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Operazionnie ysiliteli ,ZAP/AZP & (ïðîäîëæåíèå)
milstar: 1941: First (vacuum tube) op-amp An op-amp, defined as a general-purpose, DC-coupled, high gain, inverting feedback amplifier, is first found in US Patent 2,401,779 "Summing Amplifier" filed by Karl D. Swartzel Jr. of Bell labs in 1941. This design used three vacuum tubes to achieve a gain of 90dB and operated on voltage rails of ±350V. ###################################################### It had a single inverting input rather than differential inverting and non-inverting inputs, as are common in today's op-amps. Throughout World War II, Swartzel's design proved its value by being liberally used in the M9 artillery director designed at Bell Labs. ######################################################################### This artillery director worked with the SCR584 radar system to achieve extraordinary hit rates (near 90%) that ####################################################################### would not have been possible otherwise.[3] ########################### http://en.wikipedia.org/wiki/Operational_amplifier
milstar: interleaved ADC resultati 1. Single-tone at 190 MHz. Fs=2 GS/s, SFDR=79 dBc, ENOB=10.3 bits. http://spdevices.com/index.php/products2/adx4-evm-2000-12 2. 78 db SFDR na 330 mgz 2*14 bit TI ADS5474 800 msps (2*400 msps) ,ENOB 10.6 bit http://spdevices.com/index.php/products2/adx2-evm-800-14 3. 78db sfdr na 690 mgz ,10 bit ENOB 2*550 msps *12 bit TI ads5463 http://spdevices.com/index.php/products2/adx2-evm-1100-12 4. 73 db 911 mgz ,9.6 bit ENOB 2200 msps http://spdevices.com/index.php/products2/adx4-evm-2200-12
milstar: dlja srawnenija not interleaved 16 bit AD9467 Na 300 mgz ,250 msps , 12 bit ENOB , SFDR 90/93 db http://www.analog.com/static/imported-files/data_sheets/AD9467.pdf 12 bit 1 gsps ADS5400 TI 2009 na 850 mgz ENOB = 9.3 bit ,SFDR =71 db http://focus.ti.com/lit/ds/symlink/ads5400.pdf 10 bit EV10AS150A na 2500 mgz ,2.5 gsps , 7.7 bit ENOB ,59 db SFDR http://www.e2v.com/assets/media/files/documents/broadband-data-converters/doc0954B.pdf
milstar: radioljubitelskaja tochka zrenija na dinamicheskij diapazon ... toze polezna ,kak i rekord na 10 ghz s 10 watt 90 santimetrow diametrom antennoj -2000 km Conclusions When using the concept of dynamic range in Amateur Radio, we should refer to signals present simulta- neously at the antenna input. This means that BDR — implying that blocking means that the ability to copy the desired signal as blocked by a strong off-channel signal — for the FT-1000D is 96.5 dB. When the de- sired signal is placed at –77 dBm (see Note 2), the point of saturation, which was +20 dBm in QST (see Note 3) has to be compared to –77 dBm for a dy- namic range of 97 dB, ---------------------------------------- not to the MDS value measured under quite different circumstances. The value of 150 dB reported in QST is not the dynamic range for two simultaneously present signals. ------------------------------------------- It is the dynamic range for a single signal and is not of much inter- est to a radio amateur. http://www.sm5bsz.com/dynrange/qex/bdr.pdf Blocking Dynamic Range in Receivers An explanation of the different procedures and definitions that are commonly used for blocking dynamic range (BDR) measurements. By Leif Åsbrink, SM5BSZ Human sensors like the ears and the eyes have very large dynamic ranges, for example. The un- damaged ear can detect a 1 kHz sound wave at a level of 10–12 W/m2 while the upper limit is about 1 W/m2, where we start to feel pain. The dynamic range of our ears is thus about 120 dB. Our eyes can detect the light from a star in the dark sky when about ten pho- tons per second reach the retina, which converts to something like 10–13 W/m2. The Sun, with its 300 W/ m2, does not damage our eyes unless we look straight into it. Another example of dynamic range is the dynamic range of a vinyl music record. It may be on the order of 60 to 80 dB only, much less than the dy- namic range of our ears. The above examples show the dy- namic range for a single signal. ##################### The corresponding dynamic range for a receiver is not particularly interesting. ########################## Any room-temperature resistor pro- duces a noise voltage that would trans- fer –174 dBm/Hz to a matched cold resistor. ######################### With the RF preamplifier dis- abled, a typical HF receiver may pro- duce 20 dB more noise with a room- temperature dummy load at the input than would an ideal receiver that would not add any noise of its own (only amplifying the noise from the dummy load). A receiver adding 20 dB of noise is said to have a noise figure of 20 dB. If the bandwidth were 500 Hz, the noise floor referenced to the antenna input would be –174 + 20 + 27 dBm = –127 dBm. (Note that 10 log 500 ≈ 27.) This signal level is some- times improperly called MDS (mini- mum discernible signal) for such a typical receiver, even though a CW operator would easily copy a signal that is 10 dB weaker. Picking the noise floor as the low end of the dynamic range is typical for all dynamic ranges, not only in radio receivers. The noise floor power is pro- portional to the bandwidth and there- ######################### fore a receiver will have 10 dB more dynamic range when measured at a bandwidth of 200 Hz compared to when it is measured at a bandwidth of 2 kHz. ####################### It is the same receiver, though, and the dynamic range differ- ences that depend on bandwidth should not be included when different receivers are compared. For that reason, receivers should
milstar: http://www.ece.uah.edu/courses/material/EE710-Merv/Stretch.doc Stretch processing is a way of processing large bandwidth waveforms using narrow band techniques The form of means that the signal processor (i.e. matched filter) would need to have a bandwidth of . Herein lies the problem: large bandwidth signal processors are still difficult and very costly to build. Two methods of building LFM matched filters (LFM pulse compressors, LFM signal processors) are SAW (surface acoustic wave) devices and digital signal processors. According to the Skolnik Radar Handbook (page 10.11) one can build SAW compressors for bandwidths up to 1 GHz. However, I have not heard of hardware implementations with such devices. I would expect that the upper limit on bandwidth for practical SAW LFM compressors is in the 10s , or possibly low 100s, of MHz. Stretch processing relieves the signal processor bandwidth problem by giving up all-range processing to obtain a narrow band signal processor. If we were to use a matched filter we could look for targets over the entire waveform pulse repetition interval (PRI). With stretch processing we are limited to a range extent that is usually smaller than a pulse width. Thus, we couldn’t use stretch processing for search because it requires looking for targets over a large range extent, usually many pulse widths long. We could use stretch processing for track because we already know range fairly well but want a more accurate measurement of it. We must point out that, in general, wide bandwidth waveforms, and thus the need for stretch processing, is “overkill” for tracking. Generally speaking, bandwidths of 1s to 10s of MHz are sufficient for tracking In the above discussion, we have focused on the signal processor and have argued, without proof at this point, that we can use stretch processing to ease the bandwidth requirements on a signal processor used to compress wide bandwidth waveforms. Stretch processing does not relieve the bandwidth requirements on the rest of the radar. Specifically, the transmitter must be capable of generating and amplifying the wide bandwidth signal, the antenna must be capable of radiating the transmit signal and capturing the return signal, and the receiver must be capable of heterodyning and amplifying the wide bandwidth signal. This poses stringent requirements on the transmitter, antenna and receiver but current technology has advanced to be point of being able to cope with the requirements. STRETCH PROCESSOR IMPLEMENTATION We next want to turn our attention to practical implementation issues. The mixer, timing and heterodyne generation are reasonably straight forward. We want to address how to implement the spectrum analyzer. The most obvious method of implementing the spectrum analyzer is to use an FFT. To do so, we need to determine the required ADC (analog-to-digital converter) sample rate and the number of points to use in the FFT. To determine the ADC rate we need to know the expected frequency limits of the signal out of the mixer1. We will assume base-band processing in these discussions. In practice the mixer output will be at some intermediate frequency (IF). The signal could be brought to base-band using a synchronous detector or, as in some modern radars, by using IF sampling. In either case, the effective ADC rate (the sample rate of the complex, digital base-band signal) will be as derived here.
