best way to get exponential decay of signal

[deutchland]

i need to find exponentil decay of the signal and then dmping what isthe best way i am posting my vi plz help

[Henrik_Volkers]

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 ....

[deutchland]

thaks bro

here is the vi in old version i just need to find damping of the signal

[Henrik_Volkers]

Still not clear to me at what signal you need to look ...

[deutchland]

here i s the actual signal i will get 

please see attachment

[deutchland]

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

[GerdW]

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…

[deutchland]

ok i will try. thanks for your help

actually i am getting output on spring mass based system.

kind regards

deutschland

[JGoebel]

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

[Henrik_Volkers · Accepted solution]

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: