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2008-12-02 10:26 |
实现分数傅立叶变换的matlab程序
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。 +#By* ;BJ
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function FF=frft_PXJ(N,alpha); :EH=_"
%matrix t
Pf40`@
% FF is the kernel matrix of fractional Fourier transform 6RM/GM
% \copyright: zjliu U&xUfBDt
% Author's email: zjliu2001@163.com 7KPwQ?SjT
Ts=sqrt(2*pi/N); t=-(N-1)/2:(N-1)/2; t=t'; t=t*Ts; .2pK.$.
variance=N/2/pi; HH=zeros(N); HH(:,1)=1; HH(:,2)=2*t; .-=vx r
for k=3:N; AEuG v}#
HH(:,k)=HH(:,k-1).*t*2-2*(k-2)*HH(:,k-2); [V!tVDs&'o
end Ug`djIL
HH(:,1)=1/sqrt(sqrt(variance))*HH(:,1).*exp(-t.*t/2); RyN s6
for k=2:N; fatf*}eln
HH(:,k)=exp(-t.*t/2).*HH(:,k)/sqrt(2.^(k-1)*... `kr?j:g
factorial(k-1)*sqrt(variance)); W`&hp6Jq
end T KjFp%
if mod(N,2)==1; yBRC *0+Vy
W=0:N-1; k=exp(-i*alpha*W); D=diag(k); rbQR,Nf2x
else _w Ot39e&
W=0:N-2; W=cat(2,W,[N]); k=exp(-i*alpha*W); D=diag(k); aP`P)3O6)1
end B;WCTMy}
FF=Ts*HH*D*HH'*2; 66 Tpi![
% Reference: xCKRxF
% by 平先军.一种新的分数阶傅立叶变换快速算法.电子学报. Ewm9\qmg
% 2001(3),Vol.29:406-408.
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