| 摘要 |
In an orthogonal phase modulation method the first and second carriers perpendicular to each other are PM modulated by one of the two color signals or of the two luminance signals, at least one of the four signals consisting of two PM signals, the first and the second carriers are inverted or phase-shifted per 1 horizontal scanning period in such a way that these two PM signals will become phase-shifted by 180 degrees relative to each other per one horizontal scanning period by the time these two PM signals reach their inputs, and these PM signals phase-shifted by 180 degrees relative to each other are multiplexed for inputs in said input means. In a demodulation method, PM signals multiplexed by the PM modulation method are delayed by 1 horizontal scanning period and separated into two PM signals by addition and subtraction before and after the delay, and then the thus separated respective PM signals are PM demodulated by phase-shifting the phase reference signals similarly as in the modulation method.
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