| 摘要 |
PURPOSE:To obtain an R-Y color difference signal whose polarity is correct, by generating a special switching signal from one switch only when the polarity of an R-Y axis component of a burst signal does not coincide with the polarity of a chrominance subcarrier dor demodulation, which is provided to the R-Y demodulator. CONSTITUTION:The first and second static switches 12, 20 which are interlocked and switched only at the time of matching the demodulation polarity are provided, a chrominance signal of a PAL color TV signal is provided to the input terminal of the switch 12, and on the other hand, a chrominance signal whose polarity is inverted to the R-Y axis is provided. The output of this switch 12 is provided to the R-Y demodulator 6, also a chrominance subcarrier oscillator 16 is provided to the switch 20 and the third switch 21, the output of the switch 20 is provided to the demodualtor 6, also the output of the switch 21 is provided to the phase discriminator 25, and the polarity of a burst signal which has been output from the TV signal is detected. When the polarity of an R-Y axis component of the burst signal does not coincide with the polarity of a chrominance subacarrier for demodulation, which is provided to the demodulator 6, a polarity switching signal is generated from the switch 20. |
