTP server available on your network, to setup NTP on the RVP8/RCP8, you must first execute the command chkconfig service ntp on. Next you must edit the file /etc/ntp.conf and find add the line server 192.168.76.98. Of A33 RVP8 Users Manual April 2003 Software Installation course substitute the IP address of your NTP server for 192.168.76.98 in this example. There are many other lines in the /etc/ntp.conf file, but these are not used for normal configuration and must be left with a comment symbol # prefixing them. Generally, you should only have one line without a comment symbol, and that is the server ... line defined above. Next you should edit or create the file /etc/ntp/steptickers. In this file put only the IP address of your NTP server. There should be nothing before or after the IP address, and it should be the only line in the file. The /etc/ntp/steptickers file causes your computer to sync its time abruptly to the NTP servers time while your computer is booting, and the /etc/ntp.conf file causes your computer to periodically compare its time to the NTP server and make small adjustments as needed. Once again, you must reboot your computer before the above changes take effect. Adding Network Services If more network services are required (such as telnet, rlogin, ftp, ...) these can be optionally enabled. Before enabling such network services, it is advisable to review these decisions with your network administrator to make sure that the network safety of the RVP8/RCP8 is not compromised. The easiest way to enable these services is by using the ntsysv utility. When running this utility, you are presented with a list of many system services (not only network services). Services that are currently enabled have a star * in front of them. You can either enable or disable a service by scrolling to it and then pressing the space bar. This will toggle the star and thus if the service is enabled. Again, it is recommended that you discuss with your system administrator before making any changes because such changes could have a profound effect on the security of your system. After making any changes, you should reboot your computer before they will take effect. One such services that you might want to consider enabling is telnet. Telnet allows your to login to your RVP8/RCP8 from another computer on the network and is often convenient. Telnet uses a user name and password for security authentication. A34 RVP8 Users Manual April 2003 Packaging B. RVP8/RCP8 Packaging A standard RVP8/RCP8 processor consists of three separate units:

Main Chassis Section B.1 RVP8 and RCP8

Connector Panel Section B.2 RVP8 and RCP8

IFD (IF Digitizer) Section B.3 RVP8 Only Because of the similarity of the packaging for the RVP8 and RCP8, both units are described here. The main chassis and connector panel are located in a rack within 100m of the IFD. Typically the main chassis interfaces to a host computer via 100 BaseT Ethernet. For the RVP8, the IFD receiver module resides in the radar cabinet. This section describes the general features of the packaging and the electrical specifications and cabling of these units. Please read CAREFULLY the following warnings before you apply power to your system. WARNING: The Main Chassis power supply modules are NOT auto ranging. These must be set by a switch on each module for either 115/230 VAC 60/50 Hz. Verify these before applying power to the system. See Section B.1.3. WARNING: Turn off power to the main chassis before installing or removing any PCI boards. For safety, the line cord should be disconnected before opening either the IFD module or main chassis. Important: The circuit boards contain many static sensitive components. Do not handle the boards or open the IFD module unless a properly grounded wrist strap is worn. B1 RVP8 Users Manual April 2003 Packaging B.1 Main Chassis General Description SIGMETs standard main chassis is a 4U rackmount/table top enclosure (43.2 wide x 43.2 long x 17.8 cm high) or (17 wide x 17 long x 7.00 inch high) which fits a standard 19-inch EIA rack. The system comes standard with hotswap redundant power supplies. The chassis may be equipped with either a mother board or a single-board computer depending on how the unit was purchased. The chassis is shown in the following figures. Figure B1

Front View

Rear View

Side view

Internal Wiring Figure B2 Figure B3 Figure B4 The front of the unit has a plasma matrix display that is used for status information. There is also a CDRW drive (for software installation and backup) and in most cases, a floppy drive as well

(for configuration backup). Two fans are mounted behind the door on the front of the enclosure. These draw ambient air in to the unit. The air flows through the unit and exits the rear. Do not block the slots or the exhaust grills on the fans. Check airflow now and then, and also check the board and fan screen for dust accumulation. If necessary, excessive dust accumulations on the board can be cleaned at a properly equipped static-free workstation with canned air or Chemtronics TF-Plus solvent, which can be purchased through electronics distributors. The boards should be left in the chassis whenever the unit is shipped. This minimizes handling and static risk. Save the original packing provided for shipment. Important: Prior to shipment, contact support@sigmet.com to obtain a returned materials authorization (RMA) and to coordinate the shipping. A table top unit can be converted for rack mount by simply installing rack mount ears. The rack ears are installed with #8-32 flat head screws. It is strongly recommended that the rack mount slide brackets supplied with the unit should be installed in the rack for additional structural support. The internal cabling diagram in Figure B4 shows how the various disk drives, power supplies, etc. are connected within the standard Main Chassis. A mother board example is shown. Use this as a guide if you have to replace internal components. The remainder of this section describes the front and rear panel of the Main Chassis. B2 RVP8 Users Manual April 2003 Packaging Figure B1: Main Chassis- Front Panel B3 RVP8 Users Manual April 2003 Packaging Figure B2: Main Chassis- Back Panel B4 RVP8 Users Manual April 2003 Packaging Figure B3: Main Chassis- Right Side View Back Top Front B5 RVP8 Users Manual April 2003 Packaging Figure B4: Main Chassis Internal Cabling B6 RVP8 Users Manual April 2003 Packaging B.1.1 Main Chassis Front Panel The front panel is shown in Figure B1. The front panel matrix plasma display is typically connected internally by a ribbon cable to either an I/O-62 card or an RVP8/Rx card. The display is used to show status and power-up test results. Powerup features are described in detail in Section 2.3.5. The function keys beside the display are not currently used. RVP8 Receiver/Signal Processor RCP8 Radar Control Processor In addition, the CDRW and the floppy drive are located on the front panel. The various activity lights are for the CDRW (yellow), floppy drive (small green) and the hard disk drive (large red). The cabling diagram shows how to connect the activity lights. At the lower right of the unit is a power on/off switch and a green LED to indicate that power is on. B7 RVP8 Users Manual April 2003 Packaging B.1.2 Main Chassis Back Panel Figure B2 shows an example of the main chassis back panel for the case of a motherboard system. There are three main sections to the Main Chassis back panel:

Power section- on the left (looking from the rear) with the power entry module, alarm reset and three redundant hot-swap power supplies.

PC I/O section- in the lower center with connectors for keyboard, mouse, monitor, network, etc. This is for a mother board example.

PCI card section- on the right (looking from the rear) with standard PCI slots for the RVP8/RCP8 circuit cards as well as other standard commercial PCI cards that may be used (e.g., a four port serial card). Note that depending on whether your system is using a mother board or single-board computer

(SBC), the appearance of these sections may be different, but the functions are the same. These sections are described in detail in the sections below. B8 RVP8 Users Manual April 2003 Packaging B.1.3 Main Chassis Back Panel Power Section WARNING: The Main Chassis power supply modules are NOT auto ranging. These must be set by a switch on each module for either 115/230 VAC 60/50 Hz. Verify these per the procedure below, before applying power to the system. The Main Chassis back panel is equipped with a modular AC power entry device. There are three hot-swap redundant power supply modules in the system. The procedure for setting/verifying the voltage on each one is as follows:

The unit should be powered-off. This can be assured by simply not connecting the power input cord.

Remove the top power supply module by shifting the black release button to the right.

Use the handle to pull the module out.

Check the red power selector switch on the right side (rear) of the module and set it as appropriate to your line voltage (115/230).

Reinsert the module and push the chrome handle down. This switches the module in the on 1 position.

Repeat this procedure for the middle and lower modules (the order is not critical)). When the system is switchedon, the LED on each module shows green to indicate that it is functioning properly. A red light indicates a failure. There is an audio buzzer alarm in the event that a power module is turned-off, removed or fails. Note: The red button next to the power entry module will reset the buzzer alarm. The system will function if there is failure of any one power module, but is not rated to function with only one module, i.e., if two modules fail. Each power module is equipped with internal protection for over-temperature and over-current. In the event that the protection is triggered, the module LED will show red. It can be reset by removing the module for a minute and then inserting the module back into the system. It is best to do this with poweroff to the module. Note: If a power module is switched on, but the LED indicator is red, then it is not functioning. The reset procedure is to turn the power off on the failed module, remove it for one minute and then re-insert it and power it back on. B9 RVP8 Users Manual April 2003 Packaging B.1.4 Main Chassis Back Panel PC I/O Section The PC I/O section shown above is where you make all of your standard PC connections. Note pins (male) are indicated by filled black circles while sockets (female) are indicated by open circles. A standard keyboard and mouse are provided with the unit. VGA monitor is supplied by the customer or ordered as an option from SIGMET. Note that LAN 1 and LAN 2 are standard RJ45 connectors. For the G2 style mother boards the LAN port speed is 100/1000 BaseT. For the Q they are 10/100 BaseT. The keyboard and mouse are standard PS/2. You can use an adapter to plug a USB mouse into the circular mouse connector. COM1 is the DBM9 connector. COM2 is typically installed as a separate DBM9 connector in the PCI section. B10 RVP8 Users Manual April 2003 Packaging B.1.5 Main Chassis Back Panel PCI Card Section The PCI cards are installed vertically on the right of the chassis

(looking from the back). Since there are many different RVP8/RCP8 configuration options that can be ordered, there is quite a bit of variability in what PCI cards are installed. For the RCP8, however, there is typically only an I/O-62 PCI Card. Note that COM2 is typically installed as a connector in the PCI section. Vendor Functions Used on PCI Card I/O 62 RVP8/Rx RVP8 only RVP8/Tx RVP8 only HPIB COM2 RVP8 RCP8 SIGMET SIGMET SIGMET RVP8 RCP8 Market RVP8 RCP8 Market I/O to radar system control and monitoring Uplink/Downlink IFD connections. Two triggers. Two waveform outputs, clock output/input, 4 RS422 lines HPIB control for signal generator or other test equipment RS232C used for COM2. Please see Section 2.3.3 of the RVP8 Users Manual for a description of the connectors on the RVP8 PCI cards. The I/O-62 is used on both the RVP8 and RCP8. It is described in the next sections, along with the standard connector panels for the RVP8 and RCP8. B11 RVP8 Users Manual April 2003 Packaging B.2 I/O-62 and Connector Panel Figures B5 and B6 show the I/0-62 Connector Panel for the RVP8 and RCP8. This is typically mounted on the same rack as the Main Chassis. A 1:1 62position cable (standard 1.8 m/6 foot) connects the connector panel to the I/O-62. As shown in the figures, the cable can be connected to either the front or the back of the panel so that the cable run can be optimized. In most cases, it is recommended to connect the cable to the back of the panel to minimize the risk of physical damage to the cable. The panel is electrically the same for both the RVP8 and RCP8.Indeed the circuit board is identical. However, the panel labelling and the softplane configurations are different. The pin assignments to the various connectors are described in Tables B1 to B14 located at the end of this section. The tables show the basic electrical properties of each pin and the default signal assignment (if any) that is made in the factory softplane.conf file. The softplane approach provides a great deal of flexibility in assigning the I/O to the panel. The I/O62 PCI card provides forty multiprotocol digital interface lines at its 62pin faceplate connector. These lines are grouped into five independent and identical blocks, each of which contains eight lines. Moreover, each of these blocks of eight lines can be further divided into four line pairs. Each block of I/O lines can operate in one of the following modes:

As eight TTL/CMOS singleended outputs

As eight TTL/CMOS singleended inputs

As N RS422 differential transmitters or receivers, and (82N) TTL/CMOS singleended inputs. The assignment of electrical levels and signal directions are all made in the softplane.conf file. Users do not have to worry about how to configure each block of lines because inconsistent signal assignments will be checked and reported when the file is loaded. All forty I/O62 digital lines are individually protected against both overvoltage and electrostatic discharge (ESD). You may safely apply voltages between 27V and +27V to any line regardless of whether it is configured for an input or output. Likewise, external ESD pulses of 15KV

(Human body model) will be safely shunted to ground at the 62pin connector point of entry. This wide voltage tolerance effectively makes the TTL/CMOS inputs function as wide range comparators with a 2.5V logic threshold. These inputs could be connected directly to a 24V panel bulb, for example, in order to monitor its On/Off status. Note that the line protection circuitry has a side effect of raising the output impedance of the TTL/CMOS drivers to approximately 120Ohms. This should not cause any trouble unless the signal is heavily terminated at the receiving end. The RS422 drivers are not affected by the line protection, and have the standard very low output impedance. The I/O62 provides a variety of terminations for its digital I/O lines. The TTL/CMOS signals can optionally be pulled either to GND or to +5V through a 2.2KOhm resistor. Similarly, the RS422 linepairs can optionally be terminated with a 100Ohm resistor across each pair. B12 RVP8 Users Manual April 2003 Packaging There are a few additional constraints that should be kept in mind when assigning electrical signals to a block of eight I/O62 lines. These are:

When TTL/CMOS pull-up/pull-down resistors are enabled, they are applied to the entire group of eight lines. This is somewhat inconsistent with using some of those same lines as RS422.

