Signal quality evaluation apparatus, signal quality evaluation method, and reproducing device

Abstract

Provided is a signal quality evaluation apparatus, including an error pattern detection unit to which binarized data obtained by performing a PRML decoding process on a reproduced signal of bit information by partial response equalization and maximum likelihood decoding is input, the error pattern detection unit configured to detect at least one specific error pattern that is a bit pattern that is longer than a constraint length of the PRML decoding process, a metric difference calculation unit configured to calculate a metric difference of the at least one specific error pattern that has been detected by the error pattern detection unit, and an index value generation unit configured to generate an index value of a reproduced signal quality by using a distribution of the metric difference obtained by the metric difference calculation unit.