| 摘要 |
PURPOSE:To obtain excellent picture quality while fog or blur of color is reduced by transmitting a signal obtained from alternate sampling of a chrominance carrier signal at each horizontal scanning period (1H) to a transmission system and extracting alternately sampling information over >=2H at the reproduction side. CONSTITUTION:The NTSC color video signal incoming to a terminal 1 is fed to a Y/C separation circuit 2 and fed to a synchronizing separator circuit 4 through a switch circuit 3 connected to a terminal R. A horizontal synchronizing signal extracted from the synchronizing separator circuit 4 is fed to a PLL5 and a symmetrical square wave having a sampling frequency fS phase-locked to the horizontal synchronizing signal is generated. The chrominance carrier signal having a band fSC+ or -fC (fSC is sub chrominance carrier frequency) is sampled so that sampling points of adjacent N-line are shifted by tau1/N in the horizontal scanning direction, the sampling period tau1 is selected to a value larger than 1/(N.fC) and smaller than 1/fC, a gate is opened for a period tau2 satisfying an inequality of 1/fSC<tau2<tau1 to transmit the sampled chrominance carrier signal. |
