Glossary
NIPXI-562x User Manual G-6 ©NationalInstruments Corporation
N
noise anundesirable electrical signal—noise comes from external sources such as
the ACpower line, motors, generators, transformers, fluorescent lights,
solderingirons, CRT displays, computers, electrical storms, welders, radio
transmitters, and internal sources such as semiconductors, resistors, and
capacitors.N oise 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 devicememory. Onboard memory is distinct from computer memory.
overcurrent amperages abovethe maximum power level specified for a device
overrange asegment of the input range of an instrument outside of the normal
measuring range. Measurements can still be made, usually with a
degradationin specifications.
P
PCI Peripheral Component Interconnect—a high-performance expansion bus
architecture originally developedby Intel to replace ISA and EISA; it is
achievingwidespread acceptance as a standard for PCs and workstations
and offersa theoretical maximum transfer rate of 132 Mbytes/s
peakvalue theabsolute maximum or minimum amplitude of a signal (AC + DC)
PFI Programmable Function Input
PLL phase-lockedloop—an electronic circuit that controls an oscillator so that
itmaintains a constant phase angle relativeto a reference signal
PXI PCIeXtensions for Instrumentation—PXI is an open specification that
buildson the CompactPCI specification by adding instrumentation-specific
features