WISDOM: a method of synchronising distributed stations to a p.c.m. system

The principles of a method of random access for distributed static stations to a synchronised pulse-code-modulation multiplex system has been described. This paper explains the instrumentation used to build a model to demonstrate the automatic switching of stations to operate in a free channel, and the cross-connection required to apply a store-and-forward technique to pulse-coded signals. The system, which is adapted from one designed for operation with mobile outstations, has a number of limitations. These are considered, and an indication given of the solutions adopted to overcome them in a new demonstration model. The name WISDOM has been derived from `Wing´s self-synchronising delayed-delta orthogonal-channel modulator¿.