Glossary
NI PXI-562x User Manual G-6 © National Instruments Corporation
N
noise an undesirable electrical signal—noisecomes from externalsources such as
the AC power line, motors, generators, transformers, fluorescent lights,
soldering irons, 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.
O
Ohm’sLaw (R=V/I)—the relationship of voltage to current in a resistance
onboard memory the device memory. Onboard memory is distinct from computer memory.
overcurrent amperages above the maximum power level specified for a device
overrange a segment of the input range of an instrument outside of the normal
measuring range. Measurements can still be made, usually with a
degradation in specifications.
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 workstations
and offers a theoretical maximum transfer rate of 132 Mbytes/s
peak value the absolute maximum or minimum amplitude of a signal (AC + DC)
PFI Programmable Function Input
PLL phase-locked loop—an electronic circuit that controls an oscillator so that
it maintains a constant phase angle relative to a reference signal
PXI PCI eXtensions for Instrumentation—PXI is an open specification that
builds on the CompactPCI specification by adding instrumentation-specific
features
