低复杂度的可变分数时延滤波器设计

为实现低复杂度、高精度的可变分数时延滤波器设计，该文提出一种截止频率可控的高效设计法。该方法将全相位滤波器的解析设计与三次样条插值和泰勒级数展开相结合，既可以通过设置时延参数精确地调整滤波器的分数时延，又可以通过设置截止频率参数快速配置Farrow结构中各子滤波器的抽头系数，从而灵活地调整滤波器的截止频率。仿真实验表明，所提方法适用于设计具有中、低截止频率的可变分数时延滤波器，其设计复杂度相比于现有的加权最小二乘设计法低1个数量级。

Low-complexity Design of Variable Fractional Delay Filters

In order to design variable fractional delay filters with low complexity and high accuracy, an efficient design method with controllable cut-off frequency is proposed, which integrates the analytic all-phase filter design, the cubic spline interpolation and Taylor series expansion. In the proposed design, not only the time delay of the filter can be precisely adjusted by setting the delay parameter, but also the tap coefficients of each subfilter in the Farrow structure can be rapidly configured via setting the cut-off frequency parameter, thus the cut-off frequency of the filter can be adjusted flexibly. Numerical simulations show that, the proposed method is especially suitable to design variable fractional delay filters with low or middle cut-off frequencies, and its computation complexity is one order of magnitude lower than that of the existing Weighted Least Squares (WLS) design.