Abstract :
The paper discusses the benefits to be obtained by the use of automatic and remote control techniques, and explores the factors which have determined the rate of progress in introducing such techniques. Two major constraints that have affected the introduction of unattended stations, namely the reliability of television and radio transmitting equipment, and the ability to measure automatically and satisfactorily those parameters of the transmission which are indicative of a fault condition. Concurrently with the development of reliable equipment and measuring systems, there have also been developments in the field of data transmission, including telemetry and remote control systems, which have significantly contributed to the system design of unattended and remotely controlled stations. The paper begins with an examination of those factors which contribute to the reliability of television and broadcast-transmission systems, and discusses the choice of components, layout of equipment, and the overall system design. A description of standby systems is given together with the associated control systems. The use of control systems always involves the ability to measure, and, if the control systems are to be automatic in operation, then the measurements must also be automatic. The paper therefore examines the problems of automatic measurements in television and sound-transmission systems. These automatic measurement systems are not yet fully comprehensive, and most broadcasters therefore supplement the automatic control system with manual override functions which can be exercised at a distance. This creates the need for telemetry and remote control systems. The methods of providing remote control to override the automatic systems and to relay operational data to the control points are described. Finally, the paper describes some of the methods employed by broadcasters in Europe and South Africa showing how these features have been combined to provide automatic and remote- - control of national or regional networks of television and broadcasting transmitting stations. The paper represents the ?state of the art? as it was in 1976. Since that time, there have been developments, coupled with improvements in the reliability of equipment and the introduction of digital techniques within the signal-transmission paths. It is hoped that the paper will serve as a useful background to the subject.
