用加权最小二乘法设计分数延迟FIR数字滤波器。在设计中,滤波器系数表示为分数延时量的多项式,对由多项式系数构成的矩阵进行行拉直,使之成为行向量以方便计算;用积分计算目标误差函数,相对于利用大量离散点值求和的方法,精度更高;求解拉直行向量时,采用矩阵三角分解,并合理调整计算顺序以避免病态计算。仿真计算表明,利用本文方法设计的分数延迟FIR数字滤波器的精度更高,复杂度更低。
Weighted least-squares method is used to design fractional delay FIR digital filter.In the design,filter coefficient is denoted as polynomial of fractional delay parameters.The matrix composed of polynomial coefficients is made as a row for the purpose of easy evaluation.Then,the objective error function is evaluated with the closed-form integral.It is more accurate than the method which sums up a large number of discrete point values.Matrix cholesky decomposition and adjusting the order of computation are used to avoid the ill-evaluation.From the simulation,it can be found that the fractional delay FIR digital filter designed by the proposed method is more accurate with the lower complexity.