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。
> YP6/w,e kA3nhBH function FF=frft_PXJ(N,alpha);
fik*-$V` %matrix
P$LHsg] % FF is the kernel matrix of fractional Fourier transform
=! }n . % \copyright: zjliu
h'*>\eC6 % Author's email:
zjliu2001@163.com yB][
3?lv Ts=sqrt(2*pi/N); t=-(N-1)/2:(N-1)/2; t=t'; t=t*Ts;
#p 'Xq
}] variance=N/2/pi; HH=zeros(N); HH(:,1)=1; HH(:,2)=2*t;
! 6y< jJ> for k=3:N;
Uc
oVp}vl HH(:,k)=HH(:,k-1).*t*2-2*(k-2)*HH(:,k-2);
ee7#PE]} end
hcWYz HH(:,1)=1/sqrt(sqrt(variance))*HH(:,1).*exp(-t.*t/2);
qm RdO
R for k=2:N;
I+nKaN+8i
HH(:,k)=exp(-t.*t/2).*HH(:,k)/sqrt(2.^(k-1)*...
,/ {(8hn factorial(k-1)*sqrt(variance));
mqw5\7s ? end
\:>GF-Z( if mod(N,2)==1;
+um
Ua W=0:N-1; k=exp(-i*alpha*W); D=diag(k);
E=N44[`.G else
[C1 .*Q+l W=0:N-2; W=cat(2,W,[N]); k=exp(-i*alpha*W); D=diag(k);
:r5DR`Rfm end
T NwBnM e FF=Ts*HH*D*HH'*2;
M0Eq
7:Ba % Reference:
E?$|`<o{|` % by 平先军.一种新的分数阶傅立叶变换快速算法.电子学报.
b*C\0D % 2001(3),Vol.29:406-408.
