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IEEE Transactions on Signal Processing

Issue 9 • Sept. 1991

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Displaying Results 1 - 25 of 35
  • Comments on "An FFT algorithm based fast algorithm for arbitrary polynomial transformation

    Publication Year: 1991, Page(s):2140 - 2141
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (171 KB)

    Comments are made on the work by H. Krishna (see ibid., vol.37, no.10, p.1612-14, 1989). Krishna presented an elegant fast algorithm for the arbitrary polynomial transformation based on the fast Fourier transform algorithm. It is pointed out that if he applies the discrete Fourier transform (DFT) and inverse (DFT) pair defined in one of his references (H.J. Nussbaumer, 1981), then the final result... View full abstract»

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  • Minimum variance beamforming with soft response constraints

    Publication Year: 1991, Page(s):1964 - 1972
    Cited by:  Papers (68)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (744 KB)

    Soft constraints on the beamformer response to the signal are examined in the context of minimum variance beamforming. A quadratic constraint on the beamformer weights is used to control the mean-squared error between a desired response and the actual response in the signal direction. The constraint is purposely chosen to permit distortion of the signal with the goal of achieving improved interfer... View full abstract»

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  • Optimal nonnegative definite approximations of estimated moving average covariance sequences

    Publication Year: 1991, Page(s):2007 - 2015
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    The problem of finding the closest nonnegative definite moving average covariance sequence to a given estimate which may not be nonnegative definite is considered. An algorithm is developed which is based on a set of constrained minimization problems, each parameterized by the zero frequencies of the spectral density function corresponding to the optimal solution. The algorithm entails first solvi... View full abstract»

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  • H fixed-lag smoothing filter for scalar systems

    Publication Year: 1991, Page(s):1955 - 1963
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    The solution of the H∞ optimal linear fixed-lag smoothing problem is considered using a polynomial matrix description for the discrete system. The smoother is obtained from the solution of a linear equation and a spectral factorization calculation. The pole-zero properties of the optimal smoother are obvious in the polynomial representation, and insights into the measurem... View full abstract»

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  • Bearing estimation in the bispectrum domain

    Publication Year: 1991, Page(s):1994 - 2006
    Cited by:  Papers (35)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (912 KB)

    A new array processing method is presented for bearing estimation based on the cross bispectrum of the array output data. The method is based on the asymptotic distribution of cross-bispectrum estimates and uses maximum likelihood theory. It is demonstrated that, when the noise additive sources are spatially correlated Gaussian with unknown cross-spectral matrix (CSM), the cross-bispectrum method ... View full abstract»

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  • Speech enhancement based conceptually on auditory evidence

    Publication Year: 1991, Page(s):1943 - 1954
    Cited by:  Papers (53)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1312 KB)

    A new idea, enhancing speech based on auditory evidence, is explored for the problem of enhancing speech degraded by stationary and nonstationary additive white noise. Distinguishing different objectives for heavy and light noise interference, two related algorithms are developed. For speech degraded by heavy noise, the improvement in signal-to-noise ratio (SNR) is as high as 12 dB; for lightly no... View full abstract»

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  • Fast cross-correlation algorithm with application to spectral analysis

    Publication Year: 1991, Page(s):2089 - 2092
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    A method for transfer function calculation is described that derives its economy from the symmetry of the autocorrelation to double the number of lags. The imbalance in the number of lags between autocorrelations and cross-correlations is restored by calculating the negative lags of the cross-correlation without any extra computations. With both positive and negative lags available, the symmetry a... View full abstract»

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  • Multichannel filtering for wide-band direction finding

    Publication Year: 1991, Page(s):2128 - 2132
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (432 KB)

    A preprocessing stage for wide-band direction finding is formulated in the framework of multichannel filtering wherein the filter frequency response matrices are chosen to achieve signal-subspace focusing. Direction finding based on any narrow-band algorithm is then performed on the filter output. A procedure for specifying a sparse response suitable in nonstationary environments is presented. An ... View full abstract»

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  • An FPT algorithm with a modularized structure for computing two-dimensional discrete Fourier transforms

    Publication Year: 1991, Page(s):2148 - 2149
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (156 KB)

