User`s guide

frd
11-80
sysfrd = frd(sys,frequency,'Units',units)convertsan FRD model froma
TF, SS, or ZPK model while specifying the units for
frequency to be units
('rad/s' or 'Hz').
Arguments When you specify a SISO or MIMO FRD model, or an array of FRD models, the
input argument
frequency is always a vector of length Nf,whereNf is the
number of frequency data points in the FRD. The specification of the input
argument
response is summarized in the following table.
Remarks See “Frequency Response Data (FRD) Models” on page 2-17 for more
information on single FRD models, and “Building LTI Arrays Using tf, zpk, ss,
and frd” on page 4-17 for information on arrays of FRD models.
Example Type the commands
freq = logspace(1,2);
resp = .05*(freq).*exp(i*2*freq);
sys = frd(resp,freq)
to create a SISO FRD model.
See Also chgunits Change units for an FRD model
frdata Quick access to data for an FRD model
set Set the properties for an LTI model
ss Create state-space models
Table 11-14: 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)
MIMO model
with
Ny outputs
and
Nu inputs
Ny-by-Nu-by-Nf mult idimensional array for which
response(i,j,k) specifies the frequency response
from input
j to output i at frequency frequency(k)
S1
-by-...-by-Sn
array of models
with
Ny outputs
and
Nu inputs
Multidimen sio n al array of size [
Ny Nu S1 ... Sn] for
which
response(i,j,k,:) specifies the array of
frequency response data from input
j to output i at
frequency
frequency(k)