METHOD OF EVALUATING RECORDING MEDIUM, EVALUATING DEVICE AND REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an evaluating device for a recording medium capable of evaluating reproduced signals by simple processing. SOLUTION: The evaluating device for a magneto-optical disk 1 comprises evaluating the reproduced signals from the magneto-optical disk 1 by utilizing a maximum likelihood decoding method. A differential metric arithmetic and logic unit 10 determines the differential metric by subtracting the cumulative values of the branch metric calculated by the maximum likelihood decoding method from each other. Aσarithmetic and logic unit 11 calculates a standard deviationσfrom the deviation between a mean valueμand the differential metric relating to the differential metric below the mean valueμformed by aμvalue former 14. The smallest ideal value 1.5 of the differential metric is used for the mean valueμ. COPYRIGHT: (C)2003,JPO