The Recommendation considering that the hypothetical reference circuit is intended as a guide to designers and constructors of actual systems; that the costs of establishing and maintaining systems in the fixed-satellite service are critically dependent on the video bandwidth and the overall signal-to-noise ratio to be provided and these should, therefore, not be greater than is strictly necessary for acceptable transmission.
ITU-R S.354-2 FRENCH-1974 history
1974ITU-R S.354-2 FRENCH-1974 Video bandwidth and permissible noise level in the hypothetical reference circuit for the fixed-satellite service