How can I get envelope wave of any signal?

[simpson67]

Hello, everyone.

I wanna get above red waves that is the Evnvelope wave of some input signals.

But I don't know what it can.

Now, I am using DAQ(NI USB-6259BNC ) and Labview 2010 evaluate ver.

Exactly I woder that getting above red envelope is possible.

some people said if I purchase toolkit or another instrument, implementation of ET(Envelope Tracking) technology will be possible.

And they said it will be possible using hillbert transform on labview. I don't know...

If you have any example using DAQ , plz upload for me. thanks.



Have a nice day.

[JKMM]

The Sound and Vibration Measurement Suite has some VIs for detecting envelope.  If you are wanting to create you own algorithm, one way you could approach it is with peak detection, for which there are VIs in the base version of LabVIEW.  You could also write your own peak detecting algorithm, but you need to consider that you will have a variable theshold.  If you already know your envelope signal and just want to display it, you can combine the waveforms with a Build Array Function.  In the attached VI there is a basic example of this, where I display the envelope of a 100Hz sine wave multiplied by a 2000Hz sine wave.  I also use the Envelope Detection.vi from the Sound and Vibration Measurement Suite and show the envelope it detects.  You won't be able to run the VI from the suite without the suite installed so I have disabled it, but you can see that it detects the envelope pretty well in Waveform Graph 2.

[johnsold]

Duplicate thread.  Since the question is not DAQ-related, let's keep the discussion in the LV Board.

Lynn