Use modified Lomb-Scargle method to analyze electromagnetic emission spectrum

Analyzing the harmonic component from emission spectrum is an effective method to find emission source in trouble-shooting for electronic system. In some situations, to improve test efficiency, different frequency steps may be used in different bands and the emission spectrum may be unevenly spaced in different bands. Moreover, the possible environmental interferences and data missing are difficulty for analysis. A novel method using modified Lomb-Scargle periodogram to extracting the base-frequency feature is presented in this paper. In this method, segmentation multi-resolution analysis is used as a preprocessing method to separate the harmonic component and broadband component. Modified Lomb-Scargle periodogram is used to extract the base-frequency features next. Several simulation and experimental results in different situations are demonstrated then. The results show that the proposed method can extract the base-frequency features effectively from unevenly spaced frequency spectrum which may have several environmental interferences and some data missing.