| 摘要 |
PROBLEM TO BE SOLVED: To enable performing highly accurate tracking control by eliminating automatically an offset component of a tracking error signal caused by optical base deviation of an object lens and the like. SOLUTION: Such a characteristic is indicated that when offset is not caused, height of pulses of pit signals by pits of an external peripheral side out of target tracks of a recording medium are the same, but an optical base is deviated to an external peripheral side, pulses by pits of an inner peripheral side are made higher and that of an external peripheral side are made lower, this difference between peak voltage values is proportional to an offset component of a tracking error signal caused by optical base deviation. Then an offset component H is detected by a tracking offset detecting circuit 21 based on a pit signal by a pit previously recorded in land regions of both side of a track of a recording medium, and the offset component H is eliminated and compensated by analog operation in a tracking error detecting circuit 5 based on the detected signal.
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