User Guide

Glossary

pretriggering the technique used on a device to keep a buffer filled with data, so that when

the trigger conditions are met, the sample includes the data leading up

to the trigger condition

PXI PCI eXtensions for Instrumentation. PXI is an open specification that

builds off the CompactPCI specification by adding

instrumentation-specific features.

Rresistor

RAM random-access memory

real-time sampling sampling that occurs immediately

random interleaved

sampling

method of increasing the sample rate by repetitively sampling a repeated

waveform

resolution the smallest signal increment that can be detected by a measurement

system. Resolution can be expressed in bits or in digits. The number of bits

in a system is roughly equal to 3.3 times the number of digits.

rms root mean square—a measure of signal amplitude; the square root of the

average value of the square of the instantaneous signal amplitude

ROM read-only memory

RTSI bus real-time system integration bus—the National Instruments timing bus that

connects devices directly, by means of connectors on top of the boards, for

precise synchronization of functions

s seconds

S samples

S/s samples per second—used to express the rate at which an instrument

samples an analog signal. 100 MS/s would equal 100 million samples each

second.