Design of variable FIR filters using convex projections method

In this paper, we define filters capable of changing frequency response characteristics as variable filters. Digital filters capable of changing their frequency response are such as group delay, magnitude response and resonance frequency, etc.. In this paper, we propose a design method for FIR digital filters with an arbitrary variable fractional delay by convex projections algorithm. Then each coefficients of variable filter represents as different polynomials of M order using a set of spectral parameters. Finally, the usefulness of the proposed method is verified through the examples.