User`s guide

Representing Time- and Frequency-Domain Data Using iddata Objects
The following example shows how to create an iddata object using
single-input/single-output (SISO) data from
dryer2.mat.Theinputand
output each contain 1000 samples with the sampling interval of
0.08 seco nd.
load dryer2 % Load input u2 and output y2.
data = iddata(y2,u2,0.08) % Create iddata object.
MATLAB returns the following output:
Time domain data set with 1000 samples.
Sampling interv al: 0.08
Outputs Unit (if specified)
y1
Inputs Un it (if specified)
u1
The default channel name 'y1' is assigned to the first and only output
channel. When
y2 contains several channels, the channels are assigned
default names
'y1','y2','y2',...,'yn'. Similarly, the default channel
name
'u1' is assigned to the first and only output channel. For more
information about naming channels, see “Naming, Adding, and Removing
Data Channels” on page 1-63.
Constructing an iddata Object for Frequency-Domain Data
Frequency-do m ain data is the Fourier transform of the input and output
signals at specific frequency values. To represent frequency-domain data, use
the following syntax to create the
iddata object:
data = iddata(y,u,Ts,'Frequency',w)
'Frequency'
is an iddat a property that specifies the frequency values w,
where
w is the frequency column vector that defines the frequencies for
calculating the Fourier transform values of
y and u. Ts is the time interval
between successive data samples in seconds.
w, y,andu have the same
number of rows.
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