US Patent 8438001 Method and apparatus for improving noise analysis performance

Method and apparatus for improving performance of noise analysis using a threshold based combination of noise estimation and simulation. The method includes classifying a circuit into one of four defined groups, determining if an input noise is small enough to skip simulation, estimating an output noise wave, scaling down a generated wave by a scaling factor depending on the circuit type, and determining if the estimated output noise is small enough to propagate or instead requires simulation.