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IEEE Transactions on Acoustics, Speech, and Signal Processing

Issue 5 • Date May 1987

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Displaying Results 1 - 21 of 21
  • [Front cover and table of contents]

    Publication Year: 1987, Page(s): 0
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    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1987, Page(s): c4
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    Freely Available from IEEE
  • Spatial smoothing and a class of stochastic filters

    Publication Year: 1987, Page(s): 710
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    This correspondence presents a class of stochastic filters that realize spatial smoothing, a concept recently proposed to counter the effects of rank degeneracy in multiple source location and adaptive signal processing. It is shown that these filters are economic computationally, and thus preferable to direct computation of covariance matrices for achieving spatial smoothing. View full abstract»

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  • On a spatial smoothing technique for multiple source location

    Publication Year: 1987, Page(s): 709
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    This correspondence presents an alternate proof for the spatial smoothing technique recently proposed for multiple source location. Specifically, it is proved that the number of subarrays required to ensure a nonsingular covariance matrix is m + 1 where m is the nullity of the source covariance matrix. Also, it is shown that this number can be reduced if a specific basis can be found for the null ... View full abstract»

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  • A frequency-domain implementation of the block P-vector adaptive algorithm

    Publication Year: 1987, Page(s):705 - 707
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    The P-vector approximate gradient algorithm is used in place of LMS when the desired signal is not available to the processor. This correspondence presents a frequency-domain implementation for use with single-input adaptive filters in which the coefficients are updated every L samples using the average gradient observed during the block. The development follows closely that presented previously f... View full abstract»

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  • An edge gradient enhancing adaptive order statistic filter

    Publication Year: 1987, Page(s):680 - 695
    Cited by:  Papers (46)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2600 KB)

    We consider an adaptive order statistic (OS) filter that can enhance gradients of edges while suppressing impulsive and some nonimpulsive noise components. In particular, comparison and selection (CS) filters are introduced, in which the output is determined by comparing the sample mean and median values inside each window. It is shown theoretically that CS filters can enhance gradients of a varie... View full abstract»

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  • Author's reply

    Publication Year: 1987, Page(s):703 - 705
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    The arguments in the note by Janssen fail to make the distinction between a class of time-frequency distributions with particular parameterizations of them. The approach used is to satisfy two conditions by making independent "good choices." We point out that all constraints must be satisfied jointly, not separately, and demonstrate how an infinite number of good choices can readily be made. In ad... View full abstract»

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  • Transform lengths for correlation and convolution

    Publication Year: 1987, Page(s):698 - 699
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    We show that digital cross correlation is performed most efficiently when the correlation transform length is chosen optimally as a precise function of the duration of the system impulse response. The optimization method is illustrated with a digital radar pulse compression example. View full abstract»

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  • Perceived degradation effects in packet speech systems

    Publication Year: 1987, Page(s):699 - 701
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    A packet speech system's sound quality is degraded when packets do not arrive at their destination in a timely fashion. This can happen when packets are lost in a network or when network delay is excessive. Simulation results are reported which measure the effects of such losses and delays on sound quality and intelligibility. Thirty human subjects were asked to listen to the output of a simulated... View full abstract»

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  • Estimation of the speed of moving source from time delay estimate

    Publication Year: 1987, Page(s):696 - 697
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    This work studies the situation in which a signal emitted by a moving source was received by an array of sensors. The particular cases of interest are those in which the time delay between sensors can be approximated by a linear function. The procedure for estimating linear time delay functions is discussed. Based on the time delay estimate, a procedure for estimating the speed of the moving sourc... View full abstract»

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  • Effects of estimated noise covariance matrix in optimal signal detection

    Publication Year: 1987, Page(s):671 - 679
    Cited by:  Papers (39)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (792 KB)

    There is loss of efficiency when an estimated noise covariance matrix is used in the place of the unknown true noise covariance matrix in the construction of the optimum filter for signal detection. In the case of detecting a single signal specified by a real or a complex vector, we investigate the extent of this loss by obtaining an exact confidence bound for the realized signal-to-noise ratio. W... View full abstract»

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  • Detection of narrow-band sonar signals using order statistical filters

    Publication Year: 1987, Page(s):597 - 613
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1608 KB)

