| 摘要 |
PROBLEM TO BE SOLVED: To rapidly and stably perform initial operation by accurately discriminating a track pitch. SOLUTION: Positional deviation between a beam spot 3 and a track on an optical disk is outputted as a tracking error signal 5 by a tracking error signal generation circuit 4. The tracking error signal 5 is inputted to a speed control circuit 6, and a drive signal is inputted to an optical pickup 2, then the speed control is performed. The tracking error signal 5 is inputted to an amplitude measurement circuit 7, and its output is inputted to a comparison circuit 8. A threshold value corrected with a correction circuit 10 based on the correction data stored in a storage circuit 9 is inputted to the comparison circuit 8, and the amplitude of the tracking error signal 5 is compared with the threshold value by the comparison circuit 8, and its output is inputted to a controller 11, and the track pitch of the optical disk 1 is discriminated with the controller 11.
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