Abstract :
The principles used to derive the existing performance requirements for the transmission of the Pal colour signals used in the UK, as embodied in a CCIR Recommendation, are briefly reviewed, and the need to relate objective performance figures to the corresponding subjective effects is pointed out. An account is given of the changes proposed in a new CCIR Draft Recommendation that gives unified methods of measurement and performance requirements for international connections which, at different times, may carry colour-television signals to any of the Pal, SECAM or NTSC standards. It is shown that although some of the new proposals are somewhat different in form, they are neither significantly more nor significantly less stringent than the existing require ments for System I. Progress in the related field of subjective studies is also reviewed, and the available results relating to Pal colour television are collated and expressed in terms which seem likely to become an international standard. Another imortant feature affecting the operation of a television network is the effect of variability of the individual performance parameters on the overall quality of service. Some preliminary work in this area, which produced unexpected results, is reviewed and its significance in the overall design of television networks is discussed.
