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:
Jul. 16, 1996
Filed:
Jun. 05, 1995
David M Blaker, Emmaus, PA (US);
Gregory S Ellard, Forest Park, GB;
Mohammad S Mobin, Whitehall, PA (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
A digital communication system including Viterbi decoder for tracing a path through a trellis of individual state information and method of operation are disclosed. The traceback determines a decoded symbol. The trellis of surviving branch data is stored in an array of registers. Operating the system includes initiating a first traceback from a storage register at a first symbol instant. The traceback traces a path back through the trellis a first predetermined number of symbol instants to determine a first decoded symbol. A second traceback is also initiated at the first symbol instant and traces a path back through the trellis a second predetermined number symbol instants to determine a second decoded symbol. The first traceback length may be greater than or less than the second traceback length. In another embodiment of the invention several tracebacks can be executed having a fixed traceback length, followed by other tracebacks having incrementally different traceback lengths. Such multiple tracebacks may be initiated in a single symbol instant. In yet another embodiment of the invention, selective ones of the decoded symbols are used by an equalizer to provide channel adaptation.