| 摘要 |
PURPOSE:To correct the variance of track pitches on a disk by constituting the titled recorder of a device which detects the feed speed and a device which varies the reference frequency which controls a drive motor by means of said detecting means. CONSTITUTION:A mobile stage 3 is shifted by a feed mechanism consisting of a drive motor 6', a reduction gear 5' and a feed screw 4'. Then the laser light A is reflected by a mirror 10 and sent back to a laser 9 to produce a feedback function. When the beams divided by a beam splitter 11 are made incident on a disk, a detector 12 produces a signal having a frequency proportional to a shift speed. An arithmetic device 15 outputs the data to divider 14 to give a division ratio that defines a prescribed number of revolutions of the motor 6'. The divider 14 gives a reference signal obtained by dividing the output signal of a crystal oscillator 13 in said division ratio to a motor control part 8'. This can suppress the variation of the feed speed due to the variance of pitch accuracy of the screw 4'. Thus the variance of track pitches can be corrected on the disk.
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