| 摘要 |
PURPOSE:To execute an attenuation control by a few level control means, by generating 2 kinds of control signals of the upper limit and the lower limit, for controlling a signal level of a color video signal, and executing both clips of the upper limit and the lower limit in accordance with said signals. CONSTITUTION:A video limit generator 7 consisting of a noninversion amplifier 71 and an inversion amplifier 72 generates an upper limit signal UM and a lower limit signal LM which are continuously varied to the opposite polarity each other in accordance with a pedestal level, by video level control signal from a terminal 6, and supplies them to the respective level controlling circuits 3, 4. On the other hand, an input video signal is DC-clamped, becomes a VI' signal, and the upper limit processing is executed through the level controlling circuit 3 by the upper limit signal UM. Subsequently, the lower limit processing is executed through the controlling circuit 4, and an output video signal VO is obtained. In this way, an attenuation control of a video signal level being suitable for a high speed operation is executed by a few control means, without using a multiplying means, etc. |
