Multisegment Optimization Method for the Design of Even-Order Variable Fractional Delay Filters

In this study, a multisegment optimization method for the design of an even-order variable fractional delay (VFD) filter is proposed. The domain of fractional delay is segmented, and the VFD filter is designed on each segment in the minimax sense. Accordingly, the proposed VFD filters are implemented by a modified Farrow structure. The number of coefficients for each multiplier is changed from one to the number of segments. Using this method, the number of subfilters in the modified Farrow structure can be decreased by increasing the number of segments. Therefore, the number of multipliers can be reduced at the cost of more coefficients. An example demonstrates that the proposed method uses less number of multipliers compared to existing methods.