Automatic compensation for inaccuracies in quadrature mixers

[摘要] In an ideal software defined radio (SDR), all parameters are defined in software, whichmeans the radio can be reconfigured to handle any communications standard. A majortechnical challenge that needs to be overcome before this SDR can be realised, is thedesign of an RF front end that can convert any digital signal to an analogue signal at anycarrier frequency and vice versa. Quadrature mixing (QM) can be used to implement andanalogue front end, that performs up and down conversion between the complexbaseband centred around 0 Hz and the carrier frequency. By separating the tasks offrequency conversion and digital-to-analogue conversion, the latter can be performed at amuch lower sample rate, greatly reducing the demands on the hardware. Furthermore, asQM can handle variable carrier frequency and signal bandwidth, this can be done withoutsacrificing reconfigurability. Using QM as an analogue front end may therefore be thesolution to implementing SDR handsets.

[发布机构] Stellenbosch University