Cancellation of Harmonic Interference Using Multi-Rate Signal Processing Techniques

In this paper a new time-domain method using multi-rate signal processing techniques is presented for the removal of harmonic interference. The contaminated signal is first resampled to a higher but the nearest frequency that is an integer multiple of the base frequency of the harmonics. Down-sampling is then employed to divide the signal into a number of sub-sets. The harmonic interference appears as a baseline shift of each sub-set. The harmonics are then cancelled by shifting the baseline of each sub-set. As the baseline is purely generated by the harmonics, shifting baseline does not change any of the original signal and other noisy components. Compared with the wavelet packet decomposition method, the sample length is less extended when using the new time-domain method. Evaluation of the method is carried out by using a simulated piecewise smooth signal and a real pulsating signal