Improved approach for digital multiple notch filter design

A digital multiple notch filter was mainly used to remove sinusoidal interferences contained in a digital signal. To remove the shortcomings in the classic methods, an improved design approach about the filter was presented. It made use of the mapping relationship between the amplitude response of a notch filter and the phase response of an all-pass filter. It converted the design problem of the notch filter to that of the all-pass filter. The basic principle and design process of the proposed method were discussed in detail. The stability and effectiveness of the presented approach were validated by a series of simulation experiments.