| 摘要 |
PURPOSE:To lock always both signals in phase and to suppress the fluctuation due to phase difference, by controlling the phase of a color signal separated from a video signal delayed by 1H, or the delay time of the 1H delayed signal, by using the color signal separated from the video signal. CONSTITUTION:A regenerative FM input signal 1 is demodulated by a FM demodulator 3(a), supplied to a switching circuit 9, BPF 5(a) and a synchronization separating circuit 20, and switched to a 1H delayed video signal 14 by the detection pulse of a dropout detection circuit 8 in the circuit 9. The 1H delayed video signal is demodulated by a FM demodulator 3(b) in a 1H glass delay line 2 and supplied to a gate circuit 19(b) via a BPF 5(b) and limiter 16(b). The output of the BPF 5(a) is supplied to a limiter 16(a) and gate circuit 19(a). The circuits 19(a) and 19(b) are controlled by the output of a pulse separation circuit separated by the circuit 20, and both video signals are compared in phase by a phase comparing circuit 17. According to the result of the phase comparison, a phase controlling circuit 18 is controlled, and the video signal 14 is outputted from a adding circuit 7(b). |
