Digital television networks

The paper reviews the analogue networks provided by British Telecom (BT) in the UK for the broadcasting authorities, and outlines the application of digital techniques to telecommunications and television. The digital transmission systems on optical fibre cables, microwave radio and coaxial cables being used by BT to provide high-capacity links at different hierarchical bit rates for the modernisation of the BT telecommunications network are described. The requirements for digital television are outlined with reference to the discussions at CCITT/CCIR/CMTT on international digital standardisation. Particular emphasis is given to the use and properties of high-bit-rate transmission links and performance test methods. The economics of television networks are discussed, together with their likely influence on future network trends.