A work in progress

This Glossary is a concise collection of some of the terminology that you may confront; it is not intended to be a complete compendium of technical terms.


N

Native Resolution

The resolution at which a TV or monitor is designed to display images. Image signals higher or lower than a specified native resolution must be converted to be displayed accurately. For example, a TV with a native resolution of 1080i can display 1080i images but may upconvert 480p images to 1080i. In contrast, a TV with a native resolution of 480p must downconvert a 1080i signal to 480p for display. CRT-based projection TVs can have more than one native resolution, but fixed-pixel displays such as LCD and DLP are limited to display one resolution and convert all others.

Neo:6

Neo:6 decodes the conventional 2 ­channel sources for 6­ channel playback by the specific decoder. It enables playback with the full ­range channels with higher separation just like digital discrete signal playback. There are two modes available: “Music mode” for music sources and “Cinema mode” for movie sources.

Neural Surround

Neural Surround represents the latest advancement in surround technology and has been adopted by XM Satellite Radio for digital radio broadcast of surround recordings and live events in surround sound. Neural Surround™ employs psychoacoustic frequency domain processing which allows delivery of a more detailed sound stage with superior channel separation and localization of audio elements. System playback is scalable from 5.1 to 7.1 multi­channel surround playback.

Nit

A measurement of brightness. A nit is equal to one candela per square meter. The more nits, the greater the brightness.

Noninterlaced

A cathode-ray tube (CRT) display in which the electron guns paint every line on the screen each time they scan from top to bottom. This type of monitor produces less flicker than do interlaced displays.

Normalize

A process that adjusts the volume of a sound recording so that it plays back at a consistent volume.

NTSC

National Television Systems Committee, This body was established by the Federal Communications Commission (FCC) to set television and video standards in the United States. (The predominant standards outside the United States are PAL and SECAM.) The acronym refers to the television broadcast standard, which specifies 525 lines of resolution per second for broadcasts, and it combines blue, red, and green signals with an FM frequency for audio. NTSC should eventually be succeeded by HDTV (high-definition TV).

O

OLED

Organic Light-Emitting Diode, A display device that operates by sandwiching carbon-based films between two charged electrodes. OLED displays, originally developed by Kodak, are unlike LCDs in that they don't require backlighting; instead, they emit light themselves. OLED displays offer many advantages over LCDs, including less power consumption and brighter output.

Optical Fiber

A medium used for high-bandwidth data transmission in telecommunications and networking. Optical-fiber cables consist of bundles of thin glass or plastic filaments that carry beams of light. A laser transmitter encodes frequency signals into pulses of light and sends them down the optical fiber to a receiver, which translates the light signals back into frequencies. Less susceptible to noise and interference than other kinds of cable, optical fibers can transmit data for greater distances without requiring signal amplification. But because the filaments are fragile, optical-fiber cables must be run underground, which makes them expensive to install.

OSD

Onscreen Display, A dialog box that appears on a television screen and gives you access to display options and other functions, such as parental controls.

P

PAL

Phase Alternation Line, The television broadcast standard used in the U.K. and in many European countries. This standard specifies broadcasts of 625 horizontal lines of resolution per second, nearly 20 percent more than the U.S. standard, NTSC, of 525 lines.

Pan-And-Scan

Process of transferring a movie or other source material to videocassette, DVD, or broadcast so that it fits the 4:3 aspect ratio of most current TVs. This results in a significant amount of lost picture information, particularly in the width of the image, and sometimes involves panning unnaturally across the frame. At the beginning of a movie, there is often a disclaimer about the movie having been "...formatted to fit your TV." That means it's been converted to pan-and-scan.

Passive Radiator

A radiating surface (usually similar to a conventional speaker cone) that is not electrically driven but shares the same air space in a sealed cabinet withan electrically driven loudspeaker. This arrangement is functionally similar to a loudspeaker with a vented (ported) cabinet, with the passive radiator serving the duties of the air in the port.

