ResBW (Frequency vs. Time)

ResBW sets the resolution bandwidth for Frequency vs. Time analysis measurements. ResBW in the Frequency vs. Time tab is not the same as the MeasSetup > ResBW > ResBW parameter. ENBW (Equivalent Noise Bandwidth)/ResBW is used to determine by how much time to split the capture time domain data into different slices before performing FFTs. For the Freq v Time Heatmap trace, these slices are then stacked on top of each other to achieve a heatmap perspective.

When Auto is selected (default = selected), the ResBW length is determined based on a factor of the Span of the measurement. This auto checkbox is not intended to provide the ideal ResBW, but a reasonable starting place for all types of hardware. At any point, if you change the ResBW value, auto will become unchecked.