Enabling technologies for software defined radio transceivers

This paper discusses the design considerations related to the transceiver hardware elements within a software defined radio (SDR). Receiver architectures are reviewed and the viability of manufacturing these in the short to medium term is considered. The filtering functions required for a conventional receiver are examined, and the problems associated with implementation of these filters within a SDR receiver discussed, including that of image filtering. Receiver linearity requirements are evaluated in terms of typical user applications and it is shown that these will be onerous in the case of a SDR receiver. A novel technique for mixer linearisation is presented as a potentially enabling element within a re-configurable transceiver and some initial performance results are reported. The possibility of constructing an electronically tunable preselection filter using micro-electromechanical systems (MEMS) technology is examined. Some simulation and prototype measurement results are presented.