| 摘要 |
In a video signal processing system including a kinescope for reproducing an image in response to an image representative video signal, a circuit for clamping a periodic blanking level of the video signal to establish a black level for a reproduced image. A clamping device clamps the video signal to a reference voltage during periodic blanking intervals of the video signal. The clamped video signal is applied to the kinescope through a direct current coupling network having a threshold conduction level. A locally generated blanking reference signal, of a magnitude substantially equal to the difference between the reference voltage and the threshold conduction level, is added to the video signal prior to clamping, so that the clamped video signal coupled to the kinescope exhibits a desired blanking level and unimpaired peak-to-peak amplitude. |
