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?