Glossary of Terms

Glossary of Terms

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Aspect Ratio

The ratio between width and the height of an image displayed on a screen. For example, a resolution of 800 x 600 would have an aspect ratio of 4:3, or a resolution of 1365 x 768 would have an aspect ratio of 16:9. Some devices are limited to just one aspect ratio where as other devices can produce images of various aspect ratios.

ATSC

(Advanced Television Systems Committee) developed standards for digital television (DTV) in the U.S, Canada, South Korea, Taiwan and Argentina. The ATSC system supports a host of different display resolutions and frame rates.

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Bluetooth

Is an industrial specification for wireless personal area networks (PANs), also known as IEEE 802.15.1. Bluetooth provides a way to connect and exchange information between devices such as personal digital assistants (PDAs), mobile phones, laptops, PCs, printers, digital cameras and video game consoles via a secure, globally unlicensed short-range radio frequency. A short-range radio technology aimed at simplifying communications among Internet devices and between devices and the Internet. Bluetooth has no native support for IP, so it does not support TCP/IP and wireless LAN applications well. It was not originally created to support wireless LANs. Best suited for connecting PDAs, cell phones and PCs in short intervals. Products with Bluetooth technology must be qualified and pass interoperability testing by the Bluetooth Special Interest Group prior to release.

Blu-ray

Is a next-generation optical disc format designed for high-density storage of high-definition video and data. Blu-ray utilizes the 405nm-wavelength blue-violet laser technology, in contrast to the 650nm-wavelength red laser technology used in traditional DVD formats. The re-writable Blu-ray disc, with a data transfer rate of 36 Mbps, can hold up to 27 GB of data on a single-sided single layer disc (in contrast to the traditional DVD's 4.7GB capacity), which amounts to about 12 hours of standard video or more than 2 hours of high-def video.

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Chrominance

Chrominance is a color term defining the hue and saturation of a color. It does not refer to brightness.

Coated Optics

Minimize the amount of light reflected back to the lamp and the amount of ambient light that mingles with the focused light leaving the lens. Good coatings generally add 15% or more to the brightness of lenses.

Color Temperature

Color temperature measures the "whiteness" of a light source. Metal halide lamps have very high temperatures compared to halogen or incandescent lights.

Component Video

Component Video is a method of delivering quality video (RGB) in a format that contains all the components of the original image. These components are referred to as luma and chroma: they are defined as Y'Pb'Pr' for the analog component format and Y'Cb'Cr' for the digital component format. Component video is available on certain DVD players, Projectors, and televisions.

Composite Video

A type of video signal in which all information-the red, blue, green signals and sometimes audio signals as well-are all combined together. This is the type of signal used by the NTSC standard.

Compressed Resolution

Most projectors automatically accept images that are of a greater resolution than the native (true) resolution of the projector. The resulting image is scaled to fit the native resolution of the projector. Not all projectors use the same compression algorithms; therefore, the quality of compression can vary. The nature of compression in a digital device also means that some image content can be lost.

Contrast Ratio

Defined as the ratio of the luminosity of the brightest (white) and the darkest (black) color a system is capable of producing. The higher the ratio, the greater the CRT, LCD, plasma, or projector's ability to visually illustrate subtle color and detail.

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DCDi

(Directional Correlation Deinterlacing) is a digital enhancement method designed to improve low-resolution video. For example, it helps to eliminate jagged edges generated by interlaced video. The technique is often used in LCD and plasma television sets.

Digital Theater System

(DTS) Another delivery format for digital surround sound, DTS competes against Dolby Digital. Favored by many, DTS uses less compression, on average, and strives to master a film's original sound mix. Many motion picture studios, however, do not want to spend the extra money to include DTS on DVDs.

Digital Theater System

DLP

(Digital Light Processing) technology developed by Texas Instruments used by projectors and televisions. In DLP projectors, the image is created by microscopically small mirros laid out in a matrix on a semiconductor chip, known as a Digital Micromirror Device (DMD). Each mirror represents one pixel in the projected image. The rapid repositioning of the mirrors (essentially switching between 'on' and 'off') allows the DMD to vary the intensity of the light being reflected out through the lens, creating shades of grey in addition to white (mirror in 'on' position) and black (mirror in 'off' position). There are two primary methods by which DLP projection systems create a color image, those utilized by single-chip DLP projectors, and those used by three-chip projectors.

