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Topic: Why does the default fft data number change for a identification data
Replies: 1   Last Post: Apr 4, 2013 3:11 PM

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Registered: 10/8/05
Why does the default fft data number change for a identification data
Posted: Apr 4, 2013 12:46 PM
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I try to run a snippnet of identification toolbox user guide:

% Load input u2 and output y2
load dryer2;
% Create iddata object
tdata = iddata(y2,u2,0.08);
% Take the Fourier transform of the data
% transforming it to frequency domain
fdata = fft(tdata)
% Get property values of data

The length of tdata is 1000 while the length of fdata is 501. I have check function fft and I do not find anything can explain it to me. Could you help me on this question?


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