d2d (Control System Toolbox)

d2d	Examples See Also

Resample discrete-time LTI models or add input delays

Syntax

sys1 = d2d(sys,Ts)

Description

sys1 = d2d(sys,Ts) resamples the discrete-time LTI model sys to produce an equivalent discrete-time model sys1 with the new sample time Ts (in seconds). The resampling assumes zero-order hold on the inputs and is equivalent to consecutive d2c and c2d conversions.

sys1 = c2d(d2c(sys),Ts)

Example

Consider the zero-pole-gain model

with sample time 0.1 second. You can resample this model at 0.05 second by typing

H = zpk(0.7,0.5,1,0.1)
H2 = d2d(H,0.05)
Zero/pole/gain:
(z-0.8243)
----------
(z-0.7071)
 
Sampling time: 0.05

Note that the inverse resampling operation, performed by typing d2d(H2,0.1), yields back the initial model

Zero/pole/gain:
(z-0.7)
-------
(z-0.5)
 
Sampling time: 0.1