User`s guide

delay2z
11-58
11delay2z
Purpose Replace delays of discrete-time TF, SS, or ZPK models by poles at z=0, or
replace delays of FRD models by a phase shift
Syntax sys = delay2z(sys)
Description sys = delay2z(sys) maps all time delays to poles at z=0 for discrete-time TF,
ZPK, or SS models
sys. Specifically, a delay of k sampling periods is replaced
by
(1/z)^k in the transfer function corresponding to the model.
For FRD models,
delay2z absorbs all time delays into the frequency response
data, and is applicable to both continuous- and discrete-time FRDs.
Example z=tf('z',–1);
sys=(–.4*z –.1)/(z^2 + 1.05*z + .08)
Transfer function:
–0.4 z – 0.1
-------------------
z^2 + 1.05 z + 0.08
Sampling time: unspecified
sys.Inputd = 1;
sys = delay2z(sys)
Transfer function:
-0.4 z - 0.1
-----------------------
z^3 + 1.05 z^2 + 0.08 z
Sampling time: unspecified
See Also hasdelay True for LTI models with delays
pade Pade approximation of time delays
totaldelay Combine delays for an LTI model