Relationship between a pruned volterra model structure and impairments in an I/Q modulator

Abstract

The main contribution of this paper is the derivation of theoretical relationships between the impairments in an I/Q modulator and their impact on the structure of the kernels of a Volterra behavioral model. The analysis is focused on the imperfections produced by I/Q gain imbalance and quadrature error and shows how the model coefficients depend on the impairment strength. Closed-form expressions are experimentally validated with a commercial I/Q modulator for which artificially-added impairments were swept and modeled through a general complexvalued Volterra model. The excellent correspondence between measurements and analysis can help to the joint modeling of a modulator and a power amplifier connected in cascade.