| 摘要 |
PURPOSE:To correct the offset of tracking caused by the inclination of the surface of an optical disk by providing a correcting means which removes the influence of a defect in a detection surface upon a detection signal for the inclination of the surface. CONSTITUTION:A sample holding circuit 13 which receives the timing pulse 10-1 of an inclination detection position 10 holds a tracking signal 19 and outputs a signal A. A level holding circuit 14 which receives the timing pulse 12-1 of an inclination signal level detection position 12, on the other hand, holds the signal A and outputs a signal B. The timing pulse 12-1 is generated a little bit earlier than the pulse 10-1, so the signal B precedes the signal A in terms of timing. A differential amplifier 17 outputs the difference between the tracking signal 19 and signal A or B, i.e. tracking correction signal. The differential amplifier 17, therefore, regards the difference between the tracking signal 19 and signal B as a tracking correction signal if the correct tracking signal 19 is obtained from a mirror surface part 8 owing to a flaw 11, etc.
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