Abstract: The high-definition RGB television signal is converted on one side into a normal-definition color TV signal according to a chosen current standard (NTSC, PAL or SECAM), and on the other into a high-definition color TV signal slowed to a frame frequency which is a submultiple of the original scanning value, and the two color TV signals are transmitted on two independent earth TV channels or on a satellite channel. In reception, said normal-definition signal is converted into a first TV signal with a scanning frequency matching that of high definition, and said slowed high-definition color signal is converted into a second high-definition signal having its original frequency, and said first converted signal and said second converted signal are applied to a high-definition TV display respectively for the moving portions of the picture and for the fixed portions of the picture.

Abstract: In order to improve the quality of color television signals for broadcasting via satellite, the signals are transmitted on two of the channels available for transmission via satellite according to the rules established by CCIR. In the case of transmission by means of a compatible system, the NTSC, PAL or SECAM signal is transmitted on the first of the two channels and on the second channel there are transmitted the baseband R-Y and B-Y signals at from 0 to about 3 MHz sequentially on alternate lines and up to the limit of the video band the high frequency components of the luminance signal.