SIMULTANEOUS VOICE AND IN-BAND DATA

Abstract

This thesis presents a new technique for simultaneously transmitting in- band data and analog voice on a standard telephone voice-grade line. A portion of the speech spectrum is replaced with a medium speed digital data signal so that both speech and data signals are carried on a telephone channel to a remote receiver. In this work, a range of frequency components is removed from the mid-band region of the human voice spectrum. The modem then transmits data in this mid-band range. Processing at the receiving end separates the voice and data signals and demodulates the data for use by a computer. The thesis describes a prototype system and presents experimental data gathered from several tests. The thesis also discusses advantages and disadvantages of the "data in voice" modulation technique and proposes new services which could not be supported with current voiceband modems.