Amplitude and phase spectrum of a complex signal

[BreadLB]

I took this example and wanted to modify the TX VI to show the amplitude and phase spectrum of the complex signal at the very end (my modifications are uploaded as an attachment). I found this VI, which seemed to magically do the trick for me, so I attached it to the block diagram and added some indicators. However, I then found out that the input to the VI must be real, so I can't use it. Is there a way to make it accept complex inputs or is there another VI I could use for my purposes?

[kkleine]

Hello,

You can use an FFT to calculate the amplitude and phase manually. The output of the FFT function can be split into real and imaginary parts which can then be used to calculate amplitude and phase.Attached is a link to a white paper that discusses using FFT's in LabVIEW:

https://www.ni.com/en/shop/labview/using-fast-fourier-transforms-and-power-spectra-in-labview.html

Regards, 

Kevin

Applications Engineer 

National Instruments