Dolby Digital

Dolby Digital contains five full bandwidth channels and a true LFE (low frequency effects or bass) channel (known as a 5.1 configuration). A standard for high-quality digital audio that is used for the sound portion of video stored in digital format, especially videos stored on DVDs.

DolbyDigitalEX

An upgrade of Dolby Digital, uses six full bandwidth channels and a true LFE channel to create a more detailed and enveloping sound.

Dolby Pro Logic

The standard television, laserdisc, satellite, and videotape surround sound format is Dolby Pro Logic (DPL). This analog format system starts with four-channel, encodes it down to two and plays back in a four-channel format. DPL is compatible with two-channel broadcast. With DPL, the front speakers are full bandwidth with 20-20k frequencies while the rear speakers are limited in bandwidth and mono. DPL does not have a true LFE (Low Frequency Effects or bass) channel.

Dolby Pro Logic II

DPL II differs from DPL by giving the rear speakers full bandwidth. It is also able to take stereo and Pro Logic formatted sound and create a sound similar to Dolby Digital. Cable television is compatible with both Dolby Pro Logic and Pro Logic II.

DTV

(Digital Television) refers to the three types of digital television: Standard Definition Television (SDTV), Enhanced Definition TV (EDTV), and High Definition Television (HDTV).

DVI

(Digital Visual Interface) is a standard that defines the digital interface between digital devices such as projectors and personal computers. For devices that support DVI, a digital-to-digital connection can be made that eliminates the conversion to analog and thereby delivers an unblemished image.

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EDTV

(Enhanced Definition Television) refers to picture quality superior than that of NTSC, PAL, or SDTV but is not sharp enough to be considered HD. EDTV uses the 480p (progressive scan) video format. EDTV approximates the high quality of HDTV. To take advantage of the 480p standard, you must use a video source that can output that type of signal.

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FXL

The most popular halogen lamp in lower cost projectors and overhead projectors. These lamps typically last about 40 hours. For convenience, most projectors using halogen lamps carry a spare as a quick method of going to the backup lamp. Metal halide lamps and UHP lamps are used in most of the medium and higher priced, more powerful portables.

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Half Life

Means that a display device, such as a plasma display or projector, slowly loses intensity (brightness) as it is used. At the half-life point, the device is half as bright, as it was when it was new.

HDCP

(High-Bandwidth Digital Content Protection) is a method for protecting copyrighted digital content. It uses DVI or HDMI to encrypt transmission between a video source (such as a set-top box, DVD player, or computer) and a digital display device (such as a projector, monitor or television). To view digital HDCP protected content, both the sending and receiving device must support HDCP.

HDMI

(High-Definition Multimedia Interface) first industry-supported uncompressed video and audio standard. HDMI supports, standard, enhanced, high-definition video, plus multi-channel digital audio, and interactive controls on a single cable. It transmits all ATSC (Advanced Television Systems Committee) HDTV standards and supports 8-channel digital audio.

HDTV

(High Definition Television) is digital television system with a higher resolution than the NTSC, PAL, and SECAM formats. HDTV currently consists of the following formats, 720p, 1080i, and 1080p. HDTV possesses at least twice the resolution of standard televisions, allowing for much more detail to be shown compared to analog television or regular DVD. In addition, the technical standards for broadcasting HDTV are also able to handle 16:9 aspect ratio pictures without using letterboxing, thus further increasing the effective resolution for such content.

HD DVD

(High Density DVD or High Definition DVD) is a next-generation optical disc format designed for high-density storage of high-definition video and data. A HD DVD disc can store substantially more data than a standard DVD, because of the shorter wavelength (405 nm) of the blue-violet laser (DVDs use a 650-nm-wavelength red laser), which allows more information to be stored digitally in the same amount of physical space. In comparison to Blu-ray, which also uses a blue laser, HD DVD has less information capacity per layer (15 gigabytes instead of 25), though HD DVD is easier and cheaper to manufacture than a Blu-ray pre-recorded disc due to its sharing the same basic disc structure as a standard DVD. The 30 GB dual-sided HD DVDs have been used on nearly every movie released in this format. Blu-ray has only released movies on 25 GB single layer discs.

HD READY

(High Definition Ready) term often given to a display that can accept and display a HD signal of either 720p, 1080i, or 1080p using component video or digital input. However, the display does not have a built-in HDTV tuner and would require one in order to view HD television.

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Interlaced Video

Video systems in which each frame of video consists of two video fields. The odd numbered lines are contained in the first field and the even numbered lines are contained in the second field. When the image is delivered to a video device such as a television, the odd and even fields are delivered at 50 or 60 fields per second and your eye sees an integrated image.

