inverse Fourier transform

hi,

I have a matrix 120x200 called H. inside H, there are some data like x+iy. I'd like to take inverse Fourier of H, I tried to use, ifft command but it takes only one dimensional inverse Fourier. What command should I use or what code should I use to take inverse Fourier of a 120x200 matrix. Thank you

[salih]

I also wrote a code to take inverse fourier of a matrix 120x200 size. is something wrong with the code

function out = invf(H)

for t=1:120

for tao=1:200

b=zeros(120,200);

for f=1:201

b(t,tao) = b(t,tao)+ H(t,f)*exp(1i*2*pi*(5099+f)*tao*10^-3);

end

k(t,tao)= b(t,tao);

end

end

out = k(:,:);

Answer 1

[Brett Shoelson]

Look at the dimensions of your z matrix. (size(z)). Then make sure the number of x values matches the first dimen

Consider:

a = rand(3,4);
[nrows,ncols] = size(a); %Careful with this syntax if you 
%                         have higher dimensions!

THIS WORKS:

surf(1:ncols,1:nrows, a)

BUT THIS DOESN'T:

surf(1:nrows,1:ncols, a)

Cheers,

Brett

[salih]

thank you buddy, it was very helpful I solved my problem :)

Answer 2

[David Young]

ifft2

[salih]

thank you very much David for your help. can you also help me on that.

I'd like to plot 3D of inverse fourier transform. I use the following commands

x=1:120

y=1:200

z=ifft2(H(:,:))

surf(y,x,abs(z))

but I get following error

??? Error using ==> surf at 78

Data dimensions must agree.

Could you tell me how to correct it ?

[David Young]

See comment on next "answer"

Answer 3

[salih]

I'd like to plot 3D of inverse fourier transform. I use the following commands

x=1:120;

y=1:200;

z=ifft2(H(:,:));

surf(y,x,abs(z))

but I get following error

??? Error using ==> surf at 78 Data dimensions must agree. Could you tell me how to correct it ?

[salih]

no suggestion ?

[David Young]

Try

surf(x, y, abs(z))

Remember that the length of x must be the number of columns of z, and the length of y must be the number of rows.