| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk device which enables detection of a stable prepit signal(LPP signal) even in a recorded area. SOLUTION: A gain is controlled so that a value of signal amplitude which is acquired by amplifying respective output signals of split photo detectors which are split into two in the tangential direction of tracks with variable gain amplifiers (20, 21) or a value of an average signal generates a prescribed difference signal. On the basis of the difference signal generated by the gain control, a wobble signal and a prepit signal are detected. COPYRIGHT: (C)2006,JPO&NCIPI
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