PCM (Linear PCM)

PCM: “Pulse Code Modulation”. A specific way of transmitting digital sound information from one place to another. The PCM ‘style’ of data transmission sends the info “uncompressed”. This means that when it is sent from the data source (a Blu-ray disc, CD, etc.) to a piece of audio equipment – it can be instantly ‘read’ and played. Compressed data has been previously ‘packaged’, or squashed down to save space on the disc. Compressed data must be Decompressed (or “decoded”) in order to be ‘read’ – like boxing up your book collection when you move, you must unpack your books before you can read them again. PCM is different. Since the data has not been ‘boxed up’, it does not have to be ‘unboxed’ (or “decoded”) before it is usable. See Compression.

Pillar Box

The pillar box effect occurs in widescreen video displays when black bars (mattes or masking) are placed on the sides of the image.

Pixel

A single point on a computer display. In a CRT monitor, each pixel is a blend of red, green, and blue phosphor dots that are activated by electron guns. In a LCD monitor, each point in the display grid constitutes a pixel. The term is a contraction of picture element.

Pixelation

Pixelation occurs when a monitor doesn't have enough video memory to enable it to render graphics properly. The result is that you can see individual pixels: the graphics have jaggy edges.

Plasma Display Panel

An emissive flat-screen technology in which ionized gas is sandwiched between panels of glass that are embedded with wire. The wires meet at right angles, creating pixels. Images are created by sending an electrical current through selected intersections, causing the gas to break down at those points and produce plasma discharges that excite nearby phosphors and cause them to glow. These displays are slim (about 4 inches deep) and can be created in sizes as large as 60 inches diagonally; they are generally used in flat-panel TVs.

Posterization

Occurs when the color depth, sometimes called bit depth, is insufficient to accurately sample a continuous gradation of color tone. As a result, a continuous gradient appears as a series of discrete steps or bands of color — hence the name. When discussing fixed pixel displays, such as LCD and plasma televisions, this effect is also referred to as false contouring.

Progressive Scan

A method of displaying images on a CRT monitor or a high-definition TV in which all the lines of a picture are drawn in one quick burst, from left to right and from top to bottom. Compare this to interlacing, in which every other line is displayed in two successive swoops to form a complete picture.

Projector

A projection unit, typically DLP or LCD, that projects an image on a wall or screen. Projectors are much smaller than standard display units and can create various screen sizes depending on distance from the screen. Until recently most HDTV projectors were 720p capable; 1080p units are now available.

PSIP: Program and System Information Protocol.

A part of the ATSC digital television specification that enables a DTV receiver to identify program information from the station and use it to create easy-to-recognize electronic program guides for the viewer at home. The PSIP generator inserts data related to channel selection and electronic program guides into the ATSC MPEG transport stream.

PVP

Personal video player. Portable device designed to play back video files from a hard drive; may or may not include a small LCD screen.

PVR

Personal video recorder.

Q

Q

The magnification or resonance factor of any resonant device or circuit. Also the width of affected frequencies in an equalizer. Shaped somewhat like an adjustable width bell curve.

QAM

Quadrature Amplitude Modulation. Type of digital cable tuner. Televisions and other products equipped with QAM tuners can tune unscrambled digital cable channels from some cable providers, but to view scrambled channels a CableCard is required.

Quadrature Phase Shift Keying

A digital frequency modulation technique used for sending data over coaxial cable and digital satellite networks. Since it's both easy to implement and fairly resistant to noise, QPSK is used primarily for sending data from the cable subscriber upstream to the Internet.

R

Rainbow Effect

A visual artifact that occurs in single-chip DLP displays, caused by the fact that the single DLP chip uses a color wheel to create red, green, and blue, and hence all colors. Occurs primarily when the eye looks across the screen or when adjacent areas of very dark and very light material move quickly. The occurrence of these rainbows has been significantly reduced with the advent of newer, faster color wheels, and most people who watch a DLP never see rainbows at all--and the few who do, usually see them only occasionally.

