TIME DIVISION MULTIPLEXED TRANSMISSION SYSTEM FOR TELEPHONE OR LIKE SIGNALS WITH FREQUENCY BAND COMPRESSION

摘要

A digital transmission system for time division multiplexed transmission of multiple digitized telephone or similar signals is disclosed. The system achieves frequency band compression comparable to the conventional Digital Speech Interpolation system while eliminating the possibility of echo. An input circuit receives the input signals, converts them to linear signals as necessary and supplies them to a code converter where the digital signals are subjected to high efficiency code conversion such as adaptive differential P.C.M. with one bit or a greater number of variable bits based on code-converting-bit-number (C.C.B.N.) information supplied from a bit-number-assigning circuit. The output of the code converter is passed through a selection circuit to a multiplexer and to CCBN information of each channel is also sent to the multiplexer. A timing circuit supplies timing signals to all of the above named circuits.