| 摘要 |
PURPOSE:To project an inexpensive, abstract video at high operability by blanking the output video signal of a video processing circuit with the aid of horizontal and vertical blanking pulses. CONSTITUTION:A video intermediate frequency amplifier circuit 3 in a television receiver 9 outputs a video detection output signal V to both the video signal processing circuit 5 and a synchronous separator circuit 11 in an external video signal processor 19. Horizontal and vertical synchronizing signals Hs and Vs are outputted to stepped wave generator circuits 12 and 13, respectively. The outputs of voltage comparators 14-17 are wired and connected to constitute a wired OR circuit 18, lts output signal Ys is composed of the outputs C of the voltage comparators 14 and 15 and the outputs D of the comparators 16 and 17. A blanking and switching circuit 6 switches the primary color signal outputs R1, G1 and B1 of the circuit 5 and external primary color signals R2, G2 and B2 with the aid of the signal Ys, and outputs them to an output ampli fier circuit 7. While the blanking and switching signal Ys is at a high level, the output signal of the blanking and switching circuit 6 becomes an earth level to attain a blanking state.
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