User`s guide

Importing Data into the MATLAB
®
Workspace
For a data set with N
y
outputs and N
T
samples (measurements), the output
is an N
T
-by-N
y
matrix.
• Sampling time interval
If you are working with uniformly sampled data, use the actual sampling
interval from your experiment. Each data value is assigned a sample time,
which is calculated from the start time and the sampling interval. If you
are working with nonuniformly sampled data at the command line, you
can s pecify a vector of time instants using the
iddata SamplingIns tant s
property, as described in “Constructing a n iddata Object fo r T ime-Doma in
Data” on page 1-48.
For more information about importing data into the M ATL AB workspace, see
the MATLAB documentation.
After you impo rt data, you can import it into the Sy stem Identi fication Tool
GUI or create a data object for working at the command line. For more
information about importing data into the GUI, see “Importing Time-Domain
Data into the GUI” on page 1-15. To learn more about creating a data object,
see “Representing Time- and Frequency-Domain Data Using iddata Objects”
on page 1-47.
Importing Time-Series Data into MATLAB
Time-series data is time-domain or frequency-domain data that consist o f one
or more outputs y(t) with no corresponding input.
You must import your time-series data into the MATLAB workspace as the
following v ariables:
• Output data
- For single-in p ut/single-output (SI S O ) data, the output mus t be a column
vector.
- For a data set with N
y
outputs and N
T
samples (measurements), the
output is an N
T
-by-N
y
matrix.
• Sampling time interval
1-7