| 摘要 |
PROBLEM TO BE SOLVED: To provide an enhanced Viterbi detector that recovers a binary sequence from a read signal read by a disk drive system or the like. SOLUTION: This invention provides the Viterbi detector receiving a signal that represents a binary sequence having groups of no more and no fewer than a predetermined number of consecutive bits each having a first logic level, where the groups are separated from each other by respective bits having a second logic level. The Viterbi detector recovers the binary sequence from the signal by calculating a respective path metric for each of no more than four possible states of the binary sequence, and determining a surviving path from the calculated path metrics, where the binary sequence lies along the surviving path. Or the Viterbi decoder recovers the binary sequence from the signal by calculating respective path metrics for possible states of the binary sequence, calculating multiple path metrics for no more than one of the possible states, and determining the surviving path from the calculated path metrics.
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