A high performance HF software radio

With the development of affordable high performance analogue-to-digital converters and digital signal processing (DSP) technology, intermediate frequency digitisation has become increasingly popular. Now, for the first time, direct sampling, all-band digital receivers are finally becoming possible for use at HF frequencies. This class of flexible, highly re-configurable receivers, commonly termed software radios, digitise the entire band of interest and then use DSP algorithms to select, down-convert and demodulate signals of interest. This paper provide an introduction to the technology developments that are making software radios possible. A high performance, HF software radio transceiver architecture, employing direct whole-band digitisation, is introduced. The critical performance requirements dictated by the HF environment and the intended applications are identified. These are then used as a context to explain the design choices that were made in the development of a multichannel all-digital transceiver. The theoretical performance limitations of the design are analysed and shown to agree closely with performance results obtained from a laboratory prototype. Finally, the potential for application of this technology to multi-band, multi-mode radios is considered.