Baron Services DSSR-250C Pulsar Digital Solid-State Radar System User Manual

Baron Services Inc Pulsar Digital Solid-State Radar System

Host Computer Commands

Host Computer CommandsRVP8 User’s ManualMarch 20066–16. Host Computer CommandsThis chapter describes the digital commands that the host computer must use to set up andcontrol the RVP8 processor for recording data. Each command is described in detailed in aseparate 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 particularcommands.The write–up for each command includes a description of what the command does and apictorial layout of the bits in the 16-bit command word. Commands consist of an initialcommand 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, thosewords are listed as “Output 1”, “Output 2”, etc. Often each word is broken down into severalindependent fields, each consisting of one or more bits. In such cases, the pictorial layouts showthe placement of the bit fields within the word, and each field is described individually. All datatransferred 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 thedescriptions of every command. The instruction set has been designed to be as concise andorthogonal as possible. User programs should always execute the IOTEST command onpower-up to ensure that the interface connections are all intact. The diagnostic result registersfrom 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 isconceivable that PROC commands could be issued immediately to acquire and process radardata. More realistically, however, the default information is first modified to meet the usersneeds.To set up for data acquisition and processing the following sequence of commands might beexecuted. Trigger and pulse width are first established using the SETPWF commands. Rangebin placement and processor options are then chosen using LRMSK, and SOPRM, and receivernoise samples are taken with SNOISE. The noise levels are not automatically sampled onpower-up, so SNOISE must be issued at least once by the user. LFILT is executed if clutterfilters are needed. If data rays are to be synchronized with antenna motion, then LSYNC is usedto specify a table of antenna angles. After all setups are complete, PROC commands are issuedto actually collect, process, and output the data. Errors detected during the execution ofcommands 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 dataflow. This buffer is included to simplify the requirements of the user’s interface hardware. TheFIFO holds each sequential word generated by the RVP8 until such time as the user is ready toaccept it. Thus, when reading from the processor, it is permissible to fall behind by as many as4096 words before any slowdown in performance occurs. The RVP8 writes to the FIFO at fullspeed as long as it is not full, and the internal processing is not affected by the exact speed atwhich user I/O actually occurs. This continues as long as the average I/O rate on, perhaps 10msintervals, matches the average rate at which data are being produced.
Host Computer CommandsRVP8 User’s ManualMarch 20066–2The 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 usermakes 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, ofcourse, leads to a slowdown in performance, but it is not a disastrous one. The user alwaysobtains correct data no matter how long it takes to read it. One could take advantage of this factto synchronize the acquisition of data by the RVP8 with the post-processing and display of thatdata by the user. In this case, RVP8 would be instructed to output data at the maximum rate, theuser would read these words at the user’s maximum rate, and the overall system wouldautomatically 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 anotherway that the idle wait loop can be exited, that is, if the processor detects that the user isperforming a write I/O cycle. Since the user should have been reading data by now, the presenceof a write cycle is taken to mean that some more important condition has arisen. As such, thewait loop is terminated and the RVP8 accepts the write data soon afterward. If the new data arecommands, they are executed right away, but any output they try to produce may be lost in asimilar 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 anequal number of zeros. Each time the RVP8 discards an output word, it also increments aninternal 24-bit count. When FIFO space becomes available in the future, the processor replacesall 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 whichcalls for clearing of the output FIFO. When the RESET is processed, all past and present outputdata are discarded, leaving the RVP8 output section completely empty. This is useful wheneverthe 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 usefulwhen 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. Anarbitrary set of range bins are selected via an 8192-bit mask. The Nth bit in the mask determineswhether data are acquired and processed at a range equal to RES x (N-1). The Range resolutionis specified by a TTY setup question (see section 3.2.5), in the range 25 through 1000 meters.Any collection of ranges may be chosen from integer multiples of that distance. The examplebelow is given for the default resolution of 125 meters. The range mask is passed to the RVP8packed into 512 16-bit words. The least significant bit of each packed word represents thenearest range, and the most significant bit represents the furthest range in each group of 16.
Host Computer CommandsRVP8 User’s ManualMarch 20066–3According to the range bins that are selected in the mask, the signal processor computes andstores internally a range normalization table which is later used to convert receiver intensitylevels into reflectivity levels in dBZ. Note that the LRMSK command implicitly specifies thenumber of bins to be processed and output. The maximum bin count is 3072, though dependingon the computational intensity of the configuration, the RVP8 may be able to compute fewerbins. If the number of bins selected in the bit mask exceeds this maximum, the trailing bins aretruncated. If the new mask does not specify any active bins, then a single bin at range zero isforced on. The default power-up mask selects 256 bins equally spaced by 1.0km starting fromzero range.Range averaging is also determined by LRMSK. The upper byte of the command controls howmany consecutive bins are grouped together. A value of zero means no averaging; one meansthat pairs of samples are averaged; 255 means that 256 terms are summed, etc. The individualsamples 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 datasamples. Note that the limitation of 3072 sampled ranges applies to the bin count prior toaveraging.For example, suppose 100 bits are selected in the range mask and no averaging is elected. Thenparameters are computed at those 100 ranges, and 100 bins of data are output. If the averagingwere set to one, rather than zero, samples would still be taken at the same ranges, but pairs ofbins would be averaged together and only 50 ranges would result. Note that the parameters areaveraged by summing the autocorrelations for each bin. The range normalization valueassociated with the averaged bin is computed according to the midpoint of the first and lastsample.Incompletely averaged bins are discarded by the LRMSK command. In the above example, ifthe averaging were set to two so that triples of samples were summed, then only 33 bins wouldbe output. This is because the 100-bit mask left a dangling 100th sample. In the extreme casewhere there are not enough mask bits to result in even one complete bin, the RVP8 forces theaveraging to zero and turns on a single bin at zero range. 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
Host Computer CommandsRVP8 User’s ManualMarch 20066–46.3 Setup Operating Parameters (SOPRM)This command is used to configure the Signal Processor. The command should be issuedwhenever any of the parameters in the list change. The default parameter list consists of twenty16-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 | | | | | | | | | | | | | | | | || |NTh| | 0 0 0 1 0 | Command|___________________________|___|___________|___________________|NTh If 1, then no threshold values are set. This means ignore input words 4, 5, 6, 7,11, 12, 13, 14, and 18. This is usually used in conjunction with the THRESHcommand (see section 6.29), when setting individual thresholds. 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 alternatingpolarization mode, the sample size must be even. If an odd value is entered it is rounded up byone in that case. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Polar |NHD|ASZ|16B|CMS| R2| |3x3| | |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 Configures transmit polarization and Zdr processing:00 – Fixed polarization, Horizontal01 – Fixed polarization, Vertical10 – Alternating polarization pulse-to-pulse11 – Dual simultaneous transmissionNHD Disables inclusion of header words in the processed data that are output by thePROC command (See also, CFGHDR command).ASZ The “Any Spectrum Size” bit requests that DFT processing algorithms, clutter fil-ters, spectral output, etc. all operate on spectra whose size exactly matches thenumber of available pulses (rather than rounding the spectrum size down to thenext lower power-of-two).16B 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, andZdr data. However, the PROC command’s archive format always holds 8-bit data,regardless of the setting of 16B. This gives the option of extracting both 8-bit and16-bit data simultaneously from each ray.CMS Enables Clutter Microsuppression, in which individual range bins are rejected(based on excessive clutter) prior to being averaged together in range.R2 Use three lag (R0/R1/R2) algorithms for width, signal power, and clutter correc-tion.
Host Computer CommandsRVP8 User’s ManualMarch 20066–53x3 Switches on the 3x3 output filter (See Section 5.3.3). The RVP8 automaticallyhandles 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.Lsr Reflectivity speckle remover. When set, range speckles in the corrected and un-corrected reflectivity data are removed.Dsr Doppler speckle remover. When set, range speckles in the velocity and width dataare removed.Rnv 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 unitsof the 12–bit “Log of power in sample” time series outputs. One fourth of this slope is used togenerate the “Log of Measured Noise Level” output from GPARM (word 6). The recommendedvalue 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 controlflags (see below) include LOG Noise bits. The threshold value is always non-negative, and thecomparison 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 negativethan 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|_______________________________|_______________________________|The Signal Quality Index (SQI) threshold is an unsigned binary fraction in the range 0 to255/256. When the SQI for a range bin falls below the stated value it may result in thresholdingof 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 receivedsignal. When the SIG (see Section 5.2.12) falls below this comparison value it may result inthresholding of data.
Host Computer CommandsRVP8 User’s ManualMarch 20066–6 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, theRVP8 command set works in a uniform way in all modes.0000 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).0001 FFT Processing Mode. Doppler clutter filters use nonlinear frequency-domainapproach; data are processed in batches of pulses (see Section 5.2.2).0010 Random Phase Processing Mode. Data from first and second trips are dealiased inrange based on knowledge of the radar transmitter phase (see Section 5.7).0100 DPRT-1 Processing Mode. The trigger generator produces alternate short and longpulses, and Doppler autocorrelations are computed using only the short pairs (seeSection 5.5).0101 DPRT-2 Processing Mode. The trigger generator produces alternate short and longpulses, and Doppler autocorrelations are computed using both pairs (see Section5.5).11XX Four codes reserved for custom user modes. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || |UVD|PCT| 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 usercommands. The delay permits the clutter filter transients to settle down followingPRF and gain switches. The value is specified as the number of pulses, and hence,the number of filter iterations, to wait.ZER If set, then the clutter filter’s internal state variables are zeroed prior to waiting thedelay time. For some signal conditions, this may give better results than allowingthe filter to naturally flow into the new data.Window Selects the type of window that is applied to time series data prior to computingpower spectra via a DFT. Choices are: 0:Rectangular, 1:Hamming, 2:Blackman,3:Exact Blackman, 4:VonHann.PCT If set, the RVP8 will attempt to run its standard processing algorithms even when acustom trigger pattern has been selected via the SETPWF command.UVD Unfold velocities using a simple (Vhigh – Vlow) algorithm, rather than the standardalgorithm described in Section 5.6.
