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CONF ON advanced signal-processing algorithms, architectures, AND implementations

作者： FLANDRIN, P LTS-ICPI (France)

ISBN: (纸本)0819404098

In a very recent past, new techniques, referred to as time-scale methods and making use of the so-called wavelet transform, have been proposed for the analysis of nonstationary or time-varying signals. They are basically devoted to the description of signal time evolutions at different observation scales; this is achieved by using shifted and dilated versions of some elementary analyzing waveform along the time axis. The purpose of this paper is twofold: it is intended (1) to provide a brief overview of linear wavelet techniques (continuous and discrete transforms) and bilinear time-scale methods (time-scale energy distributions), and (2) to put them in some common perspective with existing signal processing tools (Gabor decompositions, constant-Q analysis, quadrature mirror filters, wideband ambiguity functions, time-frequency energy distributions). Existing or potentially relevant applications are also pointed out.

关键词： Transform theory Wavelets Electronic filtering Filtering (signal processing) Linear filtering Mirrors signal processing Time-frequency analysis Wavelet transforms

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Computationally efficient systolic architecture for computing the discrete Fourier transform

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IEEE TRANSACTIONS ON signal processing 2005年第12期53卷 4640-4651页

作者： Nash, JG Centar Los Angeles CA 90077 USA

A new high-performance systolic architecture for calculating the discrete Fourier transform (DFT) is described which is based on two levels of transform factorization. One level uses an index remapping that converts the direct transform into structured sets of arithmetically simple four-point transforms. Another level adds a row/column decomposition of the DFT. The architecture supports transform lengths that are not powers of two or based on products of coprime numbers. Compared to previous systolic implementations, the architecture is computationally more efficient and uses less hardware. It provides low latency as well as high throughput, and can do both one- and two-dimensional DFTs. An automated computer-aided design tool was used to find latency and throughput optimal designs that matched the target field programmable gate array structure and functionality.

关键词： computation fast algorithms parallel processing architectures systolic and wavefront architectures transforms

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Adaptive radar CFAR using signal based suppression

Adaptive radar CFAR using signal based suppression

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Conference on advanced signal processing - algorithms, architectures, and implementations VII

作者： Brovko, TTN Whang, YE Hughes Aircraft Co. (United States)

ISBN: (纸本)0819425842

The primary basis for adaptive radar algorithm design is that (1) a Binary Hypothesis formulation with unknown parameters is an adequate test and (2) that radar interference is composed of combinations of thermal noise, self induced clutter, and extraneous noise. This is the typical generalized likelihood formulation that yield the CFAR characteristic for the assumed conditions. implementations have shown that such formulations yield inadequate performance in complex clutter environments. As compensation measure, a secondary CFAR process then addresses the potential violation of this assumption by large ''target-like'' interference such as large Clutter discretes or a large number of targets interfering with each other. In order to detect small targets, an approach based on the Likelihood Statistic provides a technique for optimally suppressing the neighboring large signals. Performance is characterized as a function of a generalized distance and relative signal power ratios in the Joint Space-Time domain.

关键词： Target detection signal detection Doppler effect Distortion Radar Modulation Electronic filtering signal processing Interference (communication) signal to noise ratio

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Some effects of mutual coupling and noise on channel capacity between antenna arrays

Some effects of mutual coupling and noise on channel capacit...

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advanced signal processing algorithms, architectures, and implementations XV

作者： Gans, M.J. Air Force Research Laboratories IFGC 525 Brooks Road Rome NY 13441 United States

No abstract available

关键词： Antennas Amplifiers Interference (communication) Scattering Transmitters Polarization Receivers Wave propagation Radio propagation signal to noise ratio

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Local signal to noise ratio

Local signal to noise ratio

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Conference on advanced signal processing algorithms, architectures, and implementations XVI

作者： Galleani, Lorenzo Cohen, Leon Nelson, Douglas CUNY 695 Pk Ave New York NY 10021 USA US Dept Def Ft George G Meade MD 20755 USA Politecn Torino Dipartimento Elettron I-10129 Turin Italy

ISBN: (纸本)0819463922

We argue that the standard definition of signal to noise ratio may be misleading when the signal or noise are nonstationary. We introduce a new measure that we call local signal to noise ratio (LSNR) which is well suited to take into account nonstationary situations. The advantage of our measure is that it is a local property unlike the standard SNR which is a single number representing the total duration of the signal. We simulated a number of cases to show that our measure is more indicative of the noise and signal level for nonstationary situations.

关键词： signal to Noise Ratio time-frequency white noise

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Wigner equations of motion for classical systems

Wigner equations of motion for classical systems

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Conference on advanced signal processing algorithms, architectures, and implementations X

作者： Galeani, L Cohen, L CUNY New York NY 10021 USA

ISBN: (纸本)0819437611

We present a general procedure for obtaining equations of motion for the Wigner distribution of functions that are governed by ordinary and partial differential equations. For the case of fields we show that in general one must consider Wigner distributions of the four variables, position, momentum, time and frequency. We also show that in general one cannot write an equation of motion for position and momentum however it can be done in some cases, the Schrodinger equation being one such case. Our method leads to an equation of motion for the Schrodinger equation with time dependent potentials in contrast to the result obtained by Wigner and Moyal which was for time independent potentials.

