National Instruments USB-621 Series User Manual page 189

Glossary
power source
ppm
pretriggering
pulse
pulse width
Q
quadrature encoder
R
range
real time
RSE
NI USB-621x User Manual
An instrument that provides one or more sources of AC or DC power. Also
known as power supply.
Parts per million.
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.
A signal whose amplitude deviates from zero for a short period of time.
The time from the rising to the falling slope of a pulse (at 50% amplitude).
An encoding technique for a rotating device where two tracks of
information are placed on the device, with the signals on the tracks offset
by 90° from each other. This makes it possible to detect the direction of the
motion.
The maximum and minimum parameters between which a sensor,
instrument, or device operates with a specified set of characteristics. This
may be a voltage range or a frequency range.
1. Displays as it comes in; no delays.
2. A property of an event or system in which data is processed and acted
upon as it is acquired instead of being accumulated and processed at a
later time.
3. Pertaining to the performance of a computation during the actual
time that the related physical process transpires so results of the
computation can be used in guiding the physical process.
Referenced Single-Ended mode—All measurements are made with respect
to a common reference measurement system or a ground. Also called a
grounded measurement system.
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