Glossary

Vocabulary that holds the terms for the vocabulary.

d
D-VHSsearch for term

Digital VHS. Digital signals recorded onto magnetic tape. Greater capacity than typical VHS; can record compressed HDTV signals.

Diagonal Screensearch for term

A method of measuring the size of a screen or a projected image. It measures from one corner to the opposite corner. A 9FT high, 12FT wide, screen has a diagonal of 15FT. Throughout this document we assume that the diagonal dimensions are for the traditional 4:3 ratio of a computer image as per the example above. Some screens are square, others particularly wide for 35mm slides 3:2 ratio. As such even if the screen is 12x12, we would rate it 15FT diagonal since that would be the diagonal of the usable area.

Digitalsearch for term

A two state, on or off, signal system. Analogue signals can be converted to digital signals. They are sampled at a particular rate. Each sample is converted into a digital "word" that represents the analogue value of the signal at that given instant of the sample. A digital word contains many bits of on or off digital information.

Digital Light Processing™search for term

see DLP™

Distortionsearch for term

Any changes made to an original, "clean" audio or video signal, either at the recording end or at the playback end.

DLP™search for term

DLP™ technology delivers the clearest, sharpest, and most accurate images in a broad range of projection and display applications including business projectors, home entertainment projectors, large screen tabletop TVs, video walls. and projection systems used in commercial entertainment. At the core of every DLP™ projection system is an optical semiconductor called the Digital Micromirror Device, or DMD, which functions as an extremely precise light switch. The DMD chip contains an array of up to 1,310,000 hinged, microscopic mirrors, each of which corresponds to one pixel of light in a projected image. By switching these mirrors on and off up to several thousand times per second, a DLP™ projection system can translate a digital video or graphic source into a projected image with maximum fidelity.

DMDsearch for term

The Digital Micromirror Device is an optical semiconductor chip populated with up to a million or more hinged, microscopic mirrors; in a DLP™ projection system, these mirrors operate as optical switches to create a high resolution, full-color image.

Dot Crawlsearch for term

An artifact of composite video signals that appears as a moving, zipper-like, vertical border between colors.

DTCPsearch for term

(Digital Transmission Copy Protection) - DTCP Specification is to allow for protected transmission of copy-protected material between digital devices like PC's, DVD Players, and Digital TV's. The DTCP specification defines a cryptographic protocol for protecting audio/video entertainment content from illegal copying, intercepting and tampering as it traverses high performance digital buses, such as the IEEE 1394 standard. Only legitimate entertainment content delivered to a source device via another approved copy protection system (such as the DVD Content Scrambling System) will be protected by this copy protection system. The DTCP specification relies on strong cryptographic technologies to provide flexible and robust copy protection across digital buses.

DTV (Digital Television)search for term

Umbrella term used for the ATSC system that will eventually replace the NTSC system in 2006. HDTV is a subset of the DTV system. While the FCC does not recognize specific scan rates in the adopted DTV system, typically accepted rates include 480i, 480p, 720p, and 1080i.

DVI (Digital Visual Interface)search for term

Connection standard developed by Intel for connecting computers to digital monitors such as flat panels and DLP projectors. A consumer electronics version, not necessarily compatible with the PC version, is used as a connection standard for HDTV tuners and displays. Transmits an uncompressed digital signal to the display. The latter version uses HDCP copy protection to prevent unauthorized copying. See also HDMI.