Agilent Technologies N9913A User Manual page 88

 Then
 Enter a value using the numeric keypad, the ▲|▼ arrows, or the rotary knob
ExtGain xx dB is shown at the top of the screen.
Attenuation Control
Both the RF Attenuation and Pre Amp functions control the power level into the
SA.
When too much power is present at the RF Input port,
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 connector, 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.
WARNING
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
 Press Scale/Amptd .
 Then


#Atten xx dB is shown at the top of the screen. (#) means manual setting.
Preamplifier Control (Opt 235)
When very low-level signals are analyzed, an internal preamplifier can be used
to boost the signal level by approximately 22 dB. The gain of the preamp is NOT
adjustable. The displayed signal level is automatically adjusted for the increase in
system gain.
How to control the Preamp
By default, the preamp is OFF.
 Press Scale/Amptd .
88
External Gain
(positive for gain; negative for loss). Values less than 5 dB must be typed using
the numeric keypad. Then press Enter
The FieldFox can be damaged with too much power.
RF Damage Level: +27 dBm
DC Damage Level: ±50 VDC
RF Atten Auto Man.
Auto RF Attenuation is set by adjusting the Reference Level. As the Reference
Level 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.
RF Attenuation is set manually. The default Attenuation setting is 10 dB.
Man
Enter a value between 0 to 30 dB in 5 dB steps using the numeric keypad, the
▲|▼ arrows, or the rotary knob. Then press Enter
appears
ADC Over Range
FieldFox User's Guide