Estimating noise in RF systems

Predicting the noise performance of RF systems is much more complex than for linear ones. The common practice of retrofitting linear noise concepts often leads to wrong answers. For a proper understanding of RF noise, nonlinearities and synchronization, i.e. phase noise in oscillators, have to be accounted for correctly, using stochastic processes. In this tutorial, we outline how to do so for non-oscillatory and oscillatory RF systems. We emphasize basic concepts and important results, while providing sufficient details to maintain rigour. Our presentation covers: basic stochastic concepts for noise analysis; nonstationarity, cyclostationarity and frequency correlation of noise; mixing noise in driven (non-oscillatory) systems; phase noise in oscillators; and computational techniques. Our goal is to enable designers and CAD engineers to understand the basic flow of RF noise analysis and the current literature.