    The fast polynomial transform (FPT) for computing two-dimensional discrete Fourier transforms is modularized into identical modules. In this new method, only FPTs and fast Fourier transforms of the same length are required. As a consequence, the architecture is more regular and naturally suitable for multiprocessor and VLSI implementations. The modularized FPT algorithms can simplify the problems ... View full abstract»

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  • An exact forward-backward maximum likelihood autoregressive parameter estimation method

    Publication Year: 1991, Page(s):1985 - 1993
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (716 KB)

    A method for obtaining an exact maximum likelihood estimate (MLE) of the autoregressive (AR) parameters is proposed. The method is called the forward-backward maximum likelihood algorithm. Based on a new form of the log likelihood function for a Gaussian AR process, an iterative maximization is used to obtain an MLE of the inverse covariance matrix. The AR parameters are then determined via the no... View full abstract»

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  • Analysis of multichannel narrow-band filters for image texture segmentation

    Publication Year: 1991, Page(s):2025 - 2043
    Cited by:  Papers (115)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2408 KB)

    A model for texture analysis and segmentation using multiple oriented channel filters is analyzed in the general framework. Several different arguments are applied leading to the conclusion that the two-dimensional Gabor filters possess strong optimality properties for this task. Properties of the multiple-channel segmentation approach are analyzed. In particular, perturbations of textures from an... View full abstract»

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  • Direction finding in the presence of colored noise by candidate identification

    Publication Year: 1991, Page(s):1933 - 1942
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (768 KB)

    A method is developed for identifying correct angles of arrivals from a set of candidate angles that contains spurious angles and the true ones, under the assumption that the colored noise is an autoregressive process and that a uniform linear array of sensors is used. The procedure is based on a relation derived for the higher-order reflection coefficients corresponding to the autocorrelation seq... View full abstract»

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  • A content-addressable memory architecture for image coding using vector quantization

    Publication Year: 1991, Page(s):2066 - 2078
    Cited by:  Papers (32)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1072 KB)

    An architecture suitable for real-time image coding using adaptive vector quantization (VQ) is presented. This architecture is based on the concept of content-addressable memory (CAM), where the data is accessed simultaneously and in parallel on the basis of its content. VQ essentially involves, for each input vector, a search operation to obtain the best match codeword. A speedup results if a CAM... View full abstract»

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  • On the efficiency of parallel pipelined architectures

    Publication Year: 1991, Page(s):2086 - 2089
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    A new approach is presented to the synthesis of efficient dedicated parallel pipelined architectures. The results can be used to determine the execution rates and the number of operators during the design of efficient parallel pipelined processors to be used, especially in digital signal processing and image processing. The conditions for maximum efficiency considering operators with different exe... View full abstract»

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  • An improved lattice-based adaptive IIR notch filter

    Publication Year: 1991, Page(s):2124 - 2128
    Cited by:  Papers (178)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (428 KB)

    A novel lattice-based adaptive infinite impulse response (IIR) notch filter is developed which features independent tuning of the notch frequency and attenuation bandwidth. The internal structure is based on planar rotators, ensuring reliable numerical behaviour and high processing rates in CORDIC environments. A simple update law allows a simpler implementation than previously proposed designs. R... View full abstract»

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  • A Hermitian Toeplitz matrix is unitarily similar to a real Toeplitz-plus-Hankel matrix

    Publication Year: 1991, Page(s):2146 - 2148
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    Two unitary matrices are presented that transform a Hermitian Toeplitz matrix into a real Toeplitz-plus-Hankel matrix and vice versa. Additional properties and consequences of these unitary transformations are also presented. For a certain class of n-dimensional Toeplitz-plus-Hankel systems of equations, an efficient method of solution is presented. An example is given to illustrate the s... View full abstract»

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  • A unified approach to IFIR filter design using B-spline functions

    Publication Year: 1991, Page(s):2115 - 2118
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    An efficient procedure is presented for the design of interpolated finite impulse response (IFIR) filters with linear phase. The algorithm uses the uniform B-spline function as an interpolator and solves the optimal Chebyshev approximation problem on the appropriate subinterval. The technique can be used for the design of general low-pass, high-pass and bandpass filters. Although the number of mul... View full abstract»

