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11:19:49 Page 584
wave to travel through the moving flow along a welldefined path.
trigonometric series Infinite series of trigonometric
functions; applications include representing complex
waveforms in terms of frequency content.
true rms Data-reduction technique that can correctly
provide the rms value for a nonsinusoidal signal; a
signal conditioning method that integrates the signal.
true value The actual or exact value of the measured
variable.
TTL (true-transistor-logic) Switched signal that
toggles between a high (e.g., 5 V) and a low (e.g., 0 V)
state.
turndown Ratio of the highest flow rate to the lowest
flow rate that a particular flow meter can measure
within specification.
type A uncertainty An uncertainty value estimated
from the statistics of a variable.
type B uncertainty An uncertainty value estimated by
other than statistical methods.
uncertainty An estimate of probable error in a reported
value.
uncertainty analysis A process of identifying the errors
in a measurement and quantifying their effects on the
value of a stated result.
uncertainty interval An interval about a variable or
result that is expected to contain the true value.
USB (universal serial bus) A serial method of data
transmission between a computer and peripherals
using a four-wire cable.
validation Process or test to assess if test model data
behave in the same way as the physical process the test
simulates; can be used to assign uncertainty in the
model.
velocity of approach factor A coefficient used in
obstruction flow meter calculations that depends on
the ratio of flow meter throat diameter to pipe
diameter.
venturi meter In-line flow meter whose internal
diameter narrows from the pipe diameter to a smaller
diameter throat and then expands back to the pipe
diameter so as to create a pressure drop proportional to
flow rate.
verification Test designed to ensure that a measurement
system as a whole or some portion of the system is
working correctly; can be used to assign uncertainty
values to aspects of a measurement system.
vernier calipers Tool for measuring both inside and
outside dimensions.
vernier scale Technique that allows increased
resolution in reading a length scale.
volume flow rate Flow volume per unit time.
VOM Acronym for volt-ohm meter.
vortex flow meter Device that measures flow rate by
measuring the frequency of vortex shedding from a
body placed within the flow.
wheatstone bridge Electrical circuit for measuring
resistance with a high measure of accuracy and
sensitivity.
wobble meter A type of positive displacement flow
meter that measures fluid volume flow rate by the rate
of fluid displaced within alternating known volumes
created by oscillating disks.
word A collection of bits used to represent a number.
zero drift A shift away from a zero output value under a
zero input value condition.
zero-order system A system whose behavior is
independent of the time-dependent characteristics of
storage or inertia.
zero-order uncertainty Random uncertainty estimate
based only on a measurement system’s resolution or
finest increment of measure.
584 Glossary
11:19:49 Page 584
wave to travel through the moving flow along a welldefined path.
trigonometric series Infinite series of trigonometric
functions; applications include representing complex
waveforms in terms of frequency content.
true rms Data-reduction technique that can correctly
provide the rms value for a nonsinusoidal signal; a
signal conditioning method that integrates the signal.
true value The actual or exact value of the measured
variable.
TTL (true-transistor-logic) Switched signal that
toggles between a high (e.g., 5 V) and a low (e.g., 0 V)
state.
turndown Ratio of the highest flow rate to the lowest
flow rate that a particular flow meter can measure
within specification.
type A uncertainty An uncertainty value estimated
from the statistics of a variable.
type B uncertainty An uncertainty value estimated by
other than statistical methods.
uncertainty An estimate of probable error in a reported
value.
uncertainty analysis A process of identifying the errors
in a measurement and quantifying their effects on the
value of a stated result.
uncertainty interval An interval about a variable or
result that is expected to contain the true value.
USB (universal serial bus) A serial method of data
transmission between a computer and peripherals
using a four-wire cable.
validation Process or test to assess if test model data
behave in the same way as the physical process the test
simulates; can be used to assign uncertainty in the
model.
velocity of approach factor A coefficient used in
obstruction flow meter calculations that depends on
the ratio of flow meter throat diameter to pipe
diameter.
venturi meter In-line flow meter whose internal
diameter narrows from the pipe diameter to a smaller
diameter throat and then expands back to the pipe
diameter so as to create a pressure drop proportional to
flow rate.
verification Test designed to ensure that a measurement
system as a whole or some portion of the system is
working correctly; can be used to assign uncertainty
values to aspects of a measurement system.
vernier calipers Tool for measuring both inside and
outside dimensions.
vernier scale Technique that allows increased
resolution in reading a length scale.
volume flow rate Flow volume per unit time.
VOM Acronym for volt-ohm meter.
vortex flow meter Device that measures flow rate by
measuring the frequency of vortex shedding from a
body placed within the flow.
wheatstone bridge Electrical circuit for measuring
resistance with a high measure of accuracy and
sensitivity.
wobble meter A type of positive displacement flow
meter that measures fluid volume flow rate by the rate
of fluid displaced within alternating known volumes
created by oscillating disks.
word A collection of bits used to represent a number.
zero drift A shift away from a zero output value under a
zero input value condition.
zero-order system A system whose behavior is
independent of the time-dependent characteristics of
storage or inertia.
zero-order uncertainty Random uncertainty estimate
based only on a measurement system’s resolution or
finest increment of measure.
584 Glossary