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Keystone

Keystoning occurs when the projector is not perpendicular to the screen, thereby creating an image that is not rectangular.

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LCD

(Liquid Crystal Display) is a thin, flat panel display device. LCD displays utilize two sheets of polarizing material with a viscous liquid crystal solution between them. A transistor sends an electric current through the liquid, causing the crystals to align so that light, produced from a lamp behind the screen, gets filtered when passed through them.

Letterbox

Letterbox is a method of preserving the original aspect ratio of a production when it is presented on a projector with a different aspect ratio. This is accomplished by showing the full image and black where no image exists.

Lumens

Lumens measure the light-sourced colors emitted continuously from light to dark in relation to its intensity. Projectors with a higher brightness can handle a room with more light. Quality projectors possess a minimum of 1000-2000 ANSI lumens. Projectors with 600 or less ANSI lumens should be used in pitch-black rooms.

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Maximum Resolution

Maximum Resolution refers to the highest resolution that a given projector can display. If the maximum resolution exceeds the native resolution, the image is usually scaled to match or approximate the native resolution of the projector. Scaling reduces the image resolution and produces some artifacts in the image that are more apparent when viewing text than graphics or video.

Metal Halide Lamps

These types of lamps are used in many medium and all high end portable projectors. They typically have a half life of 1000-2000 hours. These lamps output a very "hot" temperature light similar to mercury vapor lamps used in streetlights. Their whites are extremely white (with slight bluish cast) and make the whites of halogen lamps appear yellow.

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Native Resolution

Refers to the physical number of pixels in a display device.

NTSC

(National Television System Committee) is an analog television system that utilizes frames displayed at a rate of 60 half frames (30 full frames) per second. Each frame consists of 484 lines out of a total of 525 (The remaining lines are used for other various information). The NTSC system interlaces its scanlines, drawing odd-numbered scanlines in odd-numbered fields and even-numbered scanlines in even-numbered fields. The NTSC standard is predominately used in Canada, Japan, North Korea, and the United States.

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PAL

(Phase Alternating Line) is an analog television system that utilizes frames displayed at a rate of 50 half frames (25 full frames) per second. Each frame consists of 576 lines out of a total 625 (The remaining lines are used for other various information). The PAL standard is used predominately through-out Europe.

Plasma

is a thin, flat panel display device. Plasma displays work by maintaining a neon/xenon gas mixture between two sealed glass plates with parallel electrodes deposited on their surfaces. The plates are sealed so that the electrodes form right angles, creating pixels. When the intersecting electrodes are charged, an electric current flows through the gas in the cell, which stimulates gas atoms to produce UV radiation. The UV radiation activates color phosphors and visible light is emitted from each pixel.

POLY-SI (Silicon) LCD

Poly-Si is a popular LCD technology for high-end LCD projectors. Monochrome Poly-Si LCDs are typically placed in each of the three-color light paths inside a projector (one each for red, green and blue). This results in increased color saturation with contrast ratios above 200:1. Poly-Si technology is also a bit faster than the Active Matrix TFT.

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QXGA

(Quantum Extended Graphics Array) 2048 x 1536, a resolution that supports up to 3,145,728 pixels.

QAM

(Quadrature Amplitude Modulation) a format by which digital cable channels are encoded and transmitted via cable. It allows a direct reception of digital cable channels without the use of an external box. QAM tuners can be likened to the cable equivalent of the ATSC tuner.

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Resolution

The number of individual pixels that a device uses to create an image on the display screen. More pixels result in a higher resolution because each pixel is smaller and less visible. Smaller pixels produce a more detailed and better quality picture.

RGB

(Red Green Blue) a type of video standard that consists of three separate signals (red, green, and blue). RGB video is commonly used by computers and with computer monitors. RGB input is often referred to as computer input; RGB output is often referred to as computer output.

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SDTV

(Standard Definition Television) refers to television systems that have resolutions that meet DTV standards, but are not considered high definition. SDTV is typically a 480i (interlaced) signal. Digital cable and digital satellite programming is widely available in SDTV format. While SDTV does not reach near the quality of HDTV, it is superior over traditional analog television.

SECAM

Is an analog television system that utilizes frames displayed at a rate of 50 half frames (25 full frames) per second. Each frame consists of 576 lines out of a total 625 (The remaining lines are used for other various information). The SECAM television standard is used by France, Eastern Europe, Russia and several nations in Africa. Although similarities exist between the two, the SECAM color component is implemented differently than PAL color component. SECAM has a higher resolution than NTSC.

