| 摘要 |
A carrier frequency extracted as a tracking error signal from a disk with an optical pickup by a push-pull method is passed either through a high-pass filter having its cut-off frequency changing proportionally with the disk revolution number or corresponding to the carrier frequency at the disk ordinary revolution, or through a band-pass filter having its center frequency changing proportionally with the disk revolution number or corresponding to the carrier center frequency at the disk ordinary revolution. Therefore, the carrier frequency can be efficiently separated from the EFM signal during recording while allowing to use one beam in reading a tracking error signal and recording an EFM signal, and allowing a compatibility with presently used CD players. Further, the carrier frequency is used for the revolution control of a spindle motor during the revolution start and end, so that even while the tracking servo is not effected the revolution of the spindle motor can be controlled to enter into a fine control capture range.
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