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.