| 摘要 |
PROBLEM TO BE SOLVED: To appropriately generate a playback signal and an error signal and to suppress reduction of an S/N ratio in an optical disc playback apparatus even if the amount of light received by an optical pickup varies or leakage light enters into a photoreceptor due to inclination of the optical pickup and the like. SOLUTION: A tracking control signal generation circuit 28 adds an offset in accordance with a control value 37 output from a tracking actuator controller 31 to an output of a tracking servo filter 27. As a result, a tracking servo pull-in operation is performed in a state where the optical pick-up 20 is forcibly tilted. The direction in which the optical pick-up 20 is forcibly tilted is determined from the result of, e.g., measuring the duty ratio of a DPD off-track signal. Therefore, a reproduction signal, a focus error signal, and a tracking error signal are correctly generated without providing a tilt mechanism in the optical pick-up 20. COPYRIGHT: (C)2009,JPO&INPIT
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