| 摘要 |
PURPOSE:To avoid an easy track jump phenomenon despite a large flaw of a disk by performing the primary compensation through a gain control circuit, etc. to the flaws of the disk and then correcting a track shift due to the disk flaws with control. CONSTITUTION:A control circuit 8 consists of an attenuator containing a resistance and an electronic switch for example. When a flaw of a disk is detected, the attenuator is actuated by a flaw detecting circuit 5 for reduction of the tracking loop gain for a flaw period. At the same time, an off-track detecting circuit 6 detects a track shift due to the disk flaw when an objective lens of a pickup 3 gets out of the flaw. Then a gain switching circuit 9 is actuated to increase the tracking loop gain and to increase the servo draw-in force. Thus the track shift is corrected and then a track jump phenomenon is compensated.
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