摘要 |
PURPOSE:To prevent the output of abnormal reproduced sound at a special speed reproducing time, a high speed retrieval time, an off tracking time, or the like by triggering a monostable multivibrator when the momentary amplitude of a tracking error signal is larger than a prescribed value. CONSTITUTION:A pulse current is supplied to a driving coil 6 from a tracking control circuit 25 so that a luminous flux is moved forcibly to an adjacent track at the special speed reproducing time, the retrieval time, or the like. In this case, the fact is used that the amplitude of the detection output of the tracking error signal is increased according as the laser luminous flux from a laser 1 and an object lens 5 traverse information recording tracks on a disc 7, and the tracking error signal is compared with a reference voltage by a comparator 23 to detect each state. A retriggerable monostable multivibrator 24 is triggered by the detection output, and a pulse output longer than a period corresponding to two rotation of the disc at least after detection is obtained to operate a switch 18, and the sound reproduced output is stopped.
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