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  • The theory of bandpass sampling

    Publication Year: 1991, Page(s):1973 - 1984
    Cited by:  Papers (422)  |  Patents (44)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (968 KB)

    The sampling of bandpass signals is discussed with respect to band position, noise considerations, and parameter sensitivity. For first-order sampling, the acceptable and unacceptable sample rates are presented, with specific discussion of the practical rates which are nonminimum. It is shown that the minimum sampling rate is pathological in that any imperfection in the implementation will cause a... View full abstract»

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  • Direction finding algorithms based on high-order statistics

    Publication Year: 1991, Page(s):2016 - 2024
    Cited by:  Papers (177)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (692 KB)

    Two direction finding algorithms are presented for nonGaussian signals, which are based on the fourth-order cumulants of the data received by the array. The first algorithm is similar to MUSIC, while the second is asymptotically minimum variance in a certain sense. The first algorithm requires singular value decomposition of the cumulant matrix, while the second is based on nonlinear minimization ... View full abstract»

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  • Bandpass nonlinear systems identification by higher order cross correlation

    Publication Year: 1991, Page(s):2092 - 2095
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    Nonlinear systems constituted by a zero-memory nonlinearity cascaded with linear filters can be identified by input-output cross correlation using a Gaussian input signal. The method is extended to complex systems through a pair of complex invariance theorems. The stated properties allow identifying the linear parts of systems characterized by magnitude/phase nonlinearities with the joint use of s... View full abstract»

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  • Image restoration with multiplicative noise: incorporating the sensor nonlinearity

    Publication Year: 1991, Page(s):2132 - 2136
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (872 KB)

    A linear minimum mean-square-error deconvolution filter in the presence of multiplicative noise is derived. The importance of incorporating the nonlinear sensor characteristics into the restoration of noisy and blurred scanned photographic images is discussed. It is proposed to restore images in the `exposure domain' where a linear convolutional relationship between the original and the observed i... View full abstract»

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  • Bistatic synthetic aperture radar inversion with application in dynamic object imaging

    Publication Year: 1991, Page(s):2044 - 2055
    Cited by:  Papers (117)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    An inversion method is presented for bistatic synthetic aperture radar imaging. The method is based on a Fourier analysis (Doppler processing) of the bistatic synthesized array's data followed by a phase modulation analysis of the Doppler data. The approach incorporates the phase information of the wavefront curvature in the transmitted waves as well as the resultant echoed signals. The Doppler da... View full abstract»

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  • Analysis of a stabilization technique for the fixed-point prewindowed RLS algorithm

    Publication Year: 1991, Page(s):2079 - 2082
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    A stable finite precision recursive least squares (RLS) algorithm is derived for the prewindowed growing memory case (forgetting factor, λ=1). The prewindowed growing memory RLS algorithm diverges under fixed-point implementation. The random walk phenomenon due to roundoff errors in the weight update causes the divergence of the algorithm. To overcome this effect, these roundoff errors are ... View full abstract»

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  • A fast parallel form IIR adaptive filter algorithm

    Publication Year: 1991, Page(s):2118 - 2122
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (340 KB)

    In real-time digital signal processing, a significant amount of computational effort can be saved if the input signals are represented in terms of a set of orthogonal signal components. This is because the representation admits processing schemes in which each of these orthogonal signal components can be independently processed. On this basis, a new infinite impulse response (IIR) adaptive filter ... View full abstract»

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  • Roundoff error analysis of the discrete Wigner distribution using fixed-point arithmetic

    Publication Year: 1991, Page(s):2096 - 2098
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    The issue of roundoff noise effects in the implementation of the discrete Wigner distribution using fixed-point arithmetic is addressed. The sign-magnitude number representation is assumed throughout the analysis. The measure of roundoff noise effects in an algorithm is the output noise-to-signal ratio. Using a statistical model, an analytical expression of the noise-to-signal ratio is derived as ... View full abstract»

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Aims & Scope

IEEE Transactions on Signal Processing covers novel theory, algorithms, performance analyses and applications of techniques for the processing, understanding, learning, retrieval, mining, and extraction of information from signals

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Meet Our Editors

Editor-in-Chief
Sergios Theodoridis
University of Athens