A novel design of IIR multiple notch filter based on an all-pass filter by using a pole-reposition technique
Amnart Thamrongmas, Chalie Charoenlarpnopparut, Panintorn Prempree · ScienceAsia · 2014
In this paper, a novel and simple method based on an all-pass filter is presented by using the benefits of a pole re-position technique.The gains at frequencies of π of each single notch filter are adjusted by adding N -1 tuning variables.The proposed method ensures that the passband gains are uniformly flat, the notch frequencies exactly meet the specifications, and the realized 3 dB bandwidths are approximately the same as those specified.This technique is very useful for designers because there are only N -1 tuning variables required to adjust, and it does not need a complicated mathematical calculation.Although this technique is simple and easy to implement, it requires many iterations to find a suitable parameter for making the passband gain between two notch frequencies uniformly flat.Hence in this paper, three searching algorithms have been applied to reduce the number of iterations.We obtain a faster search and a closer frequency response to the ideal one.