INFORMATION REPRODUCTION DEVICE AND INFORMATION REPRODUCTION METHOD

摘要

Provided is a method to calculate, in an information reproduction device, the effective reliability of even an RLL modulated data string. The device comprises the following: a maximum likelihood path determination unit that outputs a maximum likelihood path, which leads to the most probable decoding results; a conflict path determination unit that outputs a conflict path for which the decoding results differ from those of the maximum likelihood path; a likelihood calculation unit that outputs a likelihood that is the difference between the maximum likelihood path and the conflict path; an inter-signal distance calculation unit that outputs an inter-signal distance which is the distance between a maximum likelihood waveform generated from maximum likelihood path decoding results and a conflict waveform generated from conflict path decoding results; and a reliability output unit that outputs reliability on the basis of a normalization likelihood in which the likelihood is normalized by the inter-signal distance.