National Instruments Data Acquisition Device NI USB-621x User Manual page 166

Glossary
floating signal sources
FREQ OUT
frequency
ft
function
G
glitch
GND
ground
H
hardware
hardware triggering
Hz
NI USB-621x User Manual
Signal sources with voltage signals that are not connected to an absolute
reference of system ground. Also called non-referenced signal sources.
Some common examples of floating signal sources are batteries,
transformers, and thermocouples.
Frequency Output signal.
The number of alternating signals that occur per unit time.
Feet.
1. A built-in execution element, comparable to an operator, function, or
statement in a conventional language.
2. A set of software instructions executed by a single line of code that may
have input and/or output parameters and returns a value when executed.
An unwanted signal excursion of short duration that is usually unavoidable.
See ground.
1. A pin.
2. An electrically neutral wire that has the same potential as the
surrounding earth. Normally, a noncurrent-carrying circuit intended for
safety.
3. A common reference point for an electrical system.
The physical components of a computer system, such as the circuit boards,
plug-in devices, chassis, enclosures, peripherals, and cables.
A form of triggering where you set the start time of an acquisition and
gather data at a known position in time relative to a trigger signal.
1. Hertz—The SI unit for measurement of frequency. One hertz (Hz)
equals one cycle per second.
2. The number of scans read or updates written per second.
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