M-th band filter design based on cosine modulation
This paper presents a design method for a linear phase filter with arbitrary cutoff frequencies using cosine modulation. The approach can be applied to any existing linear phase filters with rational cutoff frequencies. A halfband filter is used to derive an approximately maximally-flat filter with different cutoff frequencies, and the resulting filter can be expressed in closed form when the original filter has a closed form expression. The filters satisfy M-th band conditions with comparable transition band to the original filter. Simulations are presented to confirm the design method.