Function Reference

delay2z

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.InputDelay = 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

dcgain

dlqr