Digital signal transfer system - transfers control and acknowledgement signals via highways between telephone exchange and line concentrators

摘要

The digital signal transfer system transfers control and acknowledgement signals via highways between telephone exchanges and line concentrators. It has a fast transfer speed. It can be readily integrated since it uses no analog components like band pass filters. The transmitter and receiver employ two frequencies to generate and receive pulse telegrams. The two frequencies are in a ratio of 2:1. A step-function generator produces the pulse telegrams. The receiver contains a phase control circuit with VCO and differentiators for positive and negative voltages.