“…Acceptable picture quality is defined in terms of signal-to-noise ratios or desired signal-to-interfering signal ratios at the input to the receiver. The quality of pictures as a function of these ratios and the "off-set" of co-channel picture carriers has been studied by a number of authors and organizations [ RCA, 1950;Beherend, 1957;Chapin, et al 1958; Middlekamp,195 8; TASO, 1959; Dean, I960; Towlson and Young, Fine, 1961] . In evaluating these effects, subjective judgments are made and not all viewers will agree as to an acceptable ratio.…”