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National Instruments Corporation
G-19
Glossary
signal conditioning
the manipulation of signals to prepare them for digitizing
signal divider
performing frequency division on an external signal
SIMM
single in-line memory module
SISOURCE
SI counter clock signal
SMB
a type of miniature coaxial signal connector
software trigger
a programmed event that triggers an event such as data acquisition
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)
SOURCE input pin
an counter input pin where the counter counts the signal transitions
SPDT
single-pole double throw—a property of a switch in which one terminal can
be connected to one of two other terminals
SS
simultaneous sampling—a property of a system in which each input or
output channel is digitized or updated at the same instant
S/s
samples per second—used to express the rate at which a DAQ board
samples an analog signal
STARTSCAN
start scan signal
STB
strobe input signal
STC
system timing controller
statically configured
device
a device whose logical address cannot be set through software; that is, it is
not dynamically configurable
switchless device
devices that do not require dip switches or jumpers to configure resources
on the devices—also called Plug and Play devices
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
