| 摘要 |
A tracking servo device for use with an optical disc apparatus includes a photodetector unit having a plurality of photodetectors each of which is split in association with the direction of tracks formed on the optical disc, and a tracking error generating unit for finding the difference in outputs from at least two of the photodetectors of the photodetector unit for generating a tracking error signal. The tracking servo device also includes a first correction unit for removing an offset produced in the tracking error signal when the tracking servo is on, and a second correction unit for removing an offset produced in the tracking error signal when the tracking servo is off. The tracking servo device also includes a switching unit for selecting the first correction unit or the second correction unit when the tracking servo is on or off, respectively, for producing a tracking error signal freed of the offset component, and an offset holding unit for holding an offset component extracted by the second correction unit. The tracking servo device further includes a control unit for controlling the holding time of the offset component in the offset holding unit.
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