| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk device performing the reproducing/recording operation for stable data. SOLUTION: A control signal producing part 7 is provided with a control signal arithmetic part 8 for outputting error signals of the optical disk 1 in the normal and radial directions by calculating an output signal from a photodetector, a reference signal arithmetic part 10 for producing the reference signal from the output signal of the photodetector, an automatic gain control part 12 for outputting a control signal so that the reference signal becomes a reference level, a 1st gain variable amplifier part 9 for amplifying the error signal by changing an amplification factor in accordance with the control signal, a 2nd gain variable amplifier part 11 for amplifying the reference signal by changing the amplification factor in accordance with the control signal, a recording area detecting part 16 for outputting a discrimination signal by discriminating the recorded area and the unrecorded area on the optical disk, and a gain changeover amplifier part 15 for amplifying an output of the 1st gain variable amplifier part 9 by changing the amplification factor with the discriminated signal.
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