146 Chapter 6 
Calibration
G. Calibration When the 3.5-mm Port of the 42941A is Extended
Step 2. Perform the user calibration at the other end of the extended 3.5-mm port of the 42941A 
Impedance Probe. You can use either the calibration kit supplied by Agilent Technologies 
or a user-defined calibration kit. See “User Calibration” on page  147 for the user 
calibration procedure.
Step 3. Set the port extension value in electrical length or delay time, which is equivalent to the 
electrical length between the user calibration plane and the device contacts of the test 
fixture, in accordance with “Port Extension Compensation” on page  150.
NOTE In measurements using the Agilent 4294A, the electrical length (delay time) of a 42942A 
dedicated test fixture (such as 16092A) and 42941A’s dedicated probe adapter can be 
regarded as 0.
Step 4. Perform fixture compensation at the device contacts of the test fixture. See “Fixture 
Compensation” on page  151 for the fixture compensation procedure.
NOTE If user calibration in step 2 cannot be performed for some reason, set the port extension 
value in electrical length or delay time, which is equivalent to the electrical length between 
the 3.5-mm port of the 42941A and the device contacts of the test fixture, in place of steps 
2 and 3, in accordance with “Port Extension Compensation” on page  150.