| 摘要 |
PURPOSE:To prevent surely the disorder of an image simultaneously with the release muting of by supplying to a synchronizing clamp circuit the DC signal the same in level as the bias voltage of the video signal in place of the bias signal during the muting period while closing a sampling switch. CONSTITUTION:When a mute switch 7 is changed over to a mute terminal by the output from a mute comparator circuit 14, the sampling switch 12 is closed by the operation of a differential switch 23 during the mute period. As to the mute switch 7, the output of a mute buffer amplifying circuit 22 is supplied to a level shift circuit 8 in place of the preceding recording or reproducing video signals. As a result, the DC signals of the same level as the voltage of the video signal is supplied during the mute period so that any marked difference is not caused in the level shift quantity of the level shift circuit 8 before and after the mute period.
|
