Patent ID: 7274645

Claim:
A reproduction signal processing apparatus comprising: a reproduction unit for reproducing information that is recorded on an optical disc; an A/D converter for converting a reproduction signal that is reproduced by the reproduction unit into a multi-bit digital signal; a phase-locked loop control unit for outputting a reproduction clock that is in phase with clock components included in the reproduction signal, using the multi-bit digital signal; a filter for performing digital equalization to the multi-bit digital signal that is obtained by the A/D converter; and a filter coefficient learning unit for adaptively controlling filter coefficients of the filter in accordance with the digitally equalized signal to minimize an equalization error, wherein said filter coefficient learning unit includes: an equalization error correcting unit for correcting the equalization error when the reproduction signal of a deteriorated quality is to be equalized; a provisional judgment unit for setting an equalization target value using an output signal from the filter; an equalization error detection unit for detecting an equalization error using the equalization target value that is set by the provisional judgment unit and the output signal from the filter; and a filter coefficient operating unit for updating the filter coefficients using the equalization error that is detected by the equalization error detection unit and the multi-bit digital signal that is obtained by the A/D converter; said equalization error correcting unit including a correcting unit for performing correction when a sign of the equalization target value that is set by the provisional judgment unit and a sign of the output signal from the filter are different from each other.