Azzera filtri
Azzera filtri

transfer function frequency response

2 visualizzazioni (ultimi 30 giorni)
Zhe Liu
Zhe Liu il 27 Giu 2016
Commentato: Star Strider il 28 Giu 2016
how to get transfer function from this time response plot? Red is input and blue is output....

Risposte (2)

J. Webster
J. Webster il 27 Giu 2016
Take the fourier transform of both signals, then the transfer function will be the FFT of the cavity divided by the FFT of the reference.
  1 Commento
Zhe Liu
Zhe Liu il 27 Giu 2016
Hey! Thanks for the reply. Do you mean for whole time domain or just the later periodic part? I did FFT of both signals in the whole window but the result does not make much sense to me. I want to find the natural frequency(resonance frequency) of a line-cavity system.

Accedi per commentare.


Star Strider
Star Strider il 27 Giu 2016
You are doing ‘system identification’. If you have the Signal Processing Toolbox, use the invfreqz function. (If you have the System identification Toolbox, there are several functions you can use to identify the cavity dynamics.)
You will have to experiment with the number of poles and zeros in the transfer function. I would start with 5 for both, then use the output to define an IIR filter, and then filter the input signal with it, and continue changing the number of poles and zeros (I would specify the same number for each) until you the output reasonably approximates the response to your system.
  6 Commenti
Zhe Liu
Zhe Liu il 28 Giu 2016
send you shortly...Sorry for the delay...I went home at that time...
Star Strider
Star Strider il 28 Giu 2016
I’m still here!

Accedi per commentare.

Categorie

Scopri di più su Linear Model Identification in Help Center e File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by