高精度分数时延滤波器设计的边界拟合Remez算法

在卫星星间测距模拟信号仿真及实际测试中,为提高测距模拟信号精度和系统可用带宽,提出基于边界拟合Remez算法的高精度分数时延滤波器的设计算法。该算法利用Farrow结构的多项式近似思想,采用多项式拟合Remez算法设计滤波器的冲激响应边界系数,通过多相分解实现分数时延滤波器组。该算法改善了当设计的滤波器阶数较高时冲激响应边界的不连续现象,进而降低了群时延误差,提高了精度。仿真结果表明,该算法设计的滤波器的分数时延精度得到了提高,同时系统可用带宽提高近一倍,实现时需使用的乘法器数目也有明显降低。

High accuracy fractional delay filter design based on Remez algorithm with boundary fitting

In order to improve ranging accuracy between satellites and increase available bandwidth of systems in the simulation and tests, a boundary fitting Remez algorithm for high accuracy fractional delay filter was proposed. The proposed algorithm used the polynomial approximation achieved in Farrow structure, to fit the impulse response boundary coefficients of the filter designed by Remez algorithm, and achieve fractional delay filters through the polyphase decomposition. The proposed algorithm made the impulse response boundary continuous when high-order filters was used, while reduced the group delay error and improved accuracy. The simulation results show that the proposed algorithm improves fractional delay filters accuracy a little, doubles the available bandwidth and reduces the number of multipliers need to be used.