R&D Report 1978-31 : 'CARFAX' traffic information service: an analysis of the characteristics of the ring system and receiver activation. M.J. Kalloway
The Report describes the development of a modified form of the original BBC proposal for a Traffic Information Service known as the 'ring' system. In the ring system, the motorist's receiver selects the strongest signal available from local transmitters by making use of the fm 'capture' effect in conjunction with an fm signalling system. The Report concludes that the system should perform well in practice, with low-cost receivers. The nature of the system also allows the effective service areas of transmitters to be controlled.