Smoothing scale of magnetotelluric sounding curve

Measurement signal is often distorted by noise,which seriously influences signal analysis in magnetotelluric sounding.One of important current questions is that how to filter and select a filter time scale in the data processing.In this paper de-noising,feature preservation and shape restoring of signal are reasonable balanced by anisotropic diffusion(AD) and diffusion balance(DB).Simulation and field data show:(1) filtered signal is accuracy approximated to the original signal and SNR(signal noise ratio) is up to 69.25 dB from 14.19 dB by AD and DB;(2) diffusion balance time scale is closely related to noise intensity, the more noise,the more diffusion balance time scale;(3) "outliers" are effectively removed and basic shape of signal is restored in the field data.