National Instruments NI Vision PCI-1409, User Manual, Page: 31 / 40

Glossary
NI PXI/PCI-1409 User Manual G-4 ni.com
E
EEPROM Electrically erasable programmable read-only memory. ROM that can be
erased with an electrical signal and reprogrammed.
external trigger A voltage pulse from an external source that triggers an event such as
A/D conversion.
F
field 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.
FIFO First-in first-out memory buffer. The first data stored is the first data sent
to the acceptor. FIFOs are used on image acquisition devices to temporarily
store incoming data until that data can be retrieved.
flash ADC An ADC whose output code is determined in a single step by a bank of
comparators and encoding logic.
frame A complete image. In interlaced formats, a frame is composed of two fields.
front porch The area of a video signal between the start of the horizontal blank and the
start of the horizontal synchronization signal (HSYNC).
ft Feet.
function A set of software instructions executed by a single line of code that may
have input and/or output parameters and returns a value when executed.
G
gamma The nonlinear change in the difference between the video signal’s
brightness level and the voltage level needed to produce that brightness.
genlock 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.