Glossary of Home Theater Terms

Active display area - the area on the face of the CRT that the image is displayed upon

A/D - Analog to digital conversion (or converter). Used at transmission end of broadcast.

Addressable Resolution - The highest resolution signal that a display device (TV or monitor) can accept. The device, however, may not be capable of displaying this resolution.

Advanced Television Systems Committee - Also known as ATSC, the committee responsible for digital television standards and development, as well as all 18 formats of DTV.

Analog TV - "Standard" television broadcasts analog TV. Analog signals vary continuously, representing fluctuations in color and brightness.

Anti-static - An adjective describing the class of materials which includes conductive materials that do not allow an electrical field to be built up or stored upon themselves. With an anti-static coating on the monitor’s CRT surface, no static electricity is built up, therefore, upon touching the CRT the end-user is not shocked and there is reduced dust build up.

Application-specific integrated circuit - ("ASIC") refers to an integrated circuit uniquely designed and fabricated for a particular product application. Highly sophisticated electronic products can be economically produced where high production volumes justify the initial integrated circuit design and tooling costs.

Artifacts - Unwanted visible effects in the picture created by disturbances in the transmission or image processing, such as 'edge crawl' or 'hanging dots' in analog pictures, or 'pixelation' in digital pictures.

Aspect Ratio - Refers to the width of a picture relative to its height. If an NTSC picture is 4 feet wide, it will be 3 feet high; thus it has a 4:3 aspect ratio. HDTV has a 16:9 aspect ratio.

ATV - "Advanced Television" is an earlier term used to describe the development and advance applications of digital television, now simply referred to as DTV.

Augmented Reality - or Enhanced Reality refers to a display in which simulated imagery, graphics, or symbology is superimposed on a view of the surrounding environment.

Barrel - the appearance of curved edges of the display image outwards. See pincushion.

Bandwidth - For monitors, bandwidth refers to the highest signal frequency a monitor’s circuit can display. The higher the bandwidth, the higher the resolution and the sharper the image will be.

Beam - The electron beam in the CRT, which makes contact with the phosphors on the CRT surface, activates them and causes them to produce different red, green and blue light depending on the phosphor.

Brightness - refers to the attribute of a visual sensation by which a stimulus appears more or less intense or appears to emit more or less light. (Brightness is not a photometric standard and should not be used in conjunction with photometric units such as foot lamberts.)

Channel - A 6 Mhz (bandwidth) section of broadcasting spectrum allocated for one analog NTSC transmission.

Composite Video - An analog, encoded video signal (such as NTSC) that includes vertical and horizontal synchronizing information. Since both luminance (brightness) and chrominance (color) signals are encoded together, only a single connection wire is needed (i.e. RCA cables).

Component Video Connection - The output of a video device (such as a DTV set-top box), or the input of a DTV receiver or monitor consisting of 3 primary color signals: red, green, and blue that together convey all necessary picture information. With current consumer video products, the 3 component signals have been translated into luminance (Y) and two color difference signals (PP, PR), each on a separate wire.

Composite Video Output - The monitor receives only one signal from the computer. The monitor must then decode the signal to determine and separate red, green and blue sync signals that can then be produced by the monitor.

Compression - A method of electronically reducing the number of bits required to store or transmit data within a specified time or space. The video industry uses several types of compression methods but the method adopted for DTV is called MPEG2.

Contrast - refers to the ratio of the brightest part of an image versus the darkest part of an image (for example, 100:1).

Convergence - The color monitor’s ability to scan the three electron beams (red, green and blue) onto a single point and thus producing a white dot.

Color Wheel - Central to DLP technology’s unique color filtration process, the color wheel is a small rotating disk composed of red, green and blue filters. The DMD (digital micromirror device) briefly creates an image for each color. The viewer’s eye combines these images to form a complete picture. Because the color wheel rotates at speeds exceeding 120 revolutions per second, it is impossible to distinguish the individual color images.

