Return Loss Measurements; Interference Rejection; Return Loss Measurement - Agilent Technologies FieldFox N9923A User Manual

Interference Rejection

Use this setting when you suspect that other signals in the area are interfering
with a measurement. Interference may look like a spike or lack of stability in the
measurement trace. While monitoring a measurement at a specific frequency,
toggle this setting between ON and OFF. If the measurement result decreases
while ON, then there is an interfering signal in the area. Continue to make
measurements with Interference Rejection ON. However, this will slow the
measurement speed.
Once enabled, up to SIX sweeps may be required before the interfering signal is
neutralized.
This setting can be changed at any time without affecting calibration accuracy.
How to set Interference Rejection
 Press Meas Setup 4.
 Then
 Then choose from the following:

Return Loss Measurements

Return loss can be thought of as the absolute value of the reflected power as
compared to the incident power.
When measuring an OPEN or SHORT, all incident power is reflected and
approximately 0 dB return loss is displayed.
When measuring a LOAD, very little power is reflected and values of 40 dB to 60
dB are displayed.
The minus sign is usually ignored when conveying return loss. For example, a
component is said to have 18 dB return loss, rather than –18 dB.
How to measure Return Loss
 Connect the cable or any adapter used to connect the device under test (DUT).
 Select Preset then
 Select Mode then
 Then
 Press Freq/Dist and enter
 Press Meas Setup 4 then
 Disconnect the cable or DUT and press Cal 5 then follow the calibration
CAT (Cable and Antenna Test) Mode - Option 305
Interference Rejection [current
No interference rejection and fastest possible sweep speed.
Off
o
The lowest level of Interference rejection.
Minimum
o
The medium level of Interference rejection.
Medium
o
The highest level of Interference rejection.
Maximum
o
Preset
CAT
(Default measurement).
Return Loss
measurement.
calibrating.
prompts.
setting].
Returns the FieldFox to known settings.
(Cable and Antenna Test)
and frequency values of the
Start Stop
to make appropriate settings before
Settings
39