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. 29, 1977
Filed:
Nov. 24, 1975
Robert Curtis Davis, Melbourne Beach, FL (US);
Harris Corporation, Cleveland, OH (US);
Abstract
In a convolutional code decoder, a current received input corresponds to a last data state of a received sequence. Path metrics, respective correlations of the received sequence to each of a limited number of possible sequences, are determined to choose the 'correct' possible sequence. Decoding then proceeds by known means. The current input addresses 'look-up' memories, each associated with a possible input data state and providing a 'branch metric address' output. 'Update' memories, each associated with one of the data states, are each addressed by path metrics of prior sequences which can enter its associated state and by one 'branch metric address.' In functional effect, each 'update' memory adds a separate branch metric to update each prior path metric leading into each state. Path metrics for the limited number of possible sequences are thus provided. An indication of which updated path metric is larger for each state and its value are output from each 'update' memory. The largest of the updated path metrics provided by the memories identifies the 'correct' possible sequence.