User`s guide

Creating LTI Models
2-13
produces
Zero/pole/gain:
–2 s
--------------------
(s–2) (s^2 – 2s + 2)
You can also specify zero-pole-gain models as rational expressions in the
Laplace variable s by:
1 Defining the variable s as a ZPK model
s = zpk('s')
2 Entering the transfer function as a rational e xpression in s.
For example, once
s is defined with zpk,
H = –2s/((s – 2)*(s^2 + 2*s + 2));
returns the same ZP K model as
h = zpk([0], [2 –1–i –1+i ], –2);
Note: You need only define the ZPK variable s once. All subsequent rational
expressions of
s will be ZPK models, unless you convert the variable s to TF.
See “Model Conversion” on page 2-42 for more information on conversion to
other model types.
MIMO Zero-Pole-Gain Models
Just a s with TF models, you can also specify a MIMO ZPK model by
concatenation of its SISO entries (see “Model Interconnection Functions” on
page 3-16).
You can also use the command
zpk tospecifyMIMOZPKmodels.Thesyntax
to create a p-by-m MIMO zero-pole-gain model using
zpk is
H = zpk(Z,P,K)