11-20-2016 04:08 PM
i need to find exponentil decay of the signal and then dmping what isthe best way i am posting my vi plz help
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11-20-2016 04:50 PM
I can't open your vi... still stuck with an older version....
However: Depending on your signal (pic? ) the hilbert transformation to create (and add) an 'imaginary' part, and looking at the magnitude of that complex wfrm is one way to get the decay 🙂
If you have an edjucated guess of the funktion: let the LM- Fit do the work ....
11-20-2016 06:09 PM - edited 11-20-2016 06:10 PM
thaks bro
here is the vi in old version i just need to find damping of the signal
11-21-2016 01:32 AM
Still not clear to me at what signal you need to look ...
11-21-2016 02:01 AM
here i s the actual signal i will get
please see attachment
11-21-2016 02:06 AM
dear sir
i am getting this kind of signal from oscilloscope and want to have some measurements that oscilloscope donot provide here is the example of what i get from oscilloscope then i need to find damping
11-22-2016 01:47 AM - edited 11-22-2016 01:49 AM
Hi deutchland,
it looks like a sine wave multplied by an exponential decay - kind of easy to program!
What have you tried so far? Where are you stuck?
Can't you apply a simple mathematical formula?
Edit - saw your downconverted VI now: find the peaks in your signal! From peak positions you can determine sine wave period and exponential decay parameters quite easily…
11-22-2016 01:54 AM
ok i will try. thanks for your help
actually i am getting output on spring mass based system.
kind regards
deutschland
11-22-2016 03:01 AM
Hi Deutchland,
I agree with GerdWs Answer, I think the easiest way will be to detect the maxima of the curve. You could also use the Hilberts Transformation for this, but I'm not that deep into the mathematics behind it to explain what exactly to do with it. Try using the maxima to build a new curve, and then just detect its damping, if you have trouble with this, just let me know!
Best,
Jan Göbel
Staff Applications Engineer
11-23-2016 03:15 AM - edited 11-23-2016 03:17 AM
Here is a link to a (open access 🙂 ) paper that explains and compare the two methods I mentioned before:
COMPARISON OF HILBERT TRANSFORM AND SINE FIT APPROACHES FOR THE DETERMINATION OF DAMPING PARAMETERS
more in the references 😉
for the hilbert transformation I add something to play: