Glossary
©
National Instruments Corporation
G-15
trigger
1. Any event that ca
u
ses or starts some form of data capt
u
re.
2. An external stim
u
l
u
s that initiates one or more instr
u
ment f
u
nctions.
Trigger stim
u
li incl
u
de a front panel b
u
tton, an external inp
u
t voltage
p
u
lse, or a b
u
s trigger command. The trigger may also be derived from
attrib
u
tes of the act
u
al signal to be acq
u
ired, s
u
ch as the level and slope
of the signal.
t
sc
So
u
rce clock period.
t
sp
So
u
rce p
u
lse width.
TTL
Transistor-Transistor Logic—A digital circ
u
it composed of bipolar
transistors wired in a certain manner. A typical medi
u
m-speed digital
technology. Nominal TTL logic levels are 0 and 5 V.
U
USB
Universal Serial B
u
s—A 480 Mbit/s serial b
u
s with
u
p to 12-Mbps
bandwidth for connecting comp
u
ters to keyboards, printers, and other
peripheral devices. USB 2.0 retains compatibility with the original USB
specification.
V
V
Volts.
V
cm
Common-mode voltage.
V
g
Gro
u
nd loop voltage.
V
IH
Volts, inp
u
t high.
V
IL
Volts, inp
u
t low.
V
in
Volts in.
V
m
Meas
u
red voltage.
V
OH
Volts, o
u
tp
u
t high.
V
OL
Volts, o
u
tp
u
t low.
V
o
u
t
Volts o
u
t.
