| 摘要 |
Optical disk recording device includes a beam projection section for projecting a light beam onto a write-once optical disk, and a photodetector having two light receiving surfaces divided in a radial direction of the optical disk for detecting reflected light from the optical disk, and wobble-signal reproduction circuitry for reproducing a wobble signal on the basis of reflected light detection signals output from the two light receiving surfaces of the photodetector. The wobble-signal reproduction circuitry includes peak-holding circuits for, when the optical disk device is in a reproduction mode, detecting and holding respective upper envelopes of the two light detection signals from the photodetector. The wobble-signal reproduction circuitry also includes holding circuits for, when the optical disk device is in a recording mode, detecting respective lower envelopes of the two light detection signals from the photodetector. The reproduction circuitry further includes circuits for switching, between the reproduction mode and the recording mode, the light detection signals to be held by the holding circuits, and a subtraction circuit for performing a subtraction between values held by the holding circuits. Thus, the wobble-signal reproduction circuitry is allowed to produce, with a simple structure, a high-quality wobble signal free of high-frequency signal components.
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