HP 8712C, User Manual, Page: 270 / 559

I
Calibrating for Increased Measurement
Accuracy
Check the Calibration
3. Plot the results to disk or to hard copy for later comparison.
4. Compare subsequent calibration checks against the initial one and keep
track of the time interval between the first calibration check and later
ones.
5. When the residual errors have drifted beyond what is acceptable, note
the time interval and use that information to determine what is the best
calibration interval for your measurements.
6. Repeat the process above enough times to feel confident that your
calibration interval is correct.
The calibration check feature can be used on any of the transmission or
reflection calibrations available (including the factory default calibration). See
Table 6-2.
Table 6-2. Calibration Check Error Terms
Meesurement Celibretion Error
Needed Computed
Transmission
Default Source Match, Load Match, Transmission Tracking
Response
Source Match, Load Match, Transmission Tracking
Response Isolation
Source Match, load Match, Transmission Tracking, lsolatio
Enhanced Response Source Match, load Match, Transmission Tracking
Test Source Match, Load Match, Transmission Tracking
Reflection
Default
Source Match, Reflection Tracking
One
Port
Directivity, Source Match, Reflection Tracking
Test
Directivity, Source Match, Reflection Tracking
n
1 0
Open, S Short, L Load, T Thru
2 See ‘Error Term and Typical Values”, later in this chapter.
3 Used with HP multiport test set only
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