milstar: Radar Signal Processing Robert J. Purdy, Peter E. Blankenship, Charles Edward Muehe, Charles M. Rader, Ernest Stern, and Richard C. Williamson s This article recounts the development of radar signal processing at Lincoln Laboratory. The Laboratory’s significant efforts in this field were initially driven by the need to provide detected and processed signals for air and ballistic missile defense systems. The first processing work was on the Semi-Automatic Ground Environment (SAGE) air-defense system, which led to algorithms and techniques for detection of aircraft in the presence of clutter. This work was quickly followed by processing efforts in ballistic missile defense, first in surface-acoustic-wave technology, in concurrence with the initiation of radar measurements at the Kwajalein Missile Range, and then by exploitation of the newly evolving technology of digital signal processing, which led to important contributions for ballistic missile defense and Federal Aviation Administration applications. By 1972, fabrication of the first reflective-array compressor (RAC) was initiated; this device is illustrated in Fig- ure 2. The first RAC device was a linear-FM filter with a 50-MHz bandwidth (on a 200-MHz carrier) matched to a 30-μsec-long waveform [16–18]. This arrangement yielded a time-bandwidth product of 1500, more than an order of magnitude greater than that achieved by interdigital-electrode SAW devices [19]. The response was remarkably precise; the phase deviation from an ideal linear-FM response was only about 3° root mean square (rms). Pairs of matched RACs were used in pulse-compression tests in which the first device functioned as a pulse expander and the second as a pulse compressor. The compressed pulsewidths and sidelobe levels were near ideal. Armed with these encouraging results, researchers took the next step by developing RAC devices for spe- cific Lincoln Laboratory radars. RAC Pulse Compressors for the ALCOR Radar The ARPA-Lincoln C-band Observables Radar, or ALCOR [20], on Roi-Namur, Kwajalein Atoll, Mar- shall Islands, had a wideband (512 MHz) 10-μsec- long linear-FM transmitted-pulse waveform (see the article entitled “Wideband Radar for Ballistic Missile Defense and Range-Doppler Imaging of Satellites,” by William W. Camp et al., in this issue). ALCOR was a key tool in developing discrimination tech- niques for ballistic missile defense. The wide band- width yielded a range resolution that could resolve in- dividual scatterers on reentering warhead-like objects. This waveform was normally processed with the STRETCH technique, which is a clever time-band- width exchange process developed by the Airborne Instrument Laboratory [21, 22]. The return signal is mixed with a linear-FM chirp and the low-frequency sideband is Fourier transformed to yield range infor- mation. For a variety of reasons, the output band- width and consequently the range window were lim- ited. For example, the ALCOR STRETCH processor yielded only a thirty-meter data window. Therefore, examination of a number of reentry objects, or the long ionized trails or wakes behind some objects, re- quired a sequence of transmissions. This sequential approach was inadequate in deal- ing with the challenging discrimination tasks posed by reentry complexes, which consist not only of the reentry vehicle, but also a large number of other ob- jects, including tank debris and decoys, spread out over an extended range interval. What was needed was a signal processor capable of performing pulse compression over a large range interval on each pulse. Lincoln Laboratory contracted with Hazeltine Labo- ratory to develop a 512-MHz-bandwidth all-range analog pulse compressor employing thirty-two paral- lel narrowband dispersive bridged-T networks built During 1972 and 1973, Lincoln Laboratory devel- oped a 512-MHz-bandwidth (on a 1-GHz interme- diate frequency [IF]) 10-μsec RAC linear-FM pulse compressor [23]. ############# A trimming technique was developed to achieve an adequately precise response. This tech- nique required measuring the device and the subse- quent deposition of a corrective metal pattern of vary- ing width on the crystal surface of the RAC, as illustrated in Figure 2. The resulting precision al- lowed for a phase response that was precise to about 2.5° rms, or about one part per million over the 5120 cycles of the waveform. This response yielded near-in- range sidelobes in the –35-dB range, whereas far-out sidelobes rapidly fell to better than 40 to 50 dB down, as shown in Figure 4. In Figure 5, which is a photo- graph of a RAC developed for ALCOR, the two rain- bow-colored stripes near the centerline of the crystal show light that is diffracted from the etched grating. The phase-compensating varying-width metal film strip runs down the centerline of the crystal. Pairs of approximately one-inch-long matched RAC devices were installed in ALCOR in 1974 and were used successfully in a series of reentry tests. These devices proved to be such powerful wide-band- width signal processors that advances in analog-to- digital converter technology to capture the output were required before the capability of the RAC de- vices could be fully utilized.
