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IEEE Signal Processing Letters

Issue 4 • April 1999

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Displaying Results 1 - 7 of 7
  • Alternating projection for maximum-likelihood source localization using eigendecomposition

    Publication Year: 1999, Page(s):73 - 75
    Cited by:  Papers (2)  |  Patents (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    Alternating projection allows us to make a maximum-likelihood estimation of arrival angles by one-dimensional search. In this letter, we propose an eigendecomposition-based alternating projection method that can greatly reduce computational complexity with no performance degradation as compared with the direct alternating projection. In the proposed method, initial estimation can be readily perfor... View full abstract»

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  • Homogeneous time-invariant systems

    Publication Year: 1999, Page(s):76 - 77
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (64 KB)

    It is well known that linear time-invariant (LTI) systems produce exponential outputs in response to exponential inputs. The purpose of this paper is to draw attention to the fact that the same result holds for the broader class of homogeneous time-invariant (HTI) systems, though the concept of a frequency response is of little use for such systems. View full abstract»

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  • When is instantaneous frequency the average frequency at each time?

    Publication Year: 1999, Page(s):78 - 80
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (162 KB)

    The interpretation of instantaneous frequency has been a subject of interest for many years. One interpretation is that it is the average frequency at each time in the signal. We prove that instantaneous frequency equals the average frequency at each time only when there is symmetry in the instantaneous spectrum, as previous empirical evidence has suggested. Also, when there is such symmetry, the ... View full abstract»

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  • Instantaneous frequency of multicomponent signals

    Publication Year: 1999, Page(s):81 - 83
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (98 KB)

    The failure of the traditional definition of instantaneous frequency (IF/sub t/) in the multicomponent case has been often reported. We determine the reasons for the failure of this definition. This enables us to understand and integrate all previously reported cases in a simple unified theory. As a direct consequence, we are able to extrapolate and predict the behavior of the traditional definiti... View full abstract»

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  • A new algorithm for weighted order statistics operations

    Publication Year: 1999, Page(s):84 - 86
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (65 KB)

    A new algorithm suitable for the computation of weighted order statistics operations is presented. The algorithm is based on the local histogram and a successive approximation technique. The successive approximation technique ensures that the result of the weighted order statistics operation is computed in a fixed number of steps, equal to the pixel value resolution. Comparative experimental resul... View full abstract»

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  • Blind source separation of more sources than mixtures using overcomplete representations

    Publication Year: 1999, Page(s):87 - 90
    Cited by:  Papers (187)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (110 KB)

    Empirical results were obtained for the blind source separation of more sources than mixtures using a previously proposed framework for learning overcomplete representations. This technique assumes a linear mixing model with additive noise and involves two steps: (1) learning an overcomplete representation for the observed data and (2) inferring sources given a sparse prior on the coefficients. We... View full abstract»

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  • Multidimensional smoothing using orthogonal expansions

    Publication Year: 1999, Page(s):91 - 94
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (369 KB)

    Adaptive smoothing approaches are particularly useful because the amount of smoothing imposed on the data is determined automatically from the statistical characteristics of subsets of the data itself. Although efficient methods are available for performing adaptive smoothings on one-dimensional (1-D) data, extension of these 1-D adaptive smoothing methods to higher dimensions is often difficult b... View full abstract»

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Aims & Scope

The IEEE Signal Processing Letters is a monthly, archival publication designed to provide rapid dissemination of original, cutting-edge ideas and timely, significant contributions in signal, image, speech, language and audio processing.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
James E. Fowler
Dept Electrical & Computer Engineering
Associate Director                         
Distributed Analytics and Security Institute
Mississippi State University
Mississippi State, MS 39762 USA
fowler@ece.msstate.edu