| 摘要 |
PURPOSE:To generate a composite signal for monitoring by balanced-modulating a signal obtained by balanced modulating a first carrier signal with a second carrier with an output from a right-angle two-phase modulator and adding a circuit which adds the abovementioned signal with a luminance signal. CONSTITUTION:The carrier of a low band frequency fC is phase-shifted 42 and directly impressed in a right-angle two-phase modulation circuit 40 and at the same time it is phase-shifted 12 with 90 deg. and impressed, then right-angle two-phase modulated with color difference signals R-Y and B-Y and the output from the circuit 40 and a luminance signal Y are multiplexed 26 so as to generate a recording signal. A composite signal circuit 50 is added to the former device. The carrier from the circuit 40 is balanced modulated with the carrier of the frequency fSC from an oscillator 54 in a balanced modulation circuit 52 and the signal fC+ or -fSC is outputted. The component of fC+fSC is extracted in a BPF 56 and balanced-modulated with the output fC' from the circuit 40 in the balanced-modulation circuit 58. The component of fC + fSC-fC' is extracted in the BPF 60 so as to obtain the right-angle two-phase modulated color signal of the frequency fSC. The luminance signal is added 62 to the signal to output the composite signal.
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