Patent Document ID: 4648091
Application ID: 06627368

Base Claim:
1. A tracking decoder for decoding a received message word into data word which has been encoded to form a first linear cyclic block code word including said data word and a parity word, comprising: control means; memory means coupled to said control means for storing a plurality of predetermined second linear cyclic block code words; code word means coupled to said control means for storing a cyclicly shifting a selected one of said plurality of predetermined second linear cyclic block code words; data means coupled to said control means for serially sequentially examining each bit of said received message word; Hamming means coupled to said control means for storing the Hamming distance between the contents of said code word means and contents of said data means; and scratch pad means coupled to said control means; said control means operative to monitor continuously the Hamming distance between the contents of said code word means and said data means and store the said distance in said Hamming means, and when said Hamming distance is above a predetermined value, to logically exclusively OR the contents of said code word means and the contents of said data means and store the logical result of the ORing process in said scratch pad means, said control means operating in response to the contents of said Hamming means above a predetermined value and the contents of said scratch pad means to update said code word means to a code word corresponding to the contents of said data means, the contents of said code word means, after the receipt of said message word, being decoded by said control means to retrieve said data word.

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Claim 2:
2. The decoder as in claim 1 wherein each of said code word means, said data means and said scratch pad means comprises a register.