| 摘要 |
PURPOSE:To suppress a deterioration in picture quality due to crosstalk by reducing the quantity of crosstalk according to the quantity of tracking servo signals and reproducing signals free from crosstalk generated by true tracking. CONSTITUTION:Supposed that a main beam 2b traces a track of 1b as a desired signal. At this time, bias E and output of a photodiode 3c are added by an adder 6 and inputted to a differential amplifier 4. A closed loop is formed to make the output pass through a power amplifier 8 to drive a tracking mirror 9 and control the position of a beam 2 that irradiates a disk 1. Output of an FM detector 10 enters an A/D converter 24 and becomes a digital signal. As a signal one frame before is stored in a memory 16, this output is read out and multiplied by alpha by a multiplier 17. A digital circuit 13 increases the input signal 1/(1-alpha) times.
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