| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical drive apparatus that suppresses degradation of precision caused by noise superimposed on the output signal of a photodetector in tracking servo by a DPD method. SOLUTION: The optical drive apparatus includes: a phase-difference detection-signal generating unit 57 that generates PEDr based on PEROd and PEFOd obtained by delaying a phase-lead output signal indicating a phase-lead amount of a DA with respect to DB by a predetermined time, and a logical signal X changed to high at a timing at which NAND of DA and DB is changed from high to low, and changed to low at timing at which OR of DA and DB is changed from high to low, and generates PADr based on PARFOD and PAFOd obtained by delaying a phase-lag output signal indicating a phase-lag amount of DA with respect to DB and the logical signal X; and a DPD signal generating unit that generates a phase-difference signal indicating a phase difference between the DA and the DB and generates a DPD signal based on the phase difference signal. COPYRIGHT: (C)2011,JPO&INPIT
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