Distortion Contribution Analysis with the Best Linear Approximation

A distortion contribution analysis (DCA) obtains the distortion at the output of an analog electronic circuit as a sum of distortion contributions of its subcircuits. Similar to a noise analysis, a DCA helps a designer to pinpoint the actual source of the distortion. Classically, the DCA uses the Volterra theory to model the circuit and its subcircuits. This DCA has been proven useful for small circuits or heavily simplified examples. In more complex circuits, however, the amount of contributions increases quickly, making the interpretation of the results difficult. In this paper, the best linear approximation (BLA) is used to perform the DCA instead. The BLA represents the behavior of a subcircuit as a linear circuit with the unmodeled distortion represented by a noise source. Combining the BLA with a classical noise analysis yields a DCA which is simple to understand, yet capable to handle complex excitation signals and complex strongly nonlinear circuits.