Modern broadcast repeater equipments

An account is given of 4 types of broadcast repeater equipments together with their associated equalization, switching and remote control circuits, designed and produced by Standard Telephones and Cables, Ltd., London. Type 1 is suitable for large switching centres and is capable of accepting a programme from any one of a number of circuits and of feeding the amplified signals simultaneously to all or part of a large group of lines, whose number may be as high as 60 and even 100, the number being liable to variation from time to time. Type 2 fulfils similar requirements for centres where the number of output lines involved is considerably smaller than in the above case, as, for example, where no rediffusion circuits are required. Type 3 is for the case where only one output circuit is to be connected at any given time, and Type 4 is solely for use as an intermediate repeater. Schematic layouts are given of the various types and performance data are furnished regarding gain, input and output impedance, non-linear distortion and power requirements. The methods employed for equalization and for "pre-set" and fully automatic switching are also described in some detail.