MATLAB SYSTEM IDENTIFICATION TOOLBOX 7 Guide de l'utilisateur Page 444

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 531
  • Table des matières
  • DEPANNAGE
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 443
8 Model Analysis
frequency response o f v(t).Tocomputev(t), which represents the actual noise
term in the system, use the following commands:
ysimulated = sim(m,data);
v = ymeasured-ysimulated;
ymeasured is data.y. v is the noise term v(t) , as described in “What Does a
Noise Spectrum Plot Show?” on page 8-40 and corresponds to the difference
between the simulated res po nse
ysimulated and the actual response
ymeasured.
To compute the frequency-response model of the actual noise, use
spa:
V = spa(v);
The too lbox uses the follow ing equation to compute the noise spectrum of
the actual noise:
Φ
vv
i
Re()ωτ
τ
ωτ
=
()
=−
The covariance function
R
v
is given in terms of E, which denotes the
mathematical expectation, as follows:
R Evtvt
v
ττ
()
=
()
()
To compare the parametric noise-model H to the (nonparametric)
frequency-response estimate of the actual noise v(t),use
bode:
bode(V,m('noise'))
If the parametric and the nonparametric estimates of the noise spectra are
different, then you might need a higher-order noise model.
8-46
Vue de la page 443
1 2 ... 439 440 441 442 443 444 445 446 447 448 449 ... 530 531

Commentaires sur ces manuels

Pas de commentaire