| 摘要 |
PURPOSE:To stabilize the frequency characteristics of high frequency part of a video signal, by detecting the amplitude of a color burst signal of a color TV signal and controlling the amplitude to be stable. CONSTITUTION:An outut of a frequency characteristic compensation circuit 3 is applied to an ACC circuit 6 via a chroma signal band pass filter 5, and the amplitude of the burst signal is detected at the circuit 6 and an ACC control voltage is generated. Feedback is applied to the circuit 3 so as to make the amplitude of the color burst signal constant. For example, if the high frequency characteristics of a color TV composite video signal being an output of a VIF amplifier and video signal detection circuit 2 are deteriorated and the amplitude of the color burst signal is small, the ACC control voltage generated at the circuit 6 is controlled to increase the high frequency component at the circuit 3, and if the high frequency component is excessive and the amplitude of the color burst signal is too much, the control is done to suppress it. Thus, the frequency characteristics of the high frequency component of the video signal are made stable. |
