Accession Number : ADA130129

Title :   HF Modem Test and Evaluation.

Descriptive Note : Final technical rept.,


Personal Author(s) : Cosell,Lynn K ; Kolek,Stephen R ; Monsen,Peter ; Perry,Linda C

PDF Url : ADA130129

Report Date : Jan 1983

Pagination or Media Count : 55

Abstract : The objective of this program was to evaluate a recently developed, bandwidth efficient, Decision-Feedback Equalizer 'Fast DFE' serial modem for radio communications in the High Frequency (3-30 MHz) radio band. The experimental model of the modem is realized on an AP-120B array processor. Tests of nonfading, flat and frequency selective fading were performed using a separate AP-120B array processor as the channel simulator. Successful performance of the modem operating at 2900 bps in a 2.7 KHz bandwidth was demonstrated on channels with 2 sigma fade rates up to 1 Hz and multipath delay values up to 5 milliseconds. Under slow fading conditions a significant implicit gain due to the multipath is realized. In a comparison with parallel tone modems, the Fast DFE modem significantly outperformed the USC-10, ACQ-6, and MX-190 modems in all test cases. Results reported here show considerable promise of the Fast DFE configuration and there is every indication that the preliminary design implementation which was tested can be further optimized for superior performance. (Author)

Descriptors :   *Modems, *Adaptive systems, *Multipath transmission, *Atmospherics, *Radio equipment, Fading(Electromagnetic Waves), HIgh frequency, Kalman filtering, Channels, Performance(Engineering), Frequency response, Bandwidth, Value, Models, Delay, Simulators, Parallel orientation, Case studies

Subject Categories : Cybernetics
      Radiofrequency Wave Propagation
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE