Extron Glossary of Terms
Digital AV


1080i - Interlaced HDTV transmission standard. Refers to an active pixel rate of 1920x1080 with a vertical refresh rate of up to 60 fields (30 frames) per second for NTSC countries or 50 fields (25 frames) per second for PAL/SECAM countries.

1080p - Progressive-scan HDTV standard. Refers to an active pixel rate of 1920x1080 with a vertical refresh rate of up to 60 frames per second for NTSC countries or 50 frames per second for PAL/SECAM countries. 1080p is often stated with an associated frames-per-second rate, such as: 1080p24 (24 fps, progressive), 1080p30 (30 fps, progressive) and 1080p60 (60 fps, progressive). 1080p is extremely rare in broadcasting; for example, the ATSC standard provides bandwidth sufficient only for 1080p24 and 1080p30. Blu-ray and other pre-recorded high definition schemes can support full 1080p60 content playback.

2:2 film detection - The ability to determine whether PAL video has been converted from film using 2:2 pulldown. Film material with 2:2 pulldown may result in artifacts and jaggies when the video signal is deinterlaced. By using 2:2 film detection to determine if the material originated from film and was converted to PAL, the video processing algorithm can be used to optimize any video for deinterlacing so that the images are free of artifacts.

2:2 pulldown - See "2:2 film detection."

3:2 pulldown - The process of matching the frame rate of film (24 frames per second) to the frame rate of NTSC video (30 frames per second). In 3:2 pulldown, one frame of film is converted to three fields (1 1/2 frames) of video, and the next frame of film is converted to two fields (1 frame) of video. This cadence is repeated (3 fields, 2 fields, 3 fields, 2 fields . . .) until the film is fully converted to a video of approximately the same duration.

3:2 pulldown detection - A sophisticated technology in Extron scalers used to detect the presence of a 3:2 pulldown that helps maximize image detail and sharpness. When film-originated material is detected, this technology applies video processing algorithms that optimize image reproduction and avoids causing jaggies.

3G-SDI - The SMPTE signal standard for serial digital, high definition video with at 1920x1080 resolution and a 50Hz or 60Hz progressive frame rate. Up to 32 audio channels can be carried in the ancillary data. The 3G stands for 3 gigabits per second which is 2 times the bit rate of a 1.485 Gbit HDSDI signal. Also see "SMPTE 424M."

720p - Progressive-scan HDTV transmission standard. Refers to an active pixel rate of 1280x720 with a vertical refresh rate of 60 frames per second for NTSC countries or 50 frames per second for PAL/SECAM countries. The 720p standard also allows refresh rates of 24, 25, and 30 frames per second.

A/D - Analog to Digital (converter). A device that converts an analog signal to a digital value.

AACS – Advanced Access Content System - A digital rights management standard utilized with Blu-ray Disc and other optical formats. AACS incorporates two parts: a set of embedded decryption keys within the source device, and a set of keys encoded in the content that describes each of the playback devices licensed to utilize the content. This approach allows copyright holders to revoke the keys of a particular source device, thus preventing it from playing back future content. AACS also provides for a managed copy system, that is, a mechanism by which one or several, but not an unlimited number of copies can be legally made as backups, for storage on a media server, or for use on a portable device. The ICT – Image Constraint Token is a provision within AACS that allows the content provider to limit analog output resolutions.

AC-3 - See "Dolby® Digital."

ADC - Analog to Digital Converter. A device that converts analog signals to digital signals.

Adobe RGB - A color space specification developed by Adobe® Systems, Inc., offering a wider color gamut than sRGB. Adobe RGB is supported in Photoshop® and other Adobe software, as well as some digital cameras, printers, scanners, and displays.

AES – Advanced Encryption Standard - A data encryption standard adopted by the US Government and approved by the National Security Agency for top secret information. DCP, LLP, the licensing agency for HDCP, has adopted AES 128 encryption for the new HDCP 2.0 standard.

AES/EBU - Audio Engineering Society/European Broadcasting Union. A digital audio transfer standard. The AES and EBU developed the specifications for the standard. The AES/EBU digital interface is usually implemented using 3-pin XLR connectors, the same type of connector used in a professional microphone. One cable carries both left- and right-channel audio data to the receiving device. Also see "AES3."

AES3 - A digital audio standard defined by the Audio Engineering Society. The standard specifies several basic physical interconnections between devices:
- Balanced - 3-conductor, 110 ohm cabling with an XLR connector, typically referred to as “AES/EBU audio.”
- Unbalanced - 2-conductor, 75 ohm coaxial cable with an RCA connector, typically used in consumer audio applications. In many consumer products such as DVD players and A/V receivers, this is often referred to as a “digital coaxial” connection type.
- AES-3id - A professional version of the 2-conductor 75 ohm coaxial cable terminated with a BNC connector. AES3 unbalanced and AES-3id audio can be switched or routed using a video switcher with a minimum of 150 MHz (-3 dB, fully loaded) video bandwidth.
- Optical – Plastic optical fiber using an F05 style connector, typically used in consumer audio applications. In many consumer products, this is often referred to as a “digital optical” connection type. TOSLINK is the most common implementation of this connection type.

