| 摘要 |
An optical disk apparatus has a tracking servomechanism in which the servotiming is determined by the length of the period of the tracking error signal detected on an optical disk. Because of the eccentricity of the optical disk, the period of the tracking error signal cannot be constant. If the servo loop is closed during a time interval in which the period of the tracking error signal is relatively short, it takes much time to make an optical head follow a predetermined track because the optical head crosses another track before the optical head can be made to follow the predetermined track so that feedback servocontrol must be repeated until the optical head is made to follow the predetermined track. In view of this, in the tracking servomechanism of the optical disk apparatus according to the present invention, the servo loop is closed only when the period of the tracking error signal is so long that only one performance of the feedback servocontrol can make the optical head follow the predetermined track. Consequently, the optical head can be servoed in a relatively short time.
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