TV bandwidth compression techniques using time-companded differentials and their applications to satellite transmissions

This paper describes various methods to compress the bandwidth of a National Television System Committee (NTSC) color TV signal. The methods are based on taking differences between adjacent or successive scan lines and then performing time companding on these differential signals. In the three specific methods outlined, a 4.2-MHz TV signal can be bandwidth-reduced to 3.34 MHz, 2.9 MHz, and 2.5 MHz, respectively, without loss of picture quality. When these techniques are used with time-compression multiplexing in satellite transmissions, high spectral efficiency can be obtained. Examples are shown where the transmission of two or three broadcast-quality TV's per 36-MHz transponder are possible with existing technology.