milstar: Nulling Over Extremely Wide Bandwidths When Using Stretch Processing Richard M. Davis Jose A. Torres J. David R. Kramer Ronald L. Fante The MITRE Corporation 202 Burlington Road, Bedford, MA, 01730-1420 rmdavis@mitre.org, torres@mitre.org, dkramer@mitre.org, rfante@mitre.org Adaptive Sensor Array Processing Workshop March 10-11, 1999 15121501 4/6/99 2 Outline 0 The Problem 0 Traditional Solutions 0 A New Approach 0 Numerical Results 0 Summary MITRE 4/6/99 3 The Problem 0 Given radar capable of radiating extremely wideband waveforms (100 -1000 MHz) 0 Desire protect radar against sidelobe noise jamming 0 Each frequency within jammer’s spectrum is received with different sidelobe gain. 0 Number of sidelobes jammer spreads through equals time-bandwidth product (TB) TB = D(sinθ - sinθο)B/C where T = Difference in arrival time of plane wave across array face B = Jammer bandwidth D = Array diameter θο = Time-delay steered beam pointing direction http://www.ll.mit.edu/asap/asap_99/abstract/Davis.pdf Demonstrated feasibility of sidelobe cancellation over extremely wide bandwidths on systems which use stretch processing 0 Technique exploits mapping between time and frequency implicit in stretch systems 0 Nulling can be performed in time or frequency domains - Nulling in time domain after deramper, but before FFT, shown to be analogous to traditional subbanding approach - but get subbands free - Nulling after FFT in frequency domain shown to be analogous to traditional space-time processsing - but get time taps free - One set of adaptive weights nulls all frequency bins provided phase compensation is applied to all channels - Signal cancellation can be controlled in time domain by increasing number of samples used to estimate correlations, and in frequency domain by using out-of-band correlation MITRE
milstar: http://www.prod.sandia.gov/cgi-bin/techlib/access-control.pl/2002/022127.pdf Introduction The Synthetic Aperture Radar (SAR) organization at Sandia National Laboratories is currently undertaking several R&D efforts towards the development of a “next- generation” miniaturized SAR or “Micro-SAR”. The goal of this collaborative effort is to realize a high performance SAR which has a total weight of approximately 20 pounds. In conjunction with the development of technology and techniques to miniaturize the critical subsystems of a SAR (such as the antenna, transmitter, processors, RF electronics, motion measurement, etc.), the digital radar technology development [1] has been identified as key to the Micro-SAR effort. Digital receiver techniques such as direct or bandpass sampling, bandwidth oversampling, and high-throughput DSP functions in field-programmable gate arrays (FPGA) show great improvement in the system performance, flexibility, and robustness, as well as significant reduction in physical size and weight. One key element in the realization of a “true” digital radar intermediate-frequency (IF) receiver is the track-and-hold amplifier (THA). We propose that a THA plus a high- speed (1 to 1.5 GS/s), high dynamic range (8 to 10-bit) analog-to-digital converter (ADC) be employed to directly sample a 4 GHz IF signal present in our current-generation SAR systems. A simplified block diagram of the RF subsystem, showing the 4 GHz IF output, is shown in Figure 1. A digital-waveform synthesizer (DWS) produces a linear-FM “chirped” waveform, which is up-converted to 12.6 GHz. Upper and lower sideband implementations produce wide-bandwidth (~3 GHz) transmit waveforms at Ku-band (16.6 GHz) and X-band (8.6 GHz) respectively. Because of the desired wide-bandwidth RF for fine range resolution, bandwidth compression through stretch processing is utilized. Stretch processing is a common technique whereby the wideband RF chirp is mixed or “de-ramped” with a similar receive chirp to produce a relatively narrowband IF signal (200 to 250 MHz). It is this 4 GHz IF signal, common to all of our current SAR systems, that we wish to direct sample. iz 3000 mgz - 250 mgz (pch 125-375 mgz ,dlja obrabotki ADC s skorostju bolee gigasamle) prakticehskie resultati 1000 mgz -razreschenie 250 mm 2500 mgz -100 mm 5000 mgz - 50 mm eto bez extrapoljazii polosi The RF to IF bandwidth compression increases the signal dynamic range at IF relative to RF. Even though the IF bandwidth of 200 to 250 MHz satisfies the Nyquist criteria for current state-of-the-art ADCs in the 1 to 1.5 GS/s range, the additional dynamic range places stringent requirements on the sampler, i.e., the THA and ADC combination.
milstar: n the classic sense, analog receiver system design employs cascade linearity (second and third-order intermodulation) and noise figure calculations based on individual component characteristics. We desire to use the same analysis for a proposed SAR receiver, which may employ a THA for direct 4 GHz IF sampling. Hence, we needed to first characterize component-level parameters such as the 1 dB gain compression, the output third-order intercept (TOI), signal-to-noise ratio (SNR), spurious-free dynamic-range (SFDR), and noise figure (NF) for the THA. In addition, time-domain jitter or phase noise degradation of the THA must be quantified to understand its potential impact to the Doppler-domain dynamic range performance of the SAR. The purpose of this report is to document the above mentioned measurements performed on the Rockwell Scientific RTH010 [2] THA, which has been identified as a prime candidate, and possibly the only currently available candidate THA for our application. All measurement parameters and configurations are catered specifically to the direct IF sampling application mentioned. The measured data was then analyzed (some quantitative, some qualitative) to determine the general impact of the non-idealities of the THA to SAR performance. Figure 2: Comparison of simplified block diagrams for the current SAR IF configuration and the proposed digital IF implementation employing a fast THA. The “Old Way” shows the current implementation. Currently, analog down-conversion, analog IF filtering using surface-acoustic wave (SAW) filters, and analog quadrature (I/Q) demodulation are employed. The “Digital Way” performs the necessary frequency conversion by direct sampling the IF using the THA and the ADC. IF filtering and quadrature demodulation, amongst other DSP operations, are all performed in FPGAs. We are currently developing a digital IF receiver