Digital post-processing for reducing A/D converter nonlinear distortion in wideband radio receivers

This article addresses the reduction of analog-to-digital (A/D) converter nonlinearities in radio receivers using digital signal processing (DSP). The main focus is on wideband A/D conversion where a collection of different waveforms at different frequency channels is digitized as a whole. The overall dynamic range in such composite signal can easily be in the order of tens of dB's, especially in the emerging cognitive radio type developments, and the nonlinear distortion due to strong carriers can easily block the weaker signal bands. In this article, DSP-based post-processing is proposed and demonstrated for reducing the effects of A/D converter integral nonlinearities (INL), stemming from unintentional deviations in the quantization intervals, as well as clipping due to improper input conditioning in wideband radio receiver context.