The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 08, 1994
Filed:
May. 02, 1991
Pedro M Crespo, Bedminster, NJ (US);
Michal L Honig, Montclair, NJ (US);
Bell Communications Research, Inc., Livingston, NJ (US);
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.