Preamplifier Control (Opt 235); Check For Compressed Measurements - Keysight N9913A User Manual

SA (Spectrum Analyzer) Mode
SA Mode Settings
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
— 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.
— Then

Check for Compressed Measurements

Compression occurs when too much power into an amplifier causes it to no
longer amplify in a linear manner. When too much power goes into the
FieldFox RF Input connector, the amplifiers in the SA receiver compress and
Keysight N9927-90001 User's Guide
The FieldFox can be damaged with too much power.
RF Damage Level: +25 dBm (N995xA & N996xA) and +27 dBm (all others)
DC Damage Level: ±50 VDC
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.
Man RF Attenuation is set manually. The default Attenuation setting is 10
dB. 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
Preamp ON OFF
ON, PA is shown to the left of the graticules on the display.
The underlined setting is the current setting. When
153