A Confirmation into How a CMAD Affects MIU in Regard to AE Termination Impedance in Non-Invasive Measurement

According to CISPR 32, measurement instrumentation uncertainty (MIU) in non-invasive measurement for conducted emission measurements in accordance with CISPR 16-4-2 is not an applicable factor when determining compliance with the limits of CISPR 32 due to considerable MIU in regard to undefined termination impedance of associated equipment (AE) side in non-invasive measurement.In this paper, to confirm whether MIU can be improved by attaching a common mode absorbing device (CMAD) to the cable between the equipment under test (EUT) and AE, conducted emissions on a wired network port were measured both with and without a CMAD. The results show these MIU is not improved sufficiently by using a CMAD.