Return Loss Measurements - Agilent Technologies N9913A User Manual

Coupled Frequency
This setting, especially useful for a Return Loss & DTF measurement, allows both
measurements to have different frequency ranges.
How to set Coupled Frequency
With a Return Loss & DTF measurement present:
 Press Meas Setup 4
 Select the DTF measurement (Tr2) using the ▲|▼ arrows.
 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
 Reconnect the cable or DUT.
 The return loss trace is displayed on the FieldFox screen.
CAT (Cable and Antenna Test) Mode
- Both the Return Loss and DTF traces have the same
Coupled Freq ON
frequency range settings.
Coupled Freq OFF (default setting) - Both traces are allowed to have
individual frequency range settings. When set to OFF:
The Return Loss measurement frequency settings are made in the usual
o
manner. Learn how on page 22. When a new Start or Stop frequency is
selected, Coupled Frequency is automatically set to OFF.
The DTF measurement is made using the frequencies as determined by the
o
DTF Frequency Mode setting. Learn more on page 32.
Preset
CAT
Return Loss (Default measurement).
measurement.
calibrating.
prompts.
Returns the FieldFox to known settings.
(Cable and Antenna Test)
Start and Stop frequency values of the
to make appropriate settings before
Settings
27