| 摘要 |
PURPOSE:To omit a stage command signal generating part which controls the constant tangential velocity of a head stage feeding speed, by synchronizing the rotational speed of a turntable with the feed speed of a head stage. CONSTITUTION:A laser length measuring machine 6 detects a distance from the rotational center of the turntable 1 to a head, and generates a head position signal (d). And a spindle servo circuit 8 counts rotational angle signals (b) for a unit time, and generates a spindle motor driving signal (a) so that the obtained rotational speed of a spindle motor 2 can follow a rotational speed command signal (e). Also, a frequency division circuit 9 frequency-demultiplies the signal (b), and generates the feed speed command signal (f) of the head stage 4 synchronized with the rotarional speed of the table 1. And by controlling the rotational speed of the table 1 so as to set tangential velocity at a head position on an optical original disk by a spindle signal generating part 7-1, the feed control of the head stage 4 can be also controlled at the constant tangential velocity.
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