Patent ID: 6963528

Claim:
A digital data reproduction apparatus for demodulating digital data from an optical recording medium on which digital data are recorded by recording codes having a constraint that at least three same codes should be continuous, said apparatus comprising: a half rate processing offset control means for performing offset correction control, while interpolating offset information in an amplitude direction for a missing signal, into a sampling signal which is obtained by sampling a reproduction signal that is obtained by playing the optical recording medium, with a reproduction clock having a frequency equal to half of a channel bit frequency; a half rate processing phase sync control means for performing phase sync control while interpolating phase error information of the missing signal, into a signal which is obtained by the half rate processing offset control means; a half rate processing adaptive equalization means for performing partial response adaptive equalization on the signal which has been subjected to the offset correction in the amplitude direction and the phase synchronization by the half rate processing offset control means and the half rate processing phase sync control means, respectively; and a half rate processing maximum likelihood decoding means for performing decoding adaptive to the type of partial response, on the partial-response-adaptive-equalized signal that is outputted from the half rate processing adaptive equalization means.