Abstract: A method based on threshold to denoise coulostatic response signal in wavelet domain was presented. The results of this method were compared with data smoothing in time domain and classical low pass filtering in the Fourier domain. The choice of wavelet decomposition levels was also discussed in this work. By using wavelet transform, coulostatic signal extraction from noisy data could be done both in time and frequency domains. The precision of curve fitting in time domain and reliability of spectral analysis could be improved respectively by the proposed method. Practically, this method was effective when the decomposition levels were from 5 to 7.

Key words: Coulostatic, Wavelet transform, Signal processing, Noise, Impedance spectrum