| 摘要 |
PURPOSE:To obtain a simple automatic color saturation control unit, by uniting a circuit, which limits the amplitude of the whole of the chroma signal so that the amplitude of the burst signal may be fixed, and a circuit which increases and reduces automatically the chroma signal level. CONSTITUTION:Chroma input signal 22 is input to voltage control amplifier 15 and the gain controlled by control voltage 24 proportional to the burst amplitude and has the amplitude limited. A part of chroma output 23 has only the burst part extracted by sampling circuit 17 after chroma amplitude detection and becomes control voltage 24 through filter 18. After chroma output 23 is amplified by differential amplifier 19, the chroma amplitude is decided for magnitude by filter 20. After that, voltage 25 proportional to the chroma signal level is obtained by burst control circuit 21, and the voltage control amplifier is controlled by this voltage. |
