FFT from wavefrom

[WatFin]

I have wavefrom signal in Host, which is coming from FPGA. I am tring to create FFT of that. I noticed that there are many function of FFT in labview. Which is the most accurace function to use and is there any example.

[Bob_Schor]

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@WatFin wrote:

 I noticed that there are many function of FFT in labview. Which is the most accurace function to use and is there any example.

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The "accuracy" of the FFT functions is pretty good as the default computations are done with Dbls.  Most LabVIEW functions (including many of the FFT functions) have examples included that you can find by using the Help system (either Help, Examples or read the detailed Help for the function and see what Examples are available).

Bob Schor

[Jimmie_A.]

Hi WatFin,

You are correct, we offer many FFT functions, maybe too many since it is kind of tricky as an end user to figure out when one should use a certain implementation over another.

With that said, you know that you can do FFT on the FPGA side of things? We provide shipping examples that shows how it could be implemented.

If you would like to stick with an FFT on the host side of things you could use this as guidance.

FFT VI - available in multiple instances including:

Complex FFT - accepts complex data (array) as input and outputs complex data (array)

Real FFT - assumes no complex data (read no imaginary part) only a real array and outputs real data (array).

FFT PtByPt VI - as name suggest accepts scalar data types, available in two instances (real and complex data)

FFT Power Spectrum and PSD VI - Computes the averaged auto power spectrum of time signal. Wiring the data to the time signal input determines the polymorphic instance that will be used.

FFT Spectrum (Real-Im) VI - Computes the averaged FFT spectrum of time signal. This VI returns the FFT results as real and imaginary parts. Wiring the data to the time signal input determines the polymorphic instance that will be used.

FFT Spectrum (Mag-Phase) VI - Computes the averaged FFT spectrum of time signal. This VI returns the FFT results as magnitude and phase. Wiring the data to the time signal input determines the polymorphic instance that will be used.