| 摘要 |
PURPOSE:To reduce the saturation of a charactor multiplex screen in case of a mixed screen by applying the amplifier of a multiplex character signal circuit with a positive voltage for a character multiplex screen or no voltage for a TV video screen or mixed screen of a TV image and multiplexed characters. CONSTITUTION:A chromaticity signal of a TV image is input to the base of amplifying transistor TR10, a luminance signal of the TV image from terminal 8 to the emitter. A multiplex character signal, on the other hand, is applied from input terminal 20 to the emitter of TR10 through an amplifier including TR16 and a signal from a character multiplex signal demodulator that is not shown in the figure is supplied to base input terminal 21 of amplifier TR17 connected to TR16 at their collectors. Then, its signal input is applied with a positive voltage for a character multiplex screen or no voltage for a TV video screen or mixed screen of the TV image and multiplexed characters. Consequently, the saturation of the character multiplex screen can be reduced at the time of the mixed screen. |
