Symmetry-based low-complexity variable fractional-delay FIR filters

This paper reveals the coefficient symmetry of variable fractional-delay (VFD) finite-impulse-response (FIR) digital filters and shows that the coefficient symmetry can be efficiently exploited in the VFD filter design. Compared with the conventional weighted-least-squares (WLS) design methods without using coefficient symmetry, the proposed symmetry-based WLS method requires only half of the filter coefficients to achieve higher design accuracy. This symmetry exploitation not only significantly reduces the computational complexity required in the design process, but also leads to low-cost implementation.