Sparse FIR Filter Design Based on Interpolation Technique

In this paper, a design method based on interpolation technique is proposed to design narrow-band sparse FIR filters and centrosymmetric bandpass filters. The design method is realized by cascading a model filter with a masking filter. The model filter is first designed and then interpolated to generate the desired impulse response replica. A sparse masking filter is used to mask the extra unwanted passbands. Unlike the interpolated FIR filter technique, both subfilters are designed as sparse filters by multiplierless algorithms to improve the overall sparsity of the filter. Simulation results show that the proposed cascaded realization of FIR filters results a significant improvement of sparsity than the conventional direct form or transposed direct form. It is also shown that the proposed method generates sparser solutions than the interpolated FIR filter technique due to the sparse design of subfilters.