COMPANDING OF VOICE SIGNAL FOR SIMULTANEOUS VOICE AND DATA TRANSMISSION

摘要

Companding of Voice Signal for Simultaneous Voice and Data Transmission In a simultaneous voice and data communications system, a voice signal is added to a data signal before transmission over the public switched telephonenetwork (PSTN). In particular, in every signaling interval, a signal point is selected for transmission as a function of both the voice signal and the data signal. Since the voice signal is effectively offset by the data signal, compandors normally found in the PSTN are not effective in improving the signal to noise ratio of the transmitted voice and data signal. Therefore, the voice signal is additionally companded in the transmitter before transmission over the PSTN. This additional companding by thetransmitter improves the signal to noise ratio of the combined voice and data signal.