CRT - Cathode Ray Tube

CRT Projectors - A front projection method similar to LCD, CRT (cathode ray tube) projectors output three identical images in red, green, and blue. The three images are then combined to create the final projected image.

Digital Television (DTV) - Refers to all formats of digital television, including high definition television (HDTV), and standard definition television (SDTV). Also referred to as ATV (advanced TV).

Digital Light Processing (DLP) - DLP™ technology delivers the clearest, sharpest, brightest, 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. DLP Cinema™ technology, which delivers large screen images that are superior in many respects to film, is helping to revolutionize the movie industry.

Digital Micromirror Device (DMD) - The Digital Micromirror Device is an optical semiconductor chip populated with more than a million hinged, microscopic mirrors which operate as optical switches to create a high resolution, full-color image.

DILA Projectors - Short for Digital Direct Drive Light Amplifier, DILA projectors employ microchip technology to create high definition pictures. The DILA chip integrates an improved fixed matrix display technology designed to reduce grid patterns and produce a bright picture.

Direct view display - refers to a display viewed without aid of additional optics or magnification by the unaided eye of the user. The size of the image produced by the display is the actual size viewed by the user.

Display format - refers to display addressability (e.g., 640 x 480), aspect ratio (e.g., 4:3), or video standard (e.g. VGA).

DLP Projectors - DLP (Digital Light Processing) projectors are the future of home theater projectors. DLP-based projectors are among the brightest, most reliable projectors in the industry.
At the heart of DLP technology is the Digital Micromirror Device (DMD) optical <semiconductor chip>. The DMD switch has an array of up to 1,310,000 hinged, microscopic mirrors that operate as optical switches to create a high-resolution image.

DTS - Digital Theater Systems sound. Discrete 5.1 channel surround system similar but not the same as Dolby Digital. Dolby Digital is the DTV standard, but DTS competes with it on DVD and in the movie theaters.

Dot Pitch - The distance of one phosphor dot to the nearest dot of the same color on the adjacent line.

Downconvert - A term used to describe the format conversion from a higher resolution input signal number to a lower display number, such as 1080i input to 480i display.

DVD Player (Digital Video Disc) - An integral part of many home theater systems, DVD players use digital technology for a quality viewing experience. DVD movies generally contain features including Dolby Digital Sound, several language tracks, and wide screen or normal viewing options on a single DVD-video disc.

Electronic Guns - The device in the CRT that produces the electron beam that is attracted to the phosphors on the face of the CRT; this activates the phosphors thus causing them to emit red, green or blue light.

Electrostatic - Stand alone electronically charged particles that build up on the CRT surface.

ELF - Extremely low frequency. For magnetic fields and alternating electric fields, the ELF fields range from 5Hz to 2Khz.

Emission - The emitting of different types of radio frequencies, magnetic fields and light.

Emissive displays - refer to a broad category of display technologies which generates its own light. Emissive display technologies include organic light emitting diodes, electroluminescent, field emission, plasma, and vacuum fluorescent. In contrast non-emissive displays require a separate, external source of light (such as the backlight of a liquid crystal display).

EPG - Electronic program guide. An on-screen display of channels and program data.

Ergonomic - Applies biological and engineering solutions to problems relating to the individual and their working relationship with machines.

FCC - Federal Communications Commission. The U.S. commission regulates the radio frequencies over the airwaves.

Field emission display ("FED") - refers to a flat vacuum tube display built with a multitude of tiny electron guns (micro-tip emitters) placed in a high vacuum environment. Its operation is similar to that of the CRT, in which electrons from a cold cathode are focused on a screen to create an image. Emission of electrons from the cold cathode occurs in response to an applied voltage.


Field emission - refers to the release of electrons from a surface when it is subjected to a very strong electric field.


Field of View (FOV) - describes how large the virtual image can appear to be to the viewer and is measured in degrees. >50 degree FOV per eye is possible using OLED microdisplays.


Flat-panel display - refers to video displays used in lap top computers and other devices where the monitor is desired to be as thin as possible.

Frequency - The number of times per second that a signal fluctuates. The international unit for frequency is the hertz (Hz). One thousand hertz equals 1 KHz (kilohertz). One million hertz equals 1 MHz (megahertz). One billion hertz equals 1 GHz (gigahertz). Television is broadcast in frequencies ranging from 54 MHz to 216 MHz (VHF) and 470 MHz to 806 MHz (UHF).

Frequency Range - the high and low limits of the frequencies that can be used with your monitor. Usually pertains to horizontal and vertical sync ranges.

Full-scan - The Capability to increase the size of the image to the edge of the monitor bezel.

Front Projection TV - Front projection is a method of viewing that utilizes a video projector from the ceiling. The image is projected onto a separate unit, typically a retractable movie screen. The front projection method allows for projection onto screen sizes that can exceed 300 inches. Front projection methods include DLP, CRT and LCD.

Head-mounted display - or helmet mounted display ("HMD") or Head-wearable display ("HWD") refers to a diverse family of viewing systems where one or more displays and sets of optics are attached to the head (head-mount display) or an accessory. For example, they can be designed into helmets, hardhats, or eyeglasses. Images can be projected into one eye (monocular) or both eyes (binocular).

High Definition Television (HDTV) - The generally agreed upon definition of HDTV is approximately twice the vertical and horizontal picture resolution of today's NTSC TV, which essentially makes the picture twice as sharp. HDTV also has a screen ratio of 16:9 as compared with most of today's TV screens, which have a screen ratio of 4:3. HDTV offers reduced motion artifacts (i.e. ghosting, dot crawl), and offers 5.1 independent channels of CD-quality stereo surround sound, (also referred to as AC-3).

Home Theater Receiver - The receiver is the heart of home theater systems, typically consisting of an amplifier, decoder, AM/FM tuner, audio/video switcher, and decoder.

Home Theater Screen - The home theater screen is what an image is projected onto. A high-quality screen contributes to a crisp, clear image. Front projection systems require a separate home theater screen to be utilized.

Home Theater System - A home theater system refers to a group of electronics set up in one’s home for the presentation of high-quality images and sound. Electronics that are typically found in home theater system setups include a VCR, stereo television or HDTV, receiver, and DVD.

Horizontal Frequency - The inverse of the time it takes for a monitor to scan from the beginning of one line to the beginning of the next line; typically stated in kilohertz.

Interlaced Scanning - In a television display, interlaced scanning refers to the process of re-assembling a picture from a series of electrical (video) signals. The "standard" NTSC system uses 525 scanning lines to create a picture (frame). The frame/picture is made up of two fields: The first field has 262.5 odd lines (1,3,5...) and the second field has 262.5 even lines (2,4,6...). The odd lines are scanned (or painted on the screen) in 1/60th of a second and the even lines follow in the next 1/60th of a second. This presents an entire frame/picture of 525 lines in 1/30th of a second.

Invar Shadow Mask - A monitor technology where light is emitted through a heat resistant metal sheet containing numerous holes. Basically, this thin sheet of metal has holes corresponding to each phosphor dot on the CRT and causes the correct red, green and blue electron gun beam to hit the correct color phosphor.

Image quality - refers to an objective measurement or subjective rating of the quality of a display system.

KHz (Kilohertz) - A unit of frequency equal to one thousand cycles per second.

Lambertian - light output means that the intensity of light is the same in all directions. This permits viewing from many angles and allows compact lens systems with large exit pupils to be built. A large exit pupil permits the virtual image to be seen from a larger range of angles and keeps the image stable as the pupil moves. Large exit pupil is important for long term ease of viewing with minimal fatigue.

LCD Projectors - A method of front projection, LCD projection works by separating the image into red, green, and blue. The colors are then recombined before the image is projected through the lens.

"LEP" - is an acronym for polymer-based organic light emitting diodes, derived from "light emitting polymers."

Letterbox - The term used to describe the way a 16:9 aspect ratio image is displayed on a 4:3 screen, where black areas are visible above and below the image.

