Main Content





System IdentificationIdentify models of dynamic systems from measured data


etfeEstimate empirical transfer functions and periodograms
spaEstimate frequency response with fixed frequency resolution using spectral analysis
spafdrEstimate frequency response and spectrum using spectral analysis with frequency-dependent resolution
idfrdFrequency response data or model
getpvecObtain model parameters and associated uncertainty data
setpvecModify values of model parameters
bodemag 周波数応答のゲインのみのボード線図
chgFreqUnit周波数応答データ モデルの周波数単位の変更


Estimate Frequency-Response Models in the App

You must have already imported your data into the app and performed any necessary preprocessing operations. For more information, see データの準備.

Estimate Frequency-Response Models at the Command Line

You can use the etfe, spa, and spafdr commands to estimate spectral models. The following table provides a brief description of each command and usage examples.


What is a Frequency-Response Model?

A frequency-response model is the frequency response of a linear system evaluated over a range of frequency values. The model is represented by an idfrd model object that stores the frequency response, sample time, and input-output channel information.

Data Supported by Frequency-Response Models

Characteristics of data supported for estimation of spectral analysis models.

Selecting the Method for Computing Spectral Models

How to select the method for computing spectral models during estimation in the app and at the command line.

Controlling Frequency Resolution of Spectral Models

Controlling frequency resolution of spectral models during estimation in the app and at the command line.

Spectrum Normalization

The spectrum of a signal is the square of the Fourier transform of the signal. The spectral estimate using the commands spa, spafdr, and etfe is normalized by the sample time T: