| 摘要 |
PURPOSE:To enlarge the modulation factor of a video signal or the band of a sideband by inserting a synchronizing signal to immediately before a luminance signal component and immediately before a color difference signal component, respectively and alternate ly repeating the inversion and the non-inversion in the level of the polarity of the synchronizing signal at every horizontal scanning period and transmitting them. CONSTITUTION:A digital signal supplied to a DA converter 8 is DA converted herein, the overlapping distortion due to the DA conversion is removed in a low pass filter 9, and a high frequency component is removed for the purpose of removing a cross modulation during an FM modulation in an FM modulation circuit 11 of a rear state. The output signal of the low pass filter 9 is supplied to a discrimination signal addition circuit 10, herein a speed decision signal corresponding to the reading speed set in a control circuit 6, a frame discrimination signal indicating the start and the end of a frame and the synchronizing signal such as a timing flag indication the start and the end of the luminance signal component and the color difference signal compo nent are superimposed thereon, to have a serial component signal. In this case, the polarity of the synchronizing signal is inverted at every 1H, however, the picture signal of the luminance signal and the color difference signal is not inverted.
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