Wiener-Hammerstein Modeling of Power Amplifiers

Wiener-Hammerstein modeling and memory polynomial models provide a comprehensive framework for characterizing power amplifier behavior. This methodology consists of two complementary components: the Wiener-Hammerstein structure for nonlinear system representation and memory polynomial models for capturing memory effects. The Wiener-Hammerstein approach decomposes the system into sequential linear and nonlinear blocks, typically implemented using FIR/IIR filters for the linear stages and polynomial functions for nonlinear transformations. The memory polynomial model specifically addresses system memory effects caused by frequency-dependent characteristics, mathematically expressed as y(n) = ΣΣ a_km x(n-m) |x(n-m)|^(k-1) where k represents nonlinearity order and m denotes memory depth. Key implementation advantages include efficient parameter extraction using least-squares algorithms and the ability to accurately model both AM/AM and AM/PM distortions. This combined approach effectively characterizes power amplifier nonlinearities and memory effects, making it widely applicable in electronic engineering applications such as digital predistortion systems and wireless communication design.