Sensitivity of a 1.4 GHz direct-sampling digital radiometer

This paper presents a novel direct RF sampling receiver architecture that will greatly facilitate the implementation of higher spatial resolution satellite radiometers for improved near-term climate forecasting. Direct-sampling is especially suitable for integration onto the distributed, multiple element platform used in L-band synthetic thinned array radiometry (STAR). To evaluate the direct-sampling concept, the authors have developed a statistical model that predicts the worst case radiometric sensitivity for a 1.4 GHz digital receiver. Theoretical results show that only 2-3 bits of converter resolution are needed to approach the performance of an ideal analog radiometer and that sampling jitter will not significantly degrade the performance of STAR.