The Design Method and Performance Analysis of RF Subsampling Frontend for SDR/CR Receivers

RF subsampling can be used by radio receivers to directly down convert and digitize RF signals. The goal of software-defined radio (SDR) design is to place analog-to-digital converter (ADC) as near the antenna as possible. Based on this, an RF subsampling frontend (FE) for SDR is designed and verified by a hardware platform. The effects of timing jitter, ADC resolution, and folding noise dominating SNR degradation sources in the digital FE were considered. We present an efficient method of SNR measurement and an analysis of its performance. The experimental results indicate that the three degradation sources are sufficient to estimate the performance of the RF subsampling FE, and this conclusion matches the theoretical analysis results.