Patent ID: 6119265
Filing Date: 2000-09-12
Classification: H03M

Abstract:
A Viterbi decoding apparatus comprising:reference amplitude level saving means for saving 6 values of reference amplitude levels determined by codes interference occurred by a combination of 1-bit recording data of interest, 1-bit recording data prior to said recording data of interest and 1-bit recording data subsequent to said recording data of interest;branch metric calculating means for calculating a branch metric equal to a relative value of a Euclidean distance between an inputted reproduction signal and said reference amplitude level;path metric producing means for producing a path metric by adding said branch metrics along paths of 4 states;most likelihood judgement control means for producing selection information used to select a minimum path metric from a number of said branch metrics and said path metrics and for updating said path metrics based on said selection information; anddiscrimination result output control means for outputting a discrimination result which constitutes a history of said path metric with respect to each of said four states based on said selection information, whereby most likelihood decoding is carried out by said Viterbi decoding apparatus under 6-value/4-state.