A practical method for modeling amplifier nonlinearities

A practical and efficient method to quickly model and evaluate the nonlinearities of an amplifier is presented. The proposed approach is based on “polyfit” function, provided by Matlab. As a demonstration, this method is applied to modeling amplifier nonlinearities in sigma delta modulators, however it can be applied to other type of circuits as well. This method provides the designer good accuracy (within a few dBs). At the same time it provides the speed advantage of high level programming environments like Matlab, Simulink etc. Simulation results are presented to validate the concept.