Dell 4220 User Manual

Also see for 4320: User guide Specifications User guide

Contents

Dell 4220 User Manual Manual pdf 116 page image

116 GlossaryAppendix: GlossaryANSI LUMENS — A standard for measuring the brightness. It is calculated bydividing a square meter image into nine equal rectangles, measuring the lux (orbrightness) reading at the center of each rectangle, and averaging these ninepoints.A SPECT RATIO — The most popular aspect ratio is 4:3 (4 by 3). Early television andcomputer video formats are in a 4:3 aspect ratio, which means that the width ofthe image is 4/3 times the height.Brightness — The amount of light emitted from a display or projection display orprojection device. The brightness of projector is measured by ANSI lumens.Color Temperature — The color appearance of white light. Low colortemperature implies warmer (more yellow/red) light while high color temperatureimplies a colder (more blue) light. The standard unit for color temperature isKelvin (K).Component Video — A method of delivering quality video in a format thatconsists of the luminance signal and two separate chrominance signals and aredefined as Y'Pb'Pr' for analog component and Y'Cb'Cr' for digital component.Component video is available on DVD players.Composite Video — A video signal that combines the luma (brightness), chroma(color), burst (color reference), and sync (horizontal and vertical synchronizingsignals) into a signal waveform carried on a single wire pair. There are three kindsof formats, namely, NTSC, PAL, and SECAM.Compressed Resolution — If the input images are of higher resolution than thenative resolution of the projector, the resulting image will be scaled to fit thenative resolution of the projector. The nature of compression in a digital devicemeans that some image content is lost.Contrast Ratio — Range of light and dark values in a picture, or the ratio betweentheir maximum and minimum values. There are two methods used by theprojection industry to measure the ratio:1 Full On/Off — measures the ratio of the light output of an all white image (fullon) and the light output of an all black (full off) image.2 ANSI — measures a pattern of 16 alternating black and white rectangles. Theaverage light output from the white rectangles is divided by the average lightoutput of the black rectangles to determine the ANSI contrast ratio.Full On/Off contrast is always a larger number than ANSI contrast for the sameprojector.Downloaded From projector-manual.com DELL Manuals