| 摘要 |
PURPOSE:To demodulate an exact R-Y color difference signal without controlling the phase of the line switch of fH/2, by generating a switching signal when the polarity of an output burst signal does not coincide with the polarity of a chrominance subcarrier provided to the R-Y demodulator. CONSTITUTION:A chrominance subcarrier is oscillated by the chrominance subcarrier oscillator 13 by synchronizing with a burst signal of the PAL system color TV signal, this carrier is provided to one input terminal of the first switch 17 which can be switched at every 1 horizontal scanning line, and a chrominance carrier of the R-Y axis is provided to the other input terminal. Also, a chrominance signal of the TV signal is provided to the R-Y demodulator 6, and also the output of the switch 17 is provided to the demodulator 6. Moreover, the second and third switches 22,26 which can be interlocked and switched, and the fourth switch 18 are provided, and the output of the demodulator 6 is provided to the input of the switch 22. The outputs of the switches 26, 18 are provided to the phase discriminator 27, whether the polarity of the output burst signal coincides with that of the chrominance subcarrier provided to the demodulator 6 is detected, and in the event of inconformity of the polarities, the switches 22, 26 are switched by generating a signal from the FF23. |
