Glossary
IMAQ PCI/PXI-1411 User Manual G-8 www.ni.com
P
PAL Phase Alternation Line. One of the European video color standards; uses
625 lines per frame. See also NTSC.
PCI Peripheral Component Interconnect. A high-performance expansion bus
architecture originally developed by Intel to replace ISA and EISA. PCI
offers a theoretical maximum transfer rate of 132 Mbytes/s.
pixel Picture element. The smallest division that makes up the video scan line;
for display on a computer monitor, a pixel’s optimum dimension is square
(aspect ratio of 1:1, or the width equal to the height).
pixel clock Divides the incoming horizontal video line into pixels.
pixel cou nt The total number of pixels between two horizontal synchronization signals.
The pixel count determines the frequency of the pixel clock.
PLL Phase-locked loop. Circuitry that provides a very stable pixel clock that is
referenced to another signal, for example, an incoming horizontal
synchronization signal.
protocol The exact sequence of bits, characters, and control codes used to
transferdata between computers and peripherals through a
communications channel.
pts Points.
R
RAM Random-access memory.
real time A property of an event or system in which data is processed as it is acquired
instead of being accumulated and processed at a later time.
relative accu racy A measure in LSB of the accuracy of an ADC; it includes all nonlinearity
and quantization errors but does not include offset and gain errors of the
circuitry feeding the ADC.
resolution The smallest signal increment that can be detected by a measurement
system. Resolution can be expressed in bits, in proportions, or in
percent of full scale. For example, a system has 12-bit resolution, one
part in 4,096 resolution, and 0.0244 percent of full scale.