fft/ifft transform of 2d matrix

hello! i'm little confuse.if i want to make a fft trnformation of a 2d matrix what should i do? fft(x, [], 2),fft(x, [],1),fft2(x) or what else?

Answer 1

[Walter Roberson]

It depends on your purpose. fft(x,[],2) does one fft for each row of x; fft(x,[],1) does one fft for each column of x; fft2(x) does a 2 dimensional fft (which is an fft in one direction followed by an fft in the other direction)

[jordi10]

thank u very much!i made a matlab simulation of transmiter and reciever through a plc channel and i cant take rigth result and i am not sure where the wrong is,and i thought that maybe was at ofdm.if i have a matrix x(80,2048)of 1 and -1 and i want to transform it with ifft to use it for ofdm i use the ifft(x,[],2)?

if u know about the style of simulation i said i will be very thankfull for your help!thanks again!!!!

[Rahul BHATT]

did you find an answer to your question

Answer 2

[Dr. Seis]

If you want an idea of what is going on behind the scenes of fft2, then you can check out my answer here:

http://www.mathworks.com/matlabcentral/answers/24965-fft2-function-in-matlab

I show what the discrete 2D Fourier transform looks like coded up, and then compare the results with Matlab's 2D Fast Fourier Transform.

[jordi10]

thanks!!!very usefull!!!