module upgrade to our current SAR. This module utilizes bandwidth over-sampling and high-throughput DSP functions in FPGAs. However, we have chosen not to employ a THA to direct sample the IF. Instead, classic analog down-conversion is employed due to it’s lower implementation risk. Future radars developed at Sandia National Labs may very well employ the benefits of direct sampling using a THA, assuming that the device meets the system performance requirements. Analog Bandwidth The THA must certainly support the 4 GHz direct IF sampling application. In addition, we wish to measure the gain of the THA vs. frequency to assess the possibility of using the RTH010 for future direct sampling applications up to X-band frequencies. Noise Figure The noise figure performance of the THA at 4 GHz helps determine the lower limit of the SAR dynamic range. SFDR and SNR Both SFDR and SNR are measured and compared to the same parameters for the ADC itself. Since the ADC is typically the dynamic range “bottleneck” in a SAR employing stretch processing, we want to carefully assess the effective number of bits (ENOB) of the THA and ADC as compared to the ADC alone. 4.1.4 Analog Bandwidth and Input/Output Impedance We found that the output response was not very flat over the band of DC to 7GHz when measured in the continuous-time domain. Therefore we were prompted to look at the input and output impedance of the THA and the input impedance of the 180° hybrid coupler. We found that this variation in the output response was due primarily to the impedance variation of the hybrid coupler (or balun) and the THA: • The input impedance of the THA varies from 51.85 (at 500 MHz) to 37.96 (at 4 GHz) to 74.50 (at 6 GHz) ohms. • The output impedance of the THA varies from 34.76 (at 50 MHz) to 54.94 (at 450 MHz) ohms. • The input impedance of the 180° hybrid coupler varies from 48.47 (at 50 MHz) to 100.10 (at 450 MHz) ohms. • We also tried a balun on the THA output in place of the 180° hybrid coupler. The results were similar, due to the input impedance of the balun varying from 23.23 (at 50 MHz) to 69.37 (at 400 MHz) to 53.24 (at 500 MHz) ohms. The primary components utilized in the discrete-time measurements are the ADC (Maxim MAX108) operating nominally at 1 GHz, the FPGA (Xilinx XC2V1000), and the VME interface. For each ADC vector acquisition, data is stored in RAM located in the FPGA, then transferred to a Motorola 2307 processor via the VME interface. From there, the data is accumulated (if necessary), then transferred to a PC running Matlab via an ethernet link. 10 bit e2v 2.5 gsps,8 bit ENOB,60 db SFDR awtoru ponrawilsja bolsche chem max108 i 109 (oba 8-bitnie ) w 2002 ego ne bilo ... http://www.prod.sandia.gov/cgi-bin/techlib/access-control.pl/2002/022127.pdf
milstar: x band radar s polosoj 1 ghz ,razrescheniem 150 mm ,ispolzuetsja atmel 10 bit 2.2 gsps ( teper eto e2v) High resolution range-Doppler radar demonstrator based on a commercially available FPGA card”, proceedings Radar 2008, Adelaide, Australia. pdf An X-band high resolution range-Doppler radar demonstrator has been developed, based on a commercially available 6U-VXS form-factor digital signal processing card containing all necessary base-band circuitry. The custom design covers a radio frequency up-down converter, FPGA firmware and PC software. The practical signal bandwidth is close to 1GHz and the range resolution is close to 15cm. The functionality has been demonstrated in a free space radiation experiment. By: Henning Nicolaisen#1, Tor Holmboe*2, Karina Vieira Hoel*3, Stein Kristoffersen*4 #University of Oslo, Department of Informatics P.O. Box 1080 Blindern, NO-0316 Oslo, Norway * Norwegian Defence Research Establishment The radar resolution in range and Doppler can be varied within wide limits, from the resolution typical of air target range-Doppler radars to the high resolution representative of ynthetic aperture radars (SAR) and inverse SAR (ISAR) systems. However, no radar trajectory compensation, antenna steering or target following function is implemented and the MuPuRF radar mode does not represent an operational system in this respect. The Nyquist digital signal bandwidth of MuPuRF is 1 GHz, corresponding to 15 cm theoretical range resolution. he TRITON VXS-1, produced by Tekmicro [2], is a single-slot 6U form factor card and is in accordance with the VITA 41.0 VXS specification. The advertised key applications for the TRITON VXS-1 include radar, electronic warfare, software radio and telecommunications. Figure 2 shows the main components and signal paths. The core of the TRITON VXS-1 is a Xilinx Virtex-II Pro FPGA circuit along with a 10bit ADC and a 12bit DAC. Both converters can operate at 2 GSamples/sec, giving a Nyquist digital signal bandwidth of 1 GHz. The analog 3 dB-bandwidth extends from 3 MHz to 3 GHz. http://www.tekmicro.com/products/product.cfm?id=70&gid=5 smotri link na dannoj stranize Related Article Links: High resolution range-Doppler radar demonstrator based on a commercially available FPGA card”, proceedings Radar 2008, Adelaide, Australia. pdf ingle channel single stage RF up-down conversion is employed. A more complex up-down converter may be needed in order to enable multi-purpose operation, but the present design is adequate for limited X-band lab-radar operation. The sensitivity at the RF-input connector is such that a -45 dBm input level corresponds to the full scale range of the 10 bit ADC. Any LNA gain comes in addition. A high- speed programmable, 60 dB range, attenuator can be utilized to compensate for the 1/R4 range dependency and to perform general sensitivity adjustments under software control. The radar can operate using any kind of waveform within the maximum 1 GHz bandwidth. The desired waveform is selected and generated in the PC GUI and transferred to the TRITON together with the rest of the radar parameters. The pulse length is presently limited by the Tx-FIFO memory size of 8 kSamples in the current configuration. With a full bandwidth waveform (i.e. 2 G Samples/s) this is equivalent to a 4 μs pulse. he radar has been tested in a free space radiation experiment with the combined match filter and quadrature demodulator implemented in FPGA, producing fully satisfying results for a 900 MHz bandwidth waveform. The theoretical range resolution for this bandwidth is 17 cm, which is in good accordance with the observed range resolution.
