where to find FFT

[PNHorn]

Hi Dost,

I would recommend you connect the output of your AI read to the power spectrum vi. With regards to your other questions, I'm not to clear what you are asking exactly - could you post a vi with some notes on explaining what your asking exaclty and I'll have a closer look into it.

Best regards,

Peter H.

Applications Engineer.

NIUK.

[venkatgill]

Hello Peter,

Here is a new guy to LabView and need your help in FFT. I am measuring AC 1-phase voltage which is obtained from Supply panel. I am using trnasducer to scale it to +/- 10V. I am using LView example to 'vi' to measure it. I am using PCI-MIO-16E4 and CB-68LP.

I am getting the voltage signal using this 'vi' and I want to do the Fourier analysis and observe the harmoics like 3rd and 5th harmonics in a seperate plot. I am attaching the 'vi' and please take time to solve this issue.

Thanks,
Venkat

[Dost]

thank you  peter for your suggestion . iam attaching my VI .The thing wanted to ask is from DAQ board we get voltage (from pressure transducer) than we apply a linear relation to convert this voltage in to pressure. i use formula P=P0+ gain(V-v0). i want to know if i apply direct signal from the AI read to the Power Spectrum Express VI than will it be fine as than it will be just voltage not the pressure. Secondly iwanted to know more about the out of Power spectrum Express Vi .after reading some articles on NI developer zone I think power spectrum is measure of frequency with amplitude. the power spectrum gives this energy in RMS or peakvalues.if  frequency ranges from 0 to 500 in power spectrum graph and the RMS values shows us  say a value of -180 than what does this mean how would  we interprate it .KIndly suggest me some good article to know  more about it.

[Dost]

I have used two VI in order to check my result.these are Power spectrum.VI  and FFT power spectrum separately.I have my data in the text file so first I take off my require block of the data from my text file and then pass this to the both VIs.I also used Nysquit VI in order to shift my data DC central spectrum.As u can seen in the vi attached as gif file that I also have used bundle before fedding this in to wave form .I have attached the out put in out put.gif.looking forward for ur suggestion.Please note that my data set is about 2200 in this example.

dost

[altenbach]

Continued here for some reason:

http://forums.ni.com/ni/board/message?board.id=170&message.id=238311&jump=true