Subwoofer

A speaker that carries low frequencies or bass sound. Most speakers lack the capacity to project low frequencies making the subwoofer an essential part of a home theater.

The human ear can barely hear many of the low frequencies projected by a subwoofer, yet its frequencies can be felt. Many modern day filmmakers depend on LFE (Low Frequency Effects) to heighten the tension or drama.

Surround Sound

A term used to describe a type of audio output in which the sound seems to "surround" the listener. Surround sound systems use two, three, or more channels or speakers positioned around the listener to create a surrounding effect of sound. Surround sound systems have become more popular with the rise of home theater systems.

SVGA

(Super Video Graphics Array) 800 x 600, a resolution that supports up to 480,000 pixels.

SXGA

(Super Extended Graphics Array) 1280 x 1024, a resolution that supports up to 1,310,720 pixels.

S-Video

S-Video is a video transmission standard that uses a 4-pin mini-DIN connector to send video information on two signal wires called luminance (brightness, Y) and chrominance (color, C). S-Video is also referred to as Y/C.

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TFT

(Thin Film Transistor) a type of LCD flat-panel display screen. Since each pixel is controlled by individual transistors, crosstalk between pixels is reduced which improves image stability. TFT screens provide the best resolution of all the flat-panel techniques and it is also the most expensive. TFT screens are sometimes referred to as active-matrix LCDs.

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Universal Remote Control

a universal remote allows you to combine all your remotes into one. All universal remotes are either pre-programmed with codes from the factory or permit you to program codes into the remote. Remember to select a remote with enough programmability and memory for all its necessary functions.

UXGA

(Ultra Extended Graphics Array) 1600 x 1200, a resolution that supports up to 1,920,000 pixels.

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VCHIP

An electronic blocking device that can control programming to prevent viewing of questionable content. Programs can be screened according to age and content-based ratings through the easy-to-use on screen display.

VGA

(Video Graphics Array) 640 x 480, a resolution that supports up to 307,200 pixels.

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Wi-Fi

(Wireless Fidelity) a standard based on 802.11 protocol for wireless local area networks (WLAN). It was developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE). There are four specifications in the family: 802.11, 802.11a, 802.11b, and 802.11g. All four use the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision avoidance) for path sharing.

Wi-Fi (802.11a)

An IEEE specification for wireless networking that operates in the 5 GHz frequency range (5.725 GHz to 5.850 GHz) with a maximum 54 Mbps data transfer rate. The 5 GHz frequency band is not as crowded as the 2.4 GHz frequency because the 802.11a specification offers more radio channels than the 802.11b. These additional channels can help avoid radio and microwave interference.

Wi-Fi (802.11b)

Is the international standard for wireless networking that operates in the 2.4 GHz frequency range (2.4 GHz to 2.4835 GHz) and provides a through out of up to 11 Mbps. This is a very commonly used frequency. Microwave ovens, cordless phones, Bluetooth devices and medical and scientific equipment all work within the 2.4 GHz frequency band.

Wi-Fi (802.11g)

a new higher speed standard called 802.11g features complete backwards compatibility with 802.11b but it boosts the network speed to 54 Mbps.

WSXGA

(Wide Super Extended Graphics Array) 1920 x 1080, a resolution that supports up to 2,073,600 pixels.

WUXGA

(Wide Ultra Extended Graphics Array) 1920 x 1200, a resolution that supports approximately 2,304,000 pixels with a native 16:10 aspect ratio.

WVGA

(Wide Video Graphics Array) (apx.) 854 x (apx.) 480, a resolution that supports approximately 400,000 pixels.

WXGA

(Wide Extended Graphics Array) term used to describe several resolutions including; 1280 x 720, 1280 x 768, 1365 x 768, and 1024 x 1024.

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XGA

(Extended Graphics Array) 1024 x 768, a resolution that supports up to 786,432 pixels.

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Zoom Lens Ratio

The zoom lens ratio is the ratio between the smallest and largest image that a lens can project from a fixed distance. For example, a 1.4:1 zoom lens ratio means that a ten-foot image without zoom would be a 14-foot image with full zoom. Conversely, a ten-foot diagonal image at 15 feet with no zoom would still be a ten image at 21 feet at maximum zoom (15 x 1.4 = 21 feet).

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