Signal Toolkit - pei_tseng_notch

Function File: [b, a] = pei_tseng_notch (frequencies, bandwidths)

Return coefficients for an IIR notch-filter with one or more filter frequencies and according (very narrow) bandwidths to be used with filter or filtfilt. The filter construction is based on an allpass which performs a reversal of phase at the filter frequencies. Thus, the mean of the phase-distorted and the original signal has the respective frequencies removed. See the demo for an illustration.

Original source: Pei, Soo-Chang, and Chien-Cheng Tseng "IIR Multiple Notch Filter Design Based on Allpass Filter" 1996 IEEE Tencon doi: 10.1109/TENCON.1996.608814)