Design of variable fractional delay FIR filter using symmetry

In this paper, the design of variable fractional delay FIR filter using symmetry is presented. Based on the decomposition of ideal impulse response, an implementation structure with symmetric-coefficient subfilters is first constructed to design variable fractional delay filter. Then, the weighted least squares method is used to obtain optimal coefficients of subfilters by minimizing the frequency response errors between ideal response and actual response. Finally, the design example is used to demonstrate that the proposed structure with symmetry can provide smaller design error and computational complexity than the conventional Farrow structure.