User`s guide

tf
11-225
If all SISO entries of a MIMO transfer function have the same denominator,
you can set
den to the row vector representation of this common denominator.
See “Examples” for more details.
sys = tf(num,den,Ts) creates a discrete-time transfer function with sample
time
Ts (in seconds). Set Ts = –1 or Ts = [] to leave the sample time
unspecified. The input arguments
num and den are as in t he continuous-time
case and must list the numerator and denominator coefficients in descending
powers of .
sys = tf(M) creates a static gain M (scalar or matrix).
sys = tf(num,den,ltisys) creates a transfer function with generic LTI
properties inherited from t he LTI model
ltisys (including the sample time).
See “Generic Properties” on page 2-26 for an overview of generic LTI
properties.
There are several ways to create LTI a rrays of transfer functions. To creat e
arrays of SISO or MIMO TF models, either specify the numerator and
denominator of each SISO entry using multidimensional cell arrays, or use a
for loop to successively assign each TF model in the array. See “Building LTI
Arrays” o n page 4-12 for more information.
Any of the previous syntaxes can be followed by property name/property value
pairs
'Property',Value
Each pair specifies a part icular LTI property of the model, for example, the
input names or the transfer function variable. See
set entry and the example
below for details. Note that
sys = tf(num,den,'Property1',Value1,...,'PropertyN',ValueN)
is a shortcut for
sys = tf(num,den)
set(sys,'Property1',Value1,...,'PropertyN',ValueN)
Transfer Functions as Rational Expressions in s or z
You can also use real-valued rational expressions to create a TF model. To do
so, first type either:
z