| 摘要 |
PURPOSE:To perform a precise signal processing with a simple means by obtaining the 1st video signal clamped at a certain potential and also obtaining the 2nd video signal clamped at an another voltage by changing the DC bias of an input amplifier. CONSTITUTION:The video signal is applied to an input amplifier 6 constituted of a differential stage through a clamp capacitor C and guided to a video signal processing circuit 2 which the gain the about one time. A reference voltage E1 is applied to the input amplifier 6 and two video signals A, C pedestal-clamped basically at the voltage E1 and another voltage Ep are formed by the cooperation with a trailing clamp circuit 3. The input amplifier 6 is offset adjusted to obtain a video signal offset clamped E1 by alpha and the signal is outputted to the signal processing circuit 2, so that a black signal less than the level E1 is taken out by slicing and a signal processing extending black is execute to make coincided the peak level of a black signal with the pedestal level. The output of the video signal processing circuit 2 is sent to a clamping circuit 3. |
