Abstract :
Two sets of data are fundamentally required to describe a television picture, one giving the significant changes of brightness, and the other the positions of such changes. The total information content is calculated according to Shannon, and the means are discussed for reducing bandwidth by redistributing the data in time so as to achieve a constant rate of transmission. Maximum compression is achieved by treating the two sets of data as independent quantities, and using two channels for their transmission. A compromise may be adopted, however, in which almost the maximum bandwidth compression is achieved using a single channel at the cost of an increase of signal power. The method is flexible in that it permits of an exchange to be made between the size of picture element and the continuity of grey scale, for a minimum stated bandwidth.