关键词： Ordinary differential equations Partial differential equations Fourier transforms Oscillators Differential equations Acoustics Electromagnetism signal processing Switches

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Information theoretic signal detection on the time-frequency plane

Information theoretic signal detection on the time-frequency...

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Conference on advanced signal processing algorithms architectures and implementations XIII

作者： Aviyente, S Michigan State Univ E Lansing MI 48824 USA

ISBN: (纸本)0819450782

A comprehensive theory for time-frequency based signal detection has been developed during the past decade. The time-frequency detectors proposed in literature are linear structures operating on the time-frequency representation of the signals and are equivalent to quadratic receivers that are defined in the,time domain. In this paper, an information theoretic approach for signal detection on the time-frequency plane is introduced. In recent years, Renyi entropy has been proposed as an effective measure for quantifying signal complexity on the time-frequency plane and some important properties of this measure have been proven. In this paper, a new approach that uses the entropy functional as the test statistic for signal detection is developed. The minimum error detection algorithm is derived and the performance of this new signal detection method is demonstrated through examples.

关键词： signal detection Time-frequency analysis Detection and tracking algorithms Interference (communication) Sensors Radar Algorithm development Backscatter signal to noise ratio Receivers

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Denoising using time-frequency and image processing methods

Denoising using time-frequency and image processing methods

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Conference on advanced signal processing algorithms, architectures, and implementations IX

作者： Nelson, D Cristóbal, G Kober, V Cakrak, F Loughlin, P Cohen, L US Dept Def Ft Meade MD 20755 USA

ISBN: (纸本)0819432938

We present a number of methods that use image and signed processing techniques for removal of noise from a signal. The basic idea is to first construct a time-frequency density of the noisy signal. The time-frequency density, which is a function of two variables, can then be treated as an "image", thereby enabling use of image processing methods to remove noise and enhance the image. Having obtained an enhanced time-frequency density, one then reconstructs the signal. Various time frequency-densities are used and also a number of image processing methods are investigated. Examples of human speech and whale sounds are given. In addition, new methods are presented for estimation of signal parameters from the time-frequency density.

关键词： Electronic filtering Interference (communication) Fourier transforms Time-frequency analysis Frequency modulation Fermium Transform theory signal processing Optical filters Filtering (signal processing)

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Arrays of randomly spaced sensors 6

Arrays of randomly spaced sensors

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Conference on advanced signal processing algorithms, architectures, and implementations VI

作者： Lorenzelli, F Yao, K UNIV CALIF LOS ANGELES DEPT ELECT ENGNLOS ANGELESCA 90095

ISBN: (纸本)0819422347

This paper considers a class of blind beamforming problems in which the amount of prior information is very limited. The array sensors are placed in unknown locations within a geographical region, and have unknown frequency/spatial response. The sensors communicate synchronously with a main processor unit. The array is illuminated by a source, which may be narrow- or broadband, in near or far field. Additional disturbances may be present, in the form of interferers, possibly correlated or coherent with the main signal, and additive noise. The goal is required to steer beam toward the desired signal. Four schemes are presented, each based on the type of prior available information.

关键词： blind beamforming broadband array processing random array

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PIPELINED ADAPTIVE DFE architectures 4

PIPELINED ADAPTIVE DFE ARCHITECTURES

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4TH CONF ON advanced signal processing algorithms, architectures, AND implementations

作者： SHANBHAG, NR PARHI, KK Univ. of Minnesota/Twin Cities (United States)

ISBN: (纸本)0819412767

Fine-grain pipelined adaptive decision-feedback equalizer (ADFE) architectures are developed using the relaxed look-ahead technique. This technique, which is an approximation to the conventional look-ahead computation, maintains functionality of the algorithm rather than the input-output behavior. Thus, it results in substantial hardware savings as compared to either parallel processing or look-ahead techniques. The delay relaxation, delay transfer relaxation, and sum relaxation are introduced for purposes of pipelining. Both the conventional and the predictor form of ADFE have been pipelined. The performance of the pipelined algorithms for the equalization of a magnetic recording channel is studied. It is demonstrated via simulations that, for a byte error rate of 10^-7 or less, speed-ups of up to 8 can be easily achieved with the conventional ADFE. The predictor form of ADFE allows much higher speed-ups (up to 32) for less than 1 dB of SNR degradation.

关键词： signal to noise ratio Magnetism Algorithm development Error analysis Optical filters Digital filtering Finite impulse response filters Nonlinear filtering Parallel processing Transform theory

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