Glossary
G-10
ni.com
Plug and Play
devices
devices that do not require DIP switches or jumpers to configure resources
on the devices—also called switchless devices
port
a communications connection on a computer or a remote controller
posttriggering
the technique used on a DAQ device to acquire a programmed number of
samples after trigger conditions are met
ppm
parts per million
pretriggering
the technique used on a DAQ device to keep a continuous buffer filled with
data, so that when the trigger conditions are met, the sample includes the
data leading up to the trigger condition
Q
quantization error
the inherent uncertainty in digitizing an analog value due to the finite
resolution of the conversion process
quantizer
a device that maps a variable from a continuous distribution to a discrete
distribution
R
relative accuracy
a measure in LSB of the linearity of an ADC. It includes all non-linearity
and quantization errors. It does not include offset and gain errors of the
circuitry feeding the ADC.
resolution
the smallest signal increment that can be detected by a measurement
system. Resolution can be expressed in bits, in proportions, or in percent
of full scale. For example, a system has 12-bit resolution, one part in
4,096 resolution, and 0.0244% of full scale.
rise time
the difference in time between the 10% and 90% points of the step response
of a system
rms
root mean square—the square root of the average value of the square of the
instantaneous signal amplitude; a measure of signal amplitude