Specifications

2 LTI Models
2-18
•response is a vector of length Nf of complex frequency response values for
these frequencies.
•
units is an optional string for the units of frequency: either 'rad/s' (default)
or '
Hz'
For example, the MAT-file
LTIexamples.mat contains a frequency vector freq,
and a corresponding complex frequency response data vector
respG.Toload
this frequency-domain data and construct an FRD model, type
load LTIexamples
sys = frd(respG,freq)
Continuous-time frequency response with 1 output and 1 input
at 5 frequency points.
From input 1 to:
Frequency(rad/s) output 1
---------------- --------
1 –0.812505 –0.000312i
2 –0.092593 –0.462963i
4 –0.075781 –0.001625i
5 –0.043735 –0.000390i
ThesyntaxforcreatingaMIMOFRDmodelisthesameasfortheSISOcase,
except that
response is a p-by-m-by-Nf multidimensional array, where p is the
number of outputs, m is the number of inputs, and Nf is the number of
frequency data points (the length of
frequency).
The following table summarizes the complex-valued response data format for
FRD models.
Table 2-3: Data Format for the Argument response in FRD Models
Model Form Response Data Format
SISO model Vector of length Nf for which response(i) is the
frequency response at the frequency
frequency(i)