PURPOSE: To eliminate the cause of drop-out and to improve the yield on production of recording medium by generating a dust sticking state detection signal, which indicates that the drop-out is caused by dust or the like stuck to a recording medium or a reproducing stylus, when the duration of a drop-out holding signal exceeds a specified time.
CONSTITUTION: A frequency-modulated high frequency signal of a color video signal reproduced from a disc is supplied from a reproducing device to an input terminal 1. A monostable multivibrator 5 is triggered by the fall of the drop-out detection signal to generate a pulse having a prescribed pulse width and supplies this pulse to an OR circuit 6. The OR circuit 6 ORs signals to generate the drop- out holding signal which is in the high level continuously in the time when drop- out due to a dust sticking phenomenon is generated. When the duration of the drop-out holding signal exceeds a prescribed time, a counter 8 generates a high- level latch signal and supplies it to a latch circuit 10. Thus, the reproducible drop-out due to the deformation and a flaw of the disc and transient drop-out due to dust sticking are distinguished from each other in accordance with the duration of the signal.
YOKOUCHI KENTAROU
YOSHIKAWA HIROYOSHI
TADA SHIGEAKI
| JPS57117102A | 1982-07-21 |