Accession Number : AD0645571

Title :   WIDEBAND DIGITAL MODULATION AND DETECTION TECHNIQUES FOR TROPOSCATTER.

Descriptive Note : Quarterly rept. no. 1, 1 Jul-30 Sep 66,

Corporate Author : COMMUNICATION SYSTEMS INC PARAMUS N J

Personal Author(s) : Levine,E. ; Adams,R. T. ; Grobert,P.

Report Date : JAN 1967

Pagination or Media Count : 45

Abstract : The objective of this investigation is to identify and implement in breadboard from the technique offering the best performance in the transmission of high digital data rates (primarily 2.3 mbps) over tactical troposcatter paths of 50 to 150 miles at 5 gHz. The study is concerned with higher order modulation coding and other techniques that may bring about an optimal match to counteract the fading and multipath variation normally encountered on troposcatter circuits. A preliminary analysis was made of several modulation techniques, both conventional and newly proposed, with emphasis on attaining the desired bit rates in the presence of multipath propagation. Another consideration which was given some attention was the desirability of exchanging maximum bit rate capacity for single antenna in-band diversity under certain conditions. An experimental investigation of several proposed circuit techniques was also initiated. This work was limited to active filter circuits applicable to any coherent detection scheme likely to be chosen for implementation. The results of this work were favorable, indicating feasibility of key elements in such a filter. (Author)

Descriptors :   (*DATA TRANSMISSION SYSTEMS, *MULTIPATH TRANSMISSION), BROADBAND, MODULATION, DIGITAL SYSTEMS, TROPOSPHERE, SCATTERING, SUPERHIGH FREQUENCY, CIRCUITS

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE