| 摘要 |
PROBLEM TO BE SOLVED: To provide a wobble signal demodulation circuit capable of accurately phase-demodulating the wobble signal. SOLUTION: A signal of a carrier wave section is extracted by a BPF circuit f1 having a center frequency near a fundamental frequency of the wobble signal Swb, and a clock signal Stim is produced by a PLL circuit f2. By synchronizing with this clock signal, a phase modulation wave section is phase-demodulated by a demodulation signal producing circuit 28g. Since the center frequency of the BPF circuit is being adjusted by a center frequency adjustment circuit i1 and a phase of the clock signal is being adjusted by a phase adjustment circuit i2 respectively in accordance with a linear velocity of the rotation of the optical disk, the accuracy of the clock signal is improved even when the linear velocity of the rotation of the optical disk is increased and a signal delay in the PLL circuit is large, then the wobble signal is accurately phase-demodulated. Thus, the recording operation excellent in the recording quality is attained. COPYRIGHT: (C)2005,JPO&NCIPI
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