这是关于可变分数延时滤波器的设计，适合初学者使用，相信对初学者有很大帮助-This is the variable fractional delay filter design, suitable for beginners to use, I believe there is a great help for beginners

文件是关于巴特沃斯滤波器的设计，代码中包含了滤波器的设计过程，幅频响应、群延时、滤波器零极点等。-File is the design of the butterworth filter, the code contained in the design process of the filter, amplitude frequency response, group delay, filter zero pole, etc.