Fluke 5790B Service Manual page 138

5790B
Service Manual
Error
Deviation from correct value. The different types of error defined in this glossary
are floor, gain, offset, linearity, random, scale, systematic, transfer, and zero.
Flatness
A measure of output level variation for a voltage source as frequency is varied.
Flatness limits are normally specified as a ratio (%) to nominal output level at a
reference frequency.
Floor Error
A contribution to measurement or source uncertainty that is independent of
reading or output setting. In uncertainty specifications, floor error is often
combined with fixed range errors and expressed in units such as microvolts or
counts of the least significant digit. Also see "error".
Full Scale
The upper limit of measurement or source value for which a given uncertainty
specification applies, including any "overrange". Also see "overrange" and
"range".
Gain Error
Same as scale error. An example of scale or gain error is, when the slope of a
calibrator's displayed output vs. its true output is not exactly 1. A calibrator with
only gain error (no offset or linearity error), will read 0 V with 0 V on the display,
but something other than 10 V with 10 V on the display.
Ground
The voltage reference point in a circuit. Earth ground is a connection through a
ground rod or other conductor to the earth, usually accessible through the ground
conductor in a power receptacle.
Ground Loop
Undesirable current induced when there is more than one chassis ground
potential in a system of instruments. Ground Loops can be minimized by
connecting all instruments in a system to ground at one point.
Guard
A floating shield around sensitive circuitry inside an instrument. The guard
provides a low-impedance path to ground for common-mode noise and ground
currents, thereby eliminating errors introduced by such interference.
International System of Units
Same as "SI System of Units"; the accepted system of units. See also "units",
"base units", and "derived units".
Legal Units
The highest echelon in a system of units, for example the 1990 SI volt.
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