Application of Compandors to FM Radio Systems with Frequency Division Multiplexing

Compandors are used to improve the intelligibility of speech transmission circuits by increasing the signal-to-noise ratio. Originally developed in the early 1930´s for use with transoceanic radio circuits, they have since been applied to some extent on long distance telephone circuits, usually of the carrier-derived type. Within the past few years new telephone carrier systems have been developed which include a compandor as an integral part of the equipment for each speech channel.