说明：  产生数字信号处理中常用的几种窗函数，包括ectangular window , triangular window ,cosin window , Hanning window , Hamming window , Blackman window ,Papoulis window
(producing a digital signal processing used in several window function, including ectangular window, triangular window. cosin window, Hanning window, Hamming window, Blackman window. Papoulis window)