Host Computer CommandsRVP8 User’s ManualMarch 20066–7 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 acceptedor rejected at each bin. There are four test comparisons that are made at each range, as describedabove for input words 4, 5, 6, and 7. Each test either passes and produces a code of 1, 2, 4, and8 respectively, or fails and produces a code of zero. The sum of the codes for each of the fourtests is a number between 0 and 15, which can also be interpreted as the following four-bitbinary number: 3 2 1 0| | | | || 8 | 4 | 2 | 1 ||___|___|___|___| \ \ \ \___ LOG Threshold Passes \ \ \______ CCOR Threshold Passes \ \_________ SQI Threshold Passes \____________ SIG Threshold PassesThe individual bits of the Threshold Control Flag word each specify whether data are to beaccepted (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 logicalfunction of the four threshold outcomes.The following examples show actual values of the Flag word for the stated combinations ofacceptance criteria:Value CriteriaFFFF All Pass (Thresholds disabled)0000 All Fail (No data are passed)AAAA LOG8888 LOG and CSRA0A0 LOG and SQI8080 LOG and CSR and SQIF0F0 SQIFAFA SQI or LOGC0C0 SQI and CSRF000 SQI and SIGC000 SQI and SIG and CSRFFF0 SQI or SIGCCC0 (SQI or SIG) and CSRA simple way to generate these values is to imagine four 16-bit quantities having the followingnames and values: LOG=AAAA, CSR=CCCC, SQI=F0F0, SIG=FF00. The flag value neededto represent a given logical combination of threshold outcomes is obtained as the result whenthat same logical combination is applied to these special numbers.
Host Computer CommandsRVP8 User’s ManualMarch 20066–8For example: (SQI or SIG) and CSR = (F0F0 or FF00 ) and CCCC = (FFF0) and CCCC = CCC0which 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 | | | | | | | | | | | | | | | | || Additive Offset for Measured AZ Angles (Binary Angle) | Input 15|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Additive Offset for Measured EL Angles (Binary Angle) | 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 toabsorption by atmospheric gasses. The correction is linear with range, and is added to the dataalong with range normalization. Therefore, clearing the RNV bit in Word #2 above disables thecorrection. Of course, gas attenuation compensation can still be turned off even when RNV ison, 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 G = N / 100000 else G = 0.1 + (N – 10000)/10000This format is backward compatible with the previous linear format for all values between 0.0and 0.1dB/km; but it extends the upper range of values from 0.65535 up to 5.6535. These largerattenuation 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|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–9See 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 willintroduce a bias in the Zdr values, i.e., that Zdr will be non-zero even when observing purelyspherical targets. This calibration offset permits nulling out this effect. The GDR offsetaccounts 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 convertfrom 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 differentialreceiver gain between the two channels. Note that unlike the GDR offset (used for ZDR), thegain difference does not depend on differential transmit power. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Range smoothing (0:None, 1:pairs, etc) | XARG 2|_______________________________________________________________|Range smoothing can be performed on raw moment data prior to the computation of scientificparameters. The number of bins to sum together is given here. This should generally be an oddinteger so that no range bias is introduced by the smoothing operation. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | ||Ena| | Point Clutter Thresh | Side Skip | XARG 3|___|_______________________|_______________________|___________|Point clutter detection is configured with this word. A bin will be flagged as containing clutterif it’s power exceeds that of its two neighboring bins by more than the detection threshold (indeciBels). Up to seven bins may optionally be skipped on each side of the central bin prior tomaking these two comparisons.Ena This bit is set to enable point clutter detection. Flag bits will then be reported inthe “Flg” output data type of the PROC command. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | ||Ena|All| | XARG 4|___|___|_______________________________________________________|Point clutter censoring is configured with this word.
Host Computer CommandsRVP8 User’s ManualMarch 20066–10Ena This is set to enable point clutter censoring. Raw moment data containing pointclutter will be interpolated from valid signal levels on either side.All Optionally expand the reported detection flags to show the entire replaced interval,not just the original detected bins. This gives a more honest view of the data binsthat have been altered. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Bit mask of TS playback mismatch conditions to ignore | XARG 5|_______________________________________________________________|This word is a combination of MMTS_xxx bits specifying what types of mismatches are okay(do not cause an all-zero ray to be produced) during PROC command processing of timeseriesdata that are played back from an external source into the RVP8. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Flag bits related to timeseries (playback) | XARG 6|_______________________________________________________________|Combination of OPTS_xxx bits which modify details of timeseries behavior. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || 1 | Offset in deciBels | Slope as 100 * dB/dB | XARGs 7&8|___|___________________________|_______________________________|These two words allow you to set the breakpoints and slopes that modify the LOG thresholdaccording to the Clutter-to-Noise ratio of the target. This makes the LOG threshold behaveproperly even as the noise floor becomes elevated due to very strong clutter targets. A value ofzero will restore the RVP8 defaults from the Mf menu.The default (power-up) values for the above parameters are listed below. Both the scientificunits and the integer-input required by the command to set up that value are given. Most ofthese defaults will likely be reasonable for a wide variety of radars.Table 6–1:Default Values For Operating Parameters Parameter Scientific Units InputSample Size 25 pulses 25Flag Word 0007 HexLog Slope 0.03 dB/LSB 1966LOG Threshold 0.5 dB 8CCOR Threshold –25.0 dB –400Signal Quality Index Threshold 0.5 (dimensionless) 128SIG Threshold 10.0 dB 160Calibration Reflectivity –22.0 dBZ –352Gas Attenuation 0.016 dB/km 1600Zdr Offset (GDR) 0.0 dB 0
Host Computer CommandsRVP8 User’s ManualMarch 20066–11Table 6–1:Default Values For Operating Parameters (cont.)Parameter InputScientific UnitsLDR Offset (XDR) 0.0 dB 0AGC Integration Period 8 pulses 8Radar Wavelength 5.3 cm. 5300Dual PRF Filter Stabilization 10 pulses 10UnCor Refl. Thresh. Control Flag LOG AAAA HexCor Refl. Thresh. Control Flag LOG & CSR 8888 HexVelocity Thresh. Control Flag SQI & CSR C0C0 HexWidth Thresh. Control Flag SQI & CSR & SIG C000 HexZdr Refl. Thresh. Control Flag LOG AAAA HexAZ/EL Angle Offsets 0 degrees 0000 Hex6.4 Interface Input/Output Test (IOTEST) This command is used to test both the input and output data busses of the signal processorinterface. 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 theoutput words are correct, one may conclude that there are no malfunctioning bits in the interfacehardware. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | 0 0 0 1 1 | Command|___________________________________________|___________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–12 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 additionalXARGS 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. Thecommand causes sixteen words to be output consisting of successive powers of two starting fromone. By verifying whether each output word is correct, malfunctioning bits in the interface databus can easily be isolated. This test is less stringent than the input/output test IOTEST, since theinput data paths to the processor are not being checked. Typically, the OTEST is performed onlywhen 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 canbe subtracted from subsequent measurements. Data are sampled for 256 pulses at 256 bins,beginning at a selectable range and spaced by the range resolution at that pulse width. The
Host Computer CommandsRVP8 User’s ManualMarch 20066–13internal trigger generator is temporarily set to a special noise rate (usually much lower than theoperating rate) during the process. It is ultimately the user’s responsibility to insure that noreturned power is present within the approximately 32km sampling interval. In some cases itmay be necessary to raise the antenna during the noise measurement to avoid thermal noisepickup from the ground, or from weather targets.SNOISE has the option of setting up a new sampling range and trigger generator rate each timeit is called. Two bits in the command word determine which (if any) of the new values overridesthe current values stored in the RVP8. The power-up sampling range is 250km (input value of250), and the power-up trigger rate is 200Hz (input value of 30000). These initial values persistuntil such time as they are altered here. Note that both input words must always be suppliedafter the command, even if the command calls for ignoring one or both of them. The range issupplied directly in kilometers up to a maximum of 992km. The trigger rate resulting from agiven input is 6MHz divided by the input value, i.e. the input value is the trigger period in0.1667 microsecond increments. Keep in mind that the given rate is bounded against theminimum PRT allowed for the current radar pulse width.The SNOISE command bounds the requested starting range of the noise sampling interval. Thisis to insure that the noise samples will fit within the specified PRT, and within the range maskhardware RAM. The RVP8 sets an error bit when an improper range is requested.The SNOISE command should be re-issued now and then to compensate for drift in the RF andA/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. The noise levels must bemeasured for the RVP8 to properly process data. This can be done by issuing the SNOISE atleast once after power-up, or by setting the correct values for the powerup noise levels with the“mt” setup command, see section 3.2.5. The RVP8 does not automatically take a noise sampleas part of its initialization procedure.The measured offsets are stored internally for all subsequent uses inside the RVP8. The offsetvalues may be inspected via the GPARM command, as may the current range and rate valuesthemselves. Of course, whenever the range or rate are changed the user must ensure that thenew trigger rate allows at least 32km following the new noise range. If this requirement is notmet, or if other failures are detected during the noise measurement, appropriate bits are set in theGPARM latched status word. This word should generally be checked after SNOISE to makesure that everything worked properly. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || |Action |Rat|Rng| | 0 0 1 0 1 | Command|_______________|_______|___|___|___________|___________________|Rng If 1, then the range in input word 1 is taken as the starting noise range for this andall subsequent SNOISE calls.Rat If 1, then the trigger rate in input word 2 is taken as the noise rate for this and allsubsequent SNOISE calls.Action Specifies what action is carried out by the command. 0 Compute a new noise sample based on the present IFD input signals. 1 Do not compute a noise sample, but rather, read new noise values from the hostcomputer and use them for subsequent processing. Four additional input words
Host Computer CommandsRVP8 User’s ManualMarch 20066–14supply the noise information, and GPARM words 6, 9, and 44-50 will be changedto reflect the new noise settings. 2 Do not compute a noise sample, but rather, restore the powerup noise defaults. 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|_______________________________________________________________|The following input words are optional, only if Action=1. 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) | Input 3|_______|_______________________________________________________|The is the same number as GPARM output 6. See the discussion in Sections 6.7 and 6.9. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Noise Level Standard Deviation (in 1/100 of a dB) | Input 4|_______________________________________________________________|This is the same number as the GPARM 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 | Input 5|_______________________________________________________________|This is the same number as the GPARM output 50. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || <Spare> |Err|Ttf|Ntg| Input 6|___________________________________________________|___|___|___|These fault bits will then be output in the latched status GPARM word 9 .Ntg No Trigger during noise measurement.Ttf Trigger too fast during noise measurement, i.e., some of the noise sample binswere positioned past the trigger range.Err Error detected during the SNOISE command.6.7 Initiate Processing (PROC) The PROC command controls the actual processing and output of radar data. The operatingmodes and types of data available from the RVP8 are described in detail in Chapter 1. Thatsection also describes the proper use and application of the RVP8 to different radarenvironments.PROC is a single-word command that specifies the type of processing to be performed, and thetype of output to be generated. The two mode bits in the command word select either
