Waveform FFT

[JackAlthon1]

Yes, I am reading a raw.dat. This format was took from a laser datas. I am using index to take a one choice of waveform - that is all. I have tried to take all waveforms, but when you are trying to index it doesnt work etc., insted of I need only one choice of waveform. The size is 20.000 points., the frequincy I dont know.  I know how to read a waveform etc., but I dont understand how to manage with dT and number sampling manage all these things to get a FFT. I read a lot, but I dont get it. What do you mean open a single file? Raw.dat is single file.

[JackAlthon1]

Bob, I did default and added for new a code. Please look at.

[Bob_Schor]

Almost!  In addition to wiring the waveform to a Graph, wire it to a Waveform Indicator (right-click the wire, choose "Create Indicator").  This provides us with a copy of the actual data so that we can look at it and manipulate it with functions.

Bob Schor

[Bob_Schor]

Here's a Snippet showing what I mean ...  See "First Waveform in Record"?  (This is also what I meant about not needed the Index Array function to give you the first waveform in All Waveforms).

Bob Schor

[JackAlthon1]

Thank you, I added much more indicators and got a message that the maximum file size. 6milion bytes. How to add in another way?

[JackAlthon1]

Bob, I uploaded to wetransfer. Here is a link . Please look at code. Thank you

[JackAlthon1]

It should work from uploaded file because here is not possible to upload max 6mb. Please look at code, I dont get how to manage and combine dT and sampling to obtain FFT spectrum (from waveform I dont get how to manage and comabine dT and sampling), because normaly from sin generation it is easy to get a FFT spectrum, but how to get FFT spectrum from waveform. Thank you

[JackAlthon1]

I know how to get a FFT from a usal case i.e generate a signal by sin generator, but how to get a FFT spectrum when you have a type data of waveform? What to do with dT? Only that I have is Y and dT and how to get a FFT? Any advices? Thank you.

[RavensFan]

The dT is in the waveform.

Have you worked with waveforms before?

I would recommend looking at the online LabVIEW tutorials
LabVIEW Introduction Course - Three Hours
LabVIEW Introduction Course - Six Hours

[JackAlthon1]

RavensFan, thank you for replay. I worked, but not so much, because I just needed to do calculation etc., but the first time for me when I foresee with FTT spectrum to get from waveform. I hadnot problem to get a spectrum by using sin generator. RavensFan, can you help me? I really need a help.,