October 1979 | NTIA Technical Report TR-79-29
Methods of Improving the Performances of HF Digital Radio Systems
C. C. Watterson
Abstract: The bit–error–probability performances of HF digital radio systems with respect to channel and equipment additive, multiplicative, and nonlinear distortions are evaluated with respect to the nine system design features that affect the performances. The system design features are the fundamental pulse waveform, the keying method (ASK, PSK, APSK, FSK, and CPK), the multiplexing method (frequency and concentric multiplexing ), the type of demodulator filter (matched and nonmatched nonadaptive filters and quasi–static and dynamic adaptive filters ), the detection method (coherent, partially coherent, differentially coherent and noncoherent), the transmitter power, the antennas, diversity, and error coding. Spectral efficiency (information rate/signal bandwidth) is also evaluated. The best combination of system design features is determined.
Keywords: multipath; adaptive filtering; additive distortion; APSK; ASK; bit error probability; bit error rate (BER); channel model; coding; coherent; CPK; detection; differentially coherent; digital; distortion; diversity; error rate; fading; frequency shift keying (FSK); HF; ionosphere; keying; modem; multiplexing; multiplicative distortion; noncoherent; nonlinear distortion, partially coherent; performance; phase shift keying (PSK); radio; spectral efficiency
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