MATLAB: How to create a pulse generator which outputs pulses at random time intervals in Simulink 7.9(R2012a)

parameterperiodsimulinktunable

I am trying to generate a time function/waveform with narrow pulses whose interarrival time follows an exponential statistics. The width of the pulses should be narrow but the randomness of the time between the pulses is the most important thing. How can I do this in Simulink using only basic blocks.

Best Answer

There can be multiple ways to do this. One possible way using two switch blocks. One can be used to control the 'ON period' (TON) of the pulse and the other can be used to control the total period of the pulse.We can count for the fixed width up to TON, then switch the output to zero. Then count up to the number given by the generator and reset the counter. Refer to the attached showPulse.mdl for more details.

Other possible ways of doing this could be to use MATLAB Level-2 S-functions or C MEX S functions to write your own custom source.

Related Solutions

MATLAB: How to have a Pulse Generator block that will start from 0 phase whenever the enabled subsystem it resides in is enabled in Simulink 7.8 (R2011b)

The ability to reset the state of a signal such as a Pulse Generator is currently not available in Simulink 7.8 (R2011b). This is because the Pulse Generator signal works under the following calculation, which is based on simulation time:

   if (t >= PhaseDelay) && Pulse is on
     Y(t) = Amplitude
   else
     Y(t) = 0
   end

As a workaround, the pulse generator can be connected to an external time signal which is fed by a Counter Free-Running block. Whenever the subsystem is re-enabled, the counter is reset to zero to denote zero time and therefore zero phase.

One thing to note with this is that the counter is incremented by 1 at every time step, so the period of the pulse generator signal will need to be "normalized" to account for the simulation time step size.

Please see the attached model for more information on this workaround. The pulse generator signal is interrupted with a negative pulse. When the enabled subsystem is re-enabled after this interruption, the pulse begins from its zero-phase point no matter what time the simulation is in.

MATLAB: Random pulse generator

use this block

the function is

function y = fcn(u)
%#codegen
id=rand(1)
if id>0.5 & u==0
  y=1
else
  y=0
end

or easier

Best Answer

Related Solutions

MATLAB: How to have a Pulse Generator block that will start from 0 phase whenever the enabled subsystem it resides in is enabled in Simulink 7.8 (R2011b)

MATLAB: Random pulse generator

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