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

In this article, a method able to perform “virtual” signal integrity test on twisted-wire pairs (shielded or not) is presented. The method is based on
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-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. The method, which allows a comparison between different kind of cables to be performed on a rigorous basis, is illustrated from experimental measurements made in the frequency range from 10 to 400 MHz in the case first of a square signal and second of a 100BASE-T1 fast Ethernet protocol signal.