idft.m

Signal and Sytem Using Matlab 书的源代码 注释详尽 m文件

%
%Inverse Discrete Fourer Transform
%
function x=idft(Xk)
[N,M]=size(Xk);
if M~=1 %make sure that Xk is a column vector
    Xk=Xk.';
    N=M;
end
x=zeros(N,1);
k=0:N-1;
for n=0:N-1
    x(n+1)=exp(j*2*pi*k*n/N)*Xk;
end
x=x/N;