Accession Number : AD0768999

Title :   Adaptive Data Transmission Study.

Descriptive Note : Final rept. Sep 72-Jun 73,

Corporate Author : SIGNATRON INC LEXINGTON MASS

Personal Author(s) : Monsen,Peter ; Richman,Steven H.

Report Date : AUG 1973

Pagination or Media Count : 217

Abstract : *DATA TRANSMISSION SYSTEMS, INTERSYMBOL INTERFERENCE, VITERBI DECODING, SIGNAL PROCESSING, *TROPOSPHERIC SCATTER COMMUNICATION, MAXIMUM LIKELIHOOD ESTIMATIONA study was completed of feasible techniques for transmission of up to 13 megabits/second over a tropospheric-scatter channel. The techniques identified for this study were frequency-division-multiplex/frequency modulation, parallel processing of subchannel data, transmitter time-gating, receiver time-gating, coding techniques, maximum likelihood detection including the Viterbi algorithm, and adaptive equalization. The investigation considered a realistic channel model and terminal equipment constraints in a determination of technique performance, adaptability to a changing multipath channel, and implementability. A practical realization of a feedback equalizer was found to have superior performance relative to all other practical receivers considered. Moreover, the equalizer performance was within 1 dB of a bound for an ideal maximum likelihood decoder. (Modified author abstract)

Descriptors :   (*INFORMATION THEORY, DATA TRANSMISSION SYSTEMS), (*PULSE COMMUNICATIONS, ADAPTIVE SYSTEMS), COMMUNICATION AND RADIO SYSTEMS, CODING, DECODING, FREQUENCY MODULATION, MULTIPLEXING, FREQUENCY DIVIDERS, ERRORS, PROBABILITY, STATISTICAL ANALYSIS

Subject Categories : Cybernetics
      Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE