Power Spectrum Analysis

Abstract

In the analysis of EMG signal during dynamic movement, we have proposed an estimation algorithm for the time varying parameters. The parameters correspond to less biased time varying reflection coefficients. We determine the less biased estimation using a locally quasi-stationary model and name these parameters “K-parameters”. We estimated K-parametes upto the fifth order for the surface EMG signals of masseter muscle during rapid open-close movement of the lower jaw, a ballistics contraction, and fatigue. According to the results, the time causes of the K- parameters displayed remarkable properties. In order to study the behaviour of K-parameters physiologically, we produce a muscle-structured stimulation model based on anatomical and physiological data. The stimulation results suggested that the behaviour of the third parameter is related to the number of active motor units (MU's) at the shallow layer of a muscle.