| 摘要 |
PROBLEM TO BE SOLVED: To improve tracking on/off determination for a narrow-track disk. SOLUTION: The optical disk reproducing apparatus is provided with; an optical head which radiates light to a track of an optical disk and detects the reflected light; a tracking servo means which controls the position of the optical head on the basis of a tracking error signal showing a positioning error of a radiation position of light to the track; and a tracking on/off determination means which determines whether control of the tracking servo means is possible on the basis of whether a level of the tracking error signal is within a range prescribed by a threshold. A tracking servo circuit is provided with; an operational amplifier 21 which amplified a tracking error signal 12A in accordance with a gain; a level detection circuit 22 which detects a level of the tracking error signal 12A; and a control circuit 23 which changes at least one of the gain of the operational amplifier and the threshold of the controller in the case that the absolute value of the detected level is smaller than a prescribed value. COPYRIGHT: (C)2006,JPO&NCIPI
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