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Viterbi decoder with reduced number of bits in branch metric calculation processing

  • US 6,810,095 B2
  • Filed: 12/13/2000
  • Issued: 10/26/2004
  • Est. Priority Date: 12/20/1999
  • Status: Expired due to Fees
First Claim
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1. A method of calculating a branch metric in Viterbi decoding for deriving a branch metric by comparing a codeword produced from a convolutional code with a sign of determination data obtained from conversion of received data for branch metric calculation, said method comprising the steps of:

  • dividing said determination data into a sign and a metric and outputting them;

    determining whether said divided sign matches said codeword or not and outputting a determination signal and an inverted determination signal as a result thereof;

    outputting, on a time-division basis, either the determination signal or the inverted determination signal based on timing pulses;

    selecting and outputting, based on an output of the outputting step, “

    0”

    when said divided sign matches said codeword or selecting and outputting said metric when said divided sign does not match said codeword; and

    adding outputs selected when the signs match to outputs selected when the signs do not match to calculate a branch metric.

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