A Spectrum Estimation Method for Magnetotelluric Signal Based on Continuous Wavelet Transforms
Y. F. Xu, Jia-Ying WANG · Chinese Journal of Geophysics · 2000
Abstract A method of spectrum estimation based on continuous wavelet transforms (CWT) for magnetotelluric signal is developed. The algorithm of CWT using the Morlet wavelet function is presented. The relation between scale in wavelet domain and frequency in Fourier domain and how to do wavelet coefficients shrinkaging based on thresholding are discussed in detail. Numerical examples demonstrate that averaging and shrinkaging can improve the estimated spectrum. The required length of records for the method is shorter than that of the method based on FFT used in traditional magnetotelluric data processing.