COMMUNICATION SYSTEM USING TIME-DIVISION MULTIPLEXING AND PULSE-CODE MODULATION

摘要

Thirty-six voice channels and their accompanying signalling are provided (over one pair of wires or one circuit for each direction of transmission) using time-division multiplexing and pulse-code modulation. The voice channels are carried by 36 respective channels, and the signalling is carried by a 37th channel which also provides alarm and framing information. The amplitude of each of the 36 voice channels is sequentially sampled and time-division multiplexed. Each voice sample is encoded as seven binary pulses. Binary signalling pulses are then time-division multiplexed after each frame of pulses for the 36 voice channels. Each successive group of four binary pulses is converted into a group of three ternary pulses at a reduced frequency for transmission. At the receiver, the ternary pulses are converted back to binary pulses which are then decoded and demultiplexed to respective voice and signalling channels.