Host Computer CommandsRVP8 User’s ManualMarch 20066–15Synchronous mode — The processor acquires, processes, and outputs one ray inresponse to each PROC command. Processing is begun only after each command isactually received.Free running mode — A single PROC command is issued and rays are continually outputas fast as they can be produced and consumed. This continues until any other commandis written, e.g., a NOP could be used to terminate the free running mode with no otherconsequences.Time Series mode — Always produced in a synchronous manner, this mode require anew PROC command to initiate each new set of samples. Data are output as 8-bit timeseries, 16-bit time series, or 16-bit power spectra.Optional Dual-PRF velocity unfolding is chosen by command bits eight and nine. For Dopplerdata either a 2:3, 3:4, or 4:5 PRF unfolding ratio may be selected. The RVP8 carries out all ofthe unfolding steps internally, so that mean velocity is now output with respect to the largerunambiguous interval. There is no additional velocity processing needed by the user, except ofcourse, to change the velocity scale on any displays being generated. Furthermore, spectralwidths are scaled consistently with respect to the higher PRF, and require no user modificationbefore being plotted.When unfolding is selected, the internal trigger generator automatically switches rates onalternate rays. The switch over occurs immediately after the last pulse of the current ray hasbeen acquired; thus overlapping the internal post-processing and output time, with transmitterstabilization and data acquisition at the new rate.Output data are selected by the upper six bits of the PROC command. Packed archive output isselected by setting the ARC bit. Individual byte or word display output is selected by setting anyor all of the Z, T, V, W, Zdr, and KDP command word bits. When more than one of these bits isset, the output array consists of all of the bins for the leftmost selected parameter, followed by allof 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 selectedsimultaneously, in which case the archive format is output first, followed by whicheverindividual display format values were also selected. The archive format is not recommended foruse with new drivers because it can only handle four of the many possible output parametertypes.When time series mode is selected there are three output data formats available. For backwardscompatibility, 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 willgenerally miss weak signals. We recommend the floating-point format that uses 16-bits per A/Dsample. There is also a 16-bit power spectrum output that is accurate to 0.01dB. (See alsoGPARM output word #10).In addition to the above output data, the first words of each ray optionally contain additionalinformation 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, ifTAG angle headers are requested, if the ARC, Z and V bits are all set, and if there are 100 binsselected in the current range mask, then each RVP8 output ray consists of the following:
Host Computer CommandsRVP8 User’s ManualMarch 20066–161] TAG15 – TAG0 \ From Start of Acquisition2] TAG31 – TAG16 / Interval3] TAG15 – TAG0 \ From End of Acquisition4] 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 Selects Dual–PRF unfolding scheme:00 : No Unfolding 01 : Ratio of 2:310 : Ratio of 3:4 11 : Ratio of 4:5ARC 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: 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 toSOPRM Command input word #2 (See Section 6.3). The same SOPRM word configures theRVP8 for Single or Dual polarization. The later is required for KDP, PDP, and RHV to becomputed 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 (N–128) / 127.50 : Indicates velocity data is not available at this range1 : Maximum velocity towards the radar
Host Computer CommandsRVP8 User’s ManualMarch 20066–17128 : Zero velocity255 : Maximum velocity away from the radarWhen 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 for2:3, 3:4, and 4:5 unfolding.16-Bit Velocity Format — Mean velocity in meters/second is computed from theunsigned word N as:Vm/sec = (N–32768) / 100The overall range is from –327.67m/sec to +327.66m/sec in one centimeter/sec-ond steps as follows:0 : Indicates velocity data is not available at this range1 : –327.67 m/sec (towards the radar)32768 : 0.00 m/sec65534 : +327.66 m/sec (away from the radar)65535 : Reserved CodeW Selects spectral width data.8-Bit Width Format —Spectral width is computed from the unsigned byte N as:WNyquist = N / 256The 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 theunsigned word N as:Wm/sec = N / 100The overall range is from 0.01m/sec to 655.34m/sec in one centimeter/secondsteps as follows:0 : Indicates width data is not available at this range1 : 0.01 m/sec65534 : 655.34 m/sec65535 : Reserved CodeZ Selects clutter corrected reflectivity data.8-Bit deciBel Format — The level in decibels is computed from the unsignedbyte N as:dBZ = (N–64)/2.The overall range is therefore from –31.5 dBZ to +95.5 dBZ in half-dB steps asfollows:0 : Indicates no reflectivity data available at this range1 : –31.5 dBZ64 : 0.0 dBZ128 : 32.0 dBZ
Host Computer CommandsRVP8 User’s ManualMarch 20066–18255 : +95.5 dBZ16-Bit deciBel Format — The level in decibels is computed from the unsignedword N as:dBZ = (N–32768) / 100The overall range is from –327.67dB to +327.66dB in 1/100dB steps as follows:0 : Indicates no reflectivity data available at this range1 : –327.67 dBZ32768 : 0.00 dBZ65534 : +327.66 dBZ65535 : Reserved CodeT Selects total reflectivity. Same 8-bit and 16-bit coding formats as for clutter cor-rected reflectivity above.ZDR Selects differential reflectivity data.8-Bit ZDR Format — The level in decibels is computed from the unsigned byteN as:dB = (N–128) / 16The 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 range1 : –7.9375 dB128 : 0.0000 dB255 : +7.9375 dB16-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 reducedynamic range) and then converted to a log scale separately for both signs. Theminimum 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:KDP l+0.25 600ƪN*129126 ƫThe conversion equation for negative values (codes from 1 to 127) is:KDP l+–0.25 600ƪ127*N126 ƫ16-Bit KDP Format —Same as 16-bit deciBel format, except that the units arehundredths of degrees per kilometer. No weighting by wavelength is introduced.PDP Selects dual polarization differential phase FDP data.
Host Computer CommandsRVP8 User’s ManualMarch 20066–198-Bit FDP Format — The phase angle in degrees is computed on a 180-degreeinterval from the unsigned byte N as:FDPĂ(modĂ180) = 180 (N – 1) / 2540 : Indicates no FDP data available at this range1 : 0.00 deg254 : 179.29 deg255 : Reserved Code16-Bit FDP Format —The phase angle in degrees is computed on a 360-degreeinterval from the unsigned word N as:FDPĂ(modĂ360) = 360 (N – 1) / 655340 : Indicates no FDP data available at this range1 : 0.000 deg65534 : 359.995 deg65535 : Reserved CodeRHV Selects dual polarization correlation coefficient òHV data.8-Bit òHV Format — The correlation coefficient is computed on the interval 0.0to 1.0 using a square root weighting of the unsigned byte N as:òHVĄ+Ą(N*1)253Ǹ0 : Indicates no òHV data available at this range1 : 0.0000 (dimensionless)2 : 0.0629253 : 0.9980254 : 1.0000255 : Reserved Code16-Bit òHV Format —The correlation coefficient is computed on the interval 0.0to 1.0 linearly from the unsigned word N as:òHV = (N – 1) / 655330 : Indicates no òHV data available at this range1 : 0.0 (dimensionless)65534 : 1.065535 : Reserved CodeSQI Selects Signal Quality Index data. This dimensionless parameter uses the same8-bit and 16-bit data formats as RHV ( òHV).LDR Selects Linear Depolarization Ratio, measured either on the horizontal receivechannel while transmitting vertically, or on the vertical receive channel whiletransmitting horizontally.8-Bit LDR Format — The level in decibels is computed from the unsigned byteN as:dB = –45.0 + (N–1) / 5
Host Computer CommandsRVP8 User’s ManualMarch 20066–20This spans an asymmetric interval around zero decibels, and allows for crosschannel isolation as large as 45dB. The overall range is from –45.0dB to +5.6dBin 0.2dB steps as follows:0 : Indicates no LDR data available at this range1 : –45.0 dB226 : 0.0 dB254 : +5.6 dB255 : Reserved Code16-Bit LDR Format —Same as 16-bit deciBel format.RHO Selects the cross channel correlation coefficient. This dimensionless parameteruses the same 8-bit and 16-bit data formats as RHV ( òHV).PHI Selects the cross channel differential phase. This parameter uses the same 8-bitand 16-bit angular data formats as PDP (FDP).Flg Selects flag word output, bits defined as follows:0 Reflectivity obscured at this bin1 Velocity obscured at this bin2 Width obscured at this bin3 Point clutter detected at this binThe 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 01 : Power Spectrum10 : 16-bit Time Series 11 : UnusedWhen the TSOUT bits select “Power Spectrum” then, depending on the current major mode, afurther choice may be needed to select one of several spectral view points. For the RandomPhase major mode the possible values of “Spec Type” are:0: Raw First Trip 4: Raw Second Trip1: Whitened First Trip 5: Whitened Second Trip2: Cleaned First Trip 6: Cleaned Second Trip3: Final First Trip 7: Final Second TripWhen 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 Nis the number of pulses per ray. Data samples for each bin of pulse #1 are output first, followedby those for each bin of pulse #2, etc. up to pulse #N. In other words, the data are output in thesame time-order that they were acquired.In the floating point format, three words are used for each bin:
Host Computer CommandsRVP8 User’s ManualMarch 20066–21 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 these “legacy format” floating I and Q samples to voltages: First create a 12-bitsigned integer in which bits zero through nine are copied from the Mantissa field, and bits tenand eleven are either 01 or 10 depending on whether S is 0 or 1. Then, multiply this number by2**(exponent–40), where the exponent field is interpreted as an unsigned 5-bit integer. Finallymultiply by the maximum voltage. The resulting value has 12-bits of precision and a dynamicrange of approximately 190dB. The large dynamic range is necessary to cover the full range ofdata. In summary:Voltage +VMAX (Sign,Mantissa) 2ƪExponent*40ƫNote that the resulting voltage span is actually "4 VMAX. The extra factor of four is built intothe format so that transient excursions above the full scale input voltage can still be encodedproperly. These may arise for time series data that have been processed by an IIR clutter filter.An improved “High-SNR” packed floating format is also available that offers nearly the samedynamic range but provides a 6dB improvement in SNR, i.e., a commensurate improvement insub-clutter visibility of –78dB versus –72dB. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Exponent | S | Mantissa | High–SNR|_______________|___|___________________________________________|The High-SNR packed format is similar to the legacy packed format except that it uses one extramantissa bit and one fewer exponent bit. The dynamic range lost in the exponent is recoveredthrough a formatting trick known as “soft underflow”, i.e., the mantissa is allowed to becomeunnormalized when the exponent is zero.To decode this format when the exponent is non-zero, first create a 13-bit signed integer inwhich bits zero through ten are copied from the Mantissa field, and bits eleven and twelve areeither 01 or 10 depending on whether S is 0 or 1. Then, multiply this by 2**(exponent–25),where the exponent field is interpreted as an unsigned 4-bit integer.To decode the High-SNR format when the exponent is zero simply interpret the mantissa as a12-bit signed integer and multiply by 2**-24.A complete analysis of the noise properties of the floating point codes would be fairly tricky.For the High-SNR format, the 12-bit mantissa with hidden normalization bit will vary from 2048to 4095. The SNR will therefore vary from 66dB to 72dB and we can assign a mean value of69dB. Another 9dB of useful range is contained within the code as follows:
