HF TIME-AND FREQUENCY-DISPERSION EFFECTS-EXPERIMENTAL VALIDATION OF AN FSK ERRORRATE MODEL
B. M. Sifford, H. N. Shaver, Robert F. Daly, K. D. Felperin · Defense Technical Information Center (DTIC) · 1965
An experiment has been conducted to determine the sensitivity of an HF FSK communications system to time and frequency-selective fading phenomena. Binary error rate was measured on AN/FGC-29 teletype terminal equipment over an HF path from Fort Monmouth, New Jersey to Palo Alto, California in the fall of 1964. Simultaneous measurements were made of channel signal-to-noise ratios, channel time-delay profiles, channel Doppler-shift profiles, and signal correlation between spaced antennas. Instrumentation included a phase-stable transmitter-receiver, an oblique-incidence ionospheric sounder, and a special correlation meter. The measured error rates were compared to those predicted by a mathematical model. The model for the channel considers randomly time-varying and frequency-selective effects appropriate for the HF propagation mechanism. The system model approximates the AN/FGC-29 system. Theoretical and measured error-rate curves are presented and discussed. Measured system performance showed a well-defined sensitivity to channel time- and frequency-selective effects. The asymptotic error rates measured at high signal-to-noise ratios are in reasonable agreement with those predicted from the model.