Glossary
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National Instruments Corporation
G-3
composite video
A type of color video transmission where synchronization, luma, and
chroma information are transmitted on one analog signal.
contrast
A constant multiplication factor applied to the luma and chroma
components of a color pixel in the color decoding process.
coring
The process of eliminating color information in low-color situations
(if the saturation is lower than a predefined value).
CPU
Central processing unit.
D
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 = 20log
10
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
.
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 image
acquisition board.
dynamic range
The ratio of the largest signal level a circuit can handle to the smallest
signal level it can handle (usually taken to be the noise level), normally
expressed in decibels.
