INFORMATION REPRODUCTION APPARATUS AND INFORMATION REPRODUCTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for calculating a confidence level effective even for a data row which is RLL modulated.

SOLUTION: An information reproduction apparatus comprises: a maximum likelihood path determination unit for outputting a maximum likelihood path to be the most probable decryption result; a competitive path determination unit for outputting a competitive path to be a decryption result different from the maximum likelihood path; a likelihood calculation unit for outputting likelihood which is a difference between the maximum likelihood path and the competitive path; an inter-signal distance calculation unit for outputting an inter-signal distance which is a distance between a maximum likelihood waveform generated from the decryption result of the maximum likelihood path and a competitive waveform generated from the decryption result of the competitive path; and a confidence level output unit for outputting the confidence level based on a normalized likelihood obtained by normalizing the likelihood by the inter-signal distance.

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