Enhancement of spectral analysis of myoelectric signals during static contractions using wavelet methods

Introduces wavelet packets as an alternative method for spectral analysis of surface myoelectric (ME) signals. Both computer synthesized and real ME signals are used to investigate the performance. The authors´ simulation results show that wavelet packet estimate has slightly less mean square error (MSE) than Fourier method, and both methods perform similarly on the real data. Moreover, wavelet packets give one some advantages over the traditional methods such as multiresolution of frequency, as well as its potential use for effecting time-frequency decomposition of the nonstationary signals such as the ME signals during dynamic contractions. The authors also introduce wavelet shrinkage method for improving spectral estimates by significantly reducing the MSE´s for both Fourier and wavelet packet methods.