The possibility is considered of employing pulse-code modulation (p.c.m) signals carried over wide-band links, to distribute the sound signals from the radio or television programme sources to the various transmitters and the use of a Post Office p.c.m. network for this purpose is discussed. Experimental equipment has been constructed for coding and decoding broadcast-quality sound signals.

One of the applications of p.c.m. envisaged for the near future is the incorporation of the sound signal associated with a television programme into the video waveform for distribution over existing link. Suitable equipment for combining and separating sound and vision signals at the sending and receiving ends of a link has been constructed.

It is concluded that p.c.m. systems can now be designed to meet all the requirements, both technical and operational of a high-quality sound distribution network.