Glossary
G-8
ni.com
pd
Pull-down.
PFI
Programmable function interface.
PGIA
Programmable gain instrumentation amplifier.
physical channel
See
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.
PXI Express
PCI Express eXtensions for Instrumentation—The PXI implementation
of PCI Express, a scalable full-simplex serial bus standard that operates at
2.5 Gbps and offers both asynchronous and isochronous data transfers.
Q
quantization
The process of converting an analog signal to a digital representation.
Normally performed by an analog-to-digital converter (A/D converter or
ADC).
R
range
The maximum and minimum parameters between which a sensor,
instrument, or device operates with a specified set of characteristics.
referenced signal
sources
Signal sources with voltage signals that are referenced to a system ground
such as the earth or a building ground. Also called ground signal sources.
rise time
The time for a signal to transition from 10% to 90% of the maximum signal
amplitude.
rms
Root mean square.
RTSI bus
Real-Time System Integration bus—the National Instruments timing bus
that connects DAQ devices directly, by means of connectors on top of the
devices, for precise synchronization of functions.