Glossary
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National Instruments Corporation
G-7
propagation delay
The amount of time required for a signal to pass through a circuit.
protocol
The exact sequence of bits, characters and control codes used to transfer
data between computers and peripherals through a communications
channel, such as the GPIB.
PXI
PCI eXtensions for Instrumentation—a rugged, open system for modular
instrumentation based on CompactPCI, with special mechanical, electrical,
and software features.
R
real time
A property of an event or system in which data is processed as it is acquired
instead of being accumulated and processed at a later time.
REQ
Request—Handshaking signal generated by the peripheral device,
indicating it is ready. In some transfer modes, the NI 653
X
can internally
generate a REQ signal. The REQ signal with a bar above the name indicates
it is an inverted request signal.
RGND
reserved ground
RT Series DAQ
device
A collection of one, two, or four ports and an associated timing controller.
All handshaking I/O, pattern I/O and buffered operations must be
performed on groups.
RTSI bus
Real-Time System Integration Bus—the National Instruments timing bus
that connects DAQ devices directly, by means of connectors on top of the
devices, for precise synchronization of functions
S
s
seconds
S
samples
S/s
samples per second—used to express the rate at which a DAQ device
samples an analog signal.
sample
An instantaneous measurement of a signal, normally using an
analog-to-digital convertor in a DAQ device.
