Specifications

2 LTI Models
2-26
ThesampletimepropertyTs keeps track of the sample time (in seconds) of
discrete-time systems. By convention,
Ts is 0 (zero) for continuous-time
systems, and
Ts is –1 for discrete-time systems with unspecified sample time.
Ts is always a scalar, even for MIMO systems.
The
InputDelay, OutputDelay,andioDelay properties allow you to specify
timedelaysinthe input oroutputchannels,orforeachinput/outputpair.Their
default value is zero (no delay). See “Time Delays” on page 2-43 for details on
modeling delays.
The
InputName and OutputName properties enable you to give names to the
individual input and output channels. The value of each of these properties is
a cell vector of strings with as many cells as inputs or outputs. For example,
the
OutputName property is set to
{ 'temperature' ; 'pressure' }
for a system with two outputs labeled temperature and pressure.Thedefault
value is a cell of empty strings.
Using the
InputGroup and OutputGroup properties of LTI objects, you can
create different groups of input or output channels, and assign names to the
groups. For example, you may want to designate the first four inputs of a
five-input model as
controls, and the last input as noise. See “Input Groups
and Output Groups” on page 2-36 for more information.
Finally,
Notes and Userdata are available to store additional information on
the model. The
Notes property is dedicatedto any text you want to supply with
your model, while the
Userdata property can accommodate arbitrary
user-supplied data. They are both empty by default.
For more detailed information on how to use LTI properties, see “Additional
Insight into LTI Properties” on page 2-32.
Model-Specific Properties
The remaining LTI properties are specific to one of the four model types (TF,
ZPK, SS, or FRD). For single LTI models, these are summarized in the