| 摘要 |
PURPOSE:To prevent the reduction in quantized bit number of a color signal after A/D conversion by amplifying a chrominance signal component in an input video signal up to a prescribed level, applying A/D conversion and attenuating the chrominance signal by the amplified quantity. CONSTITUTION:The video signal inputted to an input terminal 1 is subjected to Y/C separation by a 1st Y/C separation circuit 31 via an AGC circuit 2, after the chrominance signal subjected to Y/C separation is amplified to a prescribed level by a color signal amplifier 32, the result is mixed with a luminance signal by a mixer 33 and converted into a digital signal by the A/D converter 3. The color signal amplifier 32 is constituted in a way that large amplification is obtained with a small amplitude of the chrominance signal and no amplification is made with a large amplitude. The signal subjected to A/D conversion is stored in an image memory 6 after demodulation and the signal read from the memory 6 is subjected to D/A conversion and the chrominance signal is attenuated by the amplification at the color signal amplifier 32 through a color signal attenuator 35.
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