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Signal Processing Letters, IEEE

Issue 10 • Date Oct. 1994

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Displaying Results 1 - 5 of 5
  • Estimation of Markov-modulated time-series via EM algorithm

    Page(s): 153 - 155
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (298 KB)  

    We consider the estimation of various Markov-modulated time series. We obtain maximum likelihood estimates of the time-series parameters including the Markov chain transition probabilities and the time-series coefficients using the expectation maximization (EM) algorithm. In addition, the recursive EM algorithm is used to obtain on-line parameter estimates. Simulation studies show that both algorithms yield satisfactory results.<> View full abstract»

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  • Adaptive transmitting antenna arrays with feedback

    Page(s): 150 - 152
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (283 KB)  

    We address the problem of transmitting multiple cochannel signals from an antenna array to several receivers so that each receiver gets its intended signal with minimum crosstalk from the remaining signals. In addition to the usual "information" mode, we propose a "probing" mode during which probing signals received at the mobiles are fed back to the transmitter. These probing signals are used to identify an unknown propagation environment, enabling the transmitter to form the necessary transmission beampatterns.<> View full abstract»

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  • A new use of ESPRIT for detection and model order estimation

    Page(s): 147 - 149
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (234 KB)  

    This work studies the distribution of the ESPRIT roots in the complex z plane. Real source roots are tightly clustered about their true values, while pseudoroots corresponding to overestimated nonexisting sources are distributed broadly with a phase angle bias away from the real source roots. The ESPRIT roots distributions can be coupled with Neyman-Pearson tests for detection/system model order estimation. A mathematical derivation of the asymptotic distribution of the pseudoroots is given.<> View full abstract»

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  • A new initialization technique for generalized Lloyd iteration

    Page(s): 144 - 146
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (262 KB)  

    The generalized Lloyd algorithm plays an important role in the design of vector quantizers (VQ) and in feature clustering for pattern recognition. In the VQ context, this algorithm provides a procedure to iteratively improve a codebook and results in a local minimum that minimizes the average distortion function. We propose an efficient method to obtain a good initial codebook that can accelerate the convergence of the generalized Lloyd algorithm and achieve a better local minimum as well.<> View full abstract»

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  • Polynomial root finding

    Page(s): 141 - 143
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    Finding polynomial roots rapidly and accurately is an important problem in many areas of signal processing. We present a program that is superior in speed and accuracy to the best methods to our knowledge, i.e., Jenkins/Traub (1975) program and the eigenvalue method. Based on this, we give a simple approach to improve the accuracy for spectral factorization in the case that there are double roots on the unit circle.<> 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.

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Meet Our Editors

Editor-in-Chief
Peter Willett
University of Connecticut
Storrs, CT 06269
peter.willett@uconn.edu