Documentation |
Before you can import time-domain data into the System Identification app, you must import the data into the MATLAB^{®} workspace, as described in Time-Domain Data Representation.
To import data into the app:
Type the following command in the MATLAB Command Window to open the app:
systemIdentification
In the System Identification app window, select Import data > Time domain data. This action opens the Import Data dialog box.
Specify the following options:
Input — Enter the MATLAB variable name (column vector or matrix) or a MATLAB expression that represents the input data. The expression must evaluate to a column vector or matrix.
Output — Enter the MATLAB variable name (column vector or matrix) or a MATLAB expression that represents the output data. The expression must evaluate to a column vector or matrix.
Data name — Enter the name of the data set, which appears in the System Identification app window after the import operation is completed.
Starting time — Enter the starting value of the time axis for time plots.
Sampling interval — Enter the actual sampling interval in the experiment. For more information about this setting, see Specifying the Data Sampling Interval.
Tip The System Identification Toolbox™ product uses the sampling interval during model estimation and to set the horizontal axis on time plots. If you transform a time-domain signal to a frequency-domain signal, the Fourier transforms are computed as discrete Fourier transforms (DFTs) using this sampling interval. |
(Optional) In the Data Information area, click More to expand the dialog box and enter the following settings:
Input Properties
InterSample — This options specifies the behavior of the input signals between samples during data acquisition. It is used when transforming models from discrete-time to continuous-time and when resampling the data.
zoh (zero-order hold) indicates that the input was piecewise-constant during data acquisition.
foh (first-order hold) indicates that the output was piecewise-linear during data acquisition.
bl (bandwidth-limited behavior) specifies that the continuous-time input signal has zero power above the Nyquist frequency (equal to the inverse of the sampling interval).
Period — Enter Inf to specify a nonperiodic input. If the underlying time-domain data was periodic over an integer number of periods, enter the period of the input signal.
Channel Names
Input — Enter a string to specify the name of one or more input channels.
Output — Enter a string to specify the name of one or more output channels.
Physical Units of Variables
Input — Enter a string to specify the input units.
Output — Enter a string to specify the output units.
Notes — Enter comments about the experiment or the data. For example, you might enter the experiment name, date, and a description of experimental conditions. Models you estimate from this data inherit your data notes.
Click Import. This action adds a new data icon to the System Identification app window.
Click Close to close the Import Data dialog box.