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。
wB+X@AA " 7g\X$ function FF=frft_PXJ(N,alpha);
7fXta|eP0 %matrix
=Q~@dP % FF is the kernel matrix of fractional Fourier transform
<^(>o % \copyright: zjliu
%?m_;iv % Author's email:
zjliu2001@163.com :y1,OR/k Ts=sqrt(2*pi/N); t=-(N-1)/2:(N-1)/2; t=t'; t=t*Ts;
k@|Go)~ variance=N/2/pi; HH=zeros(N); HH(:,1)=1; HH(:,2)=2*t;
HB*H%>L{"B for k=3:N;
YLv5[pV HH(:,k)=HH(:,k-1).*t*2-2*(k-2)*HH(:,k-2);
^^T
xx end
Ny5$IIFe HH(:,1)=1/sqrt(sqrt(variance))*HH(:,1).*exp(-t.*t/2);
NiBly for k=2:N;
?p&( Af) HH(:,k)=exp(-t.*t/2).*HH(:,k)/sqrt(2.^(k-1)*...
&a!MT^anA~ factorial(k-1)*sqrt(variance));
JXQh$hs end
0BPUbp( if mod(N,2)==1;
~v6]6+ W=0:N-1; k=exp(-i*alpha*W); D=diag(k);
2#Du5d else
|a!]Iqz"N W=0:N-2; W=cat(2,W,[N]); k=exp(-i*alpha*W); D=diag(k);
td 5!
S] end
fk2p} FF=Ts*HH*D*HH'*2;
j@.^3: % Reference:
xQDWnpFc % by 平先军.一种新的分数阶傅立叶变换快速算法.电子学报.
N
oRPvFv % 2001(3),Vol.29:406-408.