NICAM 3: near-instantaneously companded digital transmission system for high-quality sound programmes

The paper describes a system, known as NICAM 3 (Near-Instantaneously Companded Audio Multiplex, Mark 3), which is being developed by the BBC for the transmission of sound programmes on digital circuits designed for multi-channel telephony. Subjective tests which led to the choice of this system are referred to, and the system design, which is based on a compromise between efficiency and flexibility, is discussed in some detail. Various applications are mentioned, the main one being for six channels in a dedicated bit-stream of 2048 kbit/s, but other arrangements are possible, including mixed telephony and sound-programme working.