Host Computer CommandsRVP8 User’s ManualMarch 20066–22In a floating point encoding format, the notion of fixed additive quantization noise is notreally correct. For a signal having a given power, the additive noise within eachinstantaneous sample will scale down according to the magnitude of that sample. Theensemble of noise terms thus contributes an RMS power that is smaller than thePeak–to–Noise ratio would imply. In the case of a sinusoidal input, this gives a 3dBboost in effective SNR.The format, of course, also represents negative amplitudes with the same relativeprecision as positive values. In a fixed–point format this would add 6dB (one more bit)to the overall dynamic range and large–signal SNR. In the floating format we really onlygain 3dB (half a bit) because the RMS noises add independently on the positive andnegative excursions.The packed format is used to encode timeseries (I,Q) pairs, and it’s the SNR properties ofthese pairs that we’re really concerned about. To a first approximation, having a pair ofvalues roughly doubles the information content and adds another 3dB to the SNR.The last of the three timeseries output words, the “Log of Power in Sample”, is provided mainlyfor backwards compatibility. It can be calculated from the I and Q numbers. To convert to dBmit 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 IFDVMAX = 0.5309 Volts for 12-bit IFD, 0.6310 Volts for 14-bit IFDSlope = “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. Becauseof the limited dynamic range available, this will only show strong signals, and is notrecommended for use. The I, Q, and Log power triplets are packed into two 16-bit output wordsas 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 producedby the equation:Voltage +VMAX ƪSample128 ƫWhen 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 apower of two, a smaller spectrum is computed that by averaging the spectra from the first N2
Host Computer CommandsRVP8 User’s ManualMarch 20066–23and the last N2 points. The data format is one word/bin/pulse, in the same order as for timeseries output. Each word gives the spectral power in hundredths of dB, with zero representingthe level that would result from the strongest possible input signal (PMAX ). Thus, the spectraloutput terms are almost always negative.The time series that are output by the RVP8 are the filtered versions of the raw data, whenavailable. If a non-zero time-domain clutter filter is selected at a bin, then the I and Q data forthat bin show the effects of the filter. Whenever you need to observe the raw samples, make surethat no clutter filters are being applied.In pulse pair time series mode with dual receivers, selecting (H+V) will produce data in one oftwo 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 fromthe DSP will be the averaged spectra from each channel individually. This allows theIRIS ascope utility to display either the spectrum-of-sum or sum-of-spectra according towhether 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, exceptthat the first half of these samples will be the first half of the “H” data in their normalorder. This will be followed by a zero sample if (BxN) is odd; followed by the first halfof the “V” data, also in their normal order.In other words, only the first halves of the individual “H” and “V” sample arrays areoutput by the RVP8. As an example, if you select 25 bins and 100 pulses, then the outputdata will consist of 1250 “H” samples (from all bins in the first 50 pulses), followed by1250 “V” samples from the exact same set of bins and pulses. This is the more usefuloption 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 withinthe 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 whentime series overflows occur. In such cases, the correct number of words are still output, but theyare 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 available clutter filters may be chosenindependently at each selected range. This range-dependent clutter removal is useful when theclutter characteristics vary with increasing range. Typically, clutter interference is most severe inthe immediate vicinity of the radar. Thus, a highly rejective filter might be chosen for nearranges, and a less rejective or perhaps no filter could be used at far ranges.Legacy VersionIn the legacy version of LFILT, the input words following the command specify the choice offilter to be applied at each of the 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 suchcases, the later filter codes are simply ignored for the current range mask. However, if a longer
Host Computer CommandsRVP8 User’s ManualMarch 20066–24range mask is loaded in the future, then those later codes would apply to the correspondinglynumbered bins. Put another way, each filter code is associated with a particular bin number, notwith a particular range. The correspondence between bin numbers and actual ranges is madeonly through the range mask.Only the low three bits are used in each word to specify the filter number. If the ALL bit is setin the Command, then 3072 words are loaded, corresponding to the maximum number of rangebins that are allowed. Otherwise only 512 words are loaded, and the 512th filter choice isreplicated 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|_______________________________________|___|___________________| (Legacy) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Filter #1 | Input 1|___________________________________________________|___________| . . Either 512 or 3072 Words LoadedEnhanced VersionThe RVP8 supports an enhanced version of the LFILT command that provides “Clutter Maps”,i.e., much greater flexibility by allowing filter choices to depend on antenna angle as well asrange. This lets you specify a 2D or even 3D table of clutter filter selections that aredynamically selected during live data processing.The RVP8 maintains an internal array of up to 1024 different filter-versus-range tables, each ofwhich is keyed to a particular solid angle AZ/EL sector. Each enhanced LFILT command fills inone of these slots with a filter selection table similar to that of the legacy command, except thatthe number of range bins is specified explicitly and eight bits are used for filter selection ratherthan three. Then, for each live ray being processed, the RVP8 applies clutter filters according tothe filter slot whose solid sector includes the midpoint AZ/EL of the ray. If the antenna angle ofthe ray does not fall within any of the defined filter sectors, then the all-pass filter (#0) will beused at all ranges.The low and high angle limits in each filter slot are inclusive; hence, the pair (0x000, 0xFFFF)would span the full 360-degree circle with no gaps. Also, the filter array can be sparse (not allslots filled in), and have overlapping sectors (in which case the highest numbered slot that spansa ray’s AZ/EL midpoint will be used). Choosing the highest numbered encompassing slot is asubtle but important detail that allows complex regions to be defined as a layered hierarchy ofoverlapping sectors. For example Slot-0 might define a default 360-degree filter-versus-rangetable, while Slot-1 defines special filtering within 0-90 degrees that is further modified by Slot-2filters in a 40-50 degree span. A 45-degree ray would then be filtered according to Slot-2, a60-degree ray would use Slot-1, and a 100-degree ray would use Slot-0.
Host Computer CommandsRVP8 User’s ManualMarch 20066–25If the CLR bit is set in the opcode, then no additional arguments follow and the entire internalfilter array (all slots) will be invalidated. The result is that no clutter filter will be applied to anyof the processed data, regardless of Range, AZ, or EL. Moreover, loading a given slot with atable consisting of zero bins of filter data will invalidate just that one slot. This allows somedata to be removed from the table without having to resort to a complete CLR operation.The legacy LFILT command is equivalent to calling the enhanced command first with the CLRbit set, followed by a second call that writes the legacy filter choices into slot #0 using AZ/ELlimits that cover all of space. Thus, the legacy behavior is obtained as a special case of theenhanced mechanism. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | 1 |CLR| 0 1 0 0 0 | Command|___________________________________|___|___|___________________| (Enhanced) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Internal Slot for This Filter Ray Specification (0–1023) | XARG 1|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Number of Bins of Filter Selections to Load (0–3072) | XARG 2|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Lower AZ (Binary angle) | XARG 3|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Upper AZ (Binary angle) | XARG 4|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Lower EL (Binary angle) | XARG 5|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Upper EL (Binary angle) | XARG 6|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Filter for Range Bin #2 | Filter for Range Bin #1 | Input 1|_______________________________|_______________________________| . . Total of Ceil(NBins/2) Words Loaded6.9 Get Processor Parameters (GPARM) This command is used to access status information from the RVP8 processor. Sixty-four wordsare always transferred, some later words are reserved for future compatibility and are read aszeros. For convenience, a shorthand table of the output words is given in Table 6–2.
Host Computer CommandsRVP8 User’s ManualMarch 20066–26Table 6–2: RVP8 Status Output Words Word Description Word Description1Revision / Serial number 33 LOG Threshold2 Number of Range Bins 34 CCOR Threshold3 Current trigger period 35 SQI threshold4 Current TAG00 – TAG15 36 SIG Threshold for Width5 Current TAG16 – TAG31 37 Calibration Reflectivity6 Log of Measured Noise Level 38 — Reserved —7 “I” Channel DC Offset 39 — Reserved —8 “Q” Channel DC Offset 40 Range Averaging Choice9 Latched Processor Status 41 — Reserved —10 Immediate Status Word #1 42 — Reserved —11 Diagnostic Register A 43 Header configuration of PROC data12 Diagnostic Register B 44 I-Squared Noise (Low 16-bits)13 Number of Pulses / Ray 45 I-Squared Noise (High 16-bits)14 Trigger count (Low 16-bits) 46 Q-Squared Noise (Low 16-bits)15 Trigger Count (High 8-bits) 47 Q-Squared Noise (High 16-bits)16 No. of Properly Acquired Bins 48 Log of Measured Noise Level17 No. of Properly Processed Bins 49 LOG Noise Standard Deviation18 Immediate Status Word #2 50 Horizontal/Vertical Noise Ratio19 Noise Range in Km 51 AFC/MFC Control Value20 Noise Trigger Period 52 Interference Filter Select21 Pulse Width 0 min. Trig. Period 53 Interference Filter C1 Constant22 Pulse Width 1 min. Trig. Period 54 Interference Filter C2 Constant23 Pulse Width 2 min. Trig. Period 55 Immediate Status Word #324 Pulse Width 3 min. Trig. Period 56 Burst Tracking Slew25 Pulse Width Bit Patterns 57 Polarization Algorithm Choices26 Current /Pulse Width 58 Range Mask Spacing27 Current Trigger Gen. Period 59 Immediate Status Word #428 Desired Trigger Gen. Period 60 — Reserved —29 PRT at Start of Last Ray 61 — Reserved —30 PRT at End of Last Ray 62 — Reserved —31 Processing/Threshold Flags 63 — Reserved —32 Log Slope 64 — Reserved —
Host Computer CommandsRVP8 User’s ManualMarch 20066–27 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 3–0 | Rev 6–4 | Serial Number | Output 1|_______________|___________|___________________________________|The revision and serial numbers of the particular RVP8 board are accessible here. Thisinformation is useful when computer software is being designed to handle a variety of signalprocessor revisions. The revision number is seven bits total; four of which are still in the highfour 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 15–0 | Output 4|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Current Sample of TAG bits 31–16 | 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|_______|_______________________________________________________|This value is scaled 4 times higher than the time series LOG format (see the discussion inSection 6.7). To convert to dBm, use the equation:dBm +PMAX )Slope ƪ(Valueń4) *3584 ƫ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || ”I” Channel Measured DC Offset | Output 7|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || ”Q” Channel Measured DC Offset | Output 8|_______________________________________________________________|These two words convey the measured “I” and “Q” DC offsets from the last noise sample. Theoutput format is either signed 16-bit values in which 32767 represent 1.0 (legacy format), orpacked timeseries values using the High-SNR encoding format. Bit-9 of GPARM Word-59 tellswhich format to use.
