Squelch On Industrial Frequency Noise And Its Harmonic Waves-Multi-Band Stop Digital Filter Design And Implementation

摘要

This paper designs an FIR (Finite Impulse Response) multi-band stop digital filter to reject the noise of 50 Hz and its second and third harmonic waves from power supply, whose stop bands are respectively as 48Hz-52Hz, 98Hz-102Hz,and 148Hz-152Hz. The paper debates on window function design method of FIR filter and algorithm implementation, also discusses the influences on filter frequency-response feature caused by filter order changing and different window function choice. Intensive data simulations are performed. Experiments proves that the multi-band stop filter is of deep descent transition band which suppresses the noise to –10dB, while signal spectrum line is enhanced to 13dB.