| 摘要 |
PURPOSE:To enable to detect a short dropout, by connecting an inductance load circuit to an input stage of a dropout deciding circuit. CONSTITUTION:After a reproducing FM signal from a video disc and the like is detected at a half wave rectifying circuit 3 via a limiter amplifier 2, it becomes a detected voltage with a waveform having a sharp leading with an inductance load circuit 9 including an inductance L and a voltage also at a negative side, and it is applied to a retriggerable monostable multivibrator 5. Thus, even if noise is superimposed around a zero voltage level, the dropout can be detected surely via the monostable multivibrator 5, allowing to detect the dropout stably with a short width in 200ns at an input FM signal band. |
