HP 8712ET User Manual page 396

Specifications
Definitions
All specifications and characteristics apply over a 25 °C ±5 °C range
(unless otherwise stated) and thirty minutes after the instrument has
been turned on.
Specification (spec.): Warranted performance. Specifications include
guardbands to account for the expected statistical distribution,
measurement uncertainties, and changes in performance due to
environmental conditions.
Characteristic (char.): A performance parameter that the product is
expected to meet before it leaves the factory, but is not verified in the
field and is not covered by the product warranty. A characteristic
includes the same guardbands as a specification.
Typical (typ.): Expected performance of an average unit which does not
include guardbands. It is not covered by the product warranty.
Nominal (nom.): A general descriptive term that does not imply a level
of performance. It is not covered by the product warranty.
Calibration: The process of measuring known standards from a
calibration kit to characterize the systematic (repeatable) errors of a
network analyzer.
Corrected (residual) Performance: Indicates performance after error
correction (calibration). It is determined by the quality of calibration
standards and how well "known" they are, plus system repeatability,
stability, and noise.
Uncorrected (raw) Performance: Indicates instrument performance
without error correction. The uncorrected performance affects the
stability of a calibration.
9-2 ET User's Guide