212                                                                                                                     Keysight N9927-90001 User’s Guide
RTSA (Real-Time Spectrum Analyzer) Mode—Option 350 (CPU2 Only)
RTSA Mode Settings
Figure 10-4  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.
—Then Res BW
. 
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.