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。
'] +Uu'a v$^Z6>v VI function FF=frft_PXJ(N,alpha);
}f2r!7:x %matrix
0Fu~%~#E$ % FF is the kernel matrix of fractional Fourier transform
8_N]e'WUh % \copyright: zjliu
H /}]FmjN % Author's email:
zjliu2001@163.com Nz)l<S9> Ts=sqrt(2*pi/N); t=-(N-1)/2:(N-1)/2; t=t'; t=t*Ts;
Sfdu`MQR variance=N/2/pi; HH=zeros(N); HH(:,1)=1; HH(:,2)=2*t;
R
LD`O9#j for k=3:N;
}V\N16f HH(:,k)=HH(:,k-1).*t*2-2*(k-2)*HH(:,k-2);
}l=x iAF end
"jw<V,, HH(:,1)=1/sqrt(sqrt(variance))*HH(:,1).*exp(-t.*t/2);
R4-~j gzx for k=2:N;
m)oJFF HH(:,k)=exp(-t.*t/2).*HH(:,k)/sqrt(2.^(k-1)*...
={u0_ j
W factorial(k-1)*sqrt(variance));
g e8/``= end
-44&#l^}_u if mod(N,2)==1;
G z)Nw D W=0:N-1; k=exp(-i*alpha*W); D=diag(k);
W6Y@U$P#G else
)+fh-Ui W=0:N-2; W=cat(2,W,[N]); k=exp(-i*alpha*W); D=diag(k);
cv`~y'?D end
I|Gp$ uq _ FF=Ts*HH*D*HH'*2;
x#:| }pR % Reference:
"Iix
)Ue % by 平先军.一种新的分数阶傅立叶变换快速算法.电子学报.
H*r>Y % 2001(3),Vol.29:406-408.
