A method of analyzing a transient response of an electronic circuit includes receiving at a jitter modulator circuit first and second input signals, modulating the second input signal on the first input signal in the jitter modulator circuit and outputting a modulated signal based on the first and second input signals. The jitter modulator circuit includes models of N parallel connected transmission lines and modulating includes providing the first input signal, at each of a series of times t, to the N transmission line models and selecting an output of two of the N transmission line models based on the second input. The modulated signal is formed based on the selected outputs of the two N transmission lines models.