Detecting Periodic Behavior in Nonstationary Signals

Vidya Venkatachalam and Jorge L. Aravena Department of Electrical and Computer Engineering Louisiana State University, Baton Rouge, LA 70803-5901 Tel : (504) 388-5537, Fax : (504) 388-5200 Email : [email protected] ABSTRACT This paper presents results on the multiresolution analysis of nonstationary signals with the objective of detecting underlying periodic phenomena. Wavelet packet analysis with coe cient thresholding is the basis for the detection. The e ectiveness of the method is illustrated by analyzing experimental data on sediment electrochemical redox potential in a tidal microcosm. The signi cance of the technique is that it can extract periodic phenomena from experimental data corrupted by catastrophic and random events, provide a signature of the basic periodic component, and give an estimate of the degree of deviation from periodic behavior. Consequently, it has potential applications in the analysis of quasi-periodic signals such as electrocardiograms (ECGs), where the determination of the extent of quasi-periodicity is of critical importance.