milstar: Fast Facts: Founded: November 1981 Employees: 35 Privately Held ISO 9001 Certified The QuiXilica V5 Architecture provides a simple flexible parallel interface that enables boards to be factory configured with different ADCs and DACs, thus enabling the boards to meet a robust variety of applications. High bandwidth support for ADCs and DACs operating beyond 5 GSPS is designed into the architecture. Front-end/Back-end XMC Architecture: Unique two-part XMC design separates the protocol interface (front-end) from the standard back-end interface (PMC, XMC) and provides powerful advantages at many levels for customers who need to integrate, maintain, or upgrade multiple I/O modules. New protocol interfaces can quickly be added to existing back-ends as technology becomes available. Protocol interfaces can be upgraded with new back-end interfaces as technology demands. Representative Customers Alenia Marconi Systems BAE General Dynamics L-3 Communications Lockheed Martin MIT NASA Northrop Grumman Raytheon Recon Optical Inc. Rockwell Collins http://www.tekmicro.com/about/fastfacts.cfm http://www.tekmicro.com/products/index.cfm
milstar: The AN/FPS-16 is a highly accurate ground-based monopulse single object tracking radar (SOTR), used extensively by the NASA manned space program and the U.S. Air Force. The accuracy of Radar Set AN/FPS-16 is such that the position data obtained from point-source targets has azimuth and elevation angular errors of less than 0.1 milliradian (approximately 0.006 degree) and range errors of less than 5 yards (5 m) with a signal-to-noise ratio of 20 decibels or greater. s antennoj 3.9 metra , IF /Pch -30 mgz i polosoj 8 mgz ###################################### The sum, azimuth, and elevation signals are converted to 30 MHz IF signals and amplified. The phases of the elevation and azimuth signals are then compared with the sum signal to determine error polarity. These errors are detected, commutated, amplified, and used to control the antenna-positioning servos. A part of the reference signal is detected and used as a video range tracking signal and as the video scope display. A highly precise antenna mount is required to maintain the accuracy of the angle system. t..e ne wse rezimi raboti RLS trebujut polosi 500 mgz-8000 mgz kak SAR/ISAR ,kotorie mogut razlichat yabch ot loznoj celi po kinematike dwizenija ################################################################################################# IF/PCH 30 mgz ,polosa 8 mgz -eto 16 bit AZP ... s dither , NLEQ processor eto okolo 110 db dinamicheskij diapazon s kombinaziej drugix metodow wozmozno bolsche podxodjat rjad AZP AD9467 250 msps/16 bit ,TI ADS5485 16 bit/200 msps ,LTC2209 160 msps/16 bit wse oni normirowanni dlja Fin do 300 mgz modifikazija obrabotk isignala AN/FPS-16 http://www.integrated-om-solutions.com/brochure/ESD%20PDF/rott.pdf The 3-channel Radar Signal Processor (RSP) provides state-of-the-art, digital filtering techniques for signal processing. The RSP subsystem combines the functions previously provided by the Digital Moving Target Indicator Receiver and Intelligent Range Tracker in a single VME solution. It accepts 3-channel monopulse IF inputs, digitizes the 30 mHz IF, and produces filtered angle error and target range information. Additionally, it incorporates Doppler processing to reduce the effects of stationary clutter. This subsystem works with magnetron-based transmitters in a coherent-on- receive mode and with CFA-based transmitter in a fully coherent mode. BAE SYSTEMS offers cost effective modifications and upgrades to improve performance and extend the operational life of existing radar systems. Comprehensive upgrade programs have been developed for specific types of radars including the AN/MPS-25, AN/MPS-36, AN/FPQ-6, AN/TPQ-39, NIKE systems and the AN/FPS-16. Upgrade features include the following: NASA Acq aid and telelmetry systems were co-located with the Australian radar. To obtain reliability in providing accurate trajectory data, the Mercury spacecraft was equipped with C-band and S-band cooperative beacons. The ground radar systems had to be compatible with the spacecraft radar beacons. The FPS-16 radar in use at most national missile ranges was selected to meet the C-band requirement. Although it originally had a range capability of only 250 nautical miles (460 km), most of the FPS-16 radar units selected for the project had been modified for operation up to 500 nautical miles (900 km), a NASA requirement, and modification kits were obtained for the remaining systems. In addition to the basic radar system, it was also necessary to provide the required data-handling equipment to allow data to be transmitted from all sites to the computers. The FPS-16 system originally planned for the Project Mercury tracking network did not have adequate displays and controls for reliably acquiring the spacecraft in the acquisition time available. Consequently, a contract was negotiated with a manufacturer to provide the instrumentation radar acquisition (IRACQ)[Increased RAnge Acquisition] modifications. For the near earth spacecraft involved a major limitation of the FPS-16 was its mechanical range gear box, a wonderful piece of engineering. However, for a target at a range typically, say, 700 nautical miles (1,300 km; 810 mi) at acquisition of signal [AOS], the radar was tracking second time around, that is, the pulse received in this interpulse period was that due to the previously transmitted pulse, and it would be indicating a range of 700 nmi (1,300 km; 810 mi). As the range closed the return pulse became closer and closer to the time at which the next transmitter pulse should occur. If they were allowed to coincide, remembering that the transmit-receive switch disconnected the receive (Rx) and connected the transmit (Tx) to the antenna at that instant, track would be lost. So, IRACQ provided an electronic ranging system, the function of which was to provide the necessary gating pulses to the Az and El receiver channels so that the system would maintain angle track. The system utilized a voltage controlled crystal oscillator [VCXO] as the clock generator for the range counters. An early/late gate system derived an error voltage which either increased [for a closing target] or decreased [for an opening target] the clock frequency, thus causing the gates to be generated so as to track the target. It also, when the target reached an indicated range of less than 16,000 yd (15 km), took over the generation of transmitter trigger pulses and delayed these by 16,000 yd (15 km), thus enabling the received pulses to pass through the Big Bang, as it was called, of normally timed Tx pulses. The radar operator, would, while IRACQ maintained angle track be slewing the range system from minimum range to maximum so as to regain track of the target at its true range of <500 nmi (900 km). As the target passed through point of closest approach (PCA) and increased in range the process was repeated at maximum range indication. The