Discrete Transfer Function
Purpose
Model discrete system as transfer function
Library
Control / Discrete
Description
The Discrete Transfer Function models a discrete time-invariant system that is
expressed in the -domain:
The transfer function is displayed in the block if it is large enough, otherwise a default text is shown. To resize the block, select it, then drag one of its selection handles.
Parameters
- Numerator coefficients
- A vector of the
term coefficients
for the numerator, written in descending order of powers of z. For example, the numerator
would be entered as [1,0,2,0].
The output of the Transfer Function is vectorizable by entering a matrix for the numerator. - Denominator coefficients
- A vector of the
term coefficients
for the denominator, written in descending order of powers of
.
Note The order of the denominator (highest power of) must be greater than or equal to the order of the numerator.
- Sample time
- The time interval between samples. See also the Discrete-Periodic sample time type in section Sample Times.
- Initial condition
- The initial condition vector of the internal states of the Transfer
Function in the form
. The initial conditions must be specified for the controller normal form, depicted below for the the transfer function:
where
For the normalized transfer function (with
and
) this simplifies to
and
.
Probe Signals
- Input
- The input signal.
- Output
- The output signal.