Noise diagnosis techniques in conducted electromagnetic interference (EMI) measurement: methods analysis and design

Electromagnetic interference (EMI) emission is an important matter for electrical and electronic equipment. Currently, conducted EMI emissions are measured by using a line impedance stabilization network (LISN) and the results are a mixture of common mode (CM) and differential mode (DM) noise. Several noise diagnosis networks for CM/DM signal separation are analyzed and some experimental results on performance are given for comparison. The advantages and disadvantages of these networks are also analyzed briefly. Additionally, a computer-aided CM and DM filter design is introduced on the basis of mode separation information, and, therefore, automatic conducted EMI emission diagnosis is realizable.