most difficult passses were those in which the orbit was such that the target came to PCA at a range of, say 470 nmi. That pass required the radar operator to work very hard as the radar closed, and then opened in range through the Big Bang in short order. The IRACQ Console contained a C-scope associated with which was a small joy stick which gave C-scope operator control of the antenna angle servo systems so that he could adjust the pointing angle to acquire the signal. IRACQ included a scan generator which drove the antenna in one of several pre-determined search patterns around the nominal pointing position, it being desirable that IRACQ acquire the target as early as possible. An essential feature of this modification is that it allows examination of all incoming video signals and allows establishment of angle-only track. Once the spacecraft has been acquired, in angle range. Other features of the IRACQ system included additional angle scan modes and radar phasing controls to permit multiple radar interrogation of the spacecraft beacon. The addition of a beacon local oscillator wave meter permitted the determination of spacecraft-transmitter frequency drift. Early in the installation program, it was realized that the range of the Bermuda FPS-16 should be increased beyond 500 miles (800 km). With the 500-mile (800 km)-range limitation, it was possible to track the spacecraft for only 30 seconds prior to launch-vehicle sustainer engine cut-off (SECO) during the critical insertion phase. By extending the range capability to 1,000 miles (2,000 km), the spacecraft could be acquired earlier, and additional data could be provided to the Bermuda computer and flight dynamics consort This modification also increased the probability of having valid data available to make a go/no-go decision after SECO. http://en.wikipedia.org/wiki/AN/FPS-16 C-Band Radar Transponder The C-Band Radar Transponder (Model SST-135C) is intended to increase the range and accuracy of the radar ground stations equipped with AN/FPS-16, and AN/FPQ-6 Radar Systems. C-band radar stations at the Kennedy Space Center, along the Atlantic Missile Range, and at many other locations around the world, provide global tracking capabilities. Beginning with Vehicles 204 and 501, two C-band radar transponders will be carried in the instrumentation unit (IU) to provide radar tracking capabilities independent of the vehicle attitude. This arrangement is more reliable than the antenna switching circuits necessary if only one transponder would be used. [edit] Transponder operation The transponder receives coded or single pulse interrogation from ground stations and transmits a single-pulse reply in the same frequency band. A common antenna is used for receiving and transmitting. The transponder consists of five functional systems: superheterodyne receiver, decoder, modulator, transmitter, and power supply. The duplexer (a 4-port ferromagnetic circulator) provides isolation between receiver and transmitter. Interrogating pulses are directed from the antenna to the receiver, and reply pulses are directed from the transmitter to the antenna. The preselector, consisting of three coaxial cavities, attenuates all RF signals outside the receiving band. The received signal is heterodyned to a 50 MHz intermediate frequency ################################################ ywelichena polosa do 16 mgz ? toze chto i dlja 30mgz s polosoj 8 mgz --------------------------------------------------------- Priwedennie 16 bit AZP prekrasno podxodjat #################################
milstar: http://en.wikipedia.org/wiki/AN/FPQ-6 AN/FPQ-6 vairan FPS-16 s antennoj 9 metrow The AN/FPQ-6 is a fixed, land-based C-band radar system used for long-range, small-target tracking. The AN/FPQ-6 Instrumentation Radar located at the NASA Kennedy Space Center was the principal C-Band tracking radar system for Apollo program. RCA’s Missile and Surface Radar Division developed the FPQ-6 skin tracking C-Band radar as a successor to the AN/FPS-16 radar set. The AN/FPQ-6 can provide continuous spherical coordinate information at ranges of 32,000 nautical miles (59,000 kilometers) with an accuracy of plus and minus 6 ft (1.8 m). The AN/FPS-16 has range limited to 500 nmi (930 kilometers) with an accuracy of 15 feet (5 m), although it could be modified to a maximum range of 5,000 nmi (9,300 kilometers). The AN/FPQ-6 radar employed a 2.8 megawatt peak power (4.8 kilowatt average), broad banded (5400–5900 MHz) transmitter with a frequency stability of 1×108. The 8.8 meter diameter parabolic antenna, using a Cassegrain antenna feed, had a 0.4° beamwidth and a gain of 51 dB. Its monopulse, 5 horn feed system permitted the reference and error antenna patterns to have their gains independently established as well as the slope of the error patterns optimized while supplying target return signals to the receiving system with a minimum of insertion loss. The three channel signal outputs of the antenna feed system were supplied directly to the receiving system without undergoing any additional loss-inducing signal manipulation with bandwidths optimized for the specified pulse widths of 0.5, 0.75, 1.0 and 2.4 microseconds and the receiver noise figure of 7.5 dB was improved to 3.5 dB through the addition of closed-cycle parametric RF amplifiers. This system ensured a dynamic range in excess of 120 dB. ####################################### Dlja sluschaew s wisokoj ionizaciej atmosferi ( poriw yabch serjno) yawno nuzno bolsche .... woprosi 1. Skolko boslche ? 150 db ? 180 db ? 2. Kak realizowat ochen wisokij dinamicheskij diapazon ? a.Analogowo b. AZP 16 bit s kombinaziej metodow ? c. esli realizuemo ,to kakix metodow ?
milstar: Some notes on the AN-FPQ 6 Radar The AN-FPQ 6 radar was built by RCA and was, effectively, a development of the AN-FPS 16. The Q6, as it was known by those who worked on it, was an amplitude comparison monopulse C-band radar, with a 2.8 MW peak klystron transmitter tunable from 5.4 to 5.8 GHZ, which had a 9 meter parabolic antenna, having 52 dB gain, a 0.6 degree beam width, utilizing a Cassegrainian feed with a five horn monopulse comparator. This radar had an unambiguous maximum range of 215 or 32,768 nautical miles (60,686 km), and employed uncooled parametric amplifiers with a system noise temperature of 440 K, [a noise figure of 4 dB]. A major features of the radar was its maximum unambiguous range of 32,768 nautical miles (60,686 km) despite a pulse repetition frequency [PRF]of some hundreds of pulses per second. RCA’s Missile and Surface Radar Division developed the FPQ-6 skin tracking C-Band radar as a successor to the AN/FPS-16 radar set. The AN/FPQ-6 can provide continuous spherical coordinate information at ranges of 32,000 nautical miles (59,000 kilometers) with an accuracy of plus and minus 6 ft (1.8 m). The AN/FPS-16 has range limited to 500 nmi (930 kilometers) with an accuracy of 15 feet (5 m), although it could be modified to a maximum range of 5,000 nmi (9,300 kilometers).
