| 摘要 |
PURPOSE:To change a fine adjustment control range by stopping a time base adjustment for a prescribed time after a recording and reproducing means starts the track jump and switching the center frequency of the clock of a clock response delay element for fine adjustment during this time. CONSTITUTION:A controller 40 stops rewriting a RAM 33 by the output of a vertical synchronizing signal (v) from a separating circuit 26, and a slider 9 is servo-driven with a slider servo 6 by a signal (b). A tracking open signal (a) is sent for a short time after sending of a signal (b), and a light spot jumps tracks on a disk 2 during this time. During this time, a variable range extending signal (e) is sent and a VCO 25 is controlled to reduce the center frequency of the outputted clock. Since the jump time is short, the inertia of a motor keeps continuity of time base error. Though a spindle motor 1 is servo-driven with a spindle servo 27 by an error cut signal (g), the controllable range of a CCD 24 is extended by the reduction of the center frequency of the VCO 25. Since the CCD starts the fine adjusting operation of the time base again from the operation center point by the extinction of the signal (a), the time base error does not exceed the control range and is surely controlled.
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