HP 8712ES User Manual page 243

TIP
To use the port extension feature, press
Port Extensions Port Ext's on OFF
turned on, you can add delay independently to both ports.
To add delay between PORT 1 and your DUT, press
and enter the delay value.
To add delay between PORT 2 and your DUT, press
and enter the delay value.
A good way to know when you have added enough delay is to connect a
short in place of the DUT. Adjust the port extension until the phase
response is flat. (Remember that most short-circuit standards have a
nonzero delay, so adjusting delay using this method will result in a delay
error equal to two times the short delay.)
The delay values that you enter will be automatically applied
appropriately to both transmission and reflection measurements. For
example, when measuring S
twice. When measuring S
extension delay are each applied once.
ES User's Guide
Compensating for Phase Shift in Measurement Setups
CAL
. When port extension is
, the port 1 extension delay is applied
11
, the port 1 extension delay and the port 2
21
Optimizing Measurements
More Cal
Port 1 Extension
Port 2 Extension
,
,
5-19