Detect spikes and mark times

Hi.

I am trying to detect a spike in simulink for a signal (by spike I mean when the signal exceeds a certain value with a defined height). Futhermore, because I want to do an integration of this spike I need to have the two time values. Does anybody know how this can be achieved in matlab?

Thank you very much, Angel

Answer 1

[Sebastian Castro]

You can pick out the values of these spikes using a Triggered Subsystem.

What I've done in the screenshot below is:

• Use a Compare to Constant block to create a logical signal. This tells me whether or not the signal is above the spike
• Use a Triggered Subsystem that, when triggered, picks the current simulation time. This time is supplied with a Clock block.
• To pick out t1, you can configure your Triggered Subsystem to find the RISING EDGE (i.e. when the logical signal goes from 0 to 1).
• To pick out t2, you can configure another Triggered Subsystem to find the FALLING EDGE (i.e. when the logical signal goes from 1 to 0).

If you have multiple peaks in your signal, your algorithm may have to be a little "smarter" than this. However, this should give a good start for how you can use Triggered Subsystems to capture "snapshots" in your model.

[Image Analyst]

Angelos's "Answer" moved here since it's really a reply to Sebastian, not an answer to the original question:

Thank you very much.

Angelos, you can "thank" him also by accepting his answer and voting for it.