Similarly, when RS422 terminators are enabled, they are applied to all four line pairs. This is completely inconsistent with using some of those same lines as TTL/CMOS. Thus, if line termination is required, it is usually necessary to split the TTL/CMOS and RS422 functions so that both do not appear within the same block of eight lines. B13 RVP8 Users Manual April 2003 Packaging Figure B5: RVP8 I/O-62 Connector Panel B14 RVP8 Users Manual April 2003 Packaging Figure B6: RCP8 I/O-62 Connector Panel B15 RVP8 Users Manual April 2003 Table B1: J1 AZ INPUT Packaging Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Electrical Specification RVP8 Signal Name RCP8 Signal Name sPedAZ[0]

sPedAZ[1]

sPedAZ[2]

sPedAZ[3]

sPedAZ[4]

sPedAZ[5]

sPedAZ[6]

sPedAZ[7]

sPedAZ[8]

sPedAZ[9]

sPedAZ[10]

sPedAZ[11]

sPedAZ[12]

sPedAZ[13]

sPedAZ[14]

sPedAZ[15]

sPedAZ[0]

sPedAZ[1]

sPedAZ[2]

sPedAZ[3]

sPedAZ[4]

sPedAZ[5]

sPedAZ[6]

sPedAZ[7]

sPedAZ[8]

sPedAZ[9]

sPedAZ[10]

sPedAZ[11]

sPedAZ[12]

sPedAZ[13]

sPedAZ[14]

sPedAZ[15]

TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL GND GND GND GND GND B16 RVP8 Users Manual April 2003 Table B2: J2 AZ OUTPUT Packaging Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Electrical Specification RVP8 Signal Name RCP8 Signal Name cPedAZ[0]

cPedAZ[1]

cPedAZ[2]

cPedAZ[3]

cPedAZ[4]

cPedAZ[5]

cPedAZ[6]

cPedAZ[7]

cPedAZ[8]

cPedAZ[9]

cPedAZ[10]

cPedAZ[11]

cPedAZ[12]

cPedAZ[13]

cPedAZ[14]

cPedAZ[15]

cPedAZ[0]

cPedAZ[1]

cPedAZ[2]

cPedAZ[3]

cPedAZ[4]

cPedAZ[5]

cPedAZ[6]

cPedAZ[7]

cPedAZ[8]

cPedAZ[9]

cPedAZ[10]

cPedAZ[11]

cPedAZ[12]

cPedAZ[13]

cPedAZ[14]

cPedAZ[15]

TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL GND GND GND GND GND B17 RVP8 Users Manual April 2003 Packaging Table B3: J3 RVP8: PHASE OUT; RCP8 CONTROL Pin Electrical Specification RVP8 Signal Name RCP8 Signal Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Configurable g I/O62 Digital Lines RS422+

RS422+

GND GND GND Configurable g I/O62 Digital Lines RS422 RS422 GND GND RS422+[0]

RS422+[1]

RS422[0]

RS422[1]

B18 RVP8 Users Manual April 2003 Table B4: J4 EL INPUT Packaging Pin Electrical Specification RVP8 Signal Name RCP8 Signal Name sPedEL[0]

sPedEL[1]

sPedEL[2]

sPedEL[3]

sPedEL[4]

sPedEL[5]

sPedEL[6]

sPedEL[7]

sPedEL[8]

sPedEL[9]

sPedEL[10]

sPedEL[11]

sPedEL[12]

sPedEL[13]

sPedEL[14]

sPedEL[15]

sPedEL[0]

sPedEL[1]

sPedEL[2]

sPedEL[3]

sPedEL[4]

sPedEL[5]

sPedEL[6]

sPedEL[7]

sPedEL[8]

sPedEL[9]

sPedEL[10]

sPedEL[11]

sPedEL[12]

sPedEL[13]

sPedEL[14]

sPedEL[15]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL GND GND GND GND GND B19 RVP8 Users Manual April 2003 Table B5: J5 EL OUTPUT Packaging Pin Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Electrical Specification Electrical Specification RVP8 Signal Name RVP8 Signal Name RCP8 Signal Name RCP8 Signal Name cPedEL[0]

cPedEL[1]

cPedEL[2]

cPedEL[3]

cPedEL[4]

cPedEL[5]

cPedEL[6]

cPedEL[7]

cPedEL[8]

cPedEL[9]

cPedEL[10]

cPedEL[11]

cPedEL[12]

cPedEL[13]

cPedEL[14]

cPedEL[15]

cPedEL[0]

cPedEL[1]

cPedEL[2]

cPedEL[3]

cPedEL[4]

cPedEL[5]

cPedEL[6]

cPedEL[7]

cPedEL[8]

cPedEL[9]

cPedEL[10]

cPedEL[11]

cPedEL[12]

cPedEL[13]

cPedEL[14]

cPedEL[15]

TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL GND GND GND GND GND B20 RVP8 Users Manual April 2003 Table B6: J6 RELAY Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Electrical Specification Relay K1: CT Relay K1: NO Relay K1: NC Relay K2: CT Relay K2: NO Relay K2: NC Relay K3: CT Relay K3: NO Relay K3: NC GND GND GND

+12VDC

+12VDC

+12VDC

+12VDC

+12V Unreg Return14

+12V Return15

+12V Return16

+12V Return17 GND GND Packaging RVP8 Signal Name RCP8 Signal Name Internal Relay Center Contact Internal Relay Normally Open Internal Relay Normally Closed Internal Relay Center Contact Internal Relay Normally Open Internal Relay Normally Closed Internal Relay Center Contact Internal Relay Normally Open Internal Relay Normally Closed cPWidth[0]

cPWidth[1]

External Relay y Control Power External Relay y Control Returns WARNING: To avoid possible damage to the connector panel, all external relays must be equipped with diode protection against the back EMF generated when the external relay coil is opened. Relays can be purchased with a diode installed or a diode can be added to the relay across the coil supply and return. Notes: Internal relays K1, K2, K3 on the connector panel are dry contacts:

CT NO NC Center contact Normally open contact Normally closed contact B21 RVP8 Users Manual April 2003 Packaging Table B7: J7: RVP8 SPARE; RCP8 BITE 19:0 Pin Electrical Specification RVP8 Signal Name RCP8 Signal Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL TTL GND GND GND GND GND sAux[0]

sAux[1]

sAux[2]

sAux[3]

sAux[4]

sAux[5]

sAux[6]

sAux[7]

sAux[8]

sAux[9]

sAux[10]

sAux[11]

sAux[12]

sAux[13]

sAux[14]

sAux[15]

sAux[16]

sAux[17]

sAux[18]

sAux[19]

B22 RVP8 Users Manual April 2003 Packaging Table B8: J8: RVP8 SPARE; RCP8 ANALOG IN Pin Electrical Specification RVP8 Signal Name RCP8 Signal Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 20VDC Differential Analog g Inputs p Positive Side GND GND GND 20VDC Differential Analog g Inputs p Negative Side GND GND Amux0+

Amux1+

Amux2+

Amux3+

Amux4+

Amux5+

Amux6+

Amux7+

Amux8+

Amux9+

Amux0 Amux1 Amux2 Amux3 Amux4 Amux5 Amux6 Amux7 Amux8 Amux9 Amux0+

Amux1+

Amux2+

Amux3+

Amux4+

Amux5+

Amux6+

Amux7+

Amux8+

Amux9+

Amux0 Amux1 Amux2 Amux3 Amux4 Amux5 Amux6 Amux7 Amux8 Amux9 B23 RVP8 Users Manual April 2003 Packaging Table B9: J9 RVP8: MISC I/O ; RCP8: PED/STATUS Pin Electrical Specification RVP8 Signal Name RCP8 Signal Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Configurable g I/O62 Digital Lines 6 to 70 VDC Input 6 to 70 VDC Input 10 VDC Output GND GND GND Configurable g I/O62 Digital Lines 6 to 70 VDC Input 6 to 70 VDC Input 10 VDC Output GND GND AzTach+

ElTach+

AzDrive AzTach ElTach ElDrive Note: Antenna pedestal tachometer inputs are adjusted by a potentiometer on the back of the Connector Panel. B24 RVP8 Users Manual April 2003 Table B10: J10 SERIAL Pin Electrical Specification Comment Packaging 1 2 3 4 5 6 7 8 9 GND RS232C Rx RS232C Tx GND Table B11: J11 SERIAL Pin Electrical Specification GND RS232C Rx RS232C Tx RS232C Rx GND RS232C Tx 1 2 3 4 5 6 7 8 9 Comment Channel 0 Channel 0 Channel 1 Channel 1 12VDC @ 50mA max regulated

+12VDC @ 50mA max

+5VDC @ 50mA max Regulated power supply Regulated power supply Regulated power supply B25 RVP8 Users Manual April 2003 Table B12: J12 SD Packaging Pin Electrical Specification RVP8 Signal Name RVP8 Signal Name 1 2 3 4 5 6 7 8 9 10 11 12 Nominal 90V 60Hz Synchro Signals y g GND Nominal 90V 60Hz Synchro Signals y g GND RefEL+

RefEL SyEL1 SyEL2 SyEL3 RefAZ+

RefAZ SyAZ1 SyAZ2 SyAZ3 RefEL+

RefEL SyEL1 SyEL2 SyEL3 RefAZ+

RefAZ SyAZ1 SyAZ2 SyAZ3 B26 RVP8 Users Manual April 2003 Packaging Table B13: RVP8 BNC Connector Pin Assignments Ref Designator J13 J14 J15 J16 J17 J18 Label TP1 TRIG1 TRIG2 TP2 TRIG3 TRIG4 Electrical Specification Signal Name 5V 75Ohm 12V 75Ohm 12V 75Ohm 5V 75Ohm 12V 75Ohm 12V 75Ohm Trigger[1]

Trigger[2]

Trigger[3]

Trigger[4]

Table B14: RCP8 BNC Connector Pin Assignments Ref Designator J13 J14 J15 J16 J17 J18 Label TP1 SPARE SPARE TP2 SPARE SPARE Electrical Specification Signal 5V 75Ohm 5V 75Ohm B27 RVP8 Users Manual April 2003 Packaging B.3 IFD Module (RVP8 Only) The IFD module is a small metal box which can be mounted inside the receiver cabinet. The IFD is shown in Figures B7 and B8. Cooling of the inside components is accomplished by direct conduction to the case. It is desirable to place the module in an environment that allows external convective cooling. The IFD is equipped with its own auto ranging power supply (110 to 240 VAC 50/60 Hz) which is mounted on the side of the IFD. On the other side of the IFD are two anti-aliasing filters. These analog filters must be specified for the radar IF frequency. The filters have an 8 MHz bandwidth centered about the IF frequency. B28 RVP8 Users Manual April 2003 Packaging Figure B7: RVP8/IFD Module B29 RVP8 Users Manual April 2003 Packaging Figure B8: IFD Front Panel B30 RVP8 Users Manual April 2003 Packaging B.4 DAFC Module (RVP8 only) The Digital AFC (DAFC) module is used on RVP8 for magnetron systems to interface to a digitally controlled STALO. The DAFC Ts off the coax uplink cable. Power can be provided by running discrete wires from the IFD. Note that +5 VDC is all that is required to run the DAFC. If you want to supply the STALO power over the ribbon cable to the IFD, you can connect the +24 VDC input to an appropriate power supply. Otherwise, you can power the STALO directly. The DAFC outputs up to 24 TTL lines to the STALO digital control/interface. Since these are TTL, the DAFC should be mounted within 10 to 30cm of the STALO if possible. For details on the DAFC, including pin assignment examples for some commercial STALOs, please refer to Section 2.4. Figure B9: View of DAFC Module B31 RVP8 Users Manual April 2003 Clutter Filter Characteristics C. Clutter Filter Characteristics (DRAFT) This draft appendix is based on the legacy RVP7 algorithms. The RVP8 will have some additional features and may not contain some of the legacy features. The RVP8 is shipped with a preprogrammed set of digital IIR (Infinite Impulse Response) high-pass clutter filters. There are eight filters available. The filters are fourth-order Chebyshev, and provide 40dB and 50dB stop band attenuation in seven different widths ranging from approximately 2% to 14% of the Nyquist interval. Filter #0 is an all-pass filter, so that clutter rejection can effectively be switched off. The correct choice of filter for observing different weather conditions must be determined by experiment. The filter with the highest rejection is not always the best choice, since the group delay of signals in the transition band is greater for deeper filters. This effect introduces dispersion in the Velocity/Time profile of the incoming signal. In general, try to use the shallowest filter with the shortest impulse response that will do the job for the types of weather and clutter that are typical at the radar site. The processing algorithm for the IIR clutter filter is described in Chapter 5, as follows:

