Pulse or digital communications – Repeaters – Testing
Patent
1991-05-02
1994-03-08
Chin, Stephen
Pulse or digital communications
Repeaters
Testing
375103, 375101, H03H 730
Patent
active
052934020
ABSTRACT:
A digital decision feedback equalizer utilizes a finite impulse response (FIR) filter and an infinite impulse response (IIR) filter in parallel in the feedback path. The FIR filter compensates for the rapidly changing region of the channel impulse response immediately following the cursor while the IIR filter compensates for the gradually decaying tail of the impulse response of the channel. Modifications of a sequential identification algorithm are used to adapt the filter sections. In particular, in one modification, the inputs to both the poles and zeros sections of the IIR filter are prefiltered by an all-pole filter, where the poles of this filter are the current pole estimates. In another modification, the order of the zeros section of the IIR filter and the all-pole filter are reversed, and the zeros section is adapted using the least mean squares algorithm. A recursive least squares algorithm with exponential fading can be used to adapt the poles and/or zeros section of the IIR filter.
REFERENCES:
patent: 5020078 (1991-05-01), Crespo
patent: 5027369 (1991-06-01), Kuenast
patent: 5031194 (1991-07-01), Crespo et al.
patent: 5042026 (1991-08-01), Koike et al.
patent: 5097482 (1992-03-01), Serizawa et al.
patent: 5117291 (1992-05-01), Fadavi-Ardekani et al.
"Adaptive IIR Filtering," J. J. Shynk, IEEE ASSSP Magazine, vol. 6, No. 2, pp. 4-21, Apr. 1989.
"Adaptive IIR Filtering: Current Results and Open Issues," C. R. Johnson, IEEE Transactions on Information Theory, vol. IT-30, No. 2, pp. 237-250, Mar. 1984.
"Adaptive Noise Canceling: Principles and Applications," B. Widrow et al., IEEE Proceedings vol. 63, No. 12, pp. 1692-1716, Dec. 1975.
"A New Adaptive IIR Filter," H. Fan and W. K. Jenkins, IEEE Transactions on Circuits and Systems, vol. CAS-33, No. 10, pp. 939-947, Oct. 1986.
"A Technique for the Identification of Linear Systems," K. Steiglitz and L. McBride, IEEE Transactions on Automatic Control, vol. AC-10, pp. 461-464, Oct. 1965.
"Convergence Models for Adaptive Gradient and Least Mean Squares Algorithms," M. L. Honig, IEEE Transactions on ASSP, vol. 31, No. 2, pp. 415-425, Apr. 1983.
"Lattice Filters for Adaptive Processing", by B. Friedlander, Proceeding of the IEEE, vol. 70, No. 8, pp. 829-868, Aug. 1982.
Crespo Pedro M.
Honig Michal L.
Bell Communications Research Inc.
Chin Stephen
Falk James W.
Suchyta Leonard Charles
Tse Young
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