On In-Network and Other Types of Amplifier Descriptions for Nonlinear Distortion Analysis

Basics of modelling analog weakly nonlinear amplifiers at higher frequencies for the purpose of nonlinear distortion analysis are addressed in this paper. First, the constitutive relation for this class of amplifiers, with the use of a Volterra series, is formulated. It is the basis for formulation and derivation of the so-called in-network and input-output type descriptions of an amplifier in the time domain, which are then transferred into the multi-frequency domains. Usefulness of the general models achieved, which were not published up to now in the literature, lies in the fact that they can be used for any topology in which the amplifier is incorporated and for any nonlinear distortion measure assumed. Some examples of calculations are given at the end of the paper for cascade and feedback topologies, and for harmonic distortion measure.