| 摘要 |
PURPOSE:To omit a gain control circuit for picture control and simplify circuit constitution by using a gain control circuit which makes a white level adjustment even for picture control. CONSTITUTION:A picture control voltage obtained from a variable resistor 10 is converted by a voltage-current converting circuit 60 into a control current Ic, which is applied to multiplying circuits 62R, 62G, and 62B through a switch 61 and multiplied by gain control signals SWB, SWR, and SWB for white level adjustment. Gain control amplifiers 24R, 24G, and 24B are controlled with their multiplication outputs. Consequently, the signals SWR, SWG, and SWB are multiplied by the picture control current Ic while the switch 61 is on, so a white level adjustment is made while the ratio of SWR, SWG, and SWB is held, and picture control is also performed.
|
