“Virtual” Signal Integrity Test on Shielded/Unshielded Twisted-Wire Pairs Using the Bulk Current Injection Setup

Abstract : In this paper, a method able to perform "virtual" signal integrity test on twisted-wire pairs (shielded or not) is presented. The method is based on S-parameter measurements collected in the case of a bulk current injection test setup. A common-to-differential-mode conversion is applied in postprocessing on these measurements in order to superimpose the effect of the measured disturbance to the useful signal , which is generated numerically. Then, the signal integrity of the cable under test can be verified as a function of the magnitude of the disturbance, the common-to-differential-mode conversion rate and the useful signal waveform in reason of the linearity of the problem and of the S-parameter measurements. The method, which allows a comparison between different kind of cables to be performed on a rigorous basis, is illustrated from experimental measurements performed in the frequency range 10 to 400 MHz in the case first of a square signal and second of a 100BASE-T1 fast Ethernet protocol signal.