An B0An B1An1 B2An2 B3An3 B4An4

C1An1 C2An2 C3An3 C4An4 In this algorithm, the input time series An is processed to form a filtered output time series An, and the Bs and Cs are filter coefficients. This appendix shows the magnitude response plots for the set of filters supplied with the RVP8. The Doppler 40dB and 50dB clutter filter coefficients are given in Tables C1 and C2. Table C1: Doppler 40dB Clutter Filter Coefficients B4

-C4 B3

-C3 B2

-C2 B1

-C1 B0 0.88524580 0.78366012

3.53845834 3.32323517 5.30642599 5.29330203

3.53845834 3.75363693 0.88524580 0.80657571 0.65056438

3.21913964 2.87521021 4.82513582 4.78811692

3.21913964 3.56267500 0.80657571 0.71441318 0.51038627

2.84208420 2.37084266 4.25538455 4.17592962

2.84208420 3.31122076 0.71441318 0.62870255 0.39526762

2.48861663 1.92570662 3.71996530 3.58889047

2.48861663 3.04473893 0.62870255 0.54606519 0.29819195

2.14537980 1.52275259 3.19897838 3.01019977

2.14537980 2.75072405 0.54606519 0.45879351 0.21051814

1.78052007 1.13050566 2.64427921 2.39223952

1.78052007 2.38964305 0.45879351 0.37359302 0.13969494

1.42239330 0.78656442 2.09937656 1.79477930

1.42239330 1.97031054 0.37359302 C1 RVP8 Users Manual April 2003 Clutter Filter Characteristics Table C2: Doppler 50dB Clutter Filter Coefficients B4

-C4 B3

-C3 B2

-C2 B1

-C1 B0 0.84542846 0.71474928

3.37930255 3.09659463 5.06774905 5.04399223

3.37930255 3.66187494 0.84542846 0.74382306 0.55327276

2.96868634 2.53400299 4.44973390 4.38526438

2.96868634 3.40221256 0.74382306 0.62973136 0.39656213

2.50520230 1.93990255 3.75097936 3.61978794

2.50520230 3.06459405 0.62973136 0.52882407 0.27966010

2.09326396 1.45511086 3.12899512 2.92516254

2.09326396 2.71323771 0.52882407 0.43670149 0.19073865

1.71571192 1.05300155 2.55830009 2.28497406

1.71571192 2.33441266 0.43670149 0.34541284 0.11946113

1.34050390 0.69988946 1.99080407 1.66019496

1.34050390 1.88309201 0.34541284 0.26278690 0.06966656

1.00051743 0.42488088 1.47671031 1.12951524

1.00051743 1.37925631 0.26278690 The filter responses are plotted on the following pages. Note that the plots cover only 50% of the width of the full Nyquist interval, so the pass band of the filters actually extends another full plot width off the right edge of the diagrams. In other words, a normalized velocity of 1.0 corresponds to the fold velocity of a target. The higher numbered filters are the wider ones on the plots. C2 RVP8 Users Manual April 2003 Clutter Filter Characteristics Figure C1: 40 dB IIR Clutter Filter Responses 0.0 10.0 20.0 30.0 40.0 50.0 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 C3 RVP8 Users Manual April 2003 Clutter Filter Characteristics Figure C2: 50 dB IIR Clutter Filters Responses 0.0 10.0 20.0 30.0 40.0 50.0 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 C4 RVP8 Users Manual April 2003 References and Credits D. References and Credits 1. Tang Dazhang, et.al. (1984). Evaluation of an AlternatingPRF Method for Extending the Range of Unambiguous Doppler Velocity. Preprints of the Conference on Radar Meteorology, 22nd, 1984 pp.523527. 2. Joe, Passarelli and Siggia (1995). Second Trip Unfolding by Phase Diversity Techniques. Preprints of the Conference on Radar Meteorology, 27th, 1995 pp. 770772. 3. Doviak, R. J., and Zrnic, D. S. (1993). Doppler Radar and Weather Observerations. Academic Press, San Diego. 4. The JMA internal specification for Interference Filter algorithm for use on Chitose airport Doppler weather radar is the basis for Alg.1 described in Section 5.1.4. 5. Environment Canada Aldergrove BC, kindly supplied the snapshot of receiver data that is plotted in Figure 46. D1 RVP8 Users Manual April 2003 Installation and Test Procedure E. Installation and Test Procedure

(DRAFT) Customer:

_________________________________________ Serial No. Main:

_________________________________________ AUX:

_________________________________________ Delivery Date:

_________________________________________ Radar Mfg./Type:

_________________________________________ _________________________________________ Customer Engineer:

_________________________________________ SIGMET Engineer:

_________________________________________ Overview This installation and test procedure is designed to assist SIGMET field engineers and customers with the installation and testing of the RVP8 on a radar system. Because the tests also function as an installation procedure, they must be completed in order. Failure to perform one step may effect later tests. A copy of the test results should be kept either on file or with the RVP8 Users Manual. Do not write in the manual since it will be replaced with an upgrade, instead make a copy and mark that. For IRIS systems, it is recommended that the RVP8 TTY nonvolatile setups be put into a file on your system in the ${IRIS_LISTINGS} directory. The file should be called something like RVP8.26feb2000. The UNIX script command can be used to to create this file Each test should be performed and signed off when it is completed. If a test does not pass, then the problem should be remedied and the test repeated. If the test still does not pass, then an additional sheet should be added to the test explaining the variance. A supplementary test sheet is at the end of the test procedure. After you have successfully completed the installation steps and tests in this procedure, your RVP8 will be ready for connection to your application software such as SIGMETs IRIS system. There will be additional configuration and calibration to use the RVP8 with your application software. The following page is a convenient summary check list for the tests. Use this as a check list for completing the installation and test procedure. We hope that you enjoy your new RVP8. Please contact us if you have any problems or comments regarding this product or procedure at support@sigmet.com. E1 RVP8 Users Manual April 2003 Test Summary:

Installation and Test Procedure

E.1 Installation Check

E.2 Power-up Check

E.3 Setup Terminal

E.4 Setup V Command (Internal Status)

E.5 Setup M Command (Board Configuration)

E.6 Setup Mp Command (Processing Options)

E.7 Setup Mf Command (Clutter Filters)

E.8 Setup Mt Command (General Trigger Setup)

E.9 Initial Setup of Information for Each Pulse Width

E.10 Setup Mb Command (Burst Pulse and AFC)

NO TAG Setup M* Command (Stand alone Settings)

E.11 Setup M+ Command (Debug Options)

E.12 Setup Mz Command (Transmitter Phase Control)

E.13 Display Scope Check

E.14 Burst Pulse Alignment

E.15 Bandwidth Filter Adjustment

E.16 Digital AFC Voltage Alignment

E.17 Analog AFC Voltage Alignment

E.18 MFC Functional Test

E.19 AFC Functional Test

E.20 Input IF Signal Level Check

E.21 Dynamic Range Check

E.22 Receiver Bandwidth Check

E.23 Receiver Phase Noise Check

E.24 Hardcopy of Final Setups All Tests Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E2 RVP8 Users Manual April 2003 E.1 Installation Check Test Goal Installation and Test Procedure Verify that the RVP8 is properly connected to the radar system and document some of the basic radar characteristics. There are differences for TWT/Klystron vs magnetron radar systems. Test Procedure

IF Digitizer (IFD) mounted in the radar receiver cabinet or other convenient location.

IF Digitizer Power Supply properly connect to AC Line voltage ___________VAC.

IFD IF input connection. IF Frequency ____________MHz.

RVP8 Chassis installed in (circle one) Rack Tabletop Distance between IFD and RVP8 Chassis ____________

Fiber optic connection from IFD to RVP8 Chassis.

Uplink connection from IFD to RVP8 Chassis.

Trigger connections. List triggers in section E.8. For magnetron systems only verify the following:

IFD burst pulse connected. Is RVP8 AFC output used for STALO tuning (circle one) ? Yes No

AFC connected to IFD. For Klystron or TWT systems only verify the following:

IFD COHO connected to Burst Input. Is RVP8 Phase Shift Control used and connected to chassis (circle one) ? Yes No If yes, then specify the phase shifts that correspond to the RVP8 Phase Control Output Bits (attach a separate sheet). Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E3 RVP8 Users Manual April 2003 Installation and Test Procedure E.2 Power-Up Check Test Goal Verify that the IFD and RVP8 properly powerup. Reference: RVP8 Users Manual, Tables 24 and section 2.3.5 . Test Procedure The RVP8 runs numerous power-up tests. The overall results of the tests are indicated by red and green LEDs on the IFD and text on the RVP8 Display. In addition, the main board and auxiliary board (optional) have red and green LEDs to signal test results. Apply power to the RVP8 and the IFD. Verify the following:

For the IFD with RVP8 Main Chassis power on:

When power is applied to the IFD, the red and green lights blink and then go to on.

When the uplink is disconnected, the red light blinks and the green light is off.

When the fiber cable is disconnected, the red light is on and the green light is off. For the RVP8 with the IFD power on

The front panel display shows the correct text. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E4 RVP8 Users Manual April 2003 E.3 Setup Terminal Test Goal Installation and Test Procedure Verify that the TTY Setups can be accessed and function properly. Special Test Equipment Either the IRIS dspx utility or a terminal or PC with terminal emulator (e.g., Procom or minicom). This is to be supplied by the customer. SIGMET provides an adapter and cable to convert the RJ11 connector on the RVP8 main board to a DN25M connector. Note that a null modem may be required. Reference: RVP8 Users Manual, Section 3.1 Option 1: Access to Terminal Setups via dspx chat mode at workstation. This requires that the IRIS Utilities be installed and that the RVP8 is connected to the workstation via a SCSI interface. Refer to the sample chat mode session in the dspx chapter of the IRIS Utilities Manual. At your workstation, login as operator and type dspx in a terminal window to enter the Doppler signal processor examiner utility. Now repeat the procedure in section one of this test (i.e., press ESC, etc...). Option 2: Access via a terminal or PC:

Connect the setup terminal. Configure the setup terminal for 9600 baud. Note, some terminals or PCs may require a null modem. Details of the TTY connection are provided in section 3.1. Verify the following:

Test Procedure

Press the ESC key and verify that the RVP8 banner appears (see section 3.1.1).

Type Help or ? and verify that the list of commands is displayed.

Issue the reset command * and verify that the front panel lights flash.

Type q or quit to exit the menus. Record the type of hardware/software used for the connection:

___________________________________________________________ Null modem (circle one) required not required Test Passed For Customer _____________________________________ Date ____________ For SIGMET _____________________________________ Date ____________ E5 RVP8 Users Manual April 2003 Installation and Test Procedure E.4 Setup V Command (Internal Status) Test Goal Verify that the TTY setups for the Internal Status section are properly reported. Special Test Equipment: Setup terminal. Reference: RVP8 Users Manual Section 3.1.4 Test Procedure Enter the TTY setups and issue the V command to display the internal status. Note that we will record the final values of all the settings at the end of the installation.

