| 摘要 |
PROBLEM TO BE SOLVED: To improve reproduction reliability about a drive corresponding to a disk in which a track has a wobble structure. SOLUTION: A first PLL circuit for inputting a wobble signal and reproducing a clock synchronized with a wobble period is provided with a periodic error detection circuit for detecting a periodic error about the inputted signal. Since the wobble signal is obtained by detecting a wobble formed by a fixed period with respect to a track of the disk, the operation of the PLL circuit based on periodic error detection performs pull-in operation so as to synchronize with the wobble period. As a result of adopting such a configuration, the PLL circuit is prevented from being pulled in by an erroneous frequency while being different from a conventional practice in which, for instance, an oscillation frequency of a crystal vibrator is utilized, and a fast pull-in operation can be obtained to that extent.
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