National Instruments Data Acquisition Device NI USB-621x - Manual (Page 172)

Glossary
NI USB-621x User Manual G-14 ni.com
single-buffered Describes a device that acquires a specified number of samples from one or
more channels and returns the data when the acquisition is complete.
single-ended input A circuit that responds to the voltage on one input terminal and ground.
See also
differential input .
single-ended output A circuit whose output signal is present between one output terminal and
ground.
software triggering A method of triggering in which you simulate an analog trigger using
software. Also called conditional retrieval.
source impedance A parameter of signal sources that reflects current-driving ability of voltage
sources (lower is better) and the voltage-driving ability of current sources
(higher is better).
synchronous 1. Hardware—A property of an event that is synchronized to a reference
clock.
2. Software—A property of a function that begins an operation and
returns only when the operation is complete. A synchronous process is,
therefore, locked and no other processes can run during this time.
T
task In NI-DAQmx, a collection of one or more channels, timing, and triggering
and other properties that apply to the task itself. Conceptually, a task
represents a measurement or generation you want to perform.
TC See terminal count.
terminal An object or region on a node through which data passes.
terminal count The highest value of a counter.
t
gh
Gate hold time.
t
gsu
Gate setup time.
t
gw
Gate pulse width.
Timebase The reference signals for controlling the basic accuracy of time or
frequency-based measurements. For instruments, timebase refers to the
accuracy of the internal clock.