    In detecting a narrow-band signal in noise in a sonar environment, an estimation of the background noise power has to be made so that a detection threshold can be set. Here, we consider a variety of nonlinear estimators based on order statistics. The performances of these methods in providing an estimate of the noise power and in detecting a narrow-band signal in noise have been analyzed and have ... View full abstract»

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  • A note on "Positive time-frequency distributions"

    Publication Year: 1987, Page(s):701 - 703
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    We discuss the performance of certain recently proposed positive time-frequency distribution functions with correct marginals. It turns out that for signals of the FM type, satisfactory results can only be obtained with a strongly signal dependent choice of the parameters in these distribution functions. View full abstract»

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  • Sufficient condition of extendibility for two-dimensional quadrant-symmetric autocorrelations

    Publication Year: 1987, Page(s):707 - 708
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    A sufficient condition for extendibility of two-dimensional (2-D) quadrant-symmetric measured correlations is derived via matrix decomposition. It is very simple to test whether such measured correlations satisfy this sufficiency condition because the test boils down to a positive definiteness checking of a set of Toeplitz form matrices. However, there are cases that the condition does not give an... View full abstract»

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  • On "Soft" bit allocation

    Publication Year: 1987, Page(s):614 - 617
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    If a random variable X with variance σ2is quantized optimally, being mapped into s discrete levels, the quantization error is roughly proportional to σ2/s2. In many applications in speech coding and image digitization, we are given sets of random variables and we have to quantize them in some way so as to represent their realizations with as few discretiz... View full abstract»

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  • On the splitting of classical algorithms in linear prediction theory

    Publication Year: 1987, Page(s):645 - 653
    Cited by:  Papers (74)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    The Levinson algorithm has been shown recently to be redundant in complexity. It can be broken down into two simpler algorithms; either of these "split Levinson algorithms" needs only to be processed. In the present paper it is shown that the Schur algorithm, the lattice algorithm, and the normalized lattice algorithm for computing reflection coefficients can be broken down in a similar manner. Th... View full abstract»

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  • An experimental investigation of the perceptual effects of altering the zero-crossings of a speech signal

    Publication Year: 1987, Page(s):618 - 625
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1056 KB)

    This paper presents the results of an experimental investigation of the effects of altering the zero-crossings of a speech signal. In the experiments reported, the intelligibility degradation of clipped filtered speech subjected to averaging and reordering of the zero-crossing interval sequence is presented. The results from these experiments provide an interesting perspective on the relative impo... View full abstract»

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  • Fast adaptive least squares algorithms for power spectral estimation

    Publication Year: 1987, Page(s):661 - 670
    Cited by:  Papers (22)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (792 KB)

    Power spectrum estimation is of great importance in various applications of signal processing, such as geophysics and communications. In this paper two new fast algorithms are presented that adaptively compute a least squares estimate of the power spectrum of a time series. This is achieved by modeling the input as an AR signal of order m and simultaneous minimization of the sum of the forward and... View full abstract»

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  • An efficient technique for high correlation estimation

    Publication Year: 1987, Page(s):654 - 660
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    Two sum-based estimators are proposed as fast, accurate methods for estimating the normalized acf of stationary processes. For Gaussian processes, their performances are evaluated in terms of bias and covariance, and are compared to the ones of the conventional Direct estimator and of the Hybrid-Sign and the Polarity Coincidence fast methods. For high correlation values, the proposed estimators ex... View full abstract»

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  • Analytical finite precision results for Burg's algorithm and the autocorrelation method for linear prediction

    Publication Year: 1987, Page(s):626 - 635
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (912 KB)

    This paper derives new analytical results for quantifying the performance degradation induced by finite precision arithmetic upon the autocorrelation method and Burg's algorithm for linear prediction. The main results are analytical derivations of the resulting error in the reflection coefficient computation due to finite precision (FP) arithmetic implementation. From analysis of the second-order ... View full abstract»

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  • Behavior of the ε-normalized LMS algorithm with Gaussian inputs

    Publication Year: 1987, Page(s):636 - 644
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (640 KB)

    The first and second moment behavior of one variation of the normalized LMS (ε-NLMS) algorithm is investigated for a white covariance matrix and Gaussian statistics for the data. For this model, it is shown that the ε-NLMS algorithm has neither behavior independent of the input data power nor a performance significantly better than the LMS algorithm for which the input power level also m... View full abstract»

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Aims & Scope

This Transactions ceased production in 1990. The current retitled publication is IEEE Transactions on Signal Processing.

Full Aims & Scope