| 摘要 |
PROBLEM TO BE SOLVED: To prevent signals recorded on adjacent tracks from being broken, by defocusing and rotating a disc at a high speed. SOLUTION: A tracking error (TE) signal detected by a TE signal detector circuit 24 is given to a DSP 28 which then compares the absolute value of the TE signal with a specified threshold and, if the absolute value exceeds the threshold, moves an optical lens 14 to the most remote position from a disc surface and rotates a spindle motor 36 at a high speed. When the laser beam spot moves from the present track to an adjacent track, the TE signal level varies like an upward curved line, and the off-tracking can be detected by comparing the absolute value of the TE signal with the specified threshold. At this time the beam is defocused and the disc 38 is rotated at a high speed.
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