Characterizing harmonic components of electromagnetic interference spectrum based on grey system model

A novel approach to characterize the harmonic components of the electromagnetic interference (EMI) signal spectrum is proposed based on the combination of Grey Model and Fourier Envelope Theory. A grey-period model is presented to extract the harmonics from the complicated testing data. Quantified characteristics of time-domain interference signal, including rise time and period, can be obtained by utilizing the envelope of these harmonics. An EMI testing data is examined by using the proposed method and the potential interference sources are identified. The obtained time-domain parameters for EMI sources can provide guidance for EMC design and trouble shooting.