18.2.1 The Infrastructure of Broadcasting

A complete broadcasting chain comprises many parts; the significant ones are:

1. Programmes and their production. These can be preprepared and purchased externally, e.g. films, or specially commissioned and produced for television. Programmes are often produced in segments in different places over a period of time and transmitted to a studio using high-quality links, or they can be live. This is the contribution process. In North America this is called back haul.

2. The compilation of the completed programmes into an advertised schedule and their presentation in an orderly sequence. This is often called playout. The location of the playout facilities need not coincide with the production location.

3. Network transmission from the playout centre to the terrestrial transmitter, satellite uplink site or cable head from where the signal is transmitted. This is the first stage of the distribution process and is known as primary distribution.

4. The emission or radiation of the signal from terrestrial transmitter or satellite. This second stage of distribution is known as secondary distribution. Technically, the satellite is only a repeater but actually does the broadcasting; transmitting to the satellite is part of the distribution process, but normally is deemed to be part of broadcasting. If, in the future, satellites with onboard processing capability, e.g. switching or multiplexing, become available then broadcasters will surely be among the early users of such techniques to enhance their services.

5. An industrial infrastructure which makes available to the viewers a range of realistically-priced receivers.