LabVIEW FFT

[Chishti]

Hello! 

Problem: 

I'm simulating different sine and cosine waves to generate multiple signals. I applied FFT vi and extract the frequency components of them. I want to extract specific frequencies from multiple frequencies, for example, there are 100 frequencies data available and have to extract 20, 22,28) and after that apply a machine learning algorithm on them. Can you please tell me how can I do it?

Best Regards

[GerdW]

Hi Chishti,

I want to extract specific frequencies from multiple frequencies, for example, there are 100 frequencies data available and have to extract 20, 22,28) … Can you please tell me how can I do it?

Use IndexArray on your array of FFT amplitudes!

What exactly is your problem?

Why don't you attach your VI?

[Chishti]

Please check. 

I received multiple frequencies (which I simulated in the attached vi). I want to extract frequencies only specific ones (my supervisor will give me later). Now how can I extract specific frequencies. After extracting specific frequencies I've to apply Linear Discriminant analysis to find the coefficients. 

[GerdW]

Hi Chishti,

please save your VI for LV2017. (File menu -> save for previous)

[Chishti]

Please find the '17 version 

[GerdW]

Hi Chishti,

see this:

I changed your VI to use waveforms instead of plain arrays.

Now you get a waveform-like output containing f0 and df with the amplitude data. Now you can easily calculate the amplitude index from those additional values to pick the desired frequency values from your FFT data…

[Chishti]

Can you post the VI, please?

[Chishti]

I think it's not necessary. 

Thank you so much for your quick response

[GerdW]

Hi Chishti,

sorry, didn't save the changed VI.

Basically you only need two functions: SineWaveform and FFTMagPhase…

[Chishti]

I'm getting this error. I tried the solution online but it won't work. Did you get the same error?