Rear Projection

TV system where the picture is projected onto the rear of a translucent screen via a series of mirrors and viewed as you would an average television.

Red Push

Tendency of the color decoder in many TVs to accentuate the color of red compared to blue and green. Red push is typically introduced intentionally to compensate for an overly blue color temperature.

Refresh Rate

The maximum number of times per second that a monitor can redraw an image. The refresh rate, expressed in hertz (Hz). The higher the refresh rate, the easier the monitor is to view; rates lower than 75Hz can produce irritating screen flicker.

Resolution

A measurement of the finest (smallest) detail that is visible, or can be resolved, in a video image. TV Resolutions may be expressed as "number of pixels" in an image; or more commonly, "As Total Number of (horizontally scanned) Lines used to create the image.

While a TV's Resolution can be influenced by the number of pixels in the image, it is important to note that the pixel numbers do not define ultimate resolution; ONLY the resolution of that part of the equipment. Many other variables must be taken into account - such as, the quality of lenses, display tubes, film process and film scanners, etc. used to produce the image on the screen - as well as what measurement-methods are used.

Resonant Frequency

The frequency at which any system vibrates naturally when excited by a stimulus. A tuning fork, for example, resonates at a specific frequency when struck.

Return Loss

The ratio of signal power transmitted into a system, to the power reflected or returned. This is like an echo that is reflected back by impedance changes in the system.

Variation in impedance from the source results in some returned signal. Cabling systems lack perfect impedance structure and matching, and have a measurable return loss. At every connection, the potential exists that the impedance will change, resulting in part of the signal being reflected back to the source. Each impedance change contributes to signal loss (attenuation) and directly causes return loss.

Reverberation

The reflections of sound within a closed space.

Reverberation Time

The amount of time it takes the reverberation to decay 60 dB from the level of the original sound.

RGB

The abbreviation for red, green and blue signals, the primary colors of light (and television). Cameras and telecines have red, blue and green receptors, the TV screen has red, green and blue phosphors illuminated by red, green and blue guns. Much of the picture monitoring in a production center is in RGB. RGB is digitized with 4:4:4 sampling which occupies 50 percent more data than 4:2:2.

Ribbon Speaker

A loudspeaker that consists of a thin, corrugated, metallic ribbon suspended in a magnetic field. The ribbon acts electrically like a low-impedance voice

coil and mechanically as a diaphragm.

S

Saturation

Refers to the amount of color in a picture. Zero saturation results in a black-and-white picture, while too much saturation results in garish colors.

Scaler

Circuitry or device that converts a video signal to a resolution other than its original format. Scaling can involve upconversion or downconversion, and may also include a conversion between progressive- and interlaced-scan formats. A scaler can be built into a TV, an HDTV set-top box, a DVD player, or another video source, or it may be a standalone component.

Scan velocity Modulation (SVM)

TV feature; a circuit that increases the speed of electrons to their respective phosphor dots. Often produces an artificial "hard edge," which is why it should be switched off for sources such as DVD and HDTV. Used in professional projectors as a form of dithering to reduce the visibility of scan lines. Also called velocity scan modulation or, generically, edge enhancement.

SDTV

Standard-definition television. Digital television format that includes 480-line resolution in both interlaced (480i) and progressively scanned (480p) formats; offers discernible improvement over conventional analog NTSC picture resolution, with less noise; similar to DVD or satellite TV quality but not considered high-definition television (HDTV).

SECAM

Sequential Couleur Avec Mémoire, Also called Système Électronique Couleur Avec Memoire, or sequential color with memory. Analog color television broadcast standard developed in the mid-1960s and used in France, its former possessions, and some eastern European countries, including former members of the Soviet Union; offers 819 lines of horizontal resolution. SECAM is one of three main television standards; the other two are NTSC and PAL.

