# Nonlinear distortion analysis of circuits and systems

Gerd Vandersteen, Ludwig De Locht, Piet Wambacq

Research output: Chapter in Book/Report/Conference proceedingMeeting abstract (Book)

## Abstract

This tutorial aims to demystify the nonlinear distortion analysis of circuits and systems. Combining the capabilities of analyzing large circuits through simulation-based methods, and the analytical insight provided by symbolic methods, enables the analysis of the nonlinear behavior of complex systems. The simulation-based methods make it possible to pinpoint the dominant nonlinearities, while the symbolic method can be used afterwards to get analytical insight into the nonlinear behavior. Both methods will be demonstrated using a large set of practical examples.
The tutorial first introduces the necessary notions on Volterra theory, starting from classical linear system theory. The analytical expressions provided by Volterra theory result in a better understanding of the behavior of the system. The complexity of the resulting expressions, however, limits this technique to simple systems. Second, the tutorial introduces the Best-Linear-Approximation (BLA) paradigm, which represents the nonlinear system as a linear transfer function and an additive nonlinear distortion component. It enables the separation of the various linear and nonlinear contributions and is able to pinpoint the dominant nonlinear distortions in a complex system in a hierarchical way. The main drawback of the simulation-based methods is, however, the reduced analytical insight. Finally, the power of both methods is combined to study a large set of application examples. Starting from a single-transistor circuit, the circuits' complexity gradually increases over OPAMPs to active filters, receiver front-ends, and sigma-delta modulators. Both the symbolic method and the simulation-based method are used side-by-side to gain insight in the nonlinear distortion properties of the systems. All results are finally cross-checked and compared with results available in the literature. During the course, the simulation data will be distributed to the attendees in MATLAB data format so they can get familiar with proposed techniques using MATLAB or Octave examples.
Original language English presentation of tutorial at ISCAS 2010, May 30th-June 2nd 2010 Paris, France Published - 30 May 2010 Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet - Stockholm, SwedenDuration: 21 Sep 2009 → 25 Sep 2009

### Conference

Conference Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet Sweden Stockholm 21/09/09 → 25/09/09

## Keywords

• nonlinear distortion analysis
• circuits
• systems

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