Bifurcate repeated stop-band zeros of CIC filter
Fredric J. Harris, Gordana Jovanović Doleček · 2016
The frequency response of an M-tap multistage CIC filter has repeated zeros which form maximally-flat attenuation stop bands at multiples of fs/M. By a small variation in the conventional CIC architecture, these repeated zeros can be separated, and in fact they can be redistributed, to form equal-ripple, wider bandwidth, stopbands. The wider bandwidth stopband offers the option to achieve a specified stopband width with a reduced number of cascade stages.