Patent ID: 6992964

Claim:
An information reproducing device for reproducing information recorded on a storage medium, comprising: a detecting section for detecting information recorded on a storage medium and outputting a detection signal; a converting section for converting the detection signal outputted by the detecting section into a digital signal; a correcting section for correcting the digital signal converted by the convening section in accordance with a parameter; an equalizing section for applying partial response equalization processing to the corrected digital signal corrected by the correcting section based on a predetermined coefficient and outputting an equalization signal; a maximum likelihood decoding section for applying maximum likelihood decoding processing to the equalization signal outputted by the equalizing section based on a reference level and outputting a decoding signal; an ideal waveform generating section for generating and outputting an ideal waveform signal in accordance with the equalization signal outputted from the equalizing section; a target waveform generating section that receives the ideal waveform signal from the ideal waveform generating section, judges the ideal waveform signal as one of level 0 to level 6 , shifts a value of the ideal waveform signal when the ideal waveform signal is judged as level 2 or level 4 , and generates the ideal waveform signal shifted or not shifted as a target waveform signal; and an optimizing section for calculating an error between the target waveform signal outputted by the target waveform generating section and the equalization signal outputted by the equalizing section, and optimizing at lease one of the parameter of the correcting section, the predetermined coefficient of the equalizing section and the reference level of the maximum likelihood decoding section in such a manner that the error becomes minimum.