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settling time The time required for a second-order
system to settle to within Æ10% of the final value of a
step change in input value.
shielded twisted pair Describes electrical wiring that
reduces mutual induction between conductors through
twisting the conductors around each other, and which
reduces noise through shielding.
signal Information in transit through a measurement
system; often exists in electrical or mechanical form.
single-ended connection Two-wire connection scheme
that measures the signal relative to ground.
signal conditioning stage Stage of a measurement
system that modifies the signal to a desired magnitude
and form.
signal-to-noise ratio Ratio of signal power to noise power.
single-sample uncertainty analysis Method of
uncertainty analysis used to evaluate uncertainty when
very few repeated measurements are made.
span The difference between the maximum and
minimum values of operating range of an instrument.
stage Refers to a general component in a measurement
signal flow that has a specific purpose.
standard The known or reference value used as the
basis of a calibration. Also, a test method set by
international agreement for quantifying some outcome
or device performance.
static calibration Calibration method where that the input
value is held constant while the output value is measured.
static pressure Pressure sensed by a fluid particle as it
moves with the flow.
static sensitivity The rate of change of the output signal
relative to a change in a static input signal. The slope
of the static calibration curve at a point. Also called the
static gain. See sensitivity.
steady response A portion of the time-dependent
system response that either remains constant with time
or repeats its waveform with time.
step response System time response to a step change in
input value.
stagnation pressure Pressure at the point where a flow
is brought to rest. See total pressure.
stopband Range of frequencies over which the signal
amplitude is attenuated by 3 dB or more. See passband
strain Elongation per unit length of a member subject to
an applied force.
strain gauge Sensor used to measure the strain on the
surface of a part when under load.
strain gauge rosette Two or more strain gauges arranged
at precise angles and locations relative to each other so as
to measure differing components of strain.
stress Internal force per unit area.
stroboscope High-intensity source of light that can be
made to flash at a precise rate. It is used to measure the
frequency of rotation.
Student’s t-distribution Sampling distribution that
arises when estimating the mean of a population when
the sample size is small.
systematic error The portion of error that remains
constant in repeated measurements of the same
variable. A constant offset between the indicated value
and the actual value measured.
systematic uncertainty Uncertainty assigned to a
systematic error. The uncertainty due to all the
systematic errors affecting the result.
systematic standard uncertainty The systematic
uncertainty estimated at the one standard
deviation level or at the 68% probability level for
a normal distribution. This value is often taken as
being one-half the estimated systematic
uncertainty.
temperature scale Establishes a universal means of
assigning a quantitative value to temperatures.
thermistor Temperature-sensitive semiconductor
resistor.
thermocouple Wire sensor consisting of at least two
junctions of two dissimilar conductors and used to
measure temperature.
thermoelectric Refers to a type of device that indicates
a thermally induced voltage.
thermopile A multiple junction thermocouple
circuit designed to measure a particular
temperature, an average temperature, or a
temperature difference.
Thomson effect Describes the presence of a voltage
arising through a temperature difference in a
homogeneous conductor.
time constant System property defining the time
required for a first-order system to respond to 63.2% of
a step input.
time delay The lag time between an applied input signal
and the measured output signal.
time response The complete time-dependent system
response to an input signal.
total pressure Pressure sensed at a point where the flow
is brought to rest without losses; sum of the static and
dynamic pressures; isentropic value of stagnation
pressure.
total sample period Duration of the measured signal as
represented by the data set.
transducer The portion of measurement system that
transforms the sensed information into a different
form. Also, loosely refers to a device that houses the
sensor, transducer and, often, signal conditioning
stages of a measurement system.
transient response Portion of the time-dependent
system response that decays to zero with time.
transit time flow meter Device that determines flow
rate by measuring the time it takes for an ultrasonic
Glossary 583
11:19:49 Page 583
settling time The time required for a second-order
system to settle to within Æ10% of the final value of a
step change in input value.
shielded twisted pair Describes electrical wiring that
reduces mutual induction between conductors through
twisting the conductors around each other, and which
reduces noise through shielding.
signal Information in transit through a measurement
system; often exists in electrical or mechanical form.
single-ended connection Two-wire connection scheme
that measures the signal relative to ground.
signal conditioning stage Stage of a measurement
system that modifies the signal to a desired magnitude
and form.
signal-to-noise ratio Ratio of signal power to noise power.
single-sample uncertainty analysis Method of
uncertainty analysis used to evaluate uncertainty when
very few repeated measurements are made.
span The difference between the maximum and
minimum values of operating range of an instrument.
stage Refers to a general component in a measurement
signal flow that has a specific purpose.
standard The known or reference value used as the
basis of a calibration. Also, a test method set by
international agreement for quantifying some outcome
or device performance.
static calibration Calibration method where that the input
value is held constant while the output value is measured.
static pressure Pressure sensed by a fluid particle as it
moves with the flow.
static sensitivity The rate of change of the output signal
relative to a change in a static input signal. The slope
of the static calibration curve at a point. Also called the
static gain. See sensitivity.
steady response A portion of the time-dependent
system response that either remains constant with time
or repeats its waveform with time.
step response System time response to a step change in
input value.
stagnation pressure Pressure at the point where a flow
is brought to rest. See total pressure.
stopband Range of frequencies over which the signal
amplitude is attenuated by 3 dB or more. See passband
strain Elongation per unit length of a member subject to
an applied force.
strain gauge Sensor used to measure the strain on the
surface of a part when under load.
strain gauge rosette Two or more strain gauges arranged
at precise angles and locations relative to each other so as
to measure differing components of strain.
stress Internal force per unit area.
stroboscope High-intensity source of light that can be
made to flash at a precise rate. It is used to measure the
frequency of rotation.
Student’s t-distribution Sampling distribution that
arises when estimating the mean of a population when
the sample size is small.
systematic error The portion of error that remains
constant in repeated measurements of the same
variable. A constant offset between the indicated value
and the actual value measured.
systematic uncertainty Uncertainty assigned to a
systematic error. The uncertainty due to all the
systematic errors affecting the result.
systematic standard uncertainty The systematic
uncertainty estimated at the one standard
deviation level or at the 68% probability level for
a normal distribution. This value is often taken as
being one-half the estimated systematic
uncertainty.
temperature scale Establishes a universal means of
assigning a quantitative value to temperatures.
thermistor Temperature-sensitive semiconductor
resistor.
thermocouple Wire sensor consisting of at least two
junctions of two dissimilar conductors and used to
measure temperature.
thermoelectric Refers to a type of device that indicates
a thermally induced voltage.
thermopile A multiple junction thermocouple
circuit designed to measure a particular
temperature, an average temperature, or a
temperature difference.
Thomson effect Describes the presence of a voltage
arising through a temperature difference in a
homogeneous conductor.
time constant System property defining the time
required for a first-order system to respond to 63.2% of
a step input.
time delay The lag time between an applied input signal
and the measured output signal.
time response The complete time-dependent system
response to an input signal.
total pressure Pressure sensed at a point where the flow
is brought to rest without losses; sum of the static and
dynamic pressures; isentropic value of stagnation
pressure.
total sample period Duration of the measured signal as
represented by the data set.
transducer The portion of measurement system that
transforms the sensed information into a different
form. Also, loosely refers to a device that houses the
sensor, transducer and, often, signal conditioning
stages of a measurement system.
transient response Portion of the time-dependent
system response that decays to zero with time.
transit time flow meter Device that determines flow
rate by measuring the time it takes for an ultrasonic
Glossary 583