VARIABLE_DELAY
==============

Variable delay



Block Screenshot
~~~~~~~~~~~~~~~~





Contents
~~~~~~~~


+ `Variable delay`_
  +

    + `Palette`_
    + `Description`_
    + `Dialog box`_
    + `Default properties`_
    + `Interfacing function`_
    + `Computational function`_
    + `Example`_





Palette
~~~~~~~


+ `Continuous time systems palette`_




Description
~~~~~~~~~~~

The Variable Transport Delay block can be used to simulate a variable
time delay between an action and its effect. The block might be used,
for example, to model a system with a pipe where the speed of a motor
pumping fluid in the pipe is variable.

The block accepts two inputs and one output: the first input is the
signal u(t) that passes through the block (data input); the second
input is the variable time delay τ(t).



At the current time step t, the block outputs the delayed data input
u(θ) where θ is the current simulation time t minus the time delay
parameter τ.

The equation of the output signal is:





Dialog box
~~~~~~~~~~






+ **Max delay** It defines the largest value the time delay input can
  have. The value cannot be negative. Properties : Type 'vec' of size 1.
+ **initial input** The output generated by the block until the
  simulation time first exceeds the time delay input. Properties : Type
  'vec' of size 1.
+ **Buffer size** The number of points the block can store. Properties
  : Type 'vec' of size 1.




Default properties
~~~~~~~~~~~~~~~~~~


+ **always active:** yes
+ **direct-feedthrough:** no
+ **zero-crossing:** no
+ **mode:** no
+ **regular inputs:** **- port 1 : size [1,1] / type 1** **- port 2 :
  size [1,1] / type 1**
+ **regular outputs:** **- port 1 : size [1,1] / type 1**
+ **number/sizes of activation inputs:** 0
+ **number/sizes of activation outputs:** 0
+ **continuous-time state:** no
+ **discrete-time state:** no
+ **object discrete-time state:** no
+ **name of computational function:** variable_delay




Example
~~~~~~~

In this example, the max time delay in the Block Parameters dialog box
is set to 4. The input signal is a sine wave with amplitude 1 and
frequency 0.2 Hz.

The constant block is set to 2 to introduce a delay of 2 second. The
input and output waveforms of the VARIABLE_DELAY block are shown
below:


`

`_


Interfacing function
~~~~~~~~~~~~~~~~~~~~


+ SCI/modules/scicos_blocks/macros/Linear/VARIABLE_DELAY.sci




Computational function
~~~~~~~~~~~~~~~~~~~~~~


+ SCI/modules/scicos_blocks/src/c/variable_delay.c (Type 4)


.. _Variable delay: VARIABLE_DELAY.html
.. _Default
                properties: VARIABLE_DELAY.html#Defaultproperties_VARIABLE_DELAY
.. _
      : nullscilab.xcos/xcos/examples/continuous_pal/en_US/VARIABLE_DELAY_en_US.xcos
.. _Description: VARIABLE_DELAY.html#Description_VARIABLE_DELAY
.. _Interfacing
                function: VARIABLE_DELAY.html#Interfacingfunction_VARIABLE_DELAY
.. _Continuous time systems
            palette: Continuous_pal.html
.. _Dialog
                box: VARIABLE_DELAY.html#Dialogbox_VARIABLE_DELAY
.. _Computational
                function: VARIABLE_DELAY.html#Computationalfunction_VARIABLE_DELAY
.. _Palette: VARIABLE_DELAY.html#Palette_VARIABLE_DELAY
.. _Example: VARIABLE_DELAY.html#Example_VARIABLE_DELAY