| 摘要 |
PROBLEM TO BE SOLVED: To provide a disk device capable of setting an optimum offset value respectively to a land and a groove. SOLUTION: This disk device 10 includes a DSP core 36 and when the power source of the main body of the device is turned ON and a MO disk 42 is exchanged, the core 36 executes processings for setting focus offset (offset) values. The DSP core 36 is tracked to a land/groove side to extracts a fine clock mark(FCM) signal from a reproduced signal. Concretely, it detects FCM signals of positions where offset values are shifted (scanned) by a prescribed amount in left and right deirections on the basis of a present offset value within an range in which values are decided to be equal to or higher than the prescribed value of the mean value of the level of the FCM signal. Then, the core 36 detects the defference between these two levels and decides an offset value of when the difference becomes the minimum when all ranges are scanned to be an optimum offset value. Optimum offset values are decided respectively as to the land and the groove and at the time of reproduction, these offset values are changed over corresponding to a track. Thus, an optimum reproduced signal can be obtained.
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