206                                                                                                                     Keysight N9927-90001 User’s Guide
RTSA (Real-Time Spectrum Analyzer) Mode—Option 350 (CPU2 Only)
RTSA Mode Settings
When the Center and Frequency Span values are entered, then the 
X-axis annotation on the screen shows the Center and Span 
frequencies. 
—Start
 and Stop frequencies. Start is the beginning of the X-axis and 
Stop is the end of the X-axis. When the Start and Stop frequencies 
are entered, then the X-axis annotation on the screen shows the Start 
and Stop frequencies. 
— Optionally, press More
 then:
——CF Step
 then type a step size value using the numeric keypad, 
then select a multiplier key.
——Freq Annotation
 and one of the following:
——Full Span
 the frequency span changes to 10 MHz.
— Follow each of these, when prompted, by entering a value using the 
numeric keypad, the   arrows, or the rotary knob.
— When using the   arrows, press Enter
. The increment setting of the 
arrows is based on the current span. This can be changed in RTSA Mode.
— After using the keypad, select a multiplier key. Learn more in “Multiplier 
Abbreviations” on page 41.
Scale and Units
Adjust the Y-axis scale to see the relevant portions of the data trace. 
The Y-axis is divided into 10 graticules. A acquisition is shown on the screen as 
a solid horizontal bar that can be placed at any graticule.
RTSA always uses logarithmic scale. The Y-axis reference line represents the 
specified absolute acquisition (dBm). Y-axis graticules show dB below or above 
the reference line.
When RF Attenuation set to Auto, the RF Attenuation is coupled to acquisition. 
How to set Scale
Press Scale / Amptd. Then choose from the following:
AutoSelect (Default) – The FieldFox selects a frequency annotation 
setting (CenterSpan or StartStop).
CenterSpan -The center frequency and span are displayed.
StartStop - The start and stop frequencies of the frequency span are 
displayed.