Keysight N9913B, User Manual

Page: 59 / 896

Keysight N9938-90006 User’s Guide 59
CAT (Cable and Antenna Test) Mode
Return Loss Measurements
— The Return Loss measurement frequency settings are
made in the usual manner. Learn how at “Frequency
Range” on page 53 . 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 DTF Frequency Mode setting. Learn
more in “DTF Measurement Settings” on page 66 .
Return Loss Measurements
Return loss can be thought of as the absolute value of the reflected power
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 jumper cable or any adapter used to connect the device under
test (DUT).
— Select Preset then Preset Returns the FieldFox to known settings
— Select Mode then CAT/TDR (Cable and Antenna Test)
— Then Return Loss (Default measurement).
— Press Freq/Dist and enter Start and Stop frequency values of the
measurement.
— Press Meas Setup 4 then Settings to make appropriate settings before
calibrating.
— Disconnect the jumper cable or DUT and press Cal 5 then follow the
calibration prompts.
— Reconnect the jumper cable or DUT.
— The return loss trace is displayed on the FieldFox screen.