Accession Number : AD0874038

Title :   Group Modem Terminal Study.

Descriptive Note : Final technical rept. 17 Jul 69-17 May 70,

Corporate Author : HONEYWELL COMMUNICATIONS DEVELOPMENT CENTER ST PETERSBURG FL

Personal Author(s) : Dougherty, F. J. ; Simmons, B. E. ; Tisdale, W. R.

Report Date : AUG 1970

Pagination or Media Count : 129

Abstract : An all digital transmission technique consisting of pulsed phase modulation in a frequency division format was investigated for use over a 48 kHz group channel. A breadboard feasibility model of one channel of this modem was constructed and tested. On the basis of analytical and experimental evidence it was determined that operation at the design goal of 76.8 Kbps with an E sub o/N sub o of 18.5 db and an error rate of less than one error in 100,000 bits was not possible and that this technique offered no practical advantages over a more conventional DPSK system. The remaining effort was devoted to the computer simulation of a 153.6 Kbps group modem terminal with automatic equalization. Both VSB-PAM and SSB-PAM Partial Response Systems employing automatic equalization were simulated operating over several group channel and interconnect filter configurations. The equalization and signal-to-noise requirements were investigated, as were the effects of baud timing and carrier phasing. An analysis of compensation for 18 degrees of peak-to-peak phase jitter at 60 Hz was also performed. (Author)

Descriptors :   (*DATA TRANSMISSION SYSTEMS, DIGITAL SYSTEMS), PHASE MODULATION, MULTIPLEXING, MODULATORS, DEMODULATORS, POWER SPECTRA.

Subject Categories : Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE