This paper evaluates various sidelobe suppression techniques for weather radar by generating specific test profiles using the simulation. The parameters of the model and simulation are shown. The results of the simula...
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This paper evaluates various sidelobe suppression techniques for weather radar by generating specific test profiles using the simulation. The parameters of the model and simulation are shown. The results of the simulations and evaluation are presented and discussed in details.
pulse compression is one technique of obtaining the short dwell times necessary to make high space and time resolution weather radar measurements. Range time sidelobes affect weather parameter measurements in exactly ...
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pulse compression is one technique of obtaining the short dwell times necessary to make high space and time resolution weather radar measurements. Range time sidelobes affect weather parameter measurements in exactly the same way as antenna sidelobes and we desire to minimize both. This paper collected and analyzed pulse compression weather radar data showing that moving weather targets produce the sidelobe leakage expected from the ambiguity diagrams.
In this paper, a new block coded modulation (BCM) scheme for a communication system which uses the optimum vector quantizer (VQ) as a source coder is proposed. The proposed BCM scheme minimizes the mean square distort...
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In this paper, a new block coded modulation (BCM) scheme for a communication system which uses the optimum vector quantizer (VQ) as a source coder is proposed. The proposed BCM scheme minimizes the mean square distortion of the received signal after VQ decoding. First, this paper derives the upper-bound on the mean square distortion of the signal in additive white Gaussian noise (AWGN) and Rayleigh fading channels. Next, this paper proposes a new BCM scheme which is optimized to minimize the upper-bound by the simulated annealing known as the non-linear global optimization algorithm. This paper provides the optimum BCM and shows the mean square distortion performances in the AWGN and Rayleigh fading channels. Computer simulation results show that using the proposed BCM improves the signal-to-noise ratio (S/N) performances of the output signal of the source decoder. Furthermore, the proposed BCM scheme can provide a stepwise graceful degradation in the output S/N performance against the channel S/N.
In contrast to a known feedback structure, an equivalent generalised feedforward technique for PCM-to-Noise-Shaped PCM conversion has been developed. The point of departure is a novel PCM decomposition method. The met...
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In contrast to a known feedback structure, an equivalent generalised feedforward technique for PCM-to-Noise-Shaped PCM conversion has been developed. The point of departure is a novel PCM decomposition method. The method exploits the barely known fundamental FM background of Delta-Sigma modulation (DSM) without the application of any additional oversampling. Similar to the way in which a time-continuous signal can be (partly) decomposed in arbitrary k regularly over 360 degrees phase-shifted pulse-frequency modulation (PFM) signals containing Ts duration pulses, an amplitude- and time-quantized K-bit PCM signal (sample frequency fs = 1/THz) can also be decomposed in (however) exactly k = 2K equal or near equal multiple-T shifted DSM codes. The DSM codes can be perceived as time-slotted PFM signals. The addition of these 2K decomposed codes results in the original K-bit PCM signal. If less than 2K codes are added together, then NS-PCM is always created. Adding only 2L codes (L L + 1)-level NS-PCM) includes a known feedforward conversion method. With respect to the latter, an illustrative decomposition application to enhance a video bitrate reduction system is shown, ending in exact L-bit feedforward NS-PCM for a bit-efficient conversion.
The purpose of the paper is to illustrate the means by which pulse compression can be achieved using phase coded waveforms and to indicate the effectiveness of the technique using data gathered during the trials. Prin...
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The purpose of the paper is to illustrate the means by which pulse compression can be achieved using phase coded waveforms and to indicate the effectiveness of the technique using data gathered during the trials. Principles of the detection of objects by radar are discussed.< >
We study the performance of DPCM operating over lossy channels in cell-based networks such as ATM, when statistical multiplexing is used. Since the loss of data is mainly due to traffic congestion, and the minimum uni...
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We study the performance of DPCM operating over lossy channels in cell-based networks such as ATM, when statistical multiplexing is used. Since the loss of data is mainly due to traffic congestion, and the minimum unit of loss is a cell which may contain multiple DPCM codewords, the loss process can be highly correlated. The contribution of this work comes in two parts. We first give a formulation which relates the performance of DPCM, in terms of signal-to-reconstruction-noise ratio, to the channel loss conditions. In particular we take into account any correlation that exists in the loss process. We then study in detail mechanisms which give rise to such correlation. Using simple source and multiplexing models, formulae are given which characterise the loss process as a result of statistical multiplexing. As a direct result of this treatment, we know that the maximum achievable performance of DPCM with reoptimised predictors further deteriorates when the loss process is correlated.
A 5-V CMOS programmable acoustic front-end IC for ISDN terminal and digital telephone set applications is presented. The chip performs PCM codec and filter functions, fulfilling all D3/D4 and CCITT specs. Moreover, it...
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A 5-V CMOS programmable acoustic front-end IC for ISDN terminal and digital telephone set applications is presented. The chip performs PCM codec and filter functions, fulfilling all D3/D4 and CCITT specs. Moreover, it implements the main analog interfaces required for the speech channel (low-noise microphone preamplifier, earpiece and loudspeaker drivers, sidetone, antilarsen control) and tone/ring/DTMF generation without external components. The device can be controlled by a microprocessor or a HDLC controller via a four wire separated control interface or by means of a serial control channel multiplexed with the PCM voice/data channel in a GCI compatible format. Chip area is 30 mm2 in a 1.5-mu CMOS technology. The active/stand-by power consumption is 60 mW/0.2 mW from a single 5-V supply. All circuits are designed to meet performance objectives over a voltage range from 4.5 V to 5.5 V and a temperature range from -40-degrees-C up to 85-degrees-C.
The problem of optimum energy allocation for a seven-digit PCM system and DPSK signaling is solved for two different cases: (1) For white noise, Rayleigh fading channel, and occurrence of only errors in a character an...
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The problem of optimum energy allocation for a seven-digit PCM system and DPSK signaling is solved for two different cases: (1) For white noise, Rayleigh fading channel, and occurrence of only errors in a character and (2) for white noise and nonfading Gaussian channel for the case of the occurrence of doublet errors in a character.
An explicit formula is developed for the pulse which, when convolved with itself, yields the well-known quasi-bandlimited Nyquist pulse for data transmission. As expected, the newly derived pulse produces zero intersy...
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An explicit formula is developed for the pulse which, when convolved with itself, yields the well-known quasi-bandlimited Nyquist pulse for data transmission. As expected, the newly derived pulse produces zero intersymbol interference at the output of a filter matched to itself. Comparisons are offered with the well-known class of root raised cosine pulses.
In obtaining data using a pulse code modulation (PCM) data acquisition system (DAS), there has always been difficulty viewing data real time during flight. The inability or level of difficulty to confirm that required...
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