Host Computer CommandsRVP8 User’s ManualMarch 20066–28 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 No Trigger during noise measurement.Bit 1 Trigger too fast during noise measurement, i.e., some of the noise sample binswere positioned past the trigger range.Bit 2 No trigger during PROC command.Bit 3 PRT varied by more than 10 microseconds within portions of a processing intervalthat should have been at a fixed rate.Bit 4 Error in polarization control and/or polarization status readbackBit 5 FIFO overflow during last PROC command.Bit 6 Command received while waiting for output FIFO space. The command was pro-cessed but some output data has been lost (zeroed).Bit 7 Error detected during last SNOISE command.Bit 9 Error in last Load Range Mask (LRMSK) Command. This generally means thattoo many range bins were selected.Bit 10 Error in LSIMUL command protocol.Bit 11 Measured phase sequence is incorrect.Bit 15 Invalid processor configuration. This bit is set if the last PROC command calledfor 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 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|_______________________________________________________________|Bit 0 No trigger, or, more than 50ms. since last trigger.Bit 1 Error in loading trigger angle table (See LSYNC Command).Bit 2 PWINFO command is disabled.Bit 3 Angle sync input is BCD (Else binary angle).Bit 4 Angle sync is on elevation axis (Else azimuth axis).Bit 5 Angle sync is enabled.Bit 6 Angle sync is not interruptible.Bit 7 Angle sync is dynamic (else rays begin on sync angles).Bit 8 DSP has full IAGC hardware and firmware configuration.Bit 9 DSP supports 16-bit floating time series.Bits 11,10 Current unfolding mode.Bits 13,12 Number of RVP8/PROC compute processes minus one
Host Computer CommandsRVP8 User’s ManualMarch 20066–29Bit 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 RVP8/Rx card #1 failureBit 1 RVP8/Rx card #2 failureBit 2 RVP8/Tx card #1 failureBit 3 RVP8/Tx card #2 failureBit 4 IO62 card #1 failureBit 5 IO62 card #2 failureBit 6 Error loading config/setup filesBit 7 Error attaching to antenna libraryBit 8 Problem when forking compute processesBit 9 Error(s) in softplane configurationBit 10 Signals raised during startupBit 11 RVP8 running without ’root’ privilegesBit 12 Problem creating daemon processBit 13 Inconsistent setup values detected 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|_______________________________|_______________________________|The trigger count is a running tally of the number of triggers received by the RVP8 on theTRIGIN 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|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–30 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|_______________________________________________________________|Bit 0 Processor supports FFT algorithmsBit 1 Processor supports Random Phase algorithmsBit 2 Reserved (zero)Bit 3 Processor supports DPRT-1 (Dual-PRT) algorithmsOn dual IFD systems: Bits 4,5,7, and 11 are set if either IFD fails:Bit 4 Problem in UpLink cable from RVP8/Rx ––> IFDBit 5 Problem in DownLink cable from IFD ––> RVP8/RxBit 7 IFD PLL is not locked to external user-supplied clock referenceBits 8–10 Status of burst pulse and AFC feedback 1: AFC Disabled 2: Manual Frequency Control 3: No burst pulse detected 4: AFC is waiting for warm-up 5: AFC is locked 6: AFC is trackingBit 11 IFD test switches are not in their normal operating positionBit 12 Set according to whether the RVP8 is performing trigger blanking. This allowsthe host computer to decide whether to interpret the End-TAG-0 bit in the outputray header as a blanking flag, or as a normal TAG line.Bit 13 Missing signal at IFD #1 Burst InputBit 14 Reserved (zero)Bit 15 Set when valid burst power is detected but the center-of-mass lies outside of theaperture 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 optimalplacement 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|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–31 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 widthTopMode 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 issuedSETPWF command (or power-up rate if SETPWF was never issued). The current rate may bedifferent from the desired rate due to bounding against limits for the current pulse width, orbeing in an odd ray cycle during dual-PRT processing. The measured PRT’s are forced to0xFFFF (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|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–32The PRTs from the start and end of the last ray are the actual measured values wheneverpossible, i.e., when non-simulated data are being processed, and we either have an externaltrigger, or an internal trigger that is not in any of the Dual-PRT modes. The units are the sameas for the measured current trigger period in Output #3.Outputs 31 through 37 are the current processing and threshold parameters set by SOPRM. SeeSection 6.3 for additional notes on each of these parameters. Since the threshold levels for eachdata parameter can be different (See THRESH command, Section 6.29), words 33-36 are takenfrom the velocity parameter. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Polar |NHD|ASZ|16B|CMS| R2| |3x3| | |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|_______________________________________________________________| (From V) 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|_______________________________________________________________| (From V) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | SQI Threshold | Output 35|_______________________________|_______________________________| (From V) 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|_______________________________________________________________| (From V) 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|_______________________________|_______________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–33 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Reserved (Zero) | Output 41|_______________________________________________________________| 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 Config of PROC data (CFGHDR Input #1, Section 6.22) | 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:NI+(Word 45) 2*15 )(Word 44) 2*31NQ+(Word 47) 2*15 )(Word 46) 2*31From which we obtain:dBm +PMAX )10 log10 ǒNI)NQǓ*3dBNote that the four integer values become rather small and severely quantized when the noisepower drops to low values. Historically, these four words were used to balance the individualgain 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 | | | | | | | | | | | | | | | | || Vert Noise Stdev in dB*10 | Horiz Noise Stdev in dB*10 | Output 49|_______________________________|_______________________________|The noise standard deviations for each receive channel are normalized to the mean power. Thevalues reported here will therefore hover around 0dB for ordinary exponentially distributednoise in which the standard deviation scales directly with the mean.
Host Computer CommandsRVP8 User’s ManualMarch 20066–34 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 | | | | | | | | | | | | | | | | || 16–Bit AFC/MFC Value (–32768 through +32767) | Output 51|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || PhaseSeq | IFD Sat.Power | MinRev | Inter.F | Output 52|_______________|_______________|_______________|_______________|Inter.F Specifies which interference filter is running. Zero means “none”; see Section5.1.5 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: +6.0dBmPhaseSeq Tx Phase modulation sequence (See Section 6.27) 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 Burst pulse timing adjustments can be madeBit 1 Burst pulse frequency adjustments can be madeBit 2 Burst pulse hunting is enabledBit 3 Burst pulse hunt is running right nowBit 4 Last burst pulse hunt was unsuccessfulBit 5 Processor supports DPRT-2 (Dual-PRT) algorithmsBit 6 Could not generate the requested phase sequenceBit 7 Problem with digital transmitter clockBits 8-11 User-defined Major Modes 1-4 are supported 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 6.25)
Host Computer CommandsRVP8 User’s ManualMarch 20066–35 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Polarization Algorithm Choices | Output 57|_______________________________________________________________|Bit 0 Use H transmissions for (T,Z,V,W)Bit 1 Use V transmissions for (T,Z,V,W)Bit 2 Use Co–Pol reception for (T,Z,V,W)Bit 3 Use Cross–Pol reception for (T,Z,V,W)Bit 4 Correct all polar Parameters for noiseBit 5 Use filtered data for all polar ParametersBit 6 Sign convention for PHIdp 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Range mask spacing for current pulsewidth (centimeters) | Output 58|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Immediate Status Word #4 (Current State of Affairs) | Output 59|_______________________________________________________________|Bit 0 Internal power spectra size matches sample size (else power-of-2)Bit 1 PROC command output spectra match sample size (else power-of-2)Bit 2 Trigger pattern has been altered to fit within the desired PRTBit 3 PRT has been altered to preserve the desired trigger patternBit 4 Using High–SNR packed (I,Q) formatBit 5 Trigger sequence truncated due to insufficient pattern memoryBit 6 TimeSeries data source is external to the RVP8Bit 7 WSR88D “Batch” mode is supportedBit 8 Major mode refuses to use external triggerBit 9 GPARM outputs #7 and #8 use Hi-SNR format, else linearBit 10 Receiver protection faultBit 11 IFD dual-channel inconsistency (e.g., power and/or phase out of bounds for ratioof HiGain-to-LoGain channels)Bit 12 GPS 1-pulse-per-second input clock error 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Reserved (Zero) | Output 60|_______________________________________________________________| . . 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Reserved (Zero) | Output 64|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–366.10 Load Simulated Time Series Data (LSIMUL)This command is provided as a diagnostic for proper functioning of the RVP8 algorithms. Itpermits arbitrary simulated data samples to be input to the processing routines, rather thansampled data from the A/D converters as is ordinarily the case. Since the properties of thesimulated data are known exactly, it is possible to verify that the calculations within the RVP8are proceeding correctly.The LSIMUL command (with operation=1) should be issued prior to the PROC command whichis being tested. This enables the simulated data mode. The next PROC command will then waitfor 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 beexited, and error bit #10 will be set in the GPARM latched status word. The error bit is also setif 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 simulatedsamples to be replicated over the range of bins. Most RVP8 algorithms are independent ofrange, 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 LSIMULcommand permits independent I and Q samples to be simulated at every bin of every pulse. Ifthis results in more host computer I/O than is practical, then specify fewer simulated bins andallow 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 Disable the use of simulated data. RVP8 returns to acquisition and processing oflive data from the A/D converters.1 Enable processing of simulated data. Subsequent PROC commands will use thedata supplied in the next N (N = sample size) LSIMUL commands with Opera-tion=2.The receiver noise and offset levels which are internally maintained by the RVP8are set to their special simulated values (from the M+ setup menu) by this com-mand. 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 is-sue the SNOISE command before resuming the acquisition and processing of liveradar data.2 or 3 Load one pulse of data samples beginning with the following 4-word header, andcontinuing with an array of items each representing a single instantaneous sampleof (I,Q) data. You may specify one or more bins to be loaded, and the RVP8 willreplicate these data as necessary in order to fill out the entire count of acquiredbins. If the number of bins is zero, then a zero-valued sample is applied for allchannels. 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|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–37 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|_______________________________________________________________|In the legacy Format #2 (RVP5-RVP8) each bin within the pulse is represented byfour 16-bit fixed point words. Thus, the total number of words loaded is (4+4B),where B is the bin count specified in Word #1. This takes account of the four“header” words, plus four words for every bin being defined. 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|_______________________________________________________________|...In Format #3 (new in the RVP8) each bin within the pulse is represented by two16-bit floating point words having the exact same format as the packed (I,Q) time-series data that are output by the PROC command (See Section 6.7). Compared tothe legacy 4-word format, this 2-word format uses half the I/O bandwidth, has su-perior dynamic range, and allows data to be fed back into the signal processor intheir native packed format. The total number of words loaded (including the ini-tial header section) is (4+2B), where B is the bin count specified in Word #1. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Exponent | S | Mantissa | Input 5 (I)|___________________|___|_______________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–38 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Exponent | S | Mantissa | Input 6 (Q)|___________________|___|_______________________________________|...6.11 Reset (RESET) The RESET command permits resetting either the entire RVP8 processor, or selected portionsthereof. 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 Reloads configuration from the saved nonvolatile settings. For compatibility withRPV6 and RVP7, any of 3 bits will trigger this response.Nse Reset the receiver noise levels to the power-up default value for all pulsewidths asdefined in the Mt setup questions (See Section 3.2.5).Fif Remove any data currently in the output FIFO’s. This permits flushing outputdata that was left from a previous command, so that new output can be read fromscratch. See notes in the Introduction to this chapter concerning actions taken bythe RVP8 when the output FIFO becomes full.6.12 Define Trigger Generator Waveforms (TRIGWF) Note: This opcode is obsolete, and is included only for backward compatibilitywith the RVP6. The opcode is disabled by default (See Section 3.2.1), becausethe interactive trigger setup procedure described in Section 4.3 is the preferredmethod of defining all RVP8 triggers and timing. TRIGWF should not be usedin any new code applications that drive the RVP8.The RVP8 has a built-in trigger generator that can synthesize six independent digital outputwaveforms, each having arbitrary shape and being active anywhere in a window centered aroundzero-range. The six trigger outputs can be defined by a 2048-word by 6-bit table which isloaded from the user computer. The patterns are automatically read from the table and output tothe 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 RVP8unique, in that the detailed timing of trigger and related control signals can be easily adjusted insoftware, without having to resort to reprogramming PROMs. This makes it possible for usersoftware 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 POLAR0polarization control signal. This control signal is either held low or high for the cases of fixedhorizontal or vertical polarization, or it alternates from pulse to pulse for fast-switching