milstar: mit/receive circuit. The transmit side includes phase control and field-effect transistor (FET) power amplification at 17 GHz, and a frequency doubler. On the receive side, a dual unit incorporates a transmit/receive switch and a mixer that produces the intermediate frequency (IF) at 1 to 2 GHz. This dual driving a doubler to produce output power at 34 GHz [72] t.e. Radar 34-35 ghz ,poosa 1000 mgz , IF/Pch 1-2 ghz s polosoj 1000 mgz ...seredina 80 godow Gallium-ars- enide MMIC transmit/receive-module technology is used in the X-band (8.0 to 12.0 GHz) theater-mis- sile-defense phased-array radar system [54] built by Raytheon Corporation. THAAD IF ? The measured average sidelobe level is –50 dB, close to the theoretical value. Space-based radars or airborne radars can use multiple displaced phase centers to cancel clutter, as described in the ar- ticle by Muehe and Labitt in this issue. A The Development of Phased-Array Radar Technology Alan J. Fenn, Donald H. Temme, William P. Delaney, and William E. Courtney Lincoln Laboratory has been involved in the development of phased-array radar technology since the late 1950s. Radar research activities have included theoretical analysis, application studies, hardware design, device fabrication, and system testing. Early phased-array research was centered on improving the national capability in phased-array radars. The Laboratory has developed several test-bed phased arrays, which have been used to demonstrate and evaluate components, beamforming techniques, calibration, and testing methodologies. The Laboratory has also contributed significantly in the area of phased-array antenna radiating elements, phase-shifter technology, solid-state transmit-and- receive modules, and monolithic microwave integrated circuit (MMIC) technology. A number of developmental phased-array radar systems have resulted from this research, as discussed in other articles in this issue. A wide variety of processing techniques and system components have also been developed. This article provides an overview of more than forty years of this phased-array radar research activity. http://74.6.238.254/search/srpcache?ei=UTF-8&p=lincoln+laboratory+intermediate+freuqency&fr=alltheweb&u=http://cc.bingj.com/cache.aspx?q=lincoln+laboratory+intermediate+freuqency&d=5036463472512378&mkt=en-US&setlang=en-US&w=1669e1b5,ad59e78a&icp=1&.intl=us&sig=.9Wr9D8VXb3rqwiVcHxEZA--
milstar: ALCOR operates at C-band (5672 MHz) with a signal bandwidth of 512 MHz that yields a range resolution of 0.5 m. (The ALCOR signal was heavily weighted to produce low range sidelobes with the concurrent broadening of the resolution.) Its wide- bandwidth waveform is a 10-μsec pulse linearly swept over the 512-MHz frequency range. High signal-to- noise ratio of 23 dB per pulse on a one-square-meter target at a range of a thousand kilometers is achieved with a high-power transmitter (3 MW peak and 6 kW average) and a forty-foot-diameter antenna. Cross-range resolution comparable to range resolu- tion is achievable with Doppler processing for targets rotating at least 3° in the observation time. The pulse- repetition frequency of this waveform is two hundred pulses per second Processing 500-MHz-bandwidth signals in some conventional pulse-compression scheme was not fea- sible with the technology available at the time of ALCOR’s inception. Consequently, it was necessary to greatly reduce signal bandwidth while preserving range resolution. This is accomplished in a time- bandwidth exchange technique (originated at the Air- borne Instrument Laboratory, in Mineola, New York) called stretch processing [4], which retains range reso- lution but restricts range coverage to a narrow thirty- meter window. In order to acquire and track targets and designate desired targets to the thirty-meter wideband window, ALCOR has a narrowband wave- form with a duration of 10.2 μsec and bandwidth of 6 MHz. This narrowband waveform has a much larger 2.5-km range data window. Wideband Radar for Ballistic Missile Defense and Range-Doppler Imaging of Satellites 270 LINCOLN LABORATORY JOURNALVOLUME 12
milstar: The Haystack system has a number of features that rendered this option extremely attractive. It has a large diameter (120 ft) antenna needed to achieve deep-space ranges. The antenna was designed with Cassegrainian optics and could accommodate plug-in radio-frequency (RF) boxes at the vertex of the pa- raboloidal dish. These boxes supported various com- munications, radio astronomy, and radar functions. The interchangeable boxes are 8 × 8 × 12 ft, which is large enough for the high-power (400 kW peak and 200 kW average) new transmitter and associated mi- crowave plumbing, feedhorns, and low-noise receiv- ers needed for the long-range imaging radar.1 The Haystack antenna surface tolerance allows efficient operation up to 50 GHz, thus readily supporting op- erating at X-band (10 GHz) with a bandwidth of 1024 MHz, and a resulting range resolution of 0.25 m. A system for interchanging ground-based elec- tronics and power sources supporting the various RF boxes was already in place. Using an established facil- ity with existing antenna and prime power sources greatly reduced the cost of the new system, known as the Long Range Imaging Radar, or LRIR [6]. The LRIR, which was completed in 1978, is ca- pable of detecting, tracking, and imaging satellites out to synchronous-orbit altitudes, approximately 40,000 km. The range resolution of 0.25 m is matched by a cross-range resolution of 0.25 m for tar- gets that rotate at least 3.44° during the Doppler-pro- cessing interval. The wideband waveform is 256 μsec long and the bandwidth of 1024 MHz is generated by linear frequency modulation. The pulse-repetition frequency is 1200 pulses per second. The LRIR em- ploys a time-bandwidth exchange process similar to ################################### that of ALCOR to reduce signal bandwidth from ############################## 1024 MHz to a maximum of 4 MHz, corresponding #################################### to a range window of 120 m, while preserving the ################################# range resolution of 0.25 m #################### kopija iz wische .... This is accomplished in a time- bandwidth exchange technique (originated at the Air- borne Instrument Laboratory, in Mineola, New York) called stretch processing [4], ################### which retains range reso- lution but restricts range coverage to a narrow thirty- meter window. To place a target in the wideband window, we first acquire the target with a continuous-wave acquisition pulse that is variable in length from 256 μsec (for short-range targets) to 50 msec (for long-range targets). An acquired target is then placed in active tracking by using 10-MHz- bandwidth chirped pulses, again of variable length, from 256 μsec to 50 msec. The wideband window is then designated to the target. Antenna beamwidth is 0.05°. Figure 3(a) shows an artist’s rendition of the 120-foot Haystack antenna in its 150-foot radome; Figure 3(b) shows a photograph of the LRIR feed horn and transmitter/receiver RF box in the Haystack radome
milstar: mmw radar A second 35-GHz tube was also added, which doubled the average transmitted power. These modi- fications increased the signal pulse detection range on a one-square-meter target to over two thousand kilo- meters. System bandwidth was also increased to 2 GHz, resulting in a range resolution of about 0.10 m. More recently, Lincoln Laboratory has developed and exploited several techniques for improving the 278 LINCOLN LABORATORY JOURNAL VOLUME 12, NUMBER 2, 2000 resolution of wideband coherent radar data. The first technique uses modern spectral-analysis methods for improving resolution relative to the restrictions of conventional Fourier processing. These spectral methods extrapolate signals in a radar-frequency di- mension by a process called bandwidth extrapolation. Each wideband pulse return includes the target fre- quency response over the chirped bandwidth. Mod- ern spectral-estimation techniques are then applied to extend this frequency response synthetically outside this band to a factor ranging from two to three times the bandwidth. This expanded pulse return is then re- compressed to provide finer range resolution (for practical signal-to-noise ratios, an improvement of a factor of two to three in resolution is generally real- ized), and when applied to radar imaging, it provides much improved sharpness in the radar image [9]. The second technique uses signal processing mod- els that correspond to rotating-point motion. The models allow extended coherent processing over wide target-rotation angles, resulting in improved Doppler (cross-range) resolution [10]. For sufficiently large resolution angles and for constant-amplitude scatter- ing centers, extended coherent processing also im- proves the range resolution. Extended coherent pro- cessing essentially aligns and stores radar pulses ob- tained over longer time spans as compared to conven- tional imaging. When combined with bandwidth ex- trapolation, extended coherent processing can achieve enhanced resolution in both range and Doppler (cross-range) spaces. For targets where the radar view- ing angle is at a constant aspect angle to the target’s angular-momentum vector, extended coherent pro- cessing provides high-quality three-dimensional radar images. More recently, the Laboratory has explored the possibility of achieving ultrawideband resolution by using data only over sparse subbands of the full ultra- wide bandwidth. We can view this technique as a gen- eralization of bandwidth extrapolation to multiple bands [10]. Ultrawideband’s potential as a discrimi- nation tool is much more robust, as scatterer-feature identification on a specific target is inherently more accurate when observed over a much wider band- width. Wideband Radar for Ballistic Missile Defense and Range- Doppler Imaging of Satellites William W. Camp, Joseph T. Mayhan, and Robert M. O’Donnell s Lincoln Laboratory led the nation in the development of high-power wideband radar with a unique capability for resolving target scattering centers and producing three-dimensional images of individual targets. The Laboratory fielded the first wideband radar, called ALCOR, in 1970 at Kwajalein Atoll.
