Ordinary spectrum analyzers specify their resolution bandwith (RBH).
Fx. 9 Khz, 120 Khz, and 1Mhz (hameg HM5530)
How can i see/select filter bandwith on my Picoscope. How does it relate to pico settings?
Another question that might relate. If i setup a sweep generator to sweep from, say 10Khz to 20Khz and look at the result in spectrum mode, the amplitude depends on sweep time. Slow sweep > high amplitude, fast sweep > low ampluitude.