Television as a communication problem

The title of the paper is one more indication of a gradual awakening to the necessity for conserving natural resources¿in this case ether spectrum-space. It is becoming increasingly important to achieve maximum efficiency in the transmission of television signals, and this is discussed under two main headings: Broadcast Television, where the choice of system is limited by the cost and maintenance of receiving equipment; and Television Relay, where the cost and complication of the equipment are relatively unimportant so long as a specified service can be established, e.g. transatlantic television. In broadcast television, the terminal equipment, especially the receiver, is likely to exert a decisive influence on the type of system to be adopted; in this country it will particularly affect the choice of colour-television standards. In television relaying, novel, but probably expensive, methods of compressing television signals may find application. In both cases the maximum enjoyment of the programme is an important criterion, and it should be stressed that enjoyment must not be confused with intelligibility. The characteristics of normal vision must be fully exploited, i.e. the television system must be matched to the eye-brain mechanism to give maximum overall economy. In appraising a standard the full theoretical performance must be closely approached in practice; only if that is done will defects such as spurious patterns be revealed and become an annoyance. The system musthave all necessary corrections incorporated (e.g. aperture, amplitude, phase and gamma), and must also have an adequate signal/noise ratio.