Patent ID: 7257066
Filing Date: 2007-08-14
Classification: G11B,H03M

Abstract:
1. A defect detection device for detecting a defect of recorded data in a data reproduction apparatus for reproducing data having maximum likelihood as the recorded data in accordance with a maximum likelihood decoding algorithm corresponding to partial response, the data being reproduced from sampled values obtained by sampling a reproduced signal from a recording medium, the defect detection device comprising: a waveform state detection part generating information representing a state of a waveform of the reproduced signal based on soft decision results obtained in process of reproducing the data; and a defect determination part determining the defect of the recorded data based on the information generated in said waveform state detection, wherein: said waveform state detection part generates first information distinctively representing a first state corresponding to a peak value part of the sampled values and a second state corresponding to the other part of the sampled values than the peak value part and second information distinctively representing a third state corresponding to a bottom value part of the sampled values and a fourth state corresponding to the other part of the sampled values than the bottom value part; and said defect determination part determines the defect of the recorded data based on at least one of the first and second information.