Resolution Bandwidth (Res Bw); How To Set Res Bw - Keysight A Series User Manual

RTSA (Real-Time Spectrum Analyzer) Mode—Option 350 (CPU2 Only)
RTSA Mode Settings
Figure 10-5 Real-Time Spectrum

Resolution Bandwidth (Res BW)

In RTSA Mode, the Res BW provides the ability to resolve, or see closely
spaced signals. The narrower (lower) the Res BW, the better the spectrum
analyzer can resolve signals. In addition, as the Res BW is narrowed, less noise
is measured by the spectrum analyzer ADC and the noise floor on the display
lowers as a result. This allows low level signals to be seen and measured.

How to set Res BW

— Press BW 2.
Keysight N9927-90020 User's Guide
For best results, use the AUTO setting for the Res BW values. Increasing
the resolution BW could reduce pulse measurement capability by
affecting the 100% POI duration and the minimum detectable signal level.
The resolution BW must be as narrow as possible to maintain gapless
measurements.
When Manual RBW is selected, the FieldFox attempts to set the RBW to
the setting you request, but this setting is coupled to the current span
settings. If the manually set RBW is not settable with the current
frequency span value, the FieldFox defaults to the nearest achievable
RBW setting to meet the manual RBW value.
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