Abstract
Wide introduction of digital, high-speed and broad-band technologies in the field of electronic equipment and/or systems has resulted in a serious increase of complicated EMC problems. In particular, it had been urgent need how to estimate and make appropriate countermeasures on the radiated disturbance due to the conducted common mode disturbance at telecommunication ports of the equipment. This report presents the outline of the studies on both reproducing mechanism of the conducted common mode disturbance caused by the unbalance of the telecommunications line and the relationship between the conducted disturbance and the radiated disturbance from the line by using in-situ measurements at the experimental telecommunications line. Then the outline of the study on design methods with respect to accurate and reproducible probes for measuring the disturbance at multiple pair telecommunication ports is described. Finally, the background of the limits of conducted common mode (asymmetric mode) disturbance at telecommunication ports which are defined in CISPR 22 is overviewed on the basis of the outcomes of the studies mentioned above.
