HP 8712C, User Manual, Page: 246 / 559

Measurement Calibration Overview
Measurement calibration is a process that improves measurement accuracy
by using error correction arrays to compensate for systematic measurement
errors. Measurement calibration is also called cal, accuracy enhancement,
and error correction. Measurement errors are classified as random, drift, and
systematic errors. Random errors, such as noise and connector repeatability,
are non-repeatable and not correctable by measurement calibration. Drift
errors, such as frequency and temperature drift, are also non-repeatable and
not correctable by a
Systematic errors, such as tracking and crosstalk, are the most
errors in most RF measurements. Fortunately systematic errors are
repeatable and for the most part correctable, though small residual errors may
remain. In brief, the systematic errors are correctable.
Repeatable systematic errors are due to system frequency response, isolation
between the signal paths, and mismatch and leakage in the test setup.
- -
- - - - - - - - - -
REFERENCE REFLECTED
TRANSMITTED
Figure 6-1. Sources of Errors
6-3