Glossary
©
National Instruments Corporation
G-3
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 signal
any voltage present at the instrumentation amplifier inputs with respect to
amplifier ground
counter/timer
a circuit that counts external pulses or clock pulses (timing)
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—(1) collecting and measuring electrical signals from
sensors, transducers, and test probes or fixtures and inputting them to a
computer for processing; (2) collecting and measuring the same kinds of
electrical signals with A/D and/or DIO devices plugged into a computer,
and possibly generating control signals with D/A and/or DIO devices in the
same computer
DAQ Assistant
a configuration assistant with which you define and configure your DAQ
operation
DAQ-STC
data acquisition system timing controller chip
dB
decibel—the unit for expressing a logarithmic measure of the ratio of
two signal levels: db=20·log
10
(V1/V2), for signals in volts
DC
direct current
differential input
an analog input consisting of two terminals, both of which are isolated from
computer ground, whose difference is measured
DIO
digital input/output
dithering
the addition of Gaussian noise to an analog input signal
