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National Instruments Data Acquisition Device NI USB-621x User Manual

Page 160

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Glossary

NI USB-621x User Manual

G-2

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A

A

Amperes—the unit of electric current.

A/D

Analog-to-Digital. Most often used as A/D converter.

AC

Alternating current.

accuracy

A measure of the capability of an instrument or sensor to faithfully indicate
the value of the measured signal. This term is not related to resolution;
however, the accuracy level can never be better than the resolution of the
instrument.

ADE

Application development environment.

AI

1. Analog input.

2. Analog input channel signal.

AI GND

Analog input ground signal.

AI SENSE

Analog input sense signal.

analog

A signal whose amplitude can have a continuous range of values.

analog input signal

An input signal that varies smoothly over a continuous range of values,
rather than in discrete steps.

analog output signal

An output signal that varies smoothly over a continuous range of values,
rather than in discrete steps.

analog trigger

A trigger that occurs at a user-selected point on an incoming analog signal.
Triggering can be set to occur at a specific level on either an increasing or
a decreasing signal (positive or negative slope). Analog triggering can be
implemented either in software or in hardware. When implemented in
software (LabVIEW), all data is collected, transferred into system memory,
and analyzed for the trigger condition. When analog triggering is
implemented in hardware, no data is transferred to system memory until the
trigger condition has occurred.

AO

Analog output.

AO GND

Analog output ground signal.

application

A software program that creates an end-user function.