| 摘要 |
PURPOSE:To improve S/N of a low-frequency conversion carrier chrominance signal and to reduce the delay in the vertical direction by using a decoder and a comb-shaped filter whose frequency characteristic varies in accordance with the vertical correlation of the amplitude of decoded color difference signals to process said carrier chrominance signal. CONSTITUTION:A reproduced low-frequency conversion carrier chrominance signal is inputted to an input terminal 31, then enters a decoder 20, decoded into two color difference signals, then inputted to respective comb-shaped filters 24 and 25. The color difference signals passing through said filters 24 and 25 are rectangular-two-phase-modulated by a modulator 30, and carrier chrominance signals are obtained, then outputted to an output terminal 32. In the comb-shaped filter 24, the demodulated color difference signal passes through an one-hour delay line 21 and is added to a non-delayed signal in an adder 26. For this signal, the prescribed arithmetic processing is carried out by an one-hour delay line 22, an adder 27 and a subtractor 28. Finally, an output twice of the output of adder 26 can be obtained when the vertical correlation of the color difference signal is low and the output of the adder 27 when it is strong, respectively. |
