Accession Number : AD0766256

Title :   Description of a Speech Modulation Experiment Involving Infinite Clipping,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF SYSTEMS ENGINEERING OPERATIONS

Personal Author(s) : Johnson,Walter A. ; Zamites,Charles J. , Jr

Report Date : 01 SEP 1973

Pagination or Media Count : 42

Abstract : A speech modulation system designed to operate a low carrier-to-noise ratios is described. Infinite speech clipping and phase-shift keying are used in the system, which occupies a bandwidth of 10 kHz. Sample speech tapes were produced at simulated carrier-to-noise ratios varying from +10 to -3 dB. The corresponding ratio of carrier power to noise power per unit bandwidth was varied from 50 to 37 dB above 1 Hz. In the simulated circuit, a 20-kHz biasing tone is used to suppress noise during pauses in speech. A phase lock loop in the receiver that is used to derive the detector reference is described. Some preliminary results determined by the use of the simulated link are presented. (Author)

Descriptors :   (*SPEECH TRANSMISSION, *PHASE MODULATION), LIMITERS, INTELLIGIBILITY, PHASE LOCKED SYSTEMS

Subject Categories : Voice Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE