| 摘要 |
[Problem] To increase the precision of a signal quality evaluation for the playback signal of a high-density recording. [Solution] Input is made of binarized data obtained by subjecting bit information playback signals to partial response equalization and maximum likelihood decoding. Detection is made of one or a plurality of characteristic error patterns, which are bit patterns that are longer than the constraint length of PRML decoding. In particular, an error pattern having a high bit-error occurrence is assumed to be a characteristic error pattern. The metric difference is calculated for the detected characteristic error pattern, and the index value of playback signal quality is generated using the metric difference distribution. |
