Multichannel communications system with TDM - with speech and data transmission and synchronising by way of data channel

摘要

The transmission system has a number of broad band channels (2-15), for example for speech transmission, and narrow bands (1'-16') for data signals. The latter are first applied to a sub-multiplexer (23), emerging as a single channel (16) to the main multiplexer (21) processing all the channels. The receiver end is similarly arranged. The synchronising channel carries an n-bit synchronising word in which the number of bits (n) is equal to the number of narrow band channels associated with the sub-multiplexers. With this arrangement each data channel is interrogated once in each cycle of the multiplexer scan. One particular bit in the synchronising word is associated with a specific data channel. The application of the multiplexer system is typically to mobile telecommunications systems.