The Frequency Domain Behavioral Modeling and Simulation of Nonlinear Analog Circuits and Systems

LUNSFORD II, PHILIP J. The Frequency Domain Behavioral Modeling and Simulation of Nonlinear Analog Circuits and Systems. (Under the direction of Michael B. Steer.) A new technique for the frequency–domain behavioral modeling and simulation of nonautonomous nonlinear analog subsystems is presented. This technique extracts values of the Volterra nonlinear transfer functions and stores these values in binary files. Using these files, the modeled substem can be simulated for an arbitrary periodic input expressed as a finite sum of sines and cosines. Furthermore, the extraction can be based on any circuit simulator that is capable of steady state simulation. Thus a large system can be divided into smaller subsystems, each of which is characterized by circuit level simulations or lab measurements. The total system can then be simulated using the subsystem characterization stored as tables in binary files. Using known ideal nonlinear circuits, the method extraction technique was tested for nonlinearities up to seventh order. The Volterra nonlinear transfer functions of an equalizing circuit were extracted from the results of transient simulations which utilized the shooting method. The resulting tables were then used to simulate an arbitrary waveform and the results closely matched the equivalent time domain circuit simulation.