An apparatus comprises a signal generator circuit, a test probe, a signal sensor circuit, and a defect detection circuit. The signal generator circuit is configured to generate an impulse test signal having an impulse waveform and adjust a bandwidth of the impulse test signal. The test probe is electrically coupled to the signal generator circuit and configured to apply the impulse test signal to a device under test (DUT). The signal sensor circuit is configured to sense a conducted test signal produced by applying the impulse test signal to the DUT with the test probe. The defect detection circuit is configured to generate an indication of a defect in the DUT using the conducted test signal.