National Instruments Image Acquisition Software User Manual
Page 55
Glossary
G-4
©
National Instruments Corporation
D
D/A
digital-to-analog
DAC
digital-to-analog converter; an electronic device, often an integrated circuit,
that converts a digital number into a corresponding analog voltage or
current
DAQ
data acquisition—(1) collecting and measuring electrical signals from
sensors, transducers, and test probes or fixtures and inputting them to
a computer for processing; (2) collecting and measuring the same kinds of
electrical signals with A/D or DIO boards plugged into a computer, and
possibly generating control signals with D/A and/or DIO boards in the
same computer
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
DIN
Deutsche Industrie Norme
DLL
dynamic link library—a software module in Microsoft Windows
containing executable code and data that can be called or used by Windows
applications or other DLLs; functions and data in a DLL are loaded and
linked at run time when they are referenced by a Windows application or
other DLLs
DMA
direct memory access—a method by which data can be transferred to and
from computer memory from and to a device or memory on the bus while
the processor does something else; DMA is the fastest method of
transferring data to/from computer memory
DRAM
dynamic RAM
drivers
software that controls a specific hardware device such as an IMAQ or
DAQ device
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