I am currently working on a Digital Spectrum Analyzer. We are trying to imitate a hardware Spectrum Analyzer by capturing I/Q data and performing an FFT on it. I am a bit stuck on how to imitate the Video Bandwidth setting (VBW). I believe Resolution Bandwidth is simply Sample Rate/NFFT. How would I use a VBW value to produce a plot of the spectrum? Should it influence the length of my capture?

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    $\begingroup$ These terms simply do not apply to an FFT-based spectrum visualizer. Also, they are not desirable in themselves – different tools have different knobs to turn, and the trick is not transplanting one's knobs under pain to the other, but making use of the advantages of the FFT – namely, that there's no video bandwidth other than that you get one update per FFT you compute. If you think about that, it's way better than what a classical spectrum analyzer can offer! What can be advantageous is having a knob that says "turn on averaging", and then lets the user define averaging duration. $\endgroup$ – Marcus Müller Oct 4 at 7:11

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