Abstract: In the practical experiment to electrical signal of CO2 arc welding process, it’s an important step to eliminate the disturb of noise. Wavelet packet filter method can effectively distinguish the signal and noise. Under Windows circumstance and by use of Visual C++ 6.0 program language, the wavelet packet filtering algorithm with soft threshold operation is realized. It has been proved by the experiments that the wavelet packet filtering base on soft threshold is the better de-noising method, and it can improve the effect of extracting signal characteristics.

Key words: Arc welding process, Soft threshold, Wavelet packet de-noising