| 摘要 |
PURPOSE:To enable to receive the signals other than NTSC, by switching the original signal from a delay line and a signal inverted to the original signal from the result of phase comparison between the reference signal and the horizontal detection signal. CONSTITUTION:A video signal 1 is given to a 1H delay line 3 and a 4 fsc clock oscillation circuit 14, which outputs a 2 fsc clock 15. The clock 15 is given to a 1/455 frequency division circuit 16, which outputs the reference signal 21 of 2/455 fsc to a phase comparison circuit 19. On the other hand, a horizontal detection circuit 22 outputs one hoizontal detection signal 21 from a horizontal flyback signal 23 to a circuit 19. The circuit 19 compares both input signals, and if they are coincided, the output signal 4 on a delay line 3 is given to an addition circuit 5 with a Mode discrimination circuit 24, and if not coincided, an inversion signal 11 is given to the circuit 24. Another input to the circuit 1 is the original signal 1 and two times the Y signal 6 is obtained from the circuit 1. The signal 6 is 1/2 times at a division circuit 7 to obtain the Y signal 8. The C signal 10 is obtained from a substraction circuit 9. |
