User`s guide

Table Of Contents

2 LTI Models

2-18

Here is the input frequency of each sinusoid, i = 1 ... n,andG(w)=

. The steady state output response of this system satisfies

A frequency response data (FRD) object is a model form you can use to store

frequency response data (complex frequency response, a long with a

corresponding vector of frequency points) that you obtain either through

simulationsor experimentally. In this example, the frequency response data is

obtained from the set of response pairs: .

Once you sto re y our dat a in a n FRD model, yo u can tre at it as an LTI model,

and manipulate an F RD mod el in m os t of the sa me wa ys you manipulate TF ,

SS, and ZPK model s.

The basic s yntax for creating a S ISO F RD model i s

sys = frd(response,frequencies,units)

where

•

frequencies is a real vector of length Nf.

•

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'

()

jGw

()∠()

exp

()

tGw

()∠+()

;

sin 1

…

()

(,){}

…