Agilent Technologies HP 8719D Service Manual page 314

The analyzer generates and stores factors in internal arrays when a
measurement error-correction (measurement calibration) is performed. These
factors are known by the following terms:
The analyzer creates error terms by measuring well-defined calibration devices
over the frequency range of interest and comparing the measured data with the
ideal model for the devices. The differences represent systematic (repeatable)
errors of the analyzer system. The resulting calibration coefficients are good
representations of the systematic error sources. for details on the various levels
of error-correction, refer to the "Optimizing Measurement Results" chapter
of the
HP 8719D/ZOD/ZZD Network Armlgzm User's Guide.
theory of error-correction, refer to the "Application and Operation Concepts"
chapter of the
HP 8719D/ZOD/ZZD Network Aruzlgwr User's Guide.
Error 'Ikrms Can Also Serve a Diagnostic Purpose
Specific parts of the analyzer and its accessories directly contribute to the
magnitude and shape of the error terms. Since we know this correlation and we
know what typical error terms look like, we can examine error terms to monitor
system performance (preventive maintenance) or to identify faulty components
in the system (troubleshooting).
Preventive Maintenance:
n
repeatable error terms over long time intervals, for example, six months.
If you make a hardcopy record (print or plot) of the error terms, you can
periodically compare current error terms with the record. A sudden shift in
error terms reflects a sudden shift in systematic errors, and may indicate
the need for further troubleshooting. A long-term trend often reflects drift,
A stable, repeatable system should generate
For details on the
Error Terms 11-l