Host Computer CommandsRVP8 User’s ManualMarch 20066–39polarization measurements such as Zdr. The transition point is specified as a value between 0and 2047, where 1024 represents range zero. These units are the same as the time units for thewaveforms which follow, i.e., a 2048-word array holding 6-bit trigger patterns. Bit 0 in each ofthese words affects the TGEN0 digital output line, bit 1 affects TGEN1, etc. The bits are outputat a 7.195MHz rate, and the beginning of the 1024th array word (1025th word following thecommand) corresponds exactly to the instant at which data at range zero are sampled by theRVP8. Note that the output rate can also be interpreted as a new bit coming every 1/48 km. Insome cases this is a more useful view.As an example, suppose we wish to make the TGEN0 output be a 0.42 microsecond pretriggerpulse, with a rising edge exactly five microseconds prior to range zero. This would be done bysetting bit 0 in input words 988, 989, and 990 following the TRIGWF command, and leaving allother bit 0’s clear. Further, if TGEN1 was to be a 0.14 microsecond marker strobe at 20km, wewould 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 and PRT Limits (PWINFO) The RVP8 is equipped to control the radar transmitter’s pulse width and corresponding receiverbandwidth. There are four pulse/bandwidth codes, numbered simply 0 through 3. Theassociation between codes and pulse widths is completely determined by the needs andcapabilities of the particular radar on hand. In some cases, the zero code might represent 0.25microsecond pulse width, and in other cases it may represent 2.0 microseconds. Likewise, some
Host Computer CommandsRVP8 User’s ManualMarch 20066–40radars may use all four codes, whereas others have fewer options from which to choose. ThePWINFO command defines what happens for each of the four possible codes, but does notactually 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 radarpulse/bandwidth hardware. Typically this control is via relays or solid-state switches in thetransmitter and receiver. The user decides what state the four lines assume for each pulse widthcode. This is done using word #1 following the command, which contains four codes packedinto 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 bitsusually makes the radar hardware connections very simple. For example, if pulsewidth selectionrelied on choosing one of four relays, then each PWBWn line could serve directly as a relaydriver using the default pattern.For each pulse width there is a corresponding minimum trigger PRT permitted. This bound isintended to limit the transmitter duty cycle to a safe value under all conditions. PWINFO sets upthese minimum PRT’s using words 2 through 5 following the command. The maximumfrequency of the internal trigger generator is then constrained at each pulse width to theindicated rate. This protection applies at all times, i.e., during noise sampling, during rayprocessing, 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 fourpulse width codes, it is still a good idea to set the unused PRT limits to reasonable values. Thisway protection is still provided in the event that SETPWF accidently selects one of the unusedstates. If the internal trigger generator is not being used, then the PRT limits no longer affect theactual 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 settingthe 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 cannotaccidently be changed by the host computer. When this is done the RVP8 still reads the fiveinput words, but no changes are made to the pulse width and PRT information. Thus, thecommand 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 | | | | | | | | | | | | | | | | || |UpperPW| | 0 1 1 1 1 | Command|_______________________|_______|___________|___________________|UpperPW Upper two bits of the four 4-bit pulsewidths being defined. 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|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–41 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|_______________________________________________________________|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 bits8 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 periodis internally computed as either 3/2, 4/3, or 5/4 the short period, and the trigger generatoralternates 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 | | | | | | | | | | | | | | | | || |UpperPW| (Rsv) |LowerPW| | 1 0 0 0 0 | Command|_______|_______|_______|_______|___________|___________________|UpperPW Upper two bits of overall 4-bit pulsewidth selectionLowerPW Lower two bits of overall 4-bit pulsewidth selection 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 choiceof each period. The XARGS command is first used to load an array of N 32-bit words thatdefine 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 selectedsequence. Trigger patterns such as these are intended to support research customers who use thereal–time (I,Q) data stream directly. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Lower 16–Bits of 32–Bit Trigger Period in Nanoseconds | XARG 1|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Upper 16–Bits of 32–Bit Trigger Period in Nanoseconds | XARG 2|_______________________________________________________________| . .
Host Computer CommandsRVP8 User’s ManualMarch 20066–426.15 Load Antenna Synchronization Table (LSYNC) The RVP8 can operate in a mode wherein radar data are acquired in synchronization with theantenna motion along either the azimuth or elevation axis. This special feature frees the usercomputer from having to separately monitor the antenna angles and request each data rayindividually. 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 either16-bit binary angles, or four-digit BCD. This synchronization mode is the only one whichascribes any meaning to the TAG inputs; ordinarily they are merely passed on to the usercomputer as ancillary information.Antenna synchronization is accomplished by way of a table of trigger angles. This table, whichcontains between three and 1024 angles, is used to define the angle boundaries for eachprocessed ray. The trigger angles need not be uniformly spaced, nor must they span the full360-degrees of rotation. This gives considerable flexibility in the choice of angles. Forexample, if local obstructions cause shadows in the radar image, then those regions can beskipped merely by omitting table entries in their vicinity. Likewise, as the antenna rotates datacan be acquired within one or more sectors by simply specifying the appropriate sets ofcontiguous bearings at whatever angular resolution is desired. Note that on power-up the angletable is initialized to 360 values corresponding to integer-valued degrees from zero to 359.The synchronization algorithm works automatically with either clockwise or counterclockwiseantenna rotation, and can tolerate any sequence of changes in direction, e.g., if the antenna itselfis scanning a sector, or if it is turning erratically. Moreover, the trigger angles do not have to behit exactly in order to start each new ray — the antenna need only move across them. Thisminimizes the possibility of losing data due to missing codes in the angle encoders. The RVP8will automatically produce an output ray after one second of waiting, even if no trigger angleshave been crossed. This is to avoid timeouts with the host computer when the antenna is notmoving at all.To use the synchronization mode, the trigger angle table is first loaded using the LSYNCcommand. The user chooses the number of table entries and then writes the required number ofwords to the RVP8. The angles must be supplied in a clockwise strictly increasing order, andthey must neither reach nor pass zero degrees by the table’s end. The first value, however, maybe zero. Binary angle representation is used wherein Bit 15 represents 180 degrees, Bit 14represents 90 degrees, etc. The Ld bit must be set in the command word to indicate that a newtable size and set of angles are being loaded. A flag bit is to be set (See GPARM) if errors aredetected when loading the table of angles.To actually enable synchronized operation the Ena command bit must eventually be set, and ELand BCD should be either set or cleared according to the user’s needs. These bits may be usedindependent of reloading the actual table values. Thus, antenna synchronization may be turnedon and off without having to reload the table each time. However, if there were errors when thetable was last loaded, the processor ignores the Ena bit and synchronization is forced off. Onceenabled, PROC commands are then issued in the usual manner to acquire and process the radardata. Either the single-cycle or free-run PROC mode may be used. Data collection proceeds asusual, except that the rays are now automatically aligned with the trigger angles.
Host Computer CommandsRVP8 User’s ManualMarch 20066–43The angle sync algorithm is dynamic and works as follows. Each ray begins immediately uponthe user’s 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 triggerangle. The current ray then runs until the antenna passes outside of either limit, at which pointprocessing for that ray is terminated. Once this happens, a new trigger angle is assigned basedon which limit was crossed.The maximum number of pulses that will be present in each ray during angle syncing is stillgiven the by the Sample Size field of the SOPRM command. The actual number of pulses willbe less only if a trigger angle is crossed before the full pulse count is reached. In general, youshould set the Sample Size somewhat larger than the expected pulse count so that the triggerangle crossings make the best use of every available pulse when the antenna is scanning at theexpected rate. 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 Ordinarily, the potentially lengthy sync wait loop is terminated if the user writesadditional words to the RVP8. Setting this bit prevents such interrupts. Bewarethat 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.Ena Enables antenna synchronization.El Synchronization is based on TAG15–31 (Elevation) inputs, else TAG0–15 (Azi-muth) is used.BCD Specifies that TAG angle input is in the form of 4-digit Binary Coded Decimal;otherwise, a 16-bit binary angle is assumed.Ld 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) ||_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–446.16 Set/Clear User LED (SLED) This command simply turns the red user LED on and off under program control. The LED is onduring the initial running of internal diagnostics, and then remains off unless changed by thiscommand. 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 cansimulate the typing of characters on the RVP8’s setup TTY. Characters entered in this mannerare indistinguishable from those typed on the actual TTY; hence, whatever one can do via theTTY, 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 tomonitor 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 Sends the ASCII character in the upper byte of the word to the RVP8 as if it hadbeen typed on the setup TTY’s keyboard.1 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.2 Disable the scope plotting output data.Any of the following types of data may be output by the RVP8 while the TTY monitor isrunning. The order of arrival of each data type is indeterminate, but all multi-word sequenceswill always be output as contiguous words.Individual “TTY” characters generated by the RVP8 are output in the low byte of the word, withthe 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|_______________|___________________________________________|___|
Host Computer CommandsRVP8 User’s ManualMarch 20066–45PLT 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-wordsequence. An intensity of zero represents “OFF”; one, two and three are successively brighter. 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 anoffset in deciBels equal to 20 log(R / 1km), where R is the range in kilometers. This correctionis based on a simple filled beam geometry, and is sufficiently accurate for most meteorologicalobservations. The LDRNV command is provided for applications in which an alternate customrange correction is required, for example, if the radar receiver’s LNA were to be driven by anexternal user-supplied STC waveform.LDRNV loads a 251-word custom correction table holding values in hundredths of deciBels overfive decades of log(range) from 0.01km to 1000km. There are 50 table entries per decade ofrange. Thus, the range in kilometers corresponding to an input word #N is 10ƪN*150 *2ƫ, and thedefault correction table (automatically used on power-up) is simply 40(N*101) . The table
Host Computer CommandsRVP8 User’s ManualMarch 20066–46values are stored and interpolated whenever the RVP8 loads a new range mask (See LRMSK), atwhich point custom values for the actual user ranges are computed. The LDRNV commandneed be issued only once, but it must be done prior to choosing the working set of range bins.The linear intervening gas attenuation correction (See SOPRM) is always added to thereflectivity data, regardless of whether default or custom range normalization is in effect. If thisis 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 anddiagnostic purposes. This command would not generally be used during normal data acquisitionand 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 Full operational parameter table from last SOPRM command.1 Ray history array consisting of six words per ray for the last 40 rays (in reversetime order) that were processed. Each six-word group holdsa. Actual number of samples that went into the rayb. Time since the last ray (in tenths of ms)c. Ending azimuth TAG bitsd. Ending elevation TAG bitse. Starting azimuth TAG bitsf. Starting elevation TAG bits2 Angle sync table from last LDSYNC command.
