An Analysis of the Conversion from Common to Differential-Mode Noise on the Balanced Line

Abstract

The conversion from common to differential-mode noise was investigated. Two simple parallel traces with injecting the common-mode voltage were considered for the mode conversion. The effect of the mutual cou-pling between traces on the noise mode conversion was examined experimentally. Measurements suggest that the induced differential-mode voltage should change the logic level of sensitive ICs and also that the tight coupling among the traces gives the lower mode conversion. In order to investigate the findings theoretically, an equation for determining the noise mode conversion was derived. As a result, it was confirmed that the calculated differential-mode voltages agree with the measured ones.