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Re: FFT on 320e3 points
Posted:
Mar 6, 2013 8:14 AM


On 3/6/2013 5:09 AM, Giorgio wrote: > Hello, > > I am working on a project where I need to calculate the FFT of a Signal. > > This signal is one period of a sinusoid, sampled on 64 points. > Every 100 periods the phase of the sinusoid change by a random angle (+ pi/2 or + pi) and this for 50 times. > So, at the end of simulation (Simulink), the result is one dimensional Array of 1 X 64*100*50 = 320e3 points . > I need to calculate the FFT, so I am trying to import the Array in Matlab. > > But, I have the suspect that Matlab does an approximation or a decimation of the orginal signal. > By default, the FFT is fixed on 1024 points? > > So, how I can force Matlab to calculate the fft EXACTLY on 320e3 points ? Maybe this take one hour or more, but I don't care. > > > Thanks in Advance. > > Giorgio. >
hi;
May be try fft(X,n) ?
http://www.mathworks.com/help/matlab/ref/fft.html
"Y = fft(X,n) returns the npoint DFT. fft(X) is equivalent to fft(X, n) where n is the size of X in the first nonsingleton dimension. If the length of X is less than n, X is padded with trailing zeros to length n. If the length of X is greater than n, the sequence X is truncated."



