| 摘要 |
PROBLEM TO BE SOLVED: To improve recording/reproducing performance and to shorten a set-up time, by performing tracking control with high precision independently of the eccentricity of an optical disk. SOLUTION: A tracking error signal detection circuit 11 generates tracking error signals (TE signals) by both a differential push-pull system (DPP detection circuit 23) and a phase difference detection system (DPD detection circuit 22). An eccentricity measurement circuit 16 obtains eccentricity of the optical disk by acquired TE signals. A tracking control circuit 12 controls tracking of an optical head by selecting the TE signal generated by the DPD system when the eccentricity of the optical disk is larger than a threshold, and selecting the TE signal generated by the DPP system when the eccentricity of the optical disk is larger than the threshold. COPYRIGHT: (C)2008,JPO&INPIT
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