Fluke 5790B, Руководство по обслуживанию

Страница: 143 / 172

Appendices
Glossary of AC-DC Transfer Related Terms
A
A-9
Test Uncertainty Ratio
The numerical ratio of the uncertainty of the measurement system or device
being calibrated or verified, and the uncertainty of the measurement system or
reference device.
Thermal EMF
The voltage generated when two dissimilar metals joined together are heated.
Traceability
The ability to relate individual measurement results to legally defined national
standards through an unbroken chain of comparisons. Traceability requires
evidence produced on a continuing basis, such as calibration records, that the
measurement process is producing results for which the total measurement
uncertainty relative to national standards is quantified.
Transfer
See “AC-DC transfer”.
Transfer Error
Error induced by the process of comparing one standard or instrument with
another. This does not include the uncertainty of the transfer standard.
Transfer Stability
Change in the AC-DC Difference correction over time, with stated conditions.
Transfer Standard
Any standard used to compare one measurement or source device with another.
Note that a transfer standard needs only to be stable for the duration of the
transfer. It does not need an assigned value.
Transport Standard
A transfer standard that is rugged enough to allow the shipment by common
carrier to another location.
True Value
Also called a legal value, the accepted consensus, for example, the correct value
of the quantity being measured.
Uncertainty
The range of values, usually centered on the indicated or requested value, within
which the true, accepted, or consensus value is expected to lie within stated
probability or confidence. Fluke uses 99.7 % (3
σ
) confidence limits. Uncertainty
is a quantification of accuracy.
Units
Symbols or names that define the measured quantities. Examples of units are: V,
mV, A, kW, and dBm. See also “SI System of Units”.