Low-complexity and high-accuracy odd-order variable fractional-delay digital filters

This paper presents a new minimax method for designing low-complexity and high-accuracy odd-order finite-impulse-response (FIR) variable fractional-delay (VFD) digital filters. The objective of the minimax design is to minimize the maximum absolute error of the variable frequency response (VFR) by utilizing the second-order cone programming (SOCP) and achieves a global minimax solution. We formulate the SOCP minimax design by using different-order sub-filters in the Farrow structure such that the complexity of an odd-order FIR VFD filter can be reduced. An odd-order design example is given to demonstrate the effectiveness of the new SOCP-based minimax design approach.