Agilent Technologies N4413A, User Manual

Page: 85 / 234

Using the Multiport Test System
How to Check Test Cable Repeatability
Chapter 3 75
How to Check Test Cable Repeatability
The characteristics of the test cables used with the system should not change significantly
when they are moved. To check test cable repeatability, use the following procedure:
1. Connect the short-circuit standard from your calibration kit to the cable.
2. Straighten the cable and remove as much mechanical strain as possible.
3. Pull down Utility > Manual Test-Set Control… to open the Manual Test Set dialog box.
Set the test set for reflection on the port that the cable is connected to:
S
11
for port 1
S
22
for port 2
S
33
for port 3
S
44
for port 4
4. Use the network analyzer memory controls to memorize a base-line trace by selecting
“memory minus.”
5. While observing the one-inch bend radius limit of the test cables, manipulate the cable
through a 90 degree bend and hold it there.
6. Compare the base-line trace to the current data by observing the network analyzer screen.
The multiport test system test cables should show better than
−
30 dB repeatability or a linear
difference of less than 0.03.