Status information is consistent with the board jumper settings. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E6 RVP8 Users Manual April 2003 Installation and Test Procedure E.5 Setup Mc Command (Board Configuration) Test Goal Verify that the TTY setups for the Board Configuration section are properly configured for the customer application. Special Test Equipment: Setup Terminal Reference: RVP8 Users Manual, Section 3.3.1 Test Procedure Enter the TTY setups and type the Mc command. Set all the values as required.

Parameters set. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E7 RVP8 Users Manual April 2003 Installation and Test Procedure E.6 Setup Mp Command (Processing Options) Test Goal Verify that the TTY setups for the Processing Options section are properly configured for the customer application. Special Test Equipment: Setup Terminal Reference: RVP8 Users Manual, Section 3.3.2 Test Procedure Enter the TTY setups and type the Mp command. Set all the values as required.

Parameters set. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E8 RVP8 Users Manual April 2003 Installation and Test Procedure E.7 Setup Mf Command (Clutter Filters) Test Goal Verify that the TTY setups for the Clutter Filters section are properly configured for the customer application. Special Test Equipment: Setup Terminal Reference: RVP8 Users Manual, Section 3.3.3 Test Procedure Enter the TTY setups and type the Mf command. Set all the values as required.

Parameters set. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E9 RVP8 Users Manual April 2003 Installation and Test Procedure E.8 Setup Mt Command (General Trigger Setup) Test Goal Verify that the TTY setups for the General Trigger Setup section are properly configured for the customer application. Background The RVP8 can output up to 6 different triggers. These can be delayed by different amounts, and have different pulse widths. For example trigger 0 may go to fire the transmitter, while a slightly delayed trigger 1 may be used for triggering an oscilloscope. The timing can be different for each transmitter pulsewidth. The final timing adjustments will be done later in Section E.14. Enter in the table below the purpose of each trigger, as well as the nominal start time and pulse width. Note that start times are relative to range zero (middle of the burst pulse). We recommend a nominal pulsewidth of 3 microseconds. This chart will be used in the next section. Magnetron radars using an analog COHO system often have a trigger generator circuit which produces a trigger for the COHO latching and also for the transmitter pulse. This circuit should be bypassed in an upgrade.

0 1 2 3 4 5 Purpose ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ ________________________________ Start Time ________usec ________usec ________usec ________usec ________usec ________usec Width ________usec ________usec ________usec ________usec ________usec ________usec Special Test Equipment: Setup Terminal Reference: RVP8 Users Manual, Section 3.3.4 Test Procedure Enter the TTY setups and type the Mt command. Set all the values as required. Note that the PRF and pulse width set here are the current values, and values used at power-up.

Parameters set. Test Passed For Customer _____________________________________ Date ____________ For SIGMET _____________________________________ Date ____________ E10 RVP8 Users Manual April 2003 Installation and Test Procedure E.9 Initial Setup of Information for Each Pulse Width Test Goal Enter the initial values for the TTY Setups for each of the pulse widths. Note that the final values of trigger timing, FIR filter impulse response length and bandwidth will be adjusted later. Background The duty cycle of the transmitter is the product of the PRF and the pulse width in seconds. For example, a PRF of 1000 Hz and 1 microsecond pulse width is a duty cycle of 0.001. Thus a transmitter with a 0.001 duty cycle limit could function at 1000 Hz and 1 microsecond pulse width, or 500 Hz and 2 microsecond pulse widths. The duty cycle limits of your radar should be obtained from your system documentation or radar manufacturer. The RVP8 supports up to four pulse widths (coded 0 to 3), although most transmitters typically support only two pulse widths. Record below the pulse width in microseconds and the maximum PRF that is allowed for each pulse width.

0 1 2 3 Pulse Width __________ microseconds __________ microseconds __________ microseconds __________ microseconds Max PRF ________ Hz ________ Hz ________ Hz ________ Hz Special Test Equipment: Setup Terminal Reference: RVP8 Users Manual, Section 3.3.5 Test Procedure Enter the TTY setups and type the Mt # command, once for each pulsewidth. Enter the start time and widths for each trigger as documented on the previous page. For all unused triggers, set the width to zero. Next enter the Maximum PRF from the table above. Set the initial impulse response length to 1.5 times the pulsewidth, and the initial pass bandwidth to the inverse of the pulsewidth.

Parameters set. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E11 RVP8 Users Manual April 2003 Installation and Test Procedure E.10 Setup Mb Command (Burst Pulse and AFC) Test Goal Verify that the TTY setups for the Burst Pulse and AFC Configuration section are properly configured for the customer application. Background: Magnetron vs Klystron Systems Magnetron Systems: For magnetron systems, the phase and frequency of the burst pulse from the transmitter is measured at IF. The phase measurement is used for digital phase locking and 2nd trip echo filtering and recovery. The frequency measurement is used to implement an analog

(+10V) AFC output to control the STALO frequency. Note that an external AFC can be used rather than the RVP8 AFC, but is not recommended. Klystron or TWTbased Systems: The COHO is measured instead of the burst pulse. Note that Klystron systems that use a phase shifter should input the phase shifted COHO into the IFD so that the RVP8 can digitally lock to the actual transmitted phase. For Klystron systems the AFC feedback loop is not used. Special Test Equipment: Setup Terminal Reference: RVP8 Users Manual, Section 3.3.6 Test Procedure Enter the TTY setups and type the Mb command. Set all the values as required.

Parameters set. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E12 RVP8 Users Manual April 2003 Installation and Test Procedure E.11 Setup M+ Command (Debug Options) Test Goal Verify that the TTY setups for the Debug Options section are properly configured for the customer application. Special Test Equipment: Setup Terminal Background The RVP8 supports several test features that are configured in this section. For operational systems, the simulation features should be turned off. SIGMET recommends that the LEDs be set to 1:Go/Proc so that the front panel red LED will flash during each processing cycle. Reference: RVP8 Users Manual, Section 3.3.7 Test Procedure Enter the TTY setups and type the M+ command. Set all the values as required.

Parameters set. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E13 RVP8 Users Manual April 2003 Installation and Test Procedure E.12 Setup Mz Command (Transmitter Phase Control) Test Goal Verify that the TTY setups for the Transmitter Phase Control section are properly configured for the customer application. This feature is not used for magnetron systems since these have inherent random phase that is measured, but not controlled. Special Test Equipment: Setup Terminal Reference: RVP8 Users Manual, Section 3.3.8 Test Procedure Enter the TTY setups and type the M+ command. Set all the values as required.

Parameters set. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E14 RVP8 Users Manual April 2003 Installation and Test Procedure E.13 Display Scope Test Test Goal Verify that the display scope output functions properly. Background The RVP8 can use a standard oscilloscope as a display device for local configuration and testing. This is a common item at radar sites and most technicians are familiar with its use. The oscilloscope is provided by the customer or purchased as an option from SIGMET. When using the dspx utility, the scope plot is drawn on the computer screen and an oscilloscope is not required. Reference: RVP8 Users Manual, Section 4.1 Special Test Equipment:

Setup terminal Analog oscilloscope (Optional) Dspx Test Procedure

Enter the TTY setups and issue the P+ command.

Verify that the test pattern is displayed OK. Optional Scope Test Procedure

Connect the BNC cable from the Q output on the back of the RVP8 chassis to a vertical input channel on the scope. Be sure to terminate the cable

Configure the scope per Section 4.1.

Enter the TTY setups and issue the P+ command.

Adjust the scope time base, vertical gain, horizontal and vertical offsets so that the test pattern appears as illustrated in Figure 41 of the Manual. If there is a problem doing this, you can adjust the scope plots numbers using the Mc, see Section 3.3.1.

Verify that the test pattern is displayed OK. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E15 RVP8 Users Manual April 2003 Installation and Test Procedure E.14 Burst Pulse Alignment Test Goal Verify that the burst pulse is present and that its amplitude is sufficient. This test also aligns the burst pulse in the burst pulse sample window. Special Test Equipment: Setup terminal and display scope Reference: RVP8 Users Manual, Section 4.4 Test Procedure

Use the Mt command to select pulse width 0 and a safe PRF.

Set the transmitter on to radiate.

Issue the Pb command to obtain the burst pulse display. Use the L/R commands to find the burst pulse. Use the l/r commands to fine tune the position of the burst pulse in the burst pulse window.

Adjust the width of the burst pulse window using the I/i command to be slightly larger than the burst pulse (e.g., ~50%).

Verify that the burst pulse power is in the range +1 to 12 dBm per the tabular display on the setup terminal. Record the burst pulse power Pulsewidth #0: _____________ dBm Pulsewidth #1: _____________ dBm Pulsewidth #2: _____________ dBm Pulsewidth #3: _____________ dBm

Repeat the above procedure for each pulse width. In the event that the burst pulse is not found, try to detect the burst pulse on an oscilloscope connected directly to the IF burst line (ahead of the IFD). On a magnetron radar, if the AFC is not working it is possible the IF frequency is outside the IFD anti-aliasing filter bandwidth. It may be necessary to go to manual frequency control to get this to work. If no burst pulse is detected, then the radar should be serviced by an experienced technician. If the burst pulse is power is too small or large, check the status of any attenuators or amps in the burst pulse signal path. It might be necessary to adjust the gain buy installing a fixed attenuator or amplifier. Test Passed For Customer _____________________________________ Date ____________ For SIGMET _____________________________________ Date ____________ E16 RVP8 Users Manual April 2003 Installation and Test Procedure E.15 Bandwidth Filter Adjustment Test Goal Set the band width filter for each pulse width. Reference: RVP8 Users Manual, Section 4.5 Special Test Equipment: Setup Terminal and display scope Test Procedure

Enter the Ps command mode and view the results on the display scope. Toggle the space bar to show both the spectrum of the burst pulse and the spectrum of the bandwidth filter response. Use the Z/z command to zoom the burst spectrum plot to approximately match the height of the bandwidth filter response (which will have a smoother shape than the burst pulse).

Use the Ww/Nn commands to adjust the width of the bandwidth filter plot to be slightly narrower than the burst pulse. Then use the w/n commands to fine tune the filter width such that the DCGain: is either ZERO or less than 64 dB.

Repeat for each pulse width that is used (use mt to change pulse width) and record:

Pulsewidth 0 Pulsewidth 1 Pulsewidth 2 Pulsewidth 3 Test Passed For Customer For SIGMET FIR Length __________usec __________usec __________usec __________usec Bandwidth __________MHz __________MHz __________MHz __________MHz DC Gain _________ dB _________ dB _________ dB _________ dB _____________________________________ Date ____________ _____________________________________ Date ____________ E17 RVP8 Users Manual April 2003 Installation and Test Procedure E.16 Digital AFC Voltage Alignment (Optional) Test Goal Verify that the RVP8 AFC output controls the STALO over the correct span. Special Test Equipment: Setup TTY and display scope Background The RVP8 implements an AFC based on the measurement of the burst pulse frequency. The control output is available in 8 bits on the phase control signals of the RVP8 J13 connector, or on the RxNet7 J16, or in 16+ bits on the DAFC. A frequency control span of approximately + 7 MHz is expected. If your STALO requires more control lines, jumper the higher lines. Check the specification of the STALO and document the following. To calculate the digital span take the desired frequency minus the base frequency divided by the frequency step. STALO base frequency after jumpering high bits:

STALO frequency step Desired frequency span:

Desired digital span:

_______ MHz _______ MHz _______ to _______ MHz _______ to _______ Test Procedure

Verify that JP23 and JP24 are set to AB to enable all 8 bits of digital AFC.

Use the setup terminal to set the Digital AFC span as required in the Mb section.

Use the setup terminal and display scope in the Pb (plot burst) mode to verify that the burst pulse is properly centered. Any pulsewidth can be used.

Set to MFC using the = command, and adjust the control to the lowest setting using the D command. Record the results below.

Raise the control using U to within 0.1 MHz of the IF frequency. Record the results.

Raise the control using U to the highest setting. Record the results.

