| 摘要 |
PURPOSE:To reduce the effect of a luminance signal component on a frequency band of a carrier chrominance signal by designing the circuit that only a PAL color video signal is applied and the PAL color video signal not including the carrier chrominance signal is outputted as it is, when no chrominance carrier signal exists. CONSTITUTION:When no color difference signal is included in the PAL color video signal, that is, the signal level of the carrier chrominance signal is zero, a color difference signal detecting signal is annihilated, an analog switch 11 is opened, an output of a two-multiplication circuit 6 is not applied to a multiplier circuit 7 and no signal is outputted from the multilier circuit 7, resulting that only the PAL color video signal is applied to an adder circuit 2 to which the output of the multiplier circuit 7 is applied via a low pass filter 8. Thus, when the PAL color video signal not including the carrier chrominance signal is applied to a band pass filter 1 and the adder circuit 2, the supplied PAL color video signal is outputted from the adder circuit 2 as it is. |
