| 摘要 |
PROBLEM TO BE SOLVED: To obtain a complexion color correcting circuit which is easily designed and inexpensive by providing a gain-controllable amplifier which amplifies an I-axis demodulation output and a Q-axis demodulation output and obtaining the control voltage for the gain-controlled amplifier from the multiplier output of the I and Q demodulation outputs. SOLUTION: This circuit is equipped with a macro signal input terminal 1, subcarrier(SC) input terminal 2, I-axis and Q-axis demodulation output terminals 3 and 4, a macro amplifier 5, a hue adjusting circuit 6, I-axis and Q-axis demodulating circuits 7 and 8, and a 90 deg. phase shifter 9. Further, the circuit is equipped with a multiplier 20, a voltage comparator 21, a reference power source 22, the reference power source 23 for the comparator, a switch 24, a low-pass filter 25, an absolute value detecting circuit 26, and gain-controlled amplifiers 27 and 28 for I-axis and Q-axis demodulation outputs. The gains of the gain-controlled amplifiers 27 and 28a respectively controlled with the absolute value signal of the multiplier output of the I-axis demodulation output and Q-axis demodulation output. Thus, the amplifiers 27 and 28 which amplify the I and Q demodulation outputs are provided and the control voltages of the gain- controlled amplifiers 27 and 28a respectively obtained from the multiplier output of the I and Q demodulation outputs. |