Verify that sufficient span is covered, and the the power at the end points is sufficiently high to run the AFC loop. voltage Midpoint:

_________A/D Lower limit: _________A/D Upper limit:

_________A/D frequency _________ MHz. _________ MHz. _________ MHz. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E18 RVP8 Users Manual April 2003 Installation and Test Procedure E.17 Analog AFC Voltage Alignment (Optional) Test Goal Verify that the RVP8 AFC output voltage is properly adjusted to match the STALO input control voltage. Special Test Equipment Calibrated Oscilloscope or Voltmeter. Setup TTY and display scope Background The RVP8 implements an AFC based on the measurement of the burst pulse frequency. The control output is an SMA labeled AFC on the IFD module which connects to the STALO control voltage input. The output signal is an analog voltage in the range +10V. A frequency control span of approximately + 7 MHz (for a 30 MHz IF) is expected. Some STALOs contain a nominal frequency adjustment. The alignment procedure is different in that case. Check the specification of the STALO and verify the following:

STALO analog control input range STALO frequency control range _______V to _______V

+/ __________ MHz Test Procedure, initial setup

Connect a scope or digital Voltmeter to the AFC line, either at the IFD or the STALO.

Use the setup terminal and display scope in the Pb (plot burst) mode to verify that the burst pulse is properly centered. Any pulsewidth can be used.

Set the test switches on the IFD to output the Midpoint Voltage SW1A SW2B Test Procedure, STALO without adjustment

Adjust the Offset pot by screwdriver on the IFD module until the the IF frequency dis-

play on the setup terminal is approximately the desired IF frequency (e.g., 30 MHz). Re-

cord the results below.

Set the test switches on the IFD to output the AFC low test voltage. SW1A SW2A The voltage on the monitoring scope or Voltmeter will decrease. The burst pulse frequen-

cy may either increase or decrease depending on the nature of the voltage control in the STALO.

Adjust the Gain pot by screwdriver on the IFD module until the frequency stops chang-

ing or until the burst pulse frequency is 7 MHz off the center frequency (e.g. for 30 MHz IF, either 23 or 37 MHz) whichever occurs at a higher voltage. Record the results.

Set the test switches on the IFD to output the AFC high test voltage. SW1A SW2C E19 RVP8 Users Manual April 2003 Installation and Test Procedure

Reduce the gain slightly (CCW turn) and verify that the frequency changes such that it becomes closer to the center IF frequency. If it does not change, then continue to reduce the gain until it does. If the frequency is more than 7 MHz from the IF center frequency, then reduce the gain until the frequency is 7 MHz off. Record the results below. Test Procedure, STALO with adjustment

Adjust the Offset pot by screwdriver on the IFD module until the voltage is at the middle of the desired voltage span.

Adjust the Offset pot on the STALO until the the IF frequency display on the setup ter-

minal (Pb mode) is approximately the desired IF frequency (e.g., 30 MHz). Record the results below.

Set the test switches on the IFD to output the AFC low test voltage. SW1A SW2A The voltage on the monitoring scope or Voltmeter will decrease. The burst pulse frequen-

cy may either increase or decrease depending on the nature of the voltage control in the STALO.

Adjust the Gain pot by screwdriver on the IFD module until low end of the desired voltage span is reached, or until the burst pulse frequency is 7 MHz off the center fre-

quency (e.g. for 30 MHz IF, either 23 or 37 MHz) whichever occurs at a higher voltage. Record the results below.

Set the test switches on the IFD to output the AFC high test voltage. SW1A SW2C

Reduce the gain slightly (CCW turn) and verify that the frequency changes such that it becomes closer to the center IF frequency. If it does not change, then continue to reduce the gain until it does. If the frequency is more than 7 MHz from the IF center frequency, then reduce the gain until the frequency is 7 MHz off. Record below. Test Procedure, final cleanup

Set the switches back to the run position (SW1B and SW2B), and disconnect the T for the Voltmeter or scope monitor. This cable can introduce a lot of noise into the system. voltage Midpoint:

_________Volts Lower limit: _________Volts Upper limit:

_________Volts frequency _________ MHz. _________ MHz. _________ MHz. Test Passed For Customer _____________________________________ Date ____________ For SIGMET _____________________________________ Date ____________ E20 RVP8 Users Manual April 2003 Installation and Test Procedure E.18 MFC Functional Test and Tuning (Optional) Test Goal Verify that the Manual Frequency Control (MFC) is functioning properly. Skip this test if you are not using the RVP8s AFC. Reference: RVP8 Users Manual, Section 4.5 Special Test Equipment: Setup Terminal and display scope Test Procedure Enter the Ps command (Plot burst spectrum and AFC).

Use the = command to enter the MFC (manual frequency control) mode. Verify that the MFC mode is indicated by the Manual notation next to the AFC % output indicator on the terminal.

Use the U/u and D/d commands and verify that these commands shift the measured IF frequency (as displayed on the TTY) either up or down. The U command should increase the frequency and the D command should decrease the frequency. If the sense is re-

versed, then go to the Mb command menu and change the question Burst frequency in-

creases with increasing AFC voltage.

Using the U/u and D/d commands, verify the limits of the AFC tuning and fill in the table below:

AFC %

100%

0%

+100%

Measured Freq (MHz) ____________ ____________ ____________ The 0% AFC value should be within approximately +0.2 MHz of the center IF frequen-

cy (e.g., 30 MHz) . The values at + 100% should correspond to approximately + 7 MHz of the center IF frequency, or at the maximum span that is supported by the STA-

LO, whichever is less.

Toggle the MFC mode to AFC by typing the = symbol and and verify that the terminal indicator changes from Manual to AFC. Then exit the Ps menu. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E21 RVP8 Users Manual April 2003 Installation and Test Procedure E.19 AFC Functional Test (Optional) Test Goal Verify that the AFC properly tracks the burst pulse frequency. Reference: RVP8 Users Manual, Section 4.5 Special Test Equipment: Setup Terminal and display scope Test Procedure Use the setup terminal to enter the Ps mode and observe the output on a display scope. Verify the following:

Verify that the system is in AFC mode by checking that the text on the terminal for the AFC % output says AFC.

Verify that the frequency displayed on the setup terminal is within + 15KHz of the cen-

ter IF frequency (the default value for the AFC hysteresis outer limit in the Mb com-

mand). For example in the range 29.985 to 30.015 MHz. If it is not in this range then verify that it moves within this range.

Turn radiate off for 10 minutes and then turn the radiate back on. Observe that the AFC properly tracks the magnetron frequency as the magnetron warms.

Similarly, set the control signal to the maximum and minimum values using MFC, then turn on AFC. Observe that the AFC properly tracks back to the correct frequency.

Perform the tests above for each pulse width and verify that the AFC properly tracks the center frequency.

For pulsewidth 0.

For pulsewidth 1

For pulsewidth 2.

For pulsewidth 3. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E22 RVP8 Users Manual April 2003 Installation and Test Procedure E.20 Input IF Signal Level Check Test Goal Verify that the input signal level is optimized for the IFD. This is done be observing the power in the noise using the Pr command. Reference: RVP8 Users Manual, Section 4.6 Special Test Equipment: Setup Terminal and display scope Test Procedure

Set the transmitter to radiate and elevate the antenna to >45 degrees to minimize the ef-

fects of weather or clutter echoes (including earth noise). Be sure the antenna azimuth is pointed away from the sun or any known RF interference sources you may have. Note: This entire procedure may also be performed with the transmitter off since, in theory, it is only measuring properties of the receiver. However, you may notice some noise interaction between the Tx and Rx.

Use the setup terminal to enter the Pr command and the display scope to view results. Use the Ll/Rr commands to move out in range to a start range of 50 km so that only noise is present. Record the powers displayed on the setup terminal. You can use the V/v command to increase/decrease averaging of samples to make the noise measurement more stable. Total: _________ dBm, Filtered: _________ dBm

Now remove the cable connecting the IF signal into the IFD. Again record the powers:

Total: _________ dBm, Filtered: _________ dBm

Add attenuation and/or amplification by an amount such that the Filtered noise power is approximately 7 dB higher when the signal is connected (See Section 2.2.8).

After verifying the above rise in noise level, disconnect the output cable from the LNA and verify that the noise drops to the same level as when the IFD IF-Input was discon-

nected. This verifies that the dominant noise is indeed coming from the LNA, and not from any of the subsequent IF amplifiers. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E23 RVP8 Users Manual April 2003 Installation and Test Procedure E.21 Dynamic Range Check Test Goal Verify the receiver dynamic range is in excess of 80 dB. Important: This test requires the injection of an RF test signal over a 90 dB range. Damage to the LNA could occur. Check the LNA specification to verify the maximum signal that it can accept. The output from the signal generator

(accounting for cable and coupler losses) should not be allowed to exceed this value. Reference: RVP8 Users Manual section 4.6 Special Test Equipment:

Setup Terminal and display scope RF signal generator Test Procedure

Run the radar and test signal generator for 20 minutes to allow proper warm-up of the system prior to the test. This will allow the AFC to stabilize.

After warm-up is complete, turn the radiate off but leave the receiver on since the test signal generator may be damaged by the transmitter. The antenna should be elevated to 20 degrees and the azimuth should be set to point away from any known microwave sources including the sun.

Use the setup terminal to enter the Mt command to set the pulse width to 0.

Use the Mt 0 command to temporarily configure the FIR impulse response to 2.89 usec

(I/i command) and 0.59 MHz bandwidth (N/n and W/w commands). These settings are for the purpose of benchmarking the receiver performance. Do not save this result since it would override your previously configured band width and impulse response.

Connect the test signal generator to inject a signal at RF ahead of the LNA.

Enter the Pr mode and make the following settings:

Use the space bar to toggle to the power spectrum plot. Use the L/l and R/r commands to set the start to 50 usec. Use the T/t command to set the plot span to 50 usec Use the V/v command to set averaging to 10 samples

Set the signal generator to a value that is approximately 20 dB above noise and observe the scope plot. Adjust the frequency of the test signal generator to make the frequency of the spectrum at the correct IF frequency. Turn off the signal generator RF output and record the Filtered noise power Siggen power: none RVP8 Filtered power:_________dBm E24 RVP8 Users Manual April 2003 Installation and Test Procedure Turn on the signal generator RF with about 20 dB of signal above noise. Now reduce the power until you the Filtered power is approximately 1 dB above the noise level measured in the previous step. Verify this by toggling the signal generator RF ON and OFF. The samples will be a little noisy, but getting the signal exactly 1 dB above noise is not re-

quired. Record the signal generator setting for the 1 dB above noise power (minimum detectable power). Siggen power (Pmin):__________dBm RVP8 Filtered power:_________dBm

Increase the signal generator output power by 10 dB steps until saturation of the Filtered power is observed. Important: Do not increase the signal generator power such Total Power exceeds the Safe Total Power Limit for Pr command display +10 dBm or damage to the RVP8 A/D convertor could result. Back off the siggen power to approximately 10 dB below saturation. Now use 1 dB steps to more carefully define the saturation point to within + 1 dB (e.g., for a 0.2 dB roll off). Record the signal generator setting. Siggen power (Psat):____________dBm The Receiver dynamic range is:

RVP8 Filtered power:_________dBm ______________ dB = Psat Pmin

Verify that the receiver dynamic range is greater than or equal to 80 dB.

Check that the signal generator frequency has not drifted by looking at the plot. If it is off by more than 0.1 MHz, retune and repeat the test.

Exit Pr and do a restore to restore the saved settings. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E25 RVP8 Users Manual April 2003 Installation and Test Procedure E.22 Receiver Bandwidth Check Test Goal Verify the receiver bandwidth is in excess of 14 MHz. Background For proper functioning of the high speed A/D convertors, it is necessary that approximately 14 MHz of broadband noise is available at the IFD. This noise does not interfere with the signal to noise ratio because the bandwidth filter is applied afterwards. The bandwidth of the anti-aliasing filter should be the limiting factor. This test uses the same hookup as the previous test (Section E.21). For dual polarization systems, you expect to get a narrower bandwidth. Reference: RVP8 Users Manual, section 4.6 Special Test Equipment:

Setup Terminal and display scope RF signal generator Test Procedure

Connect the test signal generator to inject a signal at RF ahead of the LNA.

