| 摘要 |
PURPOSE:To apply the accurate feed forward and to improve the trackability against flaws by storing a track error signal added to a servo loop, reading the track error signal at the preceding rotation and adding to a control loop so as to store it as track deviation information. CONSTITUTION:A signal of a rotary detector 15 is read from a control circuit 13 at the 1st rotation applied with track loop, a track error 0 signal is inputted to a memory 11, a 0 data is added to the loop, the disc position is detected via an A/D converter 9 by using one pulse per revolution generated from the detector 15 and the result is written in a memory 10. Then the signal from the detector 15 is received, the data in the memory 10 is transferred to the memory 11 and its data is added to an adder 5 via a D/A converter 12. The feed forward is applied at the point of time to improve the trackability. The signal subject to feed forward and feedback is written in the memory 10 via the A/D converter 9 to revise the data.
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