Approximate Symbolic Analysis with Emphasis on Frequency Filters

摘要

The paper deals with two error control strategies for approximate symbolic analysis in the frequency domain: the response-based approach and the eigenvalue-based approach. The response-based mechanism, which evaluates errors caused by simplification by means of comparing magnitude and phase responses with a reference solution on a set of fixed frequencies, is suitable for broadband circuits with a flat response. In case of frequency-selective circuits (i.e. filters) the simple method may not provide expected results. The eigenvalue-based method uses shifts of poles and zeros in the complex plane to evaluate the effect of circuit model simplifications. The position of poles and zeros in the complex plane provides better characterization of the frequency response of a frequency filter. An effective implementation of both methods is presented in the paper.