| 摘要 |
PURPOSE:To prevent the generation of moire and to apply large modulation in a low carrier wave, by controlling the frequency of the carrier wave and input information signals so as to provide a prescribed relation. CONSTITUTION:After a chrominance carrier signal is converted into signals in low frequency at a frequency conversion circuit 6, the signal is applied to an angular modulation circuit 20. The circuit 20 is provided with a comparison circuit 21. A reference wave signal as well as a low frequency conversion chrominance carrier signal is applied to the comparison circuit 21. A reference signal in a chrominance subcarrier frequency is outputted from a reference wave signal generator 22, applied to a multiplier 24 forming a frequency converter 23, and the output is applied to a sawtooth wave signal conversion circuit 27 via a low pass filter 25 and a multiplication circuit 26. The output of the circuit 27 is given to the comparator 21 as the reference signal. A PM modulation signal is outputted from the comparator 21. |
