National Instruments NI USB-621x 162

	Glossary
NRSE	Non-Referenced 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
offset	The unwanted DC voltage due to amplifier offset voltages added to a signal.
P
PCI	Peripheral Component Interconnect—A high-performance expansion bus
	architecture originally developed by Intel to replace ISA and EISA. It offers
	a theoretical maximum transfer rate of 132 MB/s.
PCI Express	A high-performance expansion bus architecture originally developed by
	Intel to replace PCI. PCI Express offers a theoretical maximum transfer rate
	that is dependent upon lane width. A ×1 link theoretically provides
	250 MB/s in each direction—to and from the device. Once overhead is
	accounted for, a ×1 link can provide approximately 200 MB/s of input
	capability and 200 MB/s of output capability. Increasing the number of
	lanes in a link increases maximum throughput by approximately the same
	factor.
PCIe	See PCI Express.
period	The period of a signal, most often measured from one zero crossing to the
	next zero crossing of the same slope. The period of a signal is the reciprocal
	of its frequency (in Hz). Period is designated by the symbol T.
periods	The number of periods of a signal.
PFI	Programmable Function Interface.
PGIA	Programmable Gain Instrumentation Amplifier.
physical channel	See channel.

G-13