| 摘要 |
PURPOSE:To avoid a shift of the white balance, by preventing the occurrence of an error of the DC potential between the blanking period of a video signal and the period of other signals. CONSTITUTION:During the blanking period, an emitter current IE of a transistor TR3 flows through a TR31 in the form of a constant current I42. The current IE flows through a TR32 in the form of a constant current I43 during the video signal period excepting the blanking period. Then both the constant current circuits 37 and 38 are set so as to satisfy I42=I43 in both the blanking period and other video signal period. As a result, the emitter current IE flows with a constant level in both the blanking period and other video signal period. Thus no change occurs to the current IE to avoid a shift of the white balance with a picture image. |
