matlab FFT is also discrete, how does this compare to DTFT?

[W_Heisenberg]

When we do a FFT in matlab, it shows the spectrum, but will this show all the information? It could be showing less than DTFT, is this true?

 

[Shug]

For a finite or periodic signal, as long as your FFT is long enough, the FFT contains all the information of the DTFT. The DTFT is periodic, and the FFT shows one period of the DTFT.

 

[W_Heisenberg]

thanks!
clear explaination!

For a finite or periodic signal, as long as your FFT is long enough, the FFT contains all the information of the DTFT. The DTFT is periodic, and the FFT shows one period of the DTFT.