National Instruments NI PCI-1410 User Manual page 28

Glossary
D
DAQ
DMA
driver
E
external trigger
F
field
frame
G
gamma
genlock
NI PCI-1410 User Manual
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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.
Direct memory access. A method by which data can be transferred between
computer memory and 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.
Software that controls a specific hardware device, such as an image
acquisition or DAQ device.
A voltage pulse from an external source that triggers an event such as
A/D conversion.
For an interlaced video signal, a field is half the number of horizontal lines
needed to represent a frame of video. The first field of a frame contains all
the odd-numbered lines, the second field contains all of the even-numbered
lines.
A complete image. In interlaced formats, a frame is composed of two fields.
The nonlinear change in the difference between the video signal's
brightness level and the voltage level needed to produce that brightness.
The process of synchronizing a video source to the signal from a separate
video source. The circuitry aligns the video timing signals by locking
together the horizontal, vertical, and color subcarrier frequencies and
phases and generates a pixel clock that clocks pixel data into memory
for display or into another circuit for processing.
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