Keysight N9912A User Manual page 48

 Then Settings.
 Then scroll to System Z0 and press
 Then type either 50 or 75 and press
Port Extensions
Port extensions allow you to electrically move the calibration reference plane on port
1 after you have performed a calibration.
Phase measurements, and therefore Port Extensions, are NOT available on port 2.
Why use Port Extensions
Use port extensions if you are unable to perform a calibration directly at your device
because the location is not accessible. Perform a calibration at a convenient place,
then use port extensions to compensate for the time delay (phase shift) to the
desired reference plane. On the FieldFox, port extensions does not compensate for
the loss of the additional electrical length, nor any mismatch errors beyond the
calibration reference plane.
Also use port extensions if you have already performed a calibration, and then decide
that you need to add a length of transmission line in the measurement configuration.
Use port extensions to "tell" the FieldFox that you have added the length to a specific
port.
With S11, the FieldFox doubles the port extension valued that you enter to account
for the additional delay in the forward and reverse directions.
Port extensions and Electrical Delay differ in the following ways:
 Electrical delay is applied to a specific trace.
 Port extensions are applied to specific ports.
Port Extensions and Electrical Delay can be set independently. When both are set,
the delay adds together. Learn more about Electrical Delay on page 43.
How to apply Port Extensions
 Press Meas Setup 4.
 Then
 Then
 Then
 Then enter time value using the numeric keypad, the ▲|▼ arrows, or the rotary
You can also set Port Extensions by pressing Meas Setup 4 then
(settings).
While setting Port Extension, the physical length of the extension, at the current
Velocity Factor setting, is visible to the right (red box in above image).
48
Port Extensions
Port Extensions ON
Port1 Extension
knob. Press or select a seconds (time) multiplier.
Enter
Edit
Enter
Calibration
FieldFox User's Guide