Survey of characterization techniques for nonlinear communication components and systems

This paper focuses on the measurement and modeling techniques needed for the construction and validation of system-level simulation tools, as well as the diagnosis and specification validation of hardware components and subsystems. A comparison of frequency- and time-domain measurement approaches will first be made, especially as they apply to nonlinear contexts. Based on a key vector network analyzer (VNA)-based technique developed for characterizing frequency-translating devices, a new baseband time-domain measurement system will be described that provides the state-of-the-art accuracy needed for the characterization, verification, and troubleshooting of emerging wideband communication systems. The paper´s second part addresses modeling topics such as fidelity requirements determination, n-box models for power amplifiers, and the polyspectral method, a powerful technique for system-level modeling based on time-domain measurements that can consist of operational digitally modulated signals. Concrete applications of the method to power amplifier modeling will be made, demonstrating the highest predictive fidelity levels of any approach known to the authors