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。
q[}W&t, @;;3B function FF=frft_PXJ(N,alpha);
tw
k %matrix
\&BT#8ELG % FF is the kernel matrix of fractional Fourier transform
^J~5k,7jX % \copyright: zjliu
5LaF'>1yY % Author's email:
zjliu2001@163.com
}o[NB Ts=sqrt(2*pi/N); t=-(N-1)/2:(N-1)/2; t=t'; t=t*Ts;
'u}OeS"f variance=N/2/pi; HH=zeros(N); HH(:,1)=1; HH(:,2)=2*t;
C:r3z50 for k=3:N;
03Uj0.Z|7 HH(:,k)=HH(:,k-1).*t*2-2*(k-2)*HH(:,k-2);
2,'~' end
OjWg>v\v HH(:,1)=1/sqrt(sqrt(variance))*HH(:,1).*exp(-t.*t/2);
uxx(WS for k=2:N;
z#HNJAQ#| HH(:,k)=exp(-t.*t/2).*HH(:,k)/sqrt(2.^(k-1)*...
,4mb05w;d factorial(k-1)*sqrt(variance));
Kt3T~k end
P1_6:USBM if mod(N,2)==1;
,8@q2a/ W=0:N-1; k=exp(-i*alpha*W); D=diag(k);
?+_Y!*J2b else
rczwxWK W=0:N-2; W=cat(2,W,[N]); k=exp(-i*alpha*W); D=diag(k);
p54e'Zb end
|\FJ FF=Ts*HH*D*HH'*2;
.k!<Oqa % Reference:
|BEoF[1 % by 平先军.一种新的分数阶傅立叶变换快速算法.电子学报.
;q?WU>c{? % 2001(3),Vol.29:406-408.