| 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 from the wobble signal Swb detected in a wobble signal detection circuit 28c by a BPF circuit f1 having a center frequency near a fundamental frequency of the carrier wave section, and a clock signal Stim is produced by a PLL circuit f2. Further, by synchronizing with the clock signal Stim which is phase-adjusted in a phase adjustment circuit i2, a phase modulation wave section is phase-demodulated by a demodulation signal producing circuit 28g. In this case, since the center frequency of the BPF circuit f1 and the phase of the clock signal Stim are respectively adjusted in accordance with a linear velocity of the rotation of the optical disk, the accuracy of the clock signal supplied to the demodulation signal producing circuit 28g is improved, and the phase modulation wave section is accurately phase-demodulated. COPYRIGHT: (C)2005,JPO&NCIPI
|