Host Computer CommandsRVP8 User’s ManualMarch 20066–473Reserved (was AGC table)4 Filter selection array from the last LFILT command. This returns the filter selec-tion codes, one per word, for all range bins described by filter slot #0.5Reserved (was STC table)6 Custom range normalization from last LDRNV command.7 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 isreached. Each 32-bit sample is output as a pair of 16-bit words:a. Azimuth (TAG bits 0 – 15)b. Elevation (TAG bits 16 – 31)8 Doppler clutter filter coefficients (Same format as for LFCOEFS command)9Reserved (was LOG clutter filter coefficients)10 Range mask spacing in cm for each pulsewidth11 Current value of UIQ bits from Set/Clr all prior operations12 Individual threshold configuration for each data type. This allows read back of thethreshold table set with the THRESH command (section 6.29). Outputs 7 wordsper data type. Datatypes in the order specified in the selection mask.13 Extended parameter information defined in struct dspExParmIO .14 Minimum and Maximum values of the optional I/O-62 A/D converter, sampledover at least one complete pulse period. Sixteen bit signed outputs represent thefull range of the A/D converter. When the RVP88D backpanel is connected, thefirst Min/Max pair samples the LOGVideo input, the second pair samples the Ca-thodePulse input, and the third and fourth pairs sample internal levels.15 Returns an array of struct rvp8SpecFiltIO structures for each of the non-zeroclutter filter definitions, beginning with #1. This is the same format used by theLFSPECS command to define each individual clutter filter. The order is as de-fined in the PPRMS_N_* #defines in rvp8.h.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 RVP8’s instruction stream,even if the opcode being modified does not expect any optional arguments. XARGS will be aNOP in that case.To supply optional arguments to another opcode “OP”, the XARGS command is first executedwith the additional argument count encoded in its upper 11-bits. This is followed by the array ofbetween 0 and 2047 additional arguments. At this point the XARGS command is finished andthe “OP” command is fetched as the next instruction. “OP” will execute normally, except thatthe additional arguments from XARGS can be picked up after its own input list has been read tocompletion.XARGS affects only the opcode that immediately follows it. The entire list of optionalarguments 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 itsupplies will be appended to the first set. In this way, XARGS can supply an arbitrarily largenumber of additional arguments.
Host Computer CommandsRVP8 User’s ManualMarch 20066–48 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 Load Clutter Filter Specifications (LFSPECS)The RVP8 allows seven different clutter filters (plus the fixed all-pass filter) to be resident atonce, so that an appropriate filter can be selected and applied to each processed ray based onRange, Azimuth, and/or Elevation. The LFSPECS command allows this suite of filters to beredefined on the fly. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | 0 0 0 0 0 0 0 1 1 1 1 1 | Command|_______________|_______________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Filter # | Input 1|___________________________________________________|___________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Filter Type | XARG 1|_______________________________________________________________| . . Variable number of XARGS depending on Filter TypeThe “Filter Number” tells which filter definition slot is being modified, and the “Filter Type”conveys the type of clutter filter to construct. The command is then followed by additionalXARGs that give the specific filter parameters. Beginning with the Filter Type, the completeXARG list is a struct rvp8SpecFiltIO ( Please see include/rvp8.h ) for each of the followingfilter types.Type:0 SPFILT_FIXED Fixed Width Spectral FilterLegacy clutter filter inherited from the RVP6/7, specified by a width parameter
Host Computer CommandsRVP8 User’s ManualMarch 20066–49telling how many points to remove (center zero velocity point, plus one side), plusan “Edge Points” parameter telling how many points to minimize on each side ofthe gap to compute the end points of a linear interpolation to fill the gap.Type:1 SPFILT_VARIABLE Variable Width Spectral FilterSimilar to the fixed width filter except that the width parameter is interpreted as aminimum width, and a third parameter indicates the maximum width. The actualclutter gap width will be dynamically determined at each bin based on the slopesof the spectral terms. Linear interpolation of the gap (based on “Edge Points”) isthe same as above.Type:2 SPFILT_VARLSQ Variable Width / Quadratic interpolationSimilar to the variable width filter except that quadratic gap interpolation is used.This filter is experimental and should not be used.Type:3 SPFILT_GMAP Gaussian Model Adaptive Processing Spectral FilterThis is the RVP8’s most advanced clutter filter, combining the best techniques fordetermining the clutter gap width and restoring whatever low-velocity spectralpoints are removed. This filter is characterized by a single parameter, which is theassumed clutter width expressed as a physical velocity.6.22 Configure Ray Header Words (CFGHDR)The processed data that are output by the PROC command may contain optional header wordsthat give additional information about each ray. This command configures the set of words thatmakeup each header. There are (up to) thirty two different choices of words or groups of wordsto include, as indicated by the bit mask following the command. Setting a bit requests that thosewords 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 withoutchanging 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 | | | | | | | | | | | | | | | | || |TID|PBN|SYT|MMT|UTC|Flg|Gpm|Tim|Pul|PRT|Tag| Input 1|___________________|___|___|___|___|___|___|___|___|___|___|___| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Input 2|_______________________________________________________________|Tag Four words containing two 32-Bit TAG samples, one from the beginning and onefrom the end of the ray: Word #1 TAG15–0 Start of Ray Word #2 TAG31–16 Start of Ray Word #3 TAG15–0 End of Ray Word #4 TAG31–16 End of RayWhen the RVP8 is operating in dual PRF mode, bit zero of the “start” TAG word isreplaced with a flag indicating that the ray’s PRF was low (0) or high (1).
Host Computer CommandsRVP8 User’s ManualMarch 20066–50When trigger blanking is enabled, bit zero of the “end” TAG word is replaced with a flagindicating that the trigger was blanked (0) or normal (1). Note that the data within a rayare considered to be invalid if any of the pulses that were used to compute the ray wereblanked. Also, the RVP8 will output all zeroed data whenever a ray contains any blankedpulses.PRT PRT (Pulse Repetition Time) measured at the end of the ray. Same format asGPARM Word #30. The measured PRT’s are forced to 0xFFFF (the maximumunsigned value) whenever the external trigger is expected but missing.Pul Number of pulses that were used to compute the ray.Tim Milliseconds universal time (0–999), sampled at the end of the ray.Gpm GPARM. Sends a copy of the 64-word GPARM output with each ray.Flg Ray Flag word: Bit 0: Dual PRF is in the low PRF state Bit 1: Trigger is blanked for this ray Bit 2: This ray is from one of the PRFSECT special sectors Bits4–6: Tells which PRFSECT when Bit-2 is setUTC 3-word universal time, sampled at the beginning of the ray Word 1: Milliseconds (0–999) Word 2: Low 16-bits of 32-bit UTC time Word 3: High 16-bits of 32-bit UTC timeMMT MisMatched Timeseries bits (playback versus RVP8 configuration). See theMMTS_* flags in dsp.h.SYT IFD system clock time at the beginning of the ray Word 1: Low 16-bits of 32-bit clock counter Word 2: High 16-bits of 32-bit clock counterPBN Timeseries playback version numberTID Task ID encoded as struct rvp8TaskID_IO (14 words total)6.23 Configure Interference Filter (CFGINTF) The RVP8 can optionally apply an interference filter to its incoming (I,Q) data stream, with thegoal of rejecting occasional and sparse interference from other (usually man-made) signalsources. 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).If the XARGS are not supplied, then the filter parameters will simply retain their previousvalues. Thus, CFGINTF with no XARGS can be used to turn the interference filters On/Offwithout making any other changes to their threshold constants. Likewise, if only XARG 1 issupplied, 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 5.1.5 for a de-scription of the available algorithms.
Host Computer CommandsRVP8 User’s ManualMarch 20066–51 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|_______________________________________________________________|6.24 Set AFC level (SETAFC)This command sets the AFC level to a given value. The signed 16-bit span is identical toGPARM 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 thenew level into whatever analog or digital AFC output format has been configured. The onlyexception is for the Motor/Integrator type of AFC loop, in which case this command doesnothing. 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 | | | | | | | | | | | | | | | | || 16–Bit AFC/MFC Value (–32768 through +32767) | Input 1|_______________________________________________________________|6.25 Set Trigger Timing Slew (SETSLEW)The Mt menu allows you to select a subset of triggers that can be slewed “left” and “right” inorder to place the burst pulse accurately at range zero. This command allows you to manuallyset the present amount of slew. The input argument is in hundredths of microseconds, i.e.,ranging from –327.68msec to +327.67msec. The actual span permitted by the RVP8 is +20msec.This is the same format used in GPARM Output #56 which shows the present slew value. 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|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–526.26 Hunt for Burst Pulse (BPHUNT)This command starts up the internal procedure to hunt for a missing burst pulse when we areuncertain of both its time and frequency. Depending on how the hunting process has beenconfigured in the Mb menu, the whole procedure may take several seconds to complete. TheRVP8’s host computer interface remains completely functional during this time, but any acquireddata would certainly be questionable. GPARM status bits in word #55 indicate when the huntprocedure 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 thetime BPHUNT is given.6.27 Configure Phase Modulation (CFGPHZ)This command configures the RVP8 phase control output lines, which determine the relativephase of each transmitted pulse. In some cases the phase sequence that is chosen will also haveside effects elsewhere in the processor, e.g., different algorithms may be used in Random Phasemode according to the transmit sequence that is requested.Some of the phase sequences chosen by CFGPHZ also expect additional arguments to have beensupplied by the XARGS command. Phase sequences are expressed as a list of N 16-bit binaryangles representing the desired phase sequence. The sequence is assumed to be periodic withperiod N. The Mz command defines the correspondence between phase codes and phase angles,and is described in Section 3.2.8. 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 asdefined in the Mz menu.PhSeq=1 Selects a Random Phase sequence. This is also the default phase modulation thatwill 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 eachpulse. Each code has an equal probability of being chosen each time, and thechoice is independent of any previous state. No XARG words accompany thiscommand.PhSeq=2 Selects a User Defined sequence. If no XARGS have been supplied, then theRVP8 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 RVP8will make the best match between each desired angle and the closest realizableangle that the phase modulation hardware can produce. The maximum length ofthe sequence is 1024 pulses.
