| 摘要 |
PURPOSE:To prevent distortion in an output signal or an error in the next processing circuit occurring by extending a clamping pulse setting its leading or trailing edge which becomes the forefront of a synchronizing signal pulse as an origin longer than an on-going one by the width of the synchronizing signal pulse. CONSTITUTION:The clamping pulse with prescribed width setting the leading or trailing edge of the forefront of the synchronizing signal pulse as the origin is inputted to a clamping circuit 8, and the electric charge of a coupling capacitor is discharged, then, the DC component of an image signal is reproduced. since the width of the clamping pulse outputted from a one-shot circuit 51 is decided by a time constant element assembled in the one-shot circuit 51, it is set at the pulse width within which the trailing edge of the clamping pulse can be housed in a back porch. Therefore, the clamping pulse can be added on the clamping circuit 8 earlier and longer than the on-going one. In such a way, it is possible to obtain a pedestal clamping circuit in which no distortion in the output signal or no error in the next processing circuit occurs. |
