Specifications

Pixel Response Time

For media professionals, the ability to render full-motion video or 3D graphics clearly

enough to view precise details is key. Today’s advanced LCDs such as the Apple flat-

panel displays meet this demanding requirement. Apple LCD displays are designed to

offer fast pixel response across the entire spectrum, working well with fast-moving

details in multihued images.

Digital Connection

Some flat-panel displays still use an analog interface (typically VGA) to be more

broadly compatible with graphics cards that don’t support digital output. To create

an analog signal from the digital data in graphics memory, the computer’s graphics

controller must perform a digital-to-analog (D/A) conversion. Because an LCD display

is a digital device, the incoming analog signal requires conversion back to digital form

(A/D). These two conversions (from digital to analog by the graphics card, then from

analog to digital in the LCD monitor) inevitably lead to varying degrees of image

degradation on the screen. This degradation can take many forms, including ghosting

(fuzziness around the edges of images), color shifts, incorrect vertical and/or horizontal

alignment of the viewable area, loss of vertical or horizontal synchronization, and

brightness and contrast problems. Analog conversion problems become progressively

worse as you move to monitors that have higher resolutions or use longer monitor

cables.

Apple has maximized the sharpness of its displays by driving them with an industry-

standard, pure digital signal based on the Digital Visual Interface (DVI) standard. This

standard was created by the Digital Display Working Group (DDWG) to convert analog

signals into digital signals to accommodate both analog and digital monitors. Data is

transmitted using the Transition Minimized Differential Signaling (TMDS) protocol,

providing a digital signal from the computer’s graphics subsystem to the display.

The DVI standard specifies a single connector that handles two different digital signal

bandwidths: single link and dual link. At 165MHz, the single-link bandwidth supports

HDTV and UXGA (1600-by-1200-pixel resolution) display formats. The dual-link band-

width (transmitted over a single cable) uses the same DVI connection, but it supports

much higher resolutions, such as the 2560-by-1600-pixel resolution of the 30-inch

Apple Cinema HD Display.

Technology Overview

Apple Cinema Displays

DVI

Original digital image

First-generation image

Pure digital

connection