Host Computer CommandsRVP8 User’s ManualMarch 20066–53PhSeq=3 Selects the SZ(8/64) sequence. This is a systematic code due to Sachidananda andZrnic, which does a nice job separating and recovering first and second trip echoesin “Random Phase” mode. It will usually perform better than a truly randomtransmit sequence, especially when the processing interval is fairly short (as littleas 32-pulses). With no XARGS, the RVP8 automatically generates the phase se-quence using the closest realizable angles that the phase modulation hardware canproduce. This is the recommended way to invoke SZ(8/64) coding. However,you may also supply your own 32-pulse angle sequence.6.28 Set User IQ Bits (UIQBITS)Load user-specified bits that will be included with the pulse headers in the RVP8 TimeSeriesAPI data stream. The permanent Set/Clr bits are updated in the signal processor and retain theirvalue from the last time they were defined. These bits are then repeated into all pulse headers.The ONCE bits, however, are transitory and will appear in only one pulse header each time theyare set.A FIFO history of the permanent bits is maintained so that the bits can be associated with thedata being acquired right now as the UIQBITS opcode is executed. Each 16-bit command argspecifies bits to Set/Clr in successive bytes of the structure. This allows user code to safelychange some bits without affecting others.The user bits from separate calls will never be collapsed into a single pulse header, even if theheader and bit times indicate that they could. This means that each UIQBITS opcode willalways result in at least one pulse header being tagged with exactly those data. This is generallywhat you want, since no other exact outcome could be guaranteed based on time-of-arrivalalone. 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 1–4|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || 64 Permanent User Bits to CLEAR | Inputs 5–8|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || 64 User Bits to Apply ONCE | Inputs 9–12|_______________________________________________________________|6.29 Set Individual Thresholds (THRESH)The SOPRM command in section 6.3 allows you to configure four threshold numbers used byall data types, and to select the threshold control flags for five of the data types. See that sectionfor detailed documentation on how the thresholds work. Use the THRESH command if you
Host Computer CommandsRVP8 User’s ManualMarch 20066–54wish to apply different threshold numbers to different data types. Using this command you canindividually set the thresholds and mask used for each data type, or for groups of data types.Note that the GPARM command will read out the threshold numbers set for velocity. To readback the numbers for each data type use the RBACK command (section 6.19). 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | 0 0 0 1 0 1 0 1 1 1 1 1 | Command|_______________|_______________________________________________|The first three words supply a mask that indicates which data types are being set: 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Z | T | V | W |ZDR| |KDP| | Input 1|___|___|___|___|___|___|_______|___|___________________________| 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| Input 2|_______________________|___|___|___|___|___|___|___|___|___|___| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || <all spares> | Input 3|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || LOG Threshold in 1/16 of dB (SOPRM Input 4) | Input 4|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || CCOR Threshold in 1/16 of dB (SOPRM Input 5) | Input 5|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | SQI Threshold (SOPRM Input 6) | Input 6|_______________________________|_______________________________| 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 (SOPRM Input 7) | Input 7|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Threshold Control Flags (SOPRM Input 11,12,13,14,19) | Input 8|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || <spare> | Input 9|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || <spare> | Input 10|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–556.30 Set Task Identification Information (TASKID)This command allows the user to “name” the (I,Q) data that are currently being acquired by theRVP8. This naming information then becomes associated with these data, and is available in thepulse information structures (struct rvp8PulseInfo) that are read from the Timeseries API. TheiAqMode field of the pulse headers (struct rvp8PulseHdr) will be incremented each time aTASKID opcode is received, but the continuous flow of (I,Q) data from the RVP8/Rx card(s)will not be disturbed in any way.The TASKID command defines a 16-character Null-terminated name, along with a 16-bit sweepnumber and 16-bit auxiliary (user defined) number. You may use all sixteen characters of thename, as it is stored internally in seventeen slots. The “Sweep Number” and “Scan Geometry”(one of SCAN_xxx parameters) should be filled in with values best approximating those notions.“Auxiliary Number” may be filled in with any value that you find meaningful. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | 0 0 0 1 0 1 1 1 1 1 1 1 | Command|_______________|_______________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Sweep Number | Input 1|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Auxiliary (User Defied) Number | Input 2|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Name Byte–2 | Name Byte–1 | Input 3|_______________________________|_______________________________| . . 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Name Byte–16 | Name Byte–15 | Input 10|_______________________________|_______________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Scan Geometry | XARG 1|_______________________________|_______________________________|6.31 Define PRF “Pie Slices” (PRFSECT)This command supplements the SETPWF command (Section 6.14) and allows an alternatetrigger PRF to be generated within prescribed AZ/EL sectors. As many as eight different triggersectors can be defined by invoking PRFSECT for each separate region. The trigger pattern willthen automatically change whenever the antenna enters any of these regions, but the timeseriesdata will remain continuous and uninterrupted throughout each change. The motivation behindPRFSECT is that it allows a complete volume scan to run with PRFs that have been optimized tothe radar echoes in all directions. Some caveats should be observed:
Host Computer CommandsRVP8 User’s ManualMarch 20066–56Dual-PRF unfolding can not possibly work properly at PRF sector boundaries, so werecommend not using Dual-PRF and PRFSECT at the same time.When PRF sectors are used in conjunction with angle sync’ing, it is best to set the PRFsector boundaries at the midpoint between individual sync angles. This will prevent thePRF seam from bobbling between two adjacent sync angles.The SETPWF opcode completely erases any alternate sectors that have been setup so far. Thus,the PRFSECT command can only be used after SETPWF has established the pulsewidth anddefault trigger rate for the entire AZ/EL scan volume. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | 0 0 0 1 1 0 0 1 1 1 1 1 | Command|_______________|_______________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Sector | Input 1|___________________________________________________|___________|Sector Selects which sector number is being defined to have an alternate trigger pattern.This is simply an arbitrary index from 0-7.The following four arguments define a solid sector in azimuth and elevation within which thealternate trigger pattern will be used in preference to the default (SETPWF) pattern. When thecurrent AZ/EL angle pair is contained in more than one defined sector, then the trigger patternfrom the lower numbered sector will be used. Note that the sector bounds are inclusive, i.e.,they include the Upper/Lower AZ/EL boundaries themselves. This convention makes it simplerto define several contiguous regions without generating slivers in between. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Lower AZ (Binary angle) | Input 2|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Upper AZ (Binary angle) | Input 3|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Lower EL (Binary angle) | Input 4|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Upper EL (Binary angle) | Input 5|_______________________________________________________________|The following two arguments specify a trigger period in the same manner as the optional form ofthe SETPWF command.
Host Computer CommandsRVP8 User’s ManualMarch 20066–57 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Lower 16–Bits of 32–Bit Trigger Period in Nanoseconds | Input 6|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Upper 16–Bits of 32–Bit Trigger Period in Nanoseconds | Input 7|_______________________________________________________________| . .6.32 Configure Target Simulator (TARGSIM)The RVP8 contains a built-in target simulator tool that can test and debug processing algorithmsthat work with multiple trip returns. Several real physical targets can be simulated, each havinga range span measured in kilometers, a Doppler shift in Hertz, and an echo power relative to thesaturation level of the receiver. The echoes are placed in range exactly according to how theyhave been illuminated by whatever sequence of pulses have been transmitted so far. Multipletrip returns and range folding are all modeled correctly.The target simulator can be used with both live and simulated (I,Q) data (See LSIMUL opcodein Section 6.10). In the former case, it allows you to overlay simulated physical targets on top ofreal physical targets from the radar receiver. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Oper | 0 0 0 1 1 0 1 1 1 1 1 1 | Command|_______|_______|_______________________________________________|Oper=0 Disable all target simulation activity (no additional args)Oper=1 Enable simulation of all defined targets (no additional args)Oper=2 Define a new simulated target (arg list follows) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | Co| Cx| | Targ | Input 1|_______________________________|___|___|_______________|_______|Targ Which target is being definedCo/Cx Place simulated target in Co-Pol and/or Cross-Pol Rx channels 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Target Starting Range in Tenths of Kilometers | Input 2|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Target Length in Tenths of Kilometers | Input 3|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Target Power in Tenths of dB Relative to Saturation (signed) | Input 4|_______________________________________________________________|
Host Computer CommandsRVP8 User’s ManualMarch 20066–58 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Target Power Delta over Range Span in Tenths of dB (signed) | Input 5|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Target Doppler Shift in Hertz (signed) | Input 6|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Target Doppler Delta over Range Span in Hertz (signed) | Input 7|_______________________________________________________________| 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || Four Spare Words | Inputs 8–11|_______________________________________________________________|6.33 Set Burst Pulse Processing Options (BPOPTS)Some burst pulse processing options can be set by this command. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | | | | | | | | | | | | | | | | || | 0 0 0 1 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 | | | | | | | | | | | | | | | | || |ACY|ACN|PLY|PLN| Input 1|_______________________________________________|___|___|___|___|PLY/N These bits affect whether the RVP8 will phase lock its (I,Q) data to the measuredburst pulse. The “PLY” and “PLN” bits force “Yes” and “No” responses. If bothbits are clear or both bits are set, then no change will be made.ACY/N These bits affect whether the RVP8 applies pulse-to-pulse amplitude correction toits (I,Q) data. The Yes/No bits behave the same as PLY/PLN.6.34 Custom User Opcode (USRINTR and USRCONT)These opcodes are part of the open software extensions to the RVP8, which allow customopcodes to be defined for each major mode of operation. Arguments may be passed into acustom opcode handler as an XARG list. Likewise, an optional array of words returned fromthat 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 ifdesired.CON If set, then the RVP8’s IQ data acquisition thread proceeds continuously while theopcode is executed. If clear, then the IQ stream is interrupted prior to handling thecall.
Host Computer CommandsRVP8 User’s ManualMarch 20066–59 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|_______________________________________________________________|

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