Patent ID: 6990422

Claim:
A method for determining characteristics of a system under test (SUT) comprising the steps of: providing, by an excitation means, a time-varying current-mode electrical excitation to a system under test, which time varying signal comprises a periodic or quasi-periodic waveform; detecting, by a detection means, the conjugate electrical response elicited from the system under test by the excitation; converting the detected response from an analog signal into a digital response signal by means of an analog-to-digital conversion means, controlled by a synchronous sampling clock controlling means; and performing at least one predetermined analysis of the digital response signal to determine at least one characteristic of the system under test; wherein the characteristics of the excitation signal are adjustable, said characteristics including: the amplitude of the excitation that is comprised of one or more waveforms that are generated either by analog circuitry means, or digital circuitry means; the duration of each portion of a waveform, where a portion of a waveform is bounded at each of it's end points by either zero crossing corresponding to a change of relative polarity, or by a zero amplitude value; the relative phase, with respect to a separate reference clock signal, of each waveform comprising the excitation signal.