fft algorithm for matlab

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Naga Sai 2017-6-13

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https://ww2.mathworks.cn/matlabcentral/answers/344571-fft-algorithm-for-matlab

评论： Naga Sai 2017-6-15

FFT Algorithm or code for matlab

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Adam 2017-6-13

What about it? Typing at least a sentence is usually helpful if you expect a meaningful answer.

Naga Sai 2017-6-15

在 MATLAB Online 中打开

function Y=ft2(y) % This programme is open source code of fast fourier transform in matlab. % Where y is the input argument and p is the normalized size of the input. Let % y = [1 2 3 4 ]; % x= length(y); % m= log(x); % p= ceil(m); % To call the function use % ft2(y);

 s=length(y);
 l=log(s);
 p=ceil(l); 
 Y=y; 
 N = 2^p;
 N2=N/2; 
 YY = -pi*sqrt(-1)/N2; 
 WW = exp(YY);  
 JJ = 0 : N2-1;  
 W=WW.^JJ;
 for L = 1 : p-1
    u=Y(:,1:N2);
    v=Y(:,N2+1:N);
    t=u+v;
    S=W.*(u-v);
    Y=[t ; S];
    U=W(:,1:2:N2);
    W=[U ;U];
    N=N2;
    N2=N2/2;
 end
 u=Y(:,1);
 v=Y(:,2);
 Y=[u+v;u-v];