Bump ---> Identification using invfreqs

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Sheikh
Sheikh on 12 Aug 2013
Hello all,
I want to fit a model to the data peaks at around 70 Hz and 183 Hz. But for some reason can never fit the peak at 70 Hz.
tol = 1e-7;
frd = 2*pi*F; %frequency in rad/s
[numG,denG] = invfreqs(Txy,frd,15,17,[],1000,tol);
sys = tf(numG,denG);
figure; hold on; semilogx(frd,magdbTxy,'b');
bode(sys,frd,'r'); hold off;
Is there a way to specify which peaks I want to fit a model to?
Thanks a lot.

Answers (1)

Rajiv Singh
Rajiv Singh on 12 Aug 2013
Have you tried using the weight input argument? You can specify higher weights for the frequencies around which you are interested in capturing the response.
See also: tfest and accompanying option set tfestOptions (option called "Focus" in particular). These functions belong to System Identification Toolbox.
  1 Comment
Sheikh
Sheikh on 12 Aug 2013
Thanks Rajiv. I will try that and let you know how it goes.

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