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。
#usi1UWB#Q iOXxxP%# function FF=frft_PXJ(N,alpha);
In<L?U?([D %matrix
wQ-pIi{G % FF is the kernel matrix of fractional Fourier transform
\Jq$!foYx % \copyright: zjliu
0~
!).f % Author's email:
zjliu2001@163.com `p0+j Ts=sqrt(2*pi/N); t=-(N-1)/2:(N-1)/2; t=t'; t=t*Ts;
QT)D|]bH variance=N/2/pi; HH=zeros(N); HH(:,1)=1; HH(:,2)=2*t;
{/d<Jm: for k=3:N;
B7HNNX HH(:,k)=HH(:,k-1).*t*2-2*(k-2)*HH(:,k-2);
=pSuyM' end
/E8{:>2 HH(:,1)=1/sqrt(sqrt(variance))*HH(:,1).*exp(-t.*t/2);
?XOl>IO for k=2:N;
*q**,_?; HH(:,k)=exp(-t.*t/2).*HH(:,k)/sqrt(2.^(k-1)*...
QCjC|T9 factorial(k-1)*sqrt(variance));
a
k&G=a6^ end
cXP*?N4Cf if mod(N,2)==1;
{6}H}_(] W=0:N-1; k=exp(-i*alpha*W); D=diag(k);
B.
'&[A else
wyG7SA W=0:N-2; W=cat(2,W,[N]); k=exp(-i*alpha*W); D=diag(k);
a;@G end
g>].m8DZ' FF=Ts*HH*D*HH'*2;
W>[0u3 % Reference:
4I&e_b< 30 % by 平先军.一种新的分数阶傅立叶变换快速算法.电子学报.
D3,9X#B= % 2001(3),Vol.29:406-408.