Single-tone HF data transmission with 2.4 kbps and 4.8 kbps

In the past few years powerful single-tone modems for data transmission via HF radio links became realizable. These single-tone modems overcome many of the shortcomings of conventional parallel tone-type modems, but it is very important to apply proper designed signal processing algorithms and coding schemes to cope with the disturbing effects on HF radio channels, i.e. with time-varying multipath propagation and strong additive interference. A modem for 2.4 kbps using 4 PSK, adaptive decision feedback equalization (DFE) and Reed-Solomon (RS) coding is dealt with. Some features of 4.8 kbps algorithms using 16 PSK trellis coding and Viterbi algorithm (VA) equalization/decoding are also described.<>