Issues on the method of conducted disturbances measurement by using coupling and decoupling networks for emission

Coupling and decoupling networks for emission (CDNEs) are used in an alternative method for measuring radiated emission emitted from lighting equipment in the frequency range of 30 to 300 MHz. Since CDNEs have been improved based on coupling and decoupling networks (CDNs) which are designed for immunity testing, it is necessary to evaluate whether the CDNEs method can be used for measuring conducted disturbance voltages. To assess the possibility of CDNE method as an alternative measurement method, the correlations between radiated emission measurements and conducted disturbance measurement using the CDNE method were evaluated. Moreover the effects of longitudinal conversion loss (LCL) by assuming the availability of measuring conducted disturbance voltages at ports of various types of equipment were investigated. As the results, it is found that the correlations are weak, and LCL requirements are necessary when measuring the disturbances of which differential-mode components are dominant.