| 摘要 |
PURPOSE:To easily attain making the processing stable and sure at the reception side by superimposing a pseudo random pulse train and a setup pulse for cancel ling the BC component at the sending side of a video signal onto horizontal scanning lines apart by an even number from each other. CONSTITUTION:A pseudo random pulse signal string including a video signal frequency component is superimposed on a 1st scanning period of a video signal coming to a line l3. A random pulse string including the DC component is fed to a line l4 and a setup pulse signal corresponding to the DC component of the random pulse train is fed to a line l5. Outputs of the lines l4, l5 are given to LPFs 5, 6 and extracted from lines l6, l7 and fed to a switch 7. The switch 7 selects the lines l6, l7 to superimpose the random pulse train or the setup pulse onto a 2nd scanning period apart from the 1st scanning period by even number of horizontal scanning periods. The signals between the 1st and 2nd scanning periods are calculated to exclude the horizontal synchronizing signal and the burst signal to cancel the DC component. Thus, the distortion detection at the reception side is simplified.
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