Enter the Pr mode and make the following settings:

Use the space bar to toggle to the power spectrum plot. Use the L/l and R/r commands to set the start to 50 usec. Use the T/t command to set the plot span to 50 usec Use the V/v command to set averaging to 1 sample

Set the signal generator power to a value that is approximately 60 dB above noise and observe the scope plot. Adjust the frequency of the test signal generator in 1 MHz steps to cover the whole range of the scope plot. Mark the total power measured on the plot on the next page.

Set the signal generator power to a value that is approximately 60 dB above noise and observe the scope plot. Adjust the frequency of the test signal generator in 1 MHz steps to cover the whole range of the scope plot. Mark the total power measured on the plot below.

Verify that the 3dB point gives approximately 14 MHz of bandwidth. Test Passed For Customer _____________________________________ Date ____________ For SIGMET _____________________________________ Date ____________ E26 RVP8 Users Manual April 2003 Installation and Test Procedure Graph of Total Power vs. IF frequency 10 0 10 20 30 40 50 60 70 14 16 18 20 22 24 26 28 30 32 34 36 38 40 E27 RVP8 Users Manual April 2003 Installation and Test Procedure E.23 Receiver Phase Noise Check Test Goal Verify the stability of the STALO by looking at the phase noise of a clutter target. Background For proper velocity calculations and for ground clutter rejection, it is required that the radars STALO maintain a stable frequency, and that the transmitted pulse contain no amplitude or phase artifacts. Special Test Equipment:

IRIS ascope utility, or similar program Known clutter targets with no weather signal Test Procedure

Configure the radar for normal operation expect pointing at a known clutter target.

Run the IRIS ascope program, and configure as follows: 16-bit time series, Spectrum not from DSP, spectrum size 256, Rectangular window, short pulse width, high PRF, no clut-

ter filters. Select the maximum range and number of bins to get the maximum resolution over the target. For targets < 24 km, use 201 bins, 25 km. Select the range bin of the target. Record the Az, El, range and phse noise below.

Try minor changes in Az, El, and Range to get the lowest phase noise. The goal is less than 1 degree within 20 km. Az: _____ Az: _____ Az: _____ Az: _____ Az: _____ Az: _____ El:_____ El:_____ El:_____ El:_____ El:_____ El:_____ Range:_____ Phase Noise:_____ Range:_____ Phase Noise:_____ Range:_____ Phase Noise:_____ Range:_____ Phase Noise:_____ Range:_____ Phase Noise:_____ Range:_____ Phase Noise:_____ Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E28 RVP8 Users Manual April 2003 Installation and Test Procedure E.24 Hardcopy of Final Setups Test Goal Make a hardcopy of all the final setups, and attach to the tests. Special Test Equipment: Setup Terminal Dspx Chat Mode Test Procedure

Start script logging with commands cd /usr/sigmet/config/listings, script RVP8.26feb01.

Enter the TTY setups and type the ?? command to list all the TTY setups.

Exit dspx, and exit script logging with exit.

Print the file. Terminal Test Procedure Either use a known screen capture method on your terminal or PC, or make a copy of chapter 3 of the manual, attach to this test, and mark the results in it. Test Passed For Customer For SIGMET _____________________________________ Date ____________ _____________________________________ Date ____________ E29 RVP8 Users Manual April 2003 Installation and Test Procedure E.25 IFD Stand-alone SigGen Bench Test Test Goal Verify that the IFD analog I/O is working properly in an isolated environment. Background These stand-alone production tests are are performed on every IFD prior to shipment. Special Test Equipment:

IRIS dspx utility, IF Signal Generator, Voltmeter Test Procedure

Begin by running dspx and temporarily reverting to factory settings with f.

Enter the Mb menu and choose an IF frequency fIF MHz that matches the center fre-

quency of the IFDs anti-alias bandpass filter.

Enter the Pr menu, and type RRRTTVVVVV to move the starting plot range to 30km, the plot interval to 20m sec, and the averaging factor to 10. Also type two space characters to switch to the spectral display plot.

Attach an IF SigGen to the input of the anti-alias filter that feeds the IF-In IFD input.

Set the SigGen for fIF MHz at 0dBm. Verify that the filtered power is within 0.5dB of 1dBm, and that a single clean spectral line is plotted. Use the Z or z keys to zoom Up/Down as needed.

Increase the SigGen power in 1dB steps until distortion harmonics are seen on the plot. This should occur at 67dBm.

Reduce the SigGen power to 20dBm, and sweep the frequency in 1MHz steps over a 20MHz band centered on fIF. Verify that the bandwidth of the anti-alias filter matches its designed value (14MHz BW for the 30, 57.5 and 60MHz filters, and 4MHz BW for the 16MHz filter).

Switch the SigGen off, and verify that the noise floor filtered power is between 83dBm and 81.0dBm. Note: a very good quality shielded test cable is required here.

Move the SigGen cable to the other IFD filter input, and swap the plots by flipping IFD SW2 to its A position. Repeat the above four tests, now on the Burst-In SMA port.

Place IFD SW1 in its A position, and verify that the AFC output voltage varies in a negative-zero-positive pattern as SW1 is flipped from A-B-C. Use the offset pot to set a nominal 0-Volt output, and the gain pot to set a 5V span. E30 RVP8 Users Manual May 2003 Index A A/D input, B23 Acquisition clock, TTY setup, 310 AFC algorithms, 55 analog, 214 digital, from DAFC, 227 introduction, 131 TTY setup, 327 Angle input, 220 output, 220 S/D input, 221 Angle synchronization, introduction, 127 Angle syncing, LSYNC command, 636 Autocorrelations algorithms, 512 introduction, 126 Automatic Frequency Control. See AFC Azimuth angle, B16 , B17 , B26 B Back panel, B8 Backup copy CDROM, A23 floppy, A23 ftp, A22 introduction, A17 rda_backup, A20 rda_restore, A21 BIOS settings, A6 Burst pulse, introduction, 122 C Calibration, introduction, 111 CCOR threshold algorithms, 517 qualifier, 519 Index CDROM mounting, A28 unmounting, A22 CFGINTF command, 643 Chassis connector panel, 220 direct connections, 219 installation, 218 Clutter correction. See CCOR Clutter filter algorithms, 511 characteristics, C1 comparison of FFT and pulse pair, 564 LFILT command, 621 microsuppression algorithms, 513 TTY setup, 313 TTY setup, 316 Coax uplink installation, 217 specification, 232 COHO, introduction, 114 Configuration examples dual polarization, 17 Klystron, 16 magnetron, 15 Connector panel, B12 Corrected reflectivity, introduction, 130 Correction for Tx Power, algorithms, 59 D DAFC CTI STALO example, 229 description, 227 drawings, pin out, B31 jumpers, 228 MITEQ STALO example, 231 Debug Options, TTY setup, 333 DFT/FFT, introduction, 129 Diagnostics introduction, 132 TTY setup, 34 Differential phase. See PhiDP Differential reflectivity. See ZDR Digital receiver, introduction, 117 Index1 RVP8 Users Manual May 2003 Dual polarization algorithms, 536 calibration, 561 dual channel receiver, 540 introduction, 17 , 130 KDP calculation, 549 modes, 542 notation, 542 radar systems, 538 signal generator tests, 576 simultaneous receive example, 540 standard moments, 550 thresholding, 560 Dual polarization , modes alternating dual channel, 548 alternating single channel, 547 fixed transmit, 545 simultaneous transmit, 546 Dual PRF. See Velocity unfolding Dual PRT. See Velocity unfolding E Elevation angle, B19 , B20 , B26 ENDRAY_ output, introduction, 128 Environment, 143 F Features digital transmitter, 11 open hardware and software, 12 frequency agility, 114 I/Q LAN output, 13 LAN connection, 13 pulse compression, 114 SoftPlane, 12 FFT, introduction, 129 FFT mode algorithms, 564 TTY setup, 313 Fiber optic downlink, installation, 217 FIFO, output, 61 FIR filter algorithms, 54 Index TTY setup, 323 Floppy disk formatting, A18 mounting, A19 unmounting, A22 Fourier transform. See FFT G Get processor parameters, GPARM com-

mand, 622 GPARM, command, 622 H History, 11 Host computer interface complete command list, 61 socket, 224 I I/O62 connector panel drawings, B12 pin out, B12 connector panel, 220 introduction, 115 I/Q, introduction, 13 , 130 IF bandwidth, 29 frequency selection installation, 213 TTY setup, 325 IF to I/Q processing , 123 saturation, 28 signal processing, 121 , 54 IFD adjustment, 26 drawings, B28 dynamic range, 29 I/O connections, 25 input power, 143 , 21 , 24 installation, 22 introduction, 19 LED indicators, 26 Index2 RVP8 Users Manual May 2003 mounting, 24 reference clock, 215 revision history, 23 sampling clock, 121 signal level, 211 IIR filter. See Clutter filter Initiate processing, PROC command, 613 Install utility, A28 Installation software. See Software test procedure, E1 Interference Filter algorithms, 57 CFGINTF command, 643 Intermediate frequency. See IF IOTEST command, 610 K KDP algorithm. See Dual Polarization description, 536 Klystron example, 120 introduction, 16 L Largesignal linearization, algorithms, 59 LDR algorithm. See Dual polarization description, 537 LDRNV command, 640 LEDs on IFD, 26 SLED command, 638 LFILT command, 621 LOG filter, threshold qualifier, 519 LOG threshold, algorithms, 518 Login logout, A4 operator, A3 poweroff, A4 procedure, A3 root, A3 Index LRMSK command, 62 LSIMUL command, 631 LSYNC command, 636 M Magnetron example, 118 introduction, 15 Main chassis back panel, B8 drawings, B2 general description, B2 input power, 143 , 21 , 218 , B7 , B9 PC I/O, B10 PCI cards, B11 Mean velocity. See Velocity Motherboard, introduction, 113 N Network management adding services, A34 basics, A31 default configuration, A31 DNS, A33 hostname, A32 IP address change, A32 NTP time synch, A33 socket interface, 224 telnet, A34 Noise sample, SNOISE command, 611 NOP command, 62 O Optional argument list, XARGS command, 642 OTEST command, 611 P Passwords, A2 Phase control output, 220 TTY setup, 334 Index3 RVP8 Users Manual May 2003 PhiDP algorithm. See Dual Polarization description, 536 Power off, A4 Power requirements, B7 , B9 Power requirements, 21 , 218 Power requirements, 143 PPP mode, TTY setup, 313 PRF limits, PWINFO command, 634 SETPWF command, 636 TTY setup, 318 , 323 PROC command, 613 Pulse compression, introduction, 114 Pulse pair, introduction, 129 Pulsepair processing. See PPP Pulsewidth control introduction, 131 PWINFO command, 634 SETPWF command, 636 TTY setup, 318 PWINFO command, 634 R R2 processing, TTY setup, 313 Random phase algorithms, 570 introduction, 130 TTY setup, 318 Range averaging algorithms, 513 introduction, 127 LRMSK command, 63 Range mask, load command (LRMSK), 62 Range normalization, LDRNV command, 640 Range resolution, TTY setup, 323 Range unfolding, introduction, 130 RBACK command, 641 rda_backup, A20 rda_restore, A21 Reflectivity algorithms, 513 introduction, 130 Index Reflectivity calibration, 525 Relays, B21 Reliability, 143 Reset, TTY setup, 33 RESET command, 633 Reset time, TTY setup, 35 Restore, introduction, A17 RhoHV, description, 537 ROM revision, TTY setup, 33 Round trip delay, TTY setup, 35 RVP8/Rx card, introduction, 110 RVP8/Tx card, introduction, 113 S S/D input, B26 Saturation headroom, TTY setup, 314 SBC, introduction, 113 Scope holdoff ratio, TTY setup, 312 SETPWF command, 636 SIG threshold, algorithms, 518 Simulations burst pulse, TTY setup, 332 LSIMUL command, 631 output data, TTY setup, 334 SLED command, 638 SNOISE command, 611 Socket interface, 224 Softplane, sofplane.conf, A11 Software configuration introduction, A10 softplane.conf, A11 utilities, A10 installation, A6 automatic startup, A7 BIOS, A6 FPGA flash, A8 from RDA CDROM, A7 introduction, A5 reboot test, A9 introduction, A1 login, A2 upgrade, A24 download files, A25 install utility, A28 Index4 RVP8 Users Manual May 2003 version, A24 SOPRM command, 64 Speckle filter algorithms, 521 introduction, 128 Spectrum width algorithms, 515 introduction, 130 SQI threshold algorithms, 516 qualifier, 519 STAR, 546 su, A3 Support, software upgrade, A24 Synchro input, B26 T TAG lines introduction, 127 TTY setup, 315 Test point, output , 221 Testing test procedure, E1 with signal generator, 575 Thresholding algorithms, 519 adjusting, 520 introduction, 128 Time series, algorithms, 511 Trigger blanking, 131 external input, TTY setup, 318 input, 222 installation, 222 introduction, 131 output, 222 outputs, TRIGWF command, 633 TTY setup, 318 waveform, example of Dual PRF, 535 TRIGWF command, 633 TTY setup complete listing, 31 M+ debug options, 333 Index Mb burst pulse and AFC, 325 Mc board configuration, 310 Mf clutter filters, 316 Mp processing options, 313 Mt general trigger setups, 318 Mz transmitter phase control, 334 P+ plot test pattern, 43 Pb plot burst pulse timing, 46 Pr plot receiver waveforms, 423 Ps plot burst spectra and AFC, 411 TTYOP command, 638 V view internal status, 33 TTYOP command, 638 TWT, example, 120 U Uncorrected reflectivity, introduction, 130 Unfolding, introduction. See Velocity unfold-

ing V Velocity algorithms, 515 introduction, 130 Velocity unfolding algorithms, 530 , 532 introduction, 128 W Weather signal processing, introduction, 125 WSP threshold, qualifier, 519 X XARGS command, 642 Z ZDR algorithm. See Dual polarization description, 536 Index5

