| 摘要 |
PURPOSE:To correct the offset of a tracking servo, by sampling a tracking error signal at a certain part of the irregularity signal of a magneto-optical disk, and performing the tracking servo by a signal in which an offset signal obtained by integration is subtracted from a tracking signal. CONSTITUTION:A light beam 2 reflected on the magneto-optical disk passes through an objective lens 3, a tracking error signal detector 4, and a high-cut filter 5, and is converted to a tracking error signal TE. Also, the light beam 2 passing through the objective lens 3 is converted to an irregularity detection signal IF at an irregularity signal detector 8, and outputs a thin pulse TM at a timing generator 9. An error signal TE is A/D converted at an A/D converter 10, and is inputted to an integrator 11, then being integrated, and after it is converted to an analog signal at a D/A converter 12, it is amplified at an amplifier 13, then an offset signal EC can be obtained. By subtracting the offset signal EC from the tracking error signal TE at a subtractor 14, and driving an objective lens actuator 7, the tracking servo is performed. In such a way, the correction of the offset of the tracking servo can be performed.
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