SED

Surface-Conduction Electron-Emitter Display, A display technology developed by Toshiba and Canon that uses phosphors activated by an electron emitter, just as standard CRT tube televisions do. Supposedly, the result is tube-level picture quality in a flat form factor. SED TVs are not yet available, but the partners claim these TVs will offer low power consumption, fast response time, and high resolution.

Selectable Aspect Ratios

TV feature, especially on a wide-screen and/or digital model, that allows the adjustment of screen proportions for the material being viewed; an image can be adjusted to fill the screen or to have blank bands placed at the top and bottom of a wide-screen image, or the left and right for a 4:3 image on a wide-screen set.

Selectable Color Temperature

Large-screen TV feature, especially a high-end set, that allows the adjustment of the color temperature.

Simsub

Simsub, or Simultaneous substitution is the practice by which cable, direct broadcast satellite and multichannel multipoint distribution service television distribution companies substitute a local or regional signal over a foreign or non-local signal, when two or more stations are airing the same programming at the same time. It is sometimes erroneously referred to as "simulcasting"; that term refers to the simultaneous broadcast of a program over two channels, regardless of whether or not there is signal replacement.

An interest, either of civic/national pride, or of protecting smaller commercial interests, is usually involved. The practice has close similarities between Canada and the United States.

Subpixel

Full-color displays are made by combining red, green, and blue light in varying degrees to produce different shades of colors. In a display with a fixed pixel structure, such as LCDs or plasma panels, the red, green, and blue light comes from adjacent cells in the display's physical structure. The light from these three subpixels--one for each color--combine to create a single pixel. There are also pixel structures that do not rely on three subpixels.

Subwoofer

A specialized speaker that reproduces sound from the lower frequencies of the audible spectrum, usually below 80Hz.

Surround Sound

A system for recording and reproducing sound that involves three or more channels and speakers. Such a system creates an environment in which the speaker is effectively surrounded by sound sources. In addition to being used in movie theaters, this type of arrangement is now available in the home. Surround-sound systems are available in digital and analog versions. Digital surround sound uses the 5.1 format to record sound. Dolby Pro Logic technology is used for analog surround sound.

T

Temporal Artifact

In a digital video image, a picture imperfection that occurs over several frames, often in smooth-textured areas and around high-contrast edges of moving video objects. Similar to spatial artifacts, both often referred to as mosquito noise.

Temporal Resolution

One of two possible ways to measure resolution in a video image; the other is spatial. Describes the amount of picture detail in a moving image, measured by the number of lines of resolution delivered over a given period of time. When an image moves rapidly, a 720p HDTV display will provide more picture information than a 1080i HDTV display because progressive scan produces twice as many frames in the same period of time as 1080i.

Terrestrial Broadcast

Standard over-the-air broadcasts, as opposed to satellite or cable transmission.

THD- Total Harmonic Distortion

Expressed as a percentage, it is the measurement of distortion caused by an electronic component related to the harmonics it generates relative to a fundamental frequency.


Throw Distance

Throw distance is the measurement from the projector's lens to the screen. A projector with a zoom lens will have a range of throw distances for any given image size, while a projector without a zoom lens will only be able to project one image size at a given distance from the screen. In Projector Central's articles, throw distance is normally quoted for a 100" diagonal screen.


THX - Tom Holman's eXperiment

A certification for audio equipment and installation done to a standard set by THX Ltd., a company owned by George Lucas. Usually geared towards audio playback for video and cinema.


THX Select

THX certification for speakers, receivers and DVD players designed for small to medium sized home theaters and non-dedicated rooms of around 2000 cubic feet and performing to a specified standard.

THX Select 2

THX certification specifically for receivers to a specified standard.


THX Ultra

Certification program for speakers, receivers, amplifiers and interconnects that are not room size dependent and performing to a specified standard.


THX Ultra 2

THX certification for speakers, receivers, controllers, DVD players for dedicated home theaters of about 3000 cubic feet which perform to a specified standard.

TosLink

A type of digital connection that uses optical signals to send a signal flawlessly, without losing any information. It's used for connecting MiniDisc players to stereos and certain sound cards.