Evidence for the existence of a useful periodic steady-state algorithm for nonlinear circuits

Four algorithms for computing the periodic steady state of nonlinear circuits have been compared with respect to their convergence properties. In particular, the gradient and extrapolation algorithms were compared by implementing them in the same circuit-analysis program. The results obtained on nonautonomous test circuits containing between two and fourteen nonparasitic storage elements indicate that the extrapolation algorithm is more efficient. Comparison of the experimental data with usable published results on the Newton algorithm suggests that it is the most efficient one. However, its memory requirements cast doubt on its usefulness for large circuits. Insufficient data is available on the recently proposed Newton-like two-frequency algorithm; however, it appears that, for highly nonlinear periodic circuits, its convergence properties may be comparable to those of the extrapolation algorithm.<
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