Light emitting diodes ("LED") - refers to a semiconductor device which emits light when current flows through the device. An LED is formed when p-type and n-type materials are joined. These devices have a preferred current direction. When a voltage is applied, causing electrons to flow through the structure, electrons flow into the p-type material, and holes flow into the n-type material

Liquid crystal display ("LCD") - refers to a display which uses liquid crystals with optical polarization properties that can be altered by an applied electric field. The liquid crystal materials absorb or transmit light depending on the polarization, and thus function as "light valves." In an active matrix liquid crystal display ("AMLCD"), each valve is individually controlled.

Luminance - refers to the amount of visually effective light emitted by an extended source. Typically expressed in nits, footlamberts (fL) or candelas per square meter (cd/m2).

Magnetic Field - A state produced in a medium, either by electrical current flow in a conductor or by permanent magnet, that can induce voltage in a second conductor.

MHz (Megahertz) - A unit of frequency equal to one million cycles per second.

Micro-mirror - refers to a display using a large number of small mirrors which are deflected to direct light toward or away from the viewer.

Microstructural - refers to structures near to or smaller than a few micrometers in size.

Microdisplay, or Miniature display - refers to small displays that are of such high resolution that they are only practically viewed or projected with lenses or mirrors. Microdisplays are typically magnified by optics to enlarge the image viewed by the user. For example, a miniature display smaller than 1 inch in size may be magnified to provide a 12 inch to 60 inch viewing area.

Monochrome - refers to a display that emits a single hue but may vary in intensity and saturation. For example, monochrome miniature displays used in many HMDs are typically green and are used to display symbology or sensor imagery.

MPR - A rating factor by the Swedish National Board of Measurement and Testing. This council produces the recommendations for the magnetic and electrical field emissions guidelines. The council’s name has been changed to SWEDAC.

Multiscan Monitor - Monitors that are capable of displaying a range of resolutions or graphics standards having different horizontal and vertical frequencies.

Nit - refers to a measure of luminance equivalent to 1 Cd/m2, 1fL = 3.42626 nits.

Non-emissive displays - refers to a broad category of displays which absorb or block light from a separate light source. Liquid crystal, electrochromatic, electrophoretic, ferroelectric, and micro-mirror displays fall in this category.

Non-Interlaced(Progressive Scan) - Each line is scanned during each total vertical (full) screen refresh.

"OEM" - is an acronym for "original equipment manufacturer". OEMs manufacture components and sub-assemblies which are purchased by companies which integrate the components and sub-assemblies into final products.

Organic light emitting diode (OLED) - refers to a type of display which uses organic material as a diode type light emitting material. The operating principal of OLED devices is current injection. For comparison, the operational principal of inorganic LEDs is collisional excitement due to an electric field. There are two categories of OLEDs: small molecule and polymer-based.

Personal - Viewer TM refers to Headset Monitor incorporating a flat panel display that provides data or video images privately to an individual via a virtual computer screen.

Phosphor - Phosphorescent substance of red, green and blue that emit light when activated by electrons.

Plasma displays - refer to displays which emit light from electrically excited gas mixtures. Color plasma displays use phosphors which absorb ultraviolet light that is generated by special gas mixtures.

Plasma Flat Panel Television - Ultra-thin plasma television displays make for easy placement within home theater systems. The plasma technology allows for brightness, clarity, and a viewing range of 160 degrees. The flat-panel display consists of millions of phosphor-coated miniature glass bubbles containing plasma. An electric current flows through the screen causing certain plasma-containing bubbles to emit ultraviolet rays, triggering the phosphor coating to produce the proper color (red, green, or blue).

Pin Cushion - The appearance of curved edges on the display image inward.

Pixel - is a contraction of "picture element" and refers to a single dot of light that is the smallest individually addressable unit of an image that can be displayed.

Polymer based OLEDs - refers to a category of organic light emitting diodes. When a current is passed through a cell, the polymer's molecular structure is excited, creating light emission. The output efficiency of this process is within the spectrum from blue to infrared.