 

 

Technical Manual C-Band 1 MW Transmitter Pulse Systems Part Number TR-1038 Magnetron SFD 313V August 22, 2003 Prepared By:

Pulse Systems Inc. 222 Bolivar Street Canton, MA 02021 Prepared For Barron Services 4930 Research Drive Huntsville, AL 35805 TABLE OF CONTENTS GENERAL DESCRIPTION..................................................................... 2 Introduction.................................................................................. 2 System Specifications .................................................................... 2 General Technical Discussion.......................................................... 2 Mechanical................................................................................... 4 POWER SUPPLY SECTION .................................................................. 6 Technical Approach ....................................................................... 6 Schematic Diagram........................................................................ 6 Mechanical Considerations.............................................................. 8 Interface ...................................................................................... 8 MODULATOR SECTION....................................................................... 9 Technical Approach ....................................................................... 9 Schematic diagram ........................................................................ 9 Mechanical Considerations............................................................ 10 Interface .................................................................................... 11 MAGNETRON HEATER POWER SUPPLY .............................................. 12 Technical Discussion ................................................................... 12 OPERATING INSTRUCTIONS.............................................................. 13 Procedure For Setting All System Parameters ................................... 13 MAINTENANCE................................................................................ 15 Introduction................................................................................ 15 The Power Supply Section............................................................. 15 The Modulator Section.................................................................. 15 APPENDIX...................................................................................... 16 Magnetron Specifications.............................................................. 17 Figures...................................................................................... 35 1 GENERAL DESCRIPTION Introduction The system described in this manual consists of four main parts:

A:

B. C. D. The Main High Voltage Power Supply The Modulator System The Corner Cutter Filament Power Supply In order to achieve the design objectives of this contract, our design approach has to follow state-of-the-art technology in solid-state design. The evolution of third generation IGBT technology and the various power supply topologies makes it a challenge to make the right choice for our present application. The design objective calls for generating narrow pulses of various pulse-widths under single pulsing conditions. The cathode pulses will drive a CPI Magnetron operating in the C-Band frequency with minimum peak output power 1.0 Mw. The power supply section is self-contained in an enclosure as shown in Figure 1.0. Our design is based on series resonance topology driving a full bridge circuit. The modulator is a hard-tube type, utilizing IGBT technology, and is under oil environment. The mechanical enclosure for the modulator is shown on Figure 2.0 System Specifications The specifications for the systems are outlined in the Appendix along with the magnetron specifications. General Technical Discussion As previously mentioned, the whole system consists of the high-voltage power supply and the solid-state hard tube modulator. The solid-state power supply contains the following sections:

A. B. C. D. E. Off-Line Rectifiers, Filters, and Controls Series Resonance Full Bridge Inverter Series Resonance Frequency Modulation Control High Voltage Output Section Low Voltage Power Supplies 2 F. G. Hard Tube Modulator Control Solid-State Filament Power Supply The Modulator section contains the following sections:

A. B. C. D. Switch Driver Assy PRF Driver High Power Switch Section Magnetron Peak Current Detector The input voltage for the system is 220 VAC single phase and it enters the system via a connector located in the rear lower panel of the cabinet. The input line voltage enters the system via a circuit breaker located on the control panel. The control panel is located on the front upper section of the main cabinet. Figure 3.0 shows the mechanical configuration of the system. The front view of cabinet shows the control panel located on the upper section. The main electrical system diagram is shown on figure 4.0. The main power is switched on by the circuit breaker on the control panel and is further fused before entering the power supply section. It enters the front end of the power supply and is applied to the power factor correction section. The Power Factor Correction Module performs the rectification, in-rush current limiting and preregulation of the input line voltage. The power factor module provides a preregulated DC Voltage level of 360 VDC. The above 360 VDC is applied to the input of the series resonance converter which, in turn, provides a final adjustable level of 0-900 VDC available at the modulator section. The above DC output is sent to the modulator section through three of wires leaving the back of the power supply section. The input PRF, which is TTL level, enters the control panel and is further processed by the Modulator control circuit. It enters the Modulator Control Circuit, which transforms this input signal to a selectable pulse-width level proper for triggering the modulator section of the system. The modulator control circuit performs additional functions, as will be discussed later under the Power Supply section. Figure 5.0 shows the complete power supply section of the system. The power supply also provides the low voltage bias levels required by the modulator. The modulator section receives the trigger input from the modulator control circuit located 3 in the power supply. The function of the modulator is to receive the input signal and provide a high-power pulse of 36-38 KV at the cathode of the magnetron, thus causing the magnetron to oscillate at C-Band frequency under the selected pulse width set by the modulator control circuit. The maximum cathode peak current under the above conditions is 60 Amperes peak. The above voltage and current levels result in a peak output power of 1.0 MW. In the meantime, the filament power supply requires programming according to the magnetron specifications. For the stand-by condition, the filament voltage is set to 5.0 VDC at 18-22 Amps and is reduced to 2.0 VDC at the maximum duty cycle of

.001. The cathode voltage is fed to the magnetron via the high voltage bushing located on top of the modulator. The magnetron peak current is being monitored via a wide band current transformer under the magnetron and over the modulator section. The sensitivity of the current transformer is set to 0.1v/ amp. For example, if we are looking at the scope displaying the current monitor output, a 6.0 volt peak pulse level will indicate 60 Amps peak magnetron current. Next to the modulator high voltage output terminal is a spark gap, which prevents the magnetron from reaching much higher than normal pulse voltage levels. The voltage of the spark gap is set to 45 KVPK. When the magnetron misfires the pulse output voltage could theoretically reach a maximum pulse voltage level of 76 KV. The spark gap limits this level to a maximum of 45 KV pulse thus reducing the voltage stress level of the system to a more reasonable level. Mechanical As previously mentioned, the mechanical outline drawings of both the power supply and modulator are shown in Figures 1.0 and 2.0. Figure 3.0 shows the mechanical outline of the whole system The power supply is of dry construction and is mounted on rails at the lower section of the equipment cabinet. It can be removed by first removing the rear connections at the rear section of the unit and then slide the whole assembly out of the cabinet. 4 The modulator on the other hand is contained in an oil-filled container for insulating and cooling reasons. The modulator is mounted above the power supply on its own compartment. Next to the modulator, the corner cutter assembly is mounted and its output is connected to the cathode terminal of the modulator. The magnetron is mounted above the modulator shelf and the high voltage bushing projects into the modulator compartment through a hole located on the magnetron shelf. Under this hole, the wide band current transformer is mounted and its output is terminated to a BNC connector located on the control panel. The magnetron compartment provides the space for the assembly of all the microwave components required by the system. 5 POWER SUPPLY SECTION Technical Approach In order to meet our design objectives of reliability, efficiency, simplicity and cost, our approach for the system is derived from our past experience. For the power supply, we feel that the series resonance converter topology is the best choice. First the efficiency of the system is greatly optimized under this topology and both the RFI and EMI levels are kept at a minimum. In contrast with PWM systems, the series resonance converter operates smoothly with sine wave currents, rather than square wave excitation. Efficiency levels of 95% are easily attained under the chosen power supply topology with proper design techniques. For the modulator section of the system, the approach is a hard tube modulator topology using solid-state technology switching. Schematic Diagram Figure 5.0 shows the complete schematic of the power supply. The main sections of the power supply are as follows:

The input power enters the power supply at the command of the 24-VDC-control voltage. Relay K2 receives the +24vdc level and allows the main power to enter the power supply. The control transformer T-1 when energized provides four regulated output voltage levels:

Input relay section Power factor section Full bridge inverter section High voltage output section SRI control circuit Heater PWM & Metering circuit Magnetron heater section

+24 VDC

+28 VDC

+15 VDC A:

B:

C:

D:

E:

F:

G:

A;

B:

C:

6 D:

-12 VDC The above voltage levels are regulated via linear series regulator circuits with associated filter networks. The input line voltage enters next the Power Factor Correction Circuit. The power factor modules (three) rectify the input line voltage, regulate it, and limit the input inrush current to a reasonable level. The final level of 360 VDC is applied to a capacitive input filter properly sized for the full power of the system and, finally, is applied to the full bridge circuit shown next to the power factor circuit. The full bridge circuit is driven by the SRI Control circuit, which generates, regulates and provides protection for the whole power supply system. The SRI control circuit sends two drive pulses, noted as Drive A and Drive B. Both pulses are identical in amplitude and pulse-width but they are frequency modulated, depending on the power demand of the system. This is the way the power supply regulates. When the load demands more power, the frequency of the drive pulses is raised to a higher level and when the load demand diminishes, the frequency slows down to the point that the system meets its regulating requirements. The two drive pulses are applied to the bridge circuit of the main inverter and they drive the main switches into full conduction during their on state and off during their off state. Turn-on and turn-off occur at zero current switching conditions. This alternating voltage waveform is impressed across the primary winding of the inverter transformer, with the proper turns ratio, the output is rectified and filtered to a maximum level of 900 VDC. The output voltage of the power supply is controlled by a potentiometer located at the front control panel. The top arm of the potentiometer is connected to +10 VDC and the wiper is connected to one terminal of an operational amplifier. The other input terminal of the operational amplifier is connected to the feedback terminal of the output section of the power supply. The design objective is to keep the two input terminals of the operational amplifier to an equal level. If the arm of the potentiometer is set to a higher voltage level, thus demanding higher output voltage from the power supply, the feedback signal is raised to the same corresponding level as the arm of the potentiometer. This is the way the system regulates against input and load variations. 7 Metering circuits are provided for the output voltage of the power supply, the output current, the filament voltage, the magnetron average current and the system voltage. The return section of the power supply goes through a sensing resistor whose level is detected and processed for over-current protection. Mechanical Considerations Figure 1.0 shows the mechanical configuration of the power supply. The enclosure is made of chemically treated aluminum alloy and is cooled with fans located inside the power supply frame. The power level of the power supply system is set to a maximum of 5.0. KW. The maximum temperature rise of the power supply is 25 degrees Centigrade over the ambient temperature. The system operating at maximum duty cycle of .001 requires a power level of 36,000 x 60 x .001 = 2,160 watts. If we assume a system efficiency including both the power supply and modulator of 75%, the power level of the power supply becomes 2,880 watts, which is lower than the maximum power supply limit of 5000 watts. Interface The power supply is controlled by the front panel controls of the main cabinet of the system. The local control in the front panel of the power supply adjusts the output level of the power supply and performs also the resetting action against various system faults. The radiate command and pulse width selection is done also via the front panel controls. All controls and monitors are located in the front control panel. The power supply communicates with the modulator and monitors fault conditions relating to the magnetron misfiring, over-current and over-duty conditions. Figure 4.0 is a functional diagram showing the power supply and modulator interconnected with the control panel. 8 MODULATOR SECTION Technical Approach Several solid-state modulator systems have been designed, built, and delivered by Pulse Systems. All designs feature the Mosfet or IGBT technology. Our design approach for reliable operation has been to limit the switching voltage level within the solid-state switch capability and to avoid stacking switches in series configuration. The design approach is shown in Figure 6.0 Schematic diagram For the discussion, which follows, we make reference to Figure 6.0 The whole system is enclosed in oil environment for insulating and cooling reasons. Figure 6.0 shows the main sections that are contained in the modulator system. The PRF driver is set at the front section of the system. It receives its signal from the modulator control, designed to be slaved to an external PRF generator. The only control that the external generator has over the modulator control is the frequency count. The rest of the pulse width processing and control is governed by the modulator control circuit. The complete modulator system consists off three drive circuits, a supervisory control circuit governing the operating conditions of the drive circuits and the output section. The output section consists of a solid state switch assembly, three high voltage step-

