| 摘要 |
PURPOSE:To enable the retrieval of desired track in high speed, by providing the stop means which can stop the moving means regardless of the detected output of the coincidence detecting means. CONSTITUTION:The light beam 2 from the light source 1 is converged to the disc 7, the reflected light 8 on the disc 7 is received on the two division detector 9 through the converging lens again, and it is input to the envelope detection circuits 11a, 11b respectively. The output of the detection circuits 11a, 11b gives a differential signal at the differential amplifier 12 and is input to the tracking element driving circuit 14 via the tracking control circuit 13 to drive the tracking element 15. The angle of the full reflection mirror 5 fitted with the element 15 is changed by it and the light beam 2 is in tracking. On the other hand, the output of the photodetector 9 is summed at the addition circuit and the video playback signal is obtained through the video signal playback circuit 18, and the address signal of recording track is read out with the address signal identification circuit 19 and it is input to the microcomputer 20. |
