Check For Compressed Measurements; Field Strength Measurements - Agilent Technologies N9913A User Manual

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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 signal power
will not be displayed accurately. This can occur even if
displayed. Increase the RF Attenuation value to prevent the SA receiver from
being compressed.
How to Check for a Compressed Measurement
 Using a marker at the signal peak, make note of the signal power level.
 Increase the RF Attenuation level by 5 dB.

Field Strength Measurements

To measure the strength of any signal transmitted through the air, an antenna
must be connected to the FieldFox. The Field Strength feature allows you to
enter the frequency response of the receiving antenna (the Antenna Factor) and
associated cabling, and then have amplitude corrections automatically
compensate the displayed trace for that response.
Field Strength Measurements
Trace 1 - Corrected trace with antenna factor. (Antenna = ON, Apply Corr = ON)
Trace 2
Red Trace
SA (Spectrum Analyzer) Mode
Preamp ON OFF
is shown to the left of the graticules on the display.
PA
If the signal level does NOT change, then NO compression exists. This
o
indicates that the signal is in the linear region of the FieldFox receiver.
If the signal level DOES increase, then the receiver was compressed. Set the
o
RF Attenuation value at the setting when further increases no longer result
in an increase in the displayed power level.
- (View) Uncorrected trace (Apply Corr = OFF)
- Current correction factor. See below.
The underlined setting is the current setting. When ON,
is not
ADC Over Range
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