q
Condition of the 373XXA.
q
Quality and condition of the interface connections and connec
-
tors.
q
Quality and condition of the calibration components,
through-lines, adapters and fixtures.
q
Surrounding environmental conditions at the time of the mea
-
surement.
q
Selection and performance of the calibration for the DUT being
measured.
Measurement
Conditions Check List
When determining possible measurement problems, check the follow
-
ing items:
1. Check the DUT and the calibration conditions:
q
ensure the Calibration Components Coefficients data has been
installed into the system from the Calibration Kit in use.
q
ensure the proper calibration was done for the device being
measured:
n For high insertion loss device measurements the calibra-
tion should include isolation, high number of averages,
and lower IF Bandwidth settings during the calibration.
n For high return loss device measurements the calibra-
tion should also include a sliding load calibration.
q
Check DUT mating connector(s) condition and pin depth.
q
Measure an alternate known good DUT, if possible.
q
Check if the environment is stable enough for the accuracy re
-
quired for the DUT measurement.
n
The system should not be subjected to variations in tem
-
perature.
n
The system should not be placed in direct sun light or
next to a changing cooling source, such as a fan or air
conditioning unit.
2. Check the calibration using known good components from the cal
-
ibration kit. If measurements of these devices do not produce good
results:
q
Check through-cable stability including condition and pin
depth. Replace with a known good cable, if necessary.
q
Check condition and pin depth of calibration kit components.
Replace with known good components, if necessary.
q
Check condition and pin depth of test port connectors. Replace
with known good ones if necessary.
TROUBLESHOOTING MEASUREMENT IN QUESTION
373XXA MM 5-23