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Glossary
©
National Instruments Corporation
G-13
t
p
the interval between pulses in a pulse train
t
reset
the length of the reset period
TRIG1 (EXT_TRIG)
trigger 1 signal
trigger
any event that causes or starts some form of data capture
tri-state
logic circuitry designed to have three possible outputs—0, 1, and hi-Z.
The hi-Z (high impedance) state effectively pulls the output out of its
circuit, and can be used to simplify bus communication by wire-ANDing
tri-state inputs.
TTL
transistor-transistor logic
TTL-compatible
operating in a nominal range of 0 to 5 VDC, with a signal below 1 V a logic
low, and a signal above 2.4 V a logic high
two’s complement
format
a system for digitally encoding sound that stores the amplitude values as a
signed number, with silence represented by a sample with a value of 0. For
example, with 8-bit sound samples, two’s complement values would range
from –128 to 127, with 0 meaning silence.
See also
.
U
unbalanced
differential input
an analog input channel consisting of two terminals, with different input
impedances, whose difference is measured. In the case of the NI 447
X
, one
terminal is referenced to ground through a resistor.
See also
undersampling
sampling at a rate lower than the Nyquist frequency—can cause aliasing
V
V
volts
V
CC
collector common voltage—power supply voltage
VDC
volts direct current