| 摘要 |
PURPOSE:To simplify the constitution of a circuit for extracting a reference signal, and to modulate and demodulate a color video signal by applying phase modulation to one of a color signal and a luminance signal, and multiplexing the reference signal of a frequency two times of its center frequency of a carrier wave. CONSTITUTION:The frequency of output signal of an oscillator 10 of a recording system of a system is divided into two by a frequency divider 11, applied to a phase shifter 12, and three kinds of carriers Asinomegact, Acosomegact and Asinomegact are outputted. A chrominance signal for phase-modulating the output signal of this oscillator 10 is set to a frequency two times of the frequency of a center carrier fc. A chrominance signal CRt is made by adding this -Asinomegact to a balance modulator 13 together with a color signal ER-Y, and synthesizing the result with Acosomegact. Also, a color signal EB-Y and a carrier chrominance signal CBt which has processed Acosomegact by a balancing modulator 15 are synthesized by a synthesizer 16. Subsequently, a reference signal which has passed through a BPF40 is applied to a synthesizer 17, and a carrier chrominance signal multiplexed by the synthesizer 16 and a carrier luminance signal which has passed through a BPF42 are synthesized. In such a way the constitution of a circuit is simplified. |
