| 摘要 |
PURPOSE:To reduce cross modulated beats and to improve picture quality in a part where a color level is comparatively high by reducing the noise component included in a demodulated luminance signal only while the level of a reproduced color signal exceeds a specified level. CONSTITUTION:The reproduced color signal outputted from a BPF 12 is branched and detected by a peak detector 22. The detected output is compared with a reference bias 25 in a comparison circuit 23 and a control input 24 is added to the switch 26 of a noise reduction circuit 21 in case of exceeding a reference value. Namely if the amplitude of the reproduced color signal exceeds the certain level, the switch 26 of the noise reduction circuit 21 is switched ON and the noise components included in the luminance signal are reduced. When the level of the reproduced color signal is lower than a certain level, the switch 26 keeps OFF and the noise reduction circuit 21 does not actuate, then the output, itself, from an LPF 7 is added to an adder 9.
|
