National Instruments Data Acquisition Device NI USB-621x, Руководство пользователя

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Glossary
NI USB-621x User Manual G-12 ni.com
PFI Programmable F u nction Interface.
PGIA Programmable Gain Instr u mentation Amplifier.
physical channel See channel .
posttriggering The techniq u e u sed on a DAQ device to acq u ire a programmed n u mber of
samples after trigger conditions are met.
power so u rce An instr u ment that provides one or more so u rces of AC or DC power. Also
known as power s u pply.
ppm Parts per million.
pretriggering The techniq u e u sed on a DAQ device to keep a contin u o u s b u ffer filled with
data, so that when the trigger conditions are met, the sample incl u des the
data leading u p to the trigger condition.
p u lse A signal whose amplit u de deviates from zero for a short period of time.
p u lse width The time from the rising to the falling slope of a p u lse (at 50% amplit u de).
Q
q u adrat u re encoder An encoding techniq u e 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.
R
range The maxim u m and minim u m parameters between which a sensor,
instr u ment, or device operates with a specified set of characteristics. This
may be a voltage range or a freq u ency range.
real time 1. Displays as it comes in; no delays.
2. A property of an event or system in which data is processed and acted
u pon as it is acq u ired instead of being acc u m u lated and processed at a
later time.
3. Pertaining to the performance of a comp u tation d u ring the act u al
time that the related physical process transpires so res u lts of the
comp u tation can be u sed in g u iding the physical process.