| 摘要 |
PURPOSE:To attain sure muting with a simple constitution, by detecting the difference between write and readout addresses of a time base collector correcting the time axis of a reproducing video signal and muting the reproduced output of a coded sound signal when the difference reaches a prescribed value or over. CONSTITUTION:The write address W and the readout address R from the time base collector TBC3 are given to a comparison circuit 4 and whether or not the absolute value of the difference exceeds a prescribed value D is discriminated. When D<¦W-R¦ is established, an out of synchronism pulse is formed, it is given to a retriggerable monostable multivibrator 2 and a muting signal for a prescribed period is formed. On the other hand, a reproducing sound signal PCM is reproduced and processed at a reproducing circuit 5 and applied to a muting circuit 7 via an interpolation circuit 6. If the synchronism of the reproducing signal is disturbed, the muting signal is formed and the sound signal is muted at the muting circuit 7. |
