What is Video Bandwidth?

The Video Bandwidth (VBW) filters noise and is used as a time domain low-pass filtering for averaging. The main purpose of the video bandwidth is to smooth the video trace and reduce noise. The width of the video bandwidth should be set narrow in order to filter the noise but not too much as that might considerably slow down the sweep time. VBW is applied to the IF signal after envelope detection, i.e. removal of the carrier.

Too wide VBW can make small signal observation difficult by allowing too much noise to be present on the screen. If the averaging is not required, the video bandwidth can be set wide.

Video bandwidth does not influence frequency selection or peak detection and the results of your measurement. It is applied after the data has been collected, but before the trace is actually displayed.