fft of a continuous signal

I am using Simulink, where I have a block whose output is a 3-phase current. I need to find fft of this current signal (which is a continuous, real signal). I am really confused how to do it, Any help would be appreciated.

Answer 1

[Suneesh]

Fast Fourier transform (FFT) is an algorithm to calculate the discrete Fourier transform (DFT). Now the DFT is defined only for discrete equally spaced samples of data - not for a continuous signal. If you are just studying the frequencies in your signal then it may be easier to just discretize and take the FFT. else you are looking for the Fourier transform of your continuous signal.

[Anuj]

Thanks for your reply, I know that its an algorithm to find DFT, but I have to get that only and that's where I am confused, how do I discretize the signal, do fft blocks have inbuilt sampling function to discretize them and so on.. and if yes, which toolbox to use and how?

[Suneesh]

http://www.mathworks.com/help/releases/R2013b/simulink/slref/zeroorderhold.html