milstar: linki p oadressu nize http://academic.research.microsoft.com/Paper/4586571.aspx Wideband Radar for Ballistic Missile Defense and Range- Doppler Imaging of Satellites (Citations: 3) William W. Camp, Joseph T. Mayhan, Robert M. O'Donnell Lincoln Laboratory led the nation in the development of high-power wideband radar with a unique capability for resolving target scattering centers and producing three-dimensional images of individual targets. The Laboratory fielded the first wideband radar, called ALCOR, in 1970 at Kwajalein Atoll. Since 1970 the Laboratory has developed and fielded several other wideband radars for use in ballistic-missile-defense research and space-object identification. In parallel with these radar systems, the Laboratory has developed high-capacity, high-speed signal and data processing techniques and algorithms that permit generation of target images and derivation of other target features in near real time. It has also pioneered new ways to realize improved resolution and scatterer-feature identification in wideband radars by the development and application of advanced signal processing techniques. Through the analysis of dynamic target images and other wideband observables, we can acquire knowledge of target form, structure, materials, motion, mass distribution, identifying features, and function. Such capability is of great benefit in ballistic missile decoy discrimination and in space-object identification. Published in 2000. View or Download
milstar: 35 ghz /2000 mgz mmw radar s 13.6 metra D antennoj 0.042 gradschirinoj lucha na 35 ghz(0.014 grad na 94 ghz) i razrescheniem 100 mm pri polose 2000 mgz The 100-kW millimeter-wave radar at the Kwajalein Atoll (Citations: 3) M.d. Abouzahra, R.k. Avent Published in 1994. View or Download http://academic.research.microsoft.com/Paper/1635526.aspx mplified, before being launched out of the antenna. At a specified time (which is determined in the real-time program (RTP) by extrapolating the range-tracking filter), the waveform generator is again triggered, producing the same chirped waveform. This signal is input to the correlation mixer, and is mixed with the target return, previously translated down to a center frequency of 6.44 GHz. ( 35 ghz -RF) ----------------------------------------------------------------------------------------------- Fig- ure Sb shows a theoretical target return for two point scatterers, located a distance Ar apart. This signal is shown at a point imme- diately after the frequency translator. Note that this illustration assumes that the range trigger was initiated exactly coincident in time with the reception of the in-range scatterer. In other words, both the return and the correlation ramp have a center frequency of 6.44 GHz. ------------------ Note also that it is assumed that the Doppler frequencies associated with the target have been removed. Under these assumptions, the output of the correlation mixer is a sum of two constant tones, the frequency difference of which is a function of the range difference between the two scatterers. In other words, we have effectively performed a time-delay-to-frequency conversion. This output is shown in Figure Sc, which gives the frequency differ- ence between the two point scatterers as pAr . Notice that because Ar can range over the full 7.5-km pulse, the frequency difference between two scatterers can thus range over the full chirp band- width. Because the pulse-compression network is based on a fast Fourier transform (FFT), and thus requires a sampled waveform he signal bandwidth has to be reduced to a level commensurate with today’s A/D converter technology. This band-limiting opera- tion is accomplished with a 5-MHz bandpass filter, after the signal is mixed to a center frequency of 60 MHz. --------------------------------------------------------------- The resulting 5-MHz bandpass filter is then converted to in-phase and quadrature-phase components, and Fourier transformed to yield the range display shown in Figure 8d. .... Because MMW has such an extremely high bandwidth, nei- ther all-range processors, conventional dispersive-delay lines, nor surface-acoustic-wave techniques can be employed to compress the pulse. For this reason, the concept of band limiting the range win- dow to 5 MHz, sampling the resulting signal, and using digital- spectral analysis to detect the target, was implemented. The result is that the range extent, or the amount of target space seen, is This depend- bounded, and is a function of the chirp bandwidth, W. ency can be derived by noting that the maximum fiequency devia- tion into the FFT is 5 MHz, because there is a 5-MHz band-limiting filter prior to the ,443 converter. This 5-MHz filter, denoted here as O b p , correlates to a range difference o
milstar: As shown in Figure 17, the signal is then downconverted to 60 MHz, input to an automatic- gain control (AGC) network, and band limited to 5 MHz. The resulting 60-MHz signal is once again mixed, to yield a 5-MHz sig- nal at an IF of 5 MHz. This final signal can be succinctly described as (4) where fi/ is the 5-m~ fA is the frequency-encoded range IF, term, and -2.5 MHz < f,, c 2.5 MHz. The resulting signal is sam- pled by a IO-bit 20-MHz A/D converter over the 50-its pulse, resulting in 1000 samples which are input to the digital portion of the pulse-compression system.
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