%分別采用Hamming窗、Bartlett窗、Hanning窗和Blackman窗設計近似圓對稱的
%帶通濾波器，通頻帶為[0.1,0.5]。
%首先，創建包含了期望的帶通響應的矩陣Hd
[f1,f2] = freqspace(21,'meshgrid');
Hd = ones(21);
r = sqrt(f1.^2 + f2.^2);
Hd((r<0.1)|(r>0.5)) = 0;
colormap(jet(64))
mesh(f1,f2,Hd) 
%然后，分別用一維Hamming窗、Bartlett窗、Hanning窗和Blackman窗設計濾波器，
%代碼如下：
h1 = fwind1(Hd,hamming(21));
figure,freqz2(h1)
h2 = fwind1(Hd, bartlett (21));
figure,freqz2(h2)
h3 = fwind1(Hd, hanning (21));
figure,freqz2(h3)
h4 = fwind1(Hd, blackman (21));
figure,freqz2(h4)