Satellite communication systems and the diverse engineering techniques which they require

The principles of satellite communication systems are outlined, and a comparison is made between terrestrial radio-relay and satellite systems. The development of the communication satellite is reviewed, from Telstar I to the multi-purpose satellite which will be used in the future. The complex earth-station equipment is briefly described, attention being drawn to the problems associated with the design of large steerable aerials. The interconnexion of a large number of earth stations, an essential feature of a global satellite system, is considered in some detail. The frequency division multiplex technique now being used with the Intelsat II satellite is described, and this is followed by a discussion on the use of digital methods. Reference is made to the advanced concept of a satellite in which incoming carriers are demodulated and channels are switched, multiplexed and used to modulate carriers destined for particular earth stations.