Patent ID: 6192502
Filing Date: 2001-02-20
Classification: G11B,H03M,H04L

Abstract:
An information reproducing apparatus for reproducing, according to a Viterbi decoding method, data that has been RLL (Run Length Limited) encoded and recorded on a recording medium, comprising:branch metric calculating means for calculating branch metrics for all statuses at a particular time point corresponding to an input reproduced signal;path metric updating means for selecting a maximum likelihood path metric of each of the statuses corresponding to values of which the branch metrics and preceding path metrics are added, for outputting a first selection signal corresponding to the selected maximum likelihood path metric, and for outputting a second selection signal corresponding to minimum values of the path metrics;status data generating means, having a plurality of status memories corresponding to the statuses, for updating status data that represents the statuses corresponding to the first selection signal;status data selecting means for selecting a most adequate status data from the status data stored in the status memories corresponding to the second selection signal and for outputting the selected most adequate status data;data decoding means for outputting decoded data corresponding to the selected most adequate status data and a just preceding most adequate status data;mismatch detecting means for detecting mismatches of the status data stored in the status memories;counting means for counting a number of the mismatches of the status data corresponding to output data of said mismatch detecting means; andcontrolling means for controlling a decoding process according to the number counted by said counting means.