| 摘要 |
PURPOSE:To omit a pickup position detector, to eliminate the time delay in terms of detection and to attain the satisfactory responsiveness for controlling the rotational frequency of a disk by constituting such that a controller itself detects a pickup scan position. CONSTITUTION:In normal recording, reproduction and erasure modes the controller outputs the 1st control signal corresponding to the 1st digital signal equivalent to the output signal of a tracking servo circuit 3, and controls tracking so that a pickup can be always at an on-track position. On the other hand, at the time of random access the controller 14 outputs the 2nd control signal and conveys the pickup 1 at a target track position. The controller generates the digital signal in accordance with the rotating speed of a rotating and recording medium at the time of normal recording and random access, supplies it to a rotation control motor through a D/A converter 9, and controls the rotational frequency. Thus the pickup position detector is made unnecessary. Responsiveness in terms of controlling the rotational frequency of the disk is made satisfactory, and the device can be miniaturized accordingly.
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