A MULTIPLE ACCESS VOICE COMMUNICATIONS SYSTEM FOR USE IN STS SPACECRAFT IS PROPOSED.

A MULTIPLE ACCESS VOICE COMMUNICATIONS SYSTEM FOR USE IN STS SPACECRAFT IS PROPOSED. STS CREW MEMBERS WOULD WEAR A LIGHTWEIGHT BATTERY-POWERED, (RADIO) TRANSCEIVER HEADSET WHICH OPERATES THROUGH A FULL-DUPLEX, MULTIPLE (SIMULTANEOUS) ACCESS, RADIO REPEATER. THE PROPOSED SYSTEM UTILIZES AN ADAPTIVE NOISE CANCELLATION PROCESSOR (ANCP) FOR REDUCTION OF NOISE COMPONENTS CREATED BY ENVIRONMENTAL CONTROL SYSTEM EQUIPMENT AND OTHER SOURCES. THE ANCP UTILIZES A POWERFUL ALGORITHM, PREVIOUSLY DEMONSTRATED WITH ACTUAL HARDWARE. THIS PRIOR DEMONSTRATION ACHIEVED IN EXCESS OF 40DB NOISE REDUCTION BUT REQUIRED CONSIDERABLE OPERATOR INTERVENTION AND WAS LARGE AND COSTLY. THEREFORE, THIS PROJECT IS DIRECTED TOWARD ACHIEVING A SMALL, LOW COST, LOW POWER, AUTOMATED SYSTEM. FOR THIS PURPOSE, A SOPHISTICATED, MULTI-STAGE PROCESSOR IS REQUIRED WHICH NECESSITATES AN INNOVATIVE APPROACH. DEFINITION, CONSTRUCTION, AND EVALUATION OF A SINGLE-STAGE ANCP PROTOTYPE IS THE FOCUS OF PHASE I. A STUDY EFFORT ADDRESSES FEASIBILITY AND PERFORMANCE OF A MULTI-STAGE ANCP. THE SINGLE STAGE PROTOTYPE WOULD TEST IMPLEMENTATION REFINEMENTS, VOICE QUALITY, AND NOISE REDUCTION LIMITATIONS.FURTHER, ALGORITHM CHARACTERISTICS AFFECTING MULTI-STAGE PERFORMANCE ARE INVESTIGATED WITH THE PROTOTYPE.