| 摘要 |
PROBLEM TO BE SOLVED: To discriminate a kind of an optical disk without detecting the radius position of an optical pickup. SOLUTION: A revolution is successively raised by a spindle motor 2 from a minimum revolution S to a maximum revolution L. During this operation, a center frequency is changed over between 145 kHz and 817 kHz by a band-pass filter 51. Count values of the period of wobble signals having passed through the band-pass filter 51 are measured by a cycle measuring section 52. The part where the counted value is decreased in proportion to the increase of the revolution, is detected by a distribution arithmetic section 54. By a determination arithmetic section 55, the kind of optical disk is determined from a frequency band of the band-pass filter 51 at the time when a proportionality of the revolution and the counted value is detected. COPYRIGHT: (C)2007,JPO&INPIT
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