Matlab的窗函数,矩形窗,三角窗,汉明窗,汉宁窗,布莱克曼窗

%N =51

%求矩形窗的频率响应图

wn = rectwin(51) ; %矩形窗函数

*log10(abs(WN))

[h1,w] = freqz(wn,1); figure(1);

plot(w/pi,20*log10(abs(h1/max(h1))));

axis([0 1 -100 0]);

xlabel('归一化频率 /\\pi');

ylabel('20log_{10}|W(e^{j\\omega})| /dB');

title('矩形窗的傅里叶变换');

set(gca,'YTick',[-100 -80 -60 -40 -20 0])

set(gca,'XTick',[0 :0.2: 1])

set(gca,'XAxisLocation','top'); %设置X轴在上方

set(gca,'YAxisLocation','left');%设置Y轴在左方

text(1,-108,'\\pi');%gtext('\\pi');

%求三角窗的频率响应图

wn1 = bartlett(51);

[h1,w1] = freqz(wn1,1);

figure(2);

plot(w/pi,20*log10(abs(h1/max(h1))));

axis([0 1 -100 0]);

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xlabel('归一化频率 /\\pi');

ylabel('20log_{10}|W(e^{j\\omega})| /dB');

title('三角窗的傅里叶变换');

set(gca,'YTick',[-100 -80 -60 -40 -20 0])

set(gca,'XTick',[0 :0.2: 1])

set(gca,'XAxisLocation','top');%设置X轴在上方

set(gca,'YAxisLocation','left'); %设置Y轴在左方

%hanning

wn1 = hanning(51) ;

[h1,w1] = freqz(wn1,1); figure(3);

plot(w/pi,20*log10(abs(h1/max(h1))));

axis([0 1 -100 0]);

xlabel('归一化频率 /\\pi');

ylabel('20log_{10}|W(e^{j\\omega})| /dB');

title('Hanning的傅里叶变换');

set(gca,'YTick',[-100 -80 -60 -40 -20 0]);

set(gca,'XTick',[0 :0.2: 1]);

set(gca,'XAxisLocation','top');%设置X轴在上方

set(gca,'YAxisLocation','left'); %设置Y轴在左方

%hamming

wn1 = hamming(51) ;

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[h1,w1] = freqz(wn1,1);

figure(4);

plot(w/pi,20*log10(abs(h1/max(h1))));

axis([0 1 -100 0]);

xlabel('归一化频率 /\\pi');

ylabel('20log_{10}|W(e^{j\\omega})| /dB');

title('Hamming的傅里叶变换');

set(gca,'YTick',[-100 -80 -60 -40 -20 0])

set(gca,'XTick',[0 :0.2: 1])

set(gca,'XAxisLocation','top');%设置X轴在上方

set(gca,'YAxisLocation','left'); %设置Y轴在左方

%Blackman

wn1 = blackman(51) ;

[h1,w1] = freqz(wn1,1);

figure(5);

plot(w/pi,20*log10(abs(h1/max(h1))));

axis([0 1 -100 0]);

xlabel('归一化频率 /\\pi');

ylabel('20log_{10}|W(e^{j\\omega})| /dB');

title('Blackman的傅里叶变换');

set(gca,'YTick',[-100 -80 -60 -40 -20 0])

set(gca,'XTick',[0 :0.2: 1])

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set(gca,'XAxisLocation','top');%设置X轴在上方

set(gca,'YAxisLocation','left'); %设置Y轴在左方

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