Keysight Technologies C Series - Attenuation Control

Keysight N9915-90020 User’s Guide 161
SA (Spectrum Analyzer) Mode (Option 233–Mixed Analyzers)FUTURE
SA Mode Settings
Attenuation Control
Both the RF Attenuation and Preamp functions control the power level into the
SA.
When too much power is present at the RF Input port, ADC Over Range
appears on the FieldFox screen. This does not necessarily mean that damage
has occurred, but that the measurement is probably compressed.
When high power levels are present at the RF Input port, internal attenuation
can be switched in to keep the FieldFox receiver from compressing. At
extremely high power levels, use external attenuation to protect the internal
circuitry from being damaged.
The displayed power level is automatically adjusted for RF Attenuation. As the
attenuation value changes, the displayed power level should NOT change.
How to set Attenuation
1. Press Scale/Amptd.
2. Then
RF Atten Auto Man.
— Auto RF Attenuation is set by adjusting the acquisition. As the
acquisition is lowered, for example from –10 dBm to –30 dBm, the
FieldFox assumes that you are looking at low-level signals. The RF
Attenuation value is automatically lowered in 5 dB steps to allow
low-level signals to be viewed. The RF Attenuation value is never
automatically lowered below 5 dB.
The FieldFox can be damaged with too much power. Refer to the FieldFox
Data Sheet for your model by referring to
Appendix B:,
“Specifications/Data Sheet,” on page 869
.
Maximum Input Voltages and Power:
RF Output Connector: 50V DC, +23 dBm RF
Ext Trig/Ref Connector: 5.5 V DC
RF Input:
+27 dBm RF, ±50 VDC Max. (N991xA/B, N9925B, N9926A,
N9928A, N993xA/B)
+23 dBm RF, ±50 VDC Max. (N9923A, N9923AN)
+25 dBm RF, ±40 VDC Max. (N99xxC
, N995xA/B, N996xA/B)
DC Input: 19VDC, 4ADC, 60 Watts maximum when charging battery
Learn more about ADC over range warnings by referring to
Chapter 31,
“System Settings,”
and then to “SA” on page 792.