78                                             Keysight N9927-90001 User’s Guide
TDR (Time Domain Reflectometry) - Option 215
TDR Measurement Settings
—Then DTF Cable Specifications
— Select Cable Corr
— Auto Use Cable Loss and Velocity Factor values from a Cable file. See 
“How 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 Factor.
—Then:
— Velocity Factor
 Using the numeric keypad, enter a value between 
0.01 and 1. Then press Enter
. 
— Cable Loss
 Using the numeric keypad, enter a positive Cable Loss 
value in dB/m, then press Enter
. 
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.
The Cable correction data survives a Mode Preset and Preset.
With a TDR measurement present:
—Press Meas Setup 4
—Then DTF Cable Specifications
—Then Edit/Save/Recall Cables 
—Press New Cable
 then Yes to clear all data from the existing DTF Cable 
table and reset header information to default settings.
—Then Edit Cable
 to open the Cable Editor.
— Then use the   arrows to select a field,
— When editing Cable Description information, press Edit
 then modify 
the selected field using the FieldFox labeler. 
— When editing Frequency/Loss pairs, enter numbers using the 
numeric keypad, then select a frequency suffix. Then Enter
. Learn 
more about “How the Freq/Loss pairs are applied” below.
— Optionally choose from the following:
— Previous / Next Page
 Quickly scrolls through pages of Freq/Loss 
data.
— Add Data
 Add a blank Freq/Loss pair to the table,
— Delete/Clear 
then:
— Delete Row
 Remove the selected Freq/Loss pair from the table.