National Instruments NI 781 R Series, User Manual

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Glossary
© National Instruments Corporation G-3 R Series Intelligent DAQ User Manual
C
C Celsius.
CalDAC Calibration DAC.
CH Channel—Pin or wire lead to which you apply or from which you read the
analog or digital signal. Analog signals can be single-ended or differential.
For digital signals, you group channels to form ports. Ports usually consist
of either four or eight digital channels.
cm Centimeter.
CMOS Complementary metal-oxide semiconductor.
CMRR Common-mode rejection ratio—A measure of an instrument’s ability to
reject interference from a common-mode signal, usually expressed in
decibels (dB).
common-mode voltage Any voltage present at the instrumentation amplifier inputs with respect to
amplifier ground.
CompactPCI Refers to the core specification defined by the PCI Industrial Computer
Manufacturer’s Group (PICMG).
D
D/A Digital-to-analog.
DAC Digital-to-analog converter—An electronic device, often an integrated
circuit, that converts a digital number into a corresponding analog voltage
or current.
DAQ Data acquisition—A system that uses the computer to collect, receive,
and generate electrical signals.
dB Decibel—The unit for expressing a logarithmic measure of the ratio of
two signal levels: dB = 20log10 V1/V2, for signals in volts.
DC Direct current.
DGND Digital ground signal.
DIFF Differential mode.