up pulse transformers, and a pulse shaping network. In order to generate the narrow pulses with proper rise and fall time, the pulse transformer design demands special consideration in selecting the proper magnetic material and proper winding configuration. This information is proprietary to Pulse Systems Inc. The magnetron tube also requires proper rate of rise of the cathode voltage. This level has to be kept between 90 and 110 kV/sec in order to avoid magnetron moding. In order to achieve this low rate of rise of voltage, a corner cutter is added to the system to prepare the tube before conduction. 9 The schematic diagram of the corner cutter is shown in figure 6 next to the modulator circuit diagram. The solid state switch assembly is turned on during the positive portion of the drive pulse and kept off when the drive pulse goes to a negative bias level. The output pulse-width of the system bears a close relationship to the drive pulse of the switch driver. The pulse current is monitored via a wide-band current transformer and fed back to the peak over current detector, which removes the drive pulse from the switch driver circuit if the magnetron pulse current is out of specification. The modulator control circuit has a provision and allows a number of peak over-

current conditions within the time frame of one minute. This number is selectable via a switch assembly located in the modulator control circuit. Missing magnetron pulses and magnetron misfiring occurs quite often and the above-mentioned quality of the modulator control circuit is essential to allow the system to run and overcome the magnetron temporary miss occurrences. If the abnormalities associated with magnetron continue on beyond the set limits, the system latches to the stand-by condition and a manual reset is required. The magnetron average current level is also detected in the same way and controlled. Figure 6 shows also the schematic of the corner cutter. Diodes D1-D40 are isolating special high voltage diodes and they isolate the corner cutter from the secondary high voltage pulse up to the threshold point set by the string of the zener diodes. What the corner cutter really does is to allow the cathode voltage to reach 75% of its full voltage at a very fast rate and when conduction begins the corner cutter capacitor is connected to the output pulse loading down its rate of rise. The value of the corner cutter capacitor and the resistor in series determine the rate of rise of voltage during conduction of the magnetron tube. The mechanical outline drawing of the corner cutter is shown in figure 7.0. Mechanical Considerations The modulator outline drawing is shown in Figure 2.0. The modulator top section contains all the necessary terminals for the proper operation of the system. Terminals E7, E8, and E9 are connected to the high voltage 10 section of the power supply and provide high voltage to the four modulator channels. Terminals E4 and E5 are connected to the primary winding of the heater power supply inverter transformer. There is a BNC connector located along the same line with the above terminals dedicated for the input drive pulses from the modulator control circuit. All the terminals located above the BNC connector are the control and feedback voltages to and from the modulator. Directly across the input heater terminals we see a high-voltage bushing dedicated for the cathode and heater of the magnetron tube. The cathode terminal is connected to a high voltage spark gap located next to the high voltage bushing. Interface The modulator connections to the power supply and to the rest of the system are shown in Figure 4.0. 11 MAGNETRON HEATER POWER SUPPLY Technical Discussion The magnetron heater power supply consists off three parts:

A. B. C. Heater meter control card High voltage inverter transformer Filter section The control card for the heater power supply is shown in figure 8.0. The control circuit generates a PWM signal to drive a discontinuous mode power supply. The high voltage section of the power supply is inside the modulator including the filter section and feedback. The feedback signal returns to the control circuit and regulates the heater voltage for both stand by and full duty cycle conditions. The feedback signal is fed back through the bifilar winding of the pulse transformer. The control card provides the metering circuit for the filament voltage. 12 OPERATING INSTRUCTIONS Procedure For Setting All System Parameters After the system has been received and inspected a cable should be prepared for the outside power connection to the 220 VAC 50/60 Hz. The external source should be capable of providing 220 VAC 50/60 Hz at a minimum current of 25 amps. Before we apply power to the system, we make sure that the high voltage adjust potentiometer is set all the way counter clockwise. This ensures that when the power supply turns on, it will start at almost zero volts DC. This is only essential when we first set the system up and after we have completed all the steps, the system can return to its previous settings without further adjustments. We now turn the power supply on by turning on the main circuit breaker on and the power on switch. We notice at this point that the +24VDC and the warm up light indicators are turned on. We have to wait five minutes approximately for the heater to come up to the right temperature before being able to radiate power. Also, we notice that the monitor indicating the heater voltage is up to the proper voltage level of 5.0 VDC. We monitor through an external oscilloscope the peak magnetron current. When the ready light turns on (after five minutes) we turn the radiate switch on and proceed turning the RF control potentiometer clockwise raising the modulator power to the point where a rectangular current pulse is being displayed on the oscilloscope. The sensitivity of the scope should be set to 1.0 per division indicating 10 amps/division and the total current display should be six divisions high, thus indicating 60 amps, which is the maximum magnetron current for 1.0 MW power output level. The system has to operate within the specified conditions. The modulator will power the magnetron smoothly under all pulsing conditions. Because the power supply and modulator are quite adjustable in terms of voltage amplitude and pulse width, the output system performance could easily get out of specification and either the duty cycle or the peak cathode current of the magnetron can be exceeded. The two most 13 important things to remember are the 60 Amperes of peak cathode current and the 0.001 duty cycle. The peak cathode current is easily observed on the screen of the oscilloscope. In the case of the duty cycle, each pulse condition has to be evaluated to ensure compliance with the magnetron specification. Since the product of the pulse width in usec and the pulse repetition rate in cycles gives directly the value of the duty cycle, we have to mathematically evaluate it before proceeding with any pulse condition. The pulse shape has to meet the specifications in terms of rise and fall time. Also an important parameter is the rate of rise of the cathode voltage. This parameter has been set by the manufacturer as the time of the steepest tangent, between the 70%

point of the cathode voltage crossing the zero axis. 14 MAINTENANCE Introduction This sections covers information regarding the maintenance of the system. In general, the incorporation of solid-state devices makes the system an easier system to care for as time goes on. There is basically no component in the system that has a time limit or exhibits performance degradation as a function of time. The Power Supply Section The power supply section is cooled by forced air-cooling fans located in the rear section. The reliability of the selected fans is quite high and, so far, we have not encountered any problem in this area. Periodic examination to ensure that no build up of any foreign material is accumulating in any area near the cooling fans is essential. Removing the power supply top cover for a quick examination is recommended every year to ensure that the air flow passages are clean, that no evidence of overheated parts is present, and that all other components are in normal operating condition. The Modulator Section The modulator, in contrast to the power supply, is inside an oil environment and a slight air movement inside the cabinet is sufficient to keep it cool. There should be no need ever to replace the oil of the modulator. 15 APPENDIX 16 Magnetron Specifications 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 Figures 35

 

 

Exhibit #S3:

The technical manual for the transmitter was included as Exhibit K in the application. The VHDD-

1000C radar system manual consists of lengthy documentation for the various components and system operation. Attachment S3 consists of the table of contents for each of these manuals. If the FCC requires, Baron will provide full copies of these manuals.

 

 

CHET ES. Baron Services OPERATION AND MAINTENANCE MANUAL ELEVATION OVER AZIMUTH POSITIONER AL-4017-1EBS-B For Baron Services Radars:

XDD-350C VHDD-350C HDD-350C HDD-250C BARON RADAR SERVICES, L.L.C. 4930 Research Drive Huntsville, AL 35805 PHONE: 256.881.8811 FAX: 256.881.8283 TABLE OF CONTENTS SECTION 1 DESCRIPTIONS ......cscssssssssssessssssecsssssesssssseeecsssesessssessssuscssasecsssueecsseeessneesssssecssseeees 1 11 General Description 1.2 Technical Description... 1.3 Specifications 1.4 Mechanical Sub-Assemblies. 1.4.1 Elevation Unit 1.4.2 Azimuth Unit 1.5 Electromechanical Sub-Assemblies 1.5.1 Limit Switches .. SECTION 2 INSTALLATION & OPERATION .......ssssscssssssssssssccsssssscsssecesssseesssscesssceessscessanecessese 4 21 General 2.2 Positioner Installation. 2.3. Antenna Installation ... 2.4 Operation Instructions SECTION 3 MAINTENANCE ........cccssssscsssscssssssseessnseesssssesssssuscsssssecessnseesssssesssseesssseesssecessneeessaees 7 3.1 3.2 Cleaning 3.2.1 Exterior Cleaning. 3.2.2 Interior Cleaning 3.3. Lubrication... 3.3.1 Periodicity 3.3.2 2000 Hour or 2-Month Lubrication . 3.3.3 17000 Hour or 2-year Lubrication... 3.3 Electromechanical Components. 3.3.2 General 3.3.3 Limit Switches 3.3.4 Limit Switch Adjustment Procedure (see Figure 1 3.4 Timing Belt Installation And Adjustment 3.4.1 Belt Tension (refer to Figure 2) 3.4.2 Sprocket Alignment . 3.4.3 Belt Handling... 3.4.4 Belt Storage... 3.5. Replacement of Azimuth Motor Assembl:

3.5.1 Removal of Azimuth Motor Assembly 3.5.2 Installation of Azimuth Motor Assembly SECTION 4 STORAGE AND PREPARATION FOR USE......ccssssssssssssscssessseessssesssessseesseesseess 19 SECTION 5 REPLACEMENT PARTS ......scsssssssssesssscsssssssessseesseessueesueessccesuecessessneesaeesseessesess 20 5.1 PARTS LIST 5.1.1 GENERAL. 5.1.2. ITEM NUMBER (IT!

5.1.3. DESCRIPTION. esses 5.1.4 PART NUMBER (PART No. 5.1.5 QUANTITY (QTY). 5.1.6 | ORDERING INFORMATION FOR PARTS. APPENDIX....ssssssssssssssssssssssshessssenseesesesssmumutustsnsessssssesssseeesesseeseeccecceceeensesssesscsecssctuseuesunnnseaneeeeses 22 LIST OF TABLE AND FIGURES TABLE 1. AL-4017-1EBS-B SPECIFICATIONS... ase TABLE 2. RECOMMENDED LUBRICANTS AND LUBRICATIO:

FIGURE 1. LIMIT SWITCH ASSEMBLY .... FIGURE 2: RECOMMENDED BELT TENTION. FIGURE 3. AL-4017-1EBS-B POSITIONER ASS:

TABLE 3. AL-4017-1EBS-B Parts List. BeoRnow ii RDACS Users Guide ___ August 2000 vee Baron oo Servyiecs R ACS Users Guide August 2000 Table of Contents 3. RDACS Config. 3.1 File Pull-Down Menu 3.2 Connect Commands 3.3 A-Scope Commands 3.4 Control Commands 4. Configuration Commands. 5. Installing RDACS 6. The radacs.ini Configuration File 6.1 Start-Up Section 6.2 Master Section.............:ceeee 6.3 Site Section 6.4 RadPgmN Section 6.5 Antenna Sections. 6.6 LevelN Section............cccceeeee 6.7 ModeN Section.. 6.8 AntennaCmds Section Baron yiServiccs de eeeeeteeaeeteeeeerneescenensaeees Wits 50 les eeseeeeeeeeeseseeses dyetetsteestestestestsseseseees 67