基于拉格朗日插值法的可变分数延时滤波器比较图，通过比较不同的分数时延时的滤波器特性来观察分数延时滤波器的性质与限制-Lagrange interpolation method based on variable fractional delay filter comparison chart, filter characteristics by comparing the scores of different delay time to observe nature and limitations of fractional delay filter