User Guide

Glossary

clock hardware component that controls timing for reading from or writing to

groups

CMRR common-mode rejection ratio—a measure of an instrument’s ability to

reject interference from a common-mode signal, usually expressed in

decibels (dB)

counter/timer a circuit that counts external pulses or clock pulses (timing)

coupling the manner in which a signal is connected from one location to another

dB decibel—the unit for expressing a logarithmic measure of the ratio of

two signal levels: dB=20log10 V1/V2, for signals in volts

DC direct current

default setting a default parameter value recorded in the driver. In many cases, the default

input of a control is a certain value (often 0) that means use the current

default setting.

device a plug-in data acquisition board, card, or pad. The NI 5911 is an example

of a device.

differential input an analog input consisting of two terminals, both of which are isolated from

computer ground, whose difference is measured

double insulated a device that contains the necessary insulating structures to provide electric

shock protection without the requirement of a safety ground connection

drivers software that controls a specific hardware instrument

EEPROM electrically erasable programmable read-only memory—ROM that can be

erased with an electrical signal and reprogrammed

equivalent time

sampling

any method used to sample signals in such a way that the apparent sampling

rate is higher than the real sampling rate

event the condition or state of an analog or digital signal