Represent Data

Measure or generate data, represent data using timetables, numeric matrices, and data objects, import data into the app, manipulate complex-valued data

System Identification Toolbox™ estimation, validation, and analytical functions accept input/output estimation data in multiple forms.

Time-domain data — Timetables, numeric matrices, time-domain iddata objects
Frequency-domain and frequency response data — Frequency-domain iddata objects, idfrd objects, frd objects

You can also generate custom signal data to provide the stimulation signal for experiments or to study estimated model behavior by simulating the model response to these signals.

Data types such as timetables and iddata objects also include properties that include information about the data such as sample rate, units, and, for iddata objects, intersample behavior, channel names, and experiment identifiers. Numeric matrices contain only data values, and provide no information on sample rate or any other data properties.

You can combine related data sets as long as they have the same sample rate and channel selections. In particular, you can create multiexperiment data sets that must share sample rate and channel selections but can have different durations and start times.

Functions

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Use Different Data Types

`timetable`	Tables for time series data, with timestamped rows and variables of different types
`iddata`	Input-output data and its properties for system identification in the time or frequency domain
`idfrd`	Frequency response data or model
`iddata2timetable`	Convert time-domain `iddata` object to `timetable` object (Since R2023a)

Generate Custom Signal Data

`idinput`	Generate input signals to support system identification
`sim`	Simulate response of identified model
`simOptions`	Option set for `sim`

Obtain Information About Data

`size`	Determine size of `iddata` data set
`midprefs`	Specify location for file containing System Identification app startup information

Blocks

Iddata Sink	Export simulation data as `iddata` object to MATLAB workspace
Iddata Source	Import time-domain data stored in `iddata` object in MATLAB workspace

Topics

Data Requirements

Representing Data in MATLAB Workspace
Represent time-domain, time-series, and frequency-domain data.

Work with Data Types

Data Domains and Data Types in System Identification Toolbox
System Identification Toolbox accepts timetables, numeric matrices, and data objects for model estimation in the time and frequency domains.
Use Timetable Data for Time-Domain System Identification
Create and use timetables for model estimation.
Use Matrix-Based Data for Time-Domain System Identification
Use data contained in numeric matrices for time-domain model estimation.
Convert SISO Matrix Data to Timetable
Convert matrix-based SISO estimation data to timetables for model identification.
Convert MIMO Matrix Data to Timetable for Continuous-Time Model Estimation
Estimate a continuous-time MIMO model by first converting matrix-based data to a timetable.
Representing Time- and Frequency-Domain Data Using iddata Objects
Using the iddata constructor to represent time-domain and frequency-domain data and working with iddata objects.
Managing iddata Objects
The iddata object stores time-domain data or frequency-domain data and has several properties that specify the time or frequency values.
Representing Frequency-Response Data Using idfrd Objects
Using the idfrd constructor to represent frequency-response data and working with idfrd objects.

Generate Input and Output Data

Generate Data Using Simulation
Creating input data with specific characteristics and simulating the output data from a model.

Work with Data in the App

Import Time-Domain Data into the App
Import time-domain data into the System Identification app.
Import Frequency-Domain Data into the App
Import frequency-domain input-output data and frequency-response data into the System Identification app.
Import Data Objects into the App
Import iddata and idfrd data objects.
Specifying the Data Sample Time
Specify time between successive data samples.
Managing Data in the App
You can get information about each data set in the System Identification app by right-clicking the corresponding data icon.

Use Complex-Valued Data

Manipulating Complex-Valued Data
Supported operations and limitations for handling complex data and commands for manipulating complex signals.