A system and method for analyzing a circuit with transmission lines includes determining which sources influence each of a plurality of transmission lines, based on coupling factors. Transmission line parameters are computed based on the sources, which influence each transmission line. A transient response or frequency response is analyzed for each transmission line by segmenting each line to perform an analysis on that line. The step of analyzing is repeated using waveforms determined in a previous iteration until convergence to a resultant waveform has occurred.