| 摘要 |
PURPOSE:To prevent variance of a control signal due to a synthesizing operation to perform accurate tracking control by performing tracking control with a control signal before the generation of a switching noise if this switching noise is generated. CONSTITUTION:Control signal read out from heads A and B at a reproducing time pass regenerative amplifiers 3 and 4, LPFs 5 and 6, a switch 7, a balanced modulator 9, and BPFs 11 and 12 having the first and the second frequencies and have levels detected by level detectors 13 and 14 and are compared with each other by a comparator 15, and control signals as functions of deviation of heads A and B from correct positions for a scanning track are outputted alternately. If a noise or a pulse is generated by switching of the switch 7, a noise detecting means 16 inputs the noise detection signal to a holding means 17 to keep control signals from the comparator in level just before variance, and these control signals are supplied to a motor driving amplifier 18. Consequently, accurate tracking control possible.
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