Agilent Technologies FieldFox N9913A User Manual page 34

After a calibration has been performed, for the purpose of illustrating this point,
connect an OPEN to the end of the cable – a maximum-sized fault - for 100%
reflection of the 300 MHz test signal.
Without compensation for the loss of the cable, a –20 dB response would be
visible at 100 meters, which is the OPEN at the end of the DUT. This is from 10
dB of loss through the cable in each direction.
With compensation for the loss using the manufacturer's specification, the
FieldFox compensates the trace as though the signal traveling through 100
meters was increased by +20 dB. Therefore the response will show 0 dB for 100%
reflection.
How to enter Cable Loss and Velocity Factor
Cable Loss and Velocity factor can be entered using one of the following
methods:
 Manually enter cable loss and velocity factor for the measurement.
 Select or create a cable file which contains the cable loss and velocity factor.
With a DTF measurement present:
 Press Meas Setup 4.
 Then
 Select
 Then:
How to Edit a Cable File
The FieldFox includes many predefined cable files with the manufacturer's
specifications. You can edit these files or create new cable files using the
following procedure or using the FieldFox Data Link Software. Learn more at:
The Cable correction data survives a Mode Preset and Preset.
With a DTF measurement present:
 Press Meas Setup 4
 Then
 Then
 Press
 Then
34
DTF Cable Specifications
Cable Corr
Auto
Use Cable Loss and Velocity Factor values from a Cable file. See "How
o
to Edit, Save, and Recall a Cable File" below. This will overwrite a manually-
entered value.
Man
(Default setting) Manually enter a value for Cable Loss and Velocity
o
Factor.
Velocity Factor
Using the numeric keypad, enter a value between 0.01 and
o
1. Then press Enter.
Cable Loss
Using the numeric keypad, enter a positive Cable Loss value in
o
dB/m, then press Enter.
DTF Cable Specifications
Edit/Save/Recall Cables
New Yes
then to clear all data from the existing DTF Cable table and
reset header information to default settings.
Edit Cable
to open the Cable Editor.
FieldFox User's Guide