Glossary
NI 7831R User Manual G-6 © National Instruments Corporation
N
noise An undesirable electrical signal—Noise comes from external sources such
as the AC power line, motors, generators, transformers, fluorescent lights,
CRT displays, computers, electrical storms, welders, radio transmitters,
and internal sources such as semiconductors, resistors, and capacitors.
Noise corrupts signals you are trying to send or receive.
NRSE Nonreferenced single-ended mode—All measurements are made with
respect to a common (NRSE) measurement system reference, but the
voltage at this reference can vary with respect to the measurement system
ground.
O
OUT Output pin—A counter output pin where the counter can generate various
TTL pulse waveforms.
P
PCI Peripheral Component Interconnect—A high-performance expansion bus
architecture originally developed by Intel to replace ISA and EISA. It is
achieving widespread acceptance as a standard for PCs and work-stations.
PCI offers a theoretical maximum transfer rate of 132 MB/s.
port (1) A communications connection on a computer or a remote controller.
(2) A digital port, consisting of four or eight lines of digital input and/or
output.
ppm Parts per million.
pu Pull-up.
PWM Pulse-width modulation.
PXI PCI eXtensions for Instrumentation—An open specification that builds off
the CompactPCI specification by adding instrumentation-specific features.