Factors affecting use and design of spread-spectrum modems for the HF band
A. Nejat İnce, R.E. Schemel · IEE Proceedings F Communications Radar and Signal Processing · 1986
The design of a spread-spectrum modem for HF channels to combat multipath and interference effects is considered, and the performance results obtained with a prototype system are discussed. The features of the modem include automatic synchronisation, diversity operation, provision for an ARQ mode and M-ary block coding.