说明：  各类滤波器的设计程序，包括理想低通，高通滤波器，butterworth低通，高通滤波器，高斯低通，高通滤波器，梯形低通，高通滤波器，和用其他方法编写的理想低通、理想高通、Butterworth低通、同态滤波程序
(Various types of filter design procedures, including the ideal low-pass, high-pass filter, butterworth low pass, high pass filter, Gaussian low pass, high pass filter, ladder low pass, high pass filter, and use other methods to prepare the ideal low-pass , the ideal high-pass, Butterworth low-pass, homomorphic filtering process)