| 摘要 |
PURPOSE:To improve picture quality by equipping the video signal scrambling circuit with a signal separator to separate a composite video signal into a luminance signal and a chromaticity signal, a video signal scrambler, a chromaticity signal switching device, and a mixer to mix the output signal of the video signal scrambler and the output signal of the chromaticity signal switching device and output the mixed signal. CONSTITUTION:The composite video signal is separated into the luminance signal and the chromaticity signal by a signal separator 18. Out of the signals, for the luminance signal, the level of the luminance signal is switched to either an inverted level or a noninverted level by a video signal scrambler 4, and the luminance signal is outputted. On the other hand, for the chromaticity signal, the phase of the chromaticity signal is inverted by a chromaticity signal inversion circuit 19, and the chromaticity signal is outputted as an inverted chromaticity signal. Next, the chromaticity signal and the inverted chromaticity signal are inputted to a chromaticity signal switching device 20 and switch-outputted synchronously with the switching of the video signal scrambler 4. Further, the output signal of the video signal scrambler 4 and the output signal of the chromaticity signal switching device 20 are mixed by a mixer 21 and outputted. |
