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National Instruments Network Device DAQ S User Manual

Page 163

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Glossary

NI 6124/6154 User Manual

G-10

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t

gw

Gate pulse width.

THD

Total harmonic distortion—the ratio of the total rms signal due to harmonic
distortion to the overall rms signal, in dB or percent.

THD+N

Signal-to-THD plus noise—the ratio in decibels of the overall rms signal to
the rms signal of harmonic distortion, plus noise introduced.

thermocouple

A temperature sensor created by joining two dissimilar metals. The
junction produces a small voltage as a function of the temperature.

t

off

An offset (delayed) pulse; the offset is t nanoseconds from the falling edge
of the AI CONV CLK* signal.

t

out

Output delay time.

t

p

Period of a pulse train.

transducer

See

sensor

.

t

sc

Source clock period.

t

sp

Source pulse width.

TTL

Transistor-transistor logic—a digital circuit composed of bipolar
transistors wired in a certain manner. A typical medium-speed digital
technology. Nominal TTL logic levels are 0 and 5 V.

V

V

Volts.

V

CC

Nominal +5 V power supply provided by the PC motherboard.

V

cm

Common-mode noise and ground potential.

VDC

Volts direct current.

VI, virtual instrument

1. A combination of hardware and/or software elements, typically used
with a PC, that has the functionality of a classic stand-alone instrument.

2. A LabVIEW software module (VI), which consists of a front panel user
interface and a block diagram program.

V

IH

Volts, input high.