转载一个实现分数傅立叶变换的matlab程序,作者信息在程序中有。
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<|pW rk6K0TQ8 function FF=frft_PXJ(N,alpha);
)fHr]#v %matrix
_%q~K (:: % FF is the kernel matrix of fractional Fourier transform
Q$uv
\h; % \copyright: zjliu
JIhEkY % Author's email:
zjliu2001@163.com >H^#!eaqw Ts=sqrt(2*pi/N); t=-(N-1)/2:(N-1)/2; t=t'; t=t*Ts;
(+c1 .h variance=N/2/pi; HH=zeros(N); HH(:,1)=1; HH(:,2)=2*t;
[\AOr`7 for k=3:N;
6<EGH*GQ$ HH(:,k)=HH(:,k-1).*t*2-2*(k-2)*HH(:,k-2);
AdVc1v&> end
l+[:Cni HH(:,1)=1/sqrt(sqrt(variance))*HH(:,1).*exp(-t.*t/2);
x-"8V( for k=2:N;
%xN${4)6 HH(:,k)=exp(-t.*t/2).*HH(:,k)/sqrt(2.^(k-1)*...
T'9ZR,{F factorial(k-1)*sqrt(variance));
3P9ux end
M?!@L:b[ if mod(N,2)==1;
U.KQjBi W=0:N-1; k=exp(-i*alpha*W); D=diag(k);
MjU|XQS: else
_Ao$)Gu) W=0:N-2; W=cat(2,W,[N]); k=exp(-i*alpha*W); D=diag(k);
l% T4:p4e end
lDTHK2f FF=Ts*HH*D*HH'*2;
yVII<ImqIH % Reference:
TP"cEfs x % by 平先军.一种新的分数阶傅立叶变换快速算法.电子学报.
AH|gI2 % 2001(3),Vol.29:406-408.