User`s manual

DIGITAL-LOGIC AG MPC40/A/B/C, MPC41 Manual V1.4C

4.18 LCD PanelLink (DVI)

Silicon Image’s Transition Minimized Differential Signaling is an electrical standard used to transmit digital

data to a display device. The transition minimization is achieved by implementing an advanced encoding al-

gorithm that converts 8 bits of data into a 10-bit transition minimized, DC balanced character. The signal is

optimized to reduce Electromagnetic Interference (EMI), which allows for faster signal transfer rates with in-

creased accuracy. The differential circuitry in TMDS allows complimentary limited amplitude signals to be

transmitted over twisted pair wires instead of more expensive coaxial cable. The TMDS link architecture con-

sists of a TMDS transmitter that encodes and serially transmits a data stream over the TMDS link to a TMDS

receiver. Video and sync information are serialized and sent over three sets of twisted pair wires, one set for

red, green and blue data channels. An additional pair of wires is used to transmit a clock signal for timing. At

the other end, the TMDS receiver synchronizes itself to character boundaries in each of the serial data

streams, the transmitted signal is recovered and decoded. A fundamental principle of physics known as the

"Copper Barrier" limits the amount of data that can be squeezed through a single copper wire. The limit is a

bandwidth of about 165MHz, which equates to 165 million pixels per second. A single TMDS link has a

bandwidth of 165 MHz, which enough to display resolutions of up to 1600 x 1200 (UXGA) at 60Hz. DVI,

which is the first standard specifically written for the TMDS digital interface allows for up to two TMDS links, a

total of 6 channels sharing a single clock, to be integrated into a single DVI connector to support a minimum

bandwidth of 330 mega pixels per second. That is enough bandwidth to enable digital displays to reach reso-

lutions of up to 2048 x 1536 (QXGA).

The DVI specification supports hot plug and play of display devices. DVI also supports the VESA Display

Data Channel (DDC) and Extended Display Identification Data (EDID) specifications, which enable the dis-

play, graphics adapter, and computer to communicate and automatically configure the system to support the

different features available in the display. EDID is a standard data format for information such as display

vendor, resolution and timing capabilities. A purely digital connection allows projector manufacturers to de-

sign products, which provide the sharpest, clearest image possible, without the need for any fine sync or

complex pixel clock adjustments.