Control procedure for approximate symbolic analysis of frequency-selective circuits

The paper deals with a control mechanism for approximate symbolic analysis of the Simplification-Before-Generation class with the emphasis on frequency-selective circuits. The traditional approach consists in the evaluation of errors caused by simplification by means of comparing magnitude and phase responses with a reference solution on a set of fixed frequencies. This approach is sufficient for broadband circuits but may fail for frequency filters. The paper describes a modified procedure that uses an error criterion based on shifts of poles and zeros in the complex plane. As the direct solution of the generalized eigenvalue problem is computationally expensive, an alternative method based on Jacobi-Davison iterations is used.