Polymeric display - refers to a display using light emission from polymers when an electric current is passed through the material or polymer diode.

Progressive Scan - the way a screen displays the image you see before you in a full picture per each frame, rather then the interlaced method in which it shows you the odd lines, then even. This shows you all lines at once. Ex: Computer Monitor

Projection TV - Projection TVs create a miniature picture inside the projector. In rear projection systems, the image is then shone onto a large screen located within the television unit itself. Front projection systems instead shine the image onto a screen that is separate from the television unit.

Resolution - refers to pixel density (number of pixels) or dot pitch (measured in micrometers or millimeters). Resolution is typically referenced by Rows x Columns. Commonly used resolutions include ¼ VGA (240 x 320), VGA (480 x 640), SVGA (600 x 800), XGA (768 x 1024), and SXGA (1024 x 1280). eMagin using modified nomenclature by adding a + for its color SVGA+ (852 x 600) and XGA+ (1066 x 768) designs being developed.

"RF" - applications refers to radio frequency, or very high frequency and millimeter wavelength.

Rear Projection TV - Rear projection is a method of projection that combines a projector and viewing screen into one television unit.

RGB - refers to red, green, and blue pixel combinations used to create full color.

"SBIR" - Program refers to the U.S. Government's Small Business Innovation Research program which promotes the use of small businesses for research. It is a highly competitive program whereby small business are awarded research funds targeted for technical solutions to meet the needs of various Government Departments. The Company has been awarded more than 5 SBIR programs, and is currently performing a Phase III program.

Screen Gain - Screen gain refers to a projected image’s level of brightness on a screen. A low screen gain displays a dark screen image. Conversely, a bright screen image indicates a high screen gain.

Set-top Box (DTV STB) - A unit similar to today's cable boxes, which is capable of receiving and decoding DTV broadcasts. A DTV 'Certified' STB can receive all 18 ATSC DTV formats and provide a displayable picture.

Spectrum - A range of frequencies available for over-the-air transmission.

Standard Definition Television (SDTV) - Digitally transmitted SDTV includes 480 line resolution in both interlaced and progressively scanned formats. It offers significant improvement over today's conventional NTSC picture resolution, and is similar to DVD or DBS quality because the digital transmission eliminates snow and ghosts, which can be common with the current NTSC TV format. Also, thanks to digital compression technology, several programs can be transmitted simultaneously within the same channel.

S-Video - Separated video. An encoded video signal which separates the brightness from color data. S-video can greatly improve the picture when connecting TVs to any high quality video source such as digital broadcast satellite (DBS) and DVDs.

Subwoofer - A subwoofer is an individual speaker commonly found in home theater sound systems that processes bass sounds as low as 15 hertz.

Surround Sound - Surround sound refers to a sound system arrangement designed to literally “envelop” the listener with sound.

UHF - Ultra high frequency, the range used by TV channels 14 through 69.

Upconvert - The term used to describe the conversion of a lower apparent resolution to a higher number, such as "upconverting" 720p to 1080i. This is a misnomer, though, since to accomplish this, the horizontal scanning frequency is actually lowered from 45kHz to 33.75kHz. Resolution quality is not improved by this method.

Vacuum fluorescent - display refers to a display using hot wire electron emission which is directed toward a cathodoluminescent phosphor to emit light. These displays are found in some clock radios and automobile indicators.

VHF - Very high frequency, the range used by TV channels 2 through 13.


Viewing Angle - A screen’s viewing range indicates the maximum angle that an image can be viewed at from an off-center point.


Virtual reality ("VR") - or artificial reality refers to an electronic system which is designed to create a simulated environment around the viewer. Such as system must be interactive with the user to be considered true VR.


Y, PB, PR - Generally used where a digital TV signal source is employed. The video signal is separated into its component parts of brightness and color differentials. The most advanced method for interconnecting decoded video data.

Y, U, V - Also sometimes referred to as Y, Cr, Cb, where a video signal is separated into components of brightness and color, arguably to a degree more advanced than S-video.