| 摘要 |
The precision of a direction detection signal DIR is judged from the duty ratio of the direction detection signal DIR, and the direction detection signal DIR which is used for track search control or tracking pull-in control is judged as valid or invalid according to the precision, thereby to improve the precision of the track search control or the tracking pull-in control. Therefore, even when the direction detection is not performed accurately due to a difference in the reflected light quantity on the optical disk, a defect on the optical disk, a delay in the track cross speed during search, or a delay in the detection circuit, the track search control and the tracking pull-in control can be performed with stability.
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