Analog Sunset - When used colloquially, may refer to the general trend of digital video technologies displacing analog, such as when US broadcast television switched to digital transmission, or the increasing use of DVI, HDMI, and DisplayPort video on PCs instead of RGB, etc. In a narrowly defined legal sense, the analog sunset refers to AACS licensing restrictions placed on Blu-ray Disc players where licensed players produced after 2010 must limit analog video output to standard definition, and licensed players produced after 2013 must not output any analog video, when playing protected content.

Apple Cinema Display - One of the first very high resolution monitors on the market and one of the first to utilize a dual-link DVI connection. The 30" version provides a native resolution of 2560x1600 pixels.

Aspect ratio - The relationship of the horizontal dimension to the vertical dimension of an image. In viewing screens, standard TV is 4:3, or 1.33:1; HDTV is 16:9, or 1.78:1. Sometimes the “:1” is implicit, making TV = 1.33 and HDTV = 1.78.

ATSC - Advanced Television Systems Committee. The ATSC was formed to establish voluntary technical standards for advanced television systems, including digital high definition television (HDTV). The ATSC is supported by its members, who are subject to certain qualification requirements.

Auto-Image™ - An Extron technology for scan converters and signal processors that simplifies setup by executing image sizing, centering, and filtering adjustments with a single button push.

Auto-input switching - The feature that enables a product to detect which input has an active sync signal and switch to that input.

Bandwidth - The total range of frequencies required to pass a specific signal without significant distortion or loss of data. In analog terms, the lower and upper frequency limits are defined as the half power, or -3 dB signal strength drop, compared to the signal strength of the middle frequency, or the maximum signal strength of any frequency, expressed as xx Hz to xx kHz (or MHz) @ -3 dB. In digital terms, it is the maximum bit rate at a specified error rate, expressed in bits per second (bps). A device's bandwidth should be wider than the highest possible bandwidth of the signals it may handle. (In general, the wider the bandwidth, the better the performance. However, bandwidth that is too wide may pass excessive noise with the signal.)

Bit - The shortened form of “binary digit” (0 or 1). A bit is the smallest unit of information in a computer.

Bit depth - The number of bits per pixel. Bit depth determines the number of shades of gray or variations of color that can be displayed by a computer monitor. For example, a monitor with a bit depth of 1 can display only black and white; a monitor with a bit depth of 16 can display 65,536 different colors; a monitor with a bit depth of 24 can display 16,777,216 colors

Bit Rate - The number of bits that are conveyed or processed per unit of time. The bit rate is quantified using the bits per second (bit/s or bps) unit, often in conjunction with an SI prefix such as kilo- (kbit/s or kbps), mega- (Mbit/s or Mbps), giga- (Gbit/s or Gbps).

Blu-ray Disc - An optical disc storage medium developed by Sony as the replacement for DVD. Blu-ray is capable of storing high-definition video, audio, and data with a capacity of 50GB per disc. Blu-ray players are backward-compatible with standard DVDs and audio CDs.

BT.2020 - Formally ITU-R Recommendation BT.2020, and also known as Rec. 2020. The international standard for Ultra HD video that specifies the 3840x2160 and 7680x4320 resolutions, color space parameters that define a much wider color gamut than previous specifications, frame rates up to 120 fps, color bit depth up to 36 bits per pixel, digital color encoding, chroma subsampling, and more.

BT.709 - Formally ITU-R Recommendation BT.709, and also known as Rec. 709. The international standard for high-definition video that specifies resolutions, frame rates, digital color encoding, color space parameters, and more.

CAT 5 - Category 5. Describes the network cabling standard that consists of four unshielded twisted pairs of copper wire terminated by RJ-45 connectors. CAT 5 cabling supports data rates up to 100 Mbps. CAT 5 is based on the EIA/TIA 568 Commercial Building Telecommunications Wiring Standard.

CAT 5e - Enhanced Category 5. The standard for the next higher grade of unshielded twisted pair (UTP) beyond Category 5. The CAT 5e specification was developed to provide more robust support for 1000Base-T. CAT 5e specifies tighter limits than CAT 5 for NEXT, ELFEXT, and return loss.

CAT 6 - Category 6. The standard for the next higher grade of unshielded twisted pair (UTP) cabling beyond CAT 5e. The standard defines components (cable and connecting hardware) and cabling (basic link and channel) for Category 6 channels, as well as Level III field tester requirements.

CAT 7 - Category 7. The cable standard for 10 Gigabit Ethernet using shielded twisted pair – STP) cable. Cat 7 features strict guidelines for crosstalk and system noise, requiring shielding for each pair of wires and the cable as a whole.

CCIR - Comite Consultatif International des Radio-Communications, the International Radio Consultative Committee. The CCIR has been superseded by the International Telecommunications Union, or ITU. Also see "ITU."

CCIR 601 - See "ITU-R BT.601."

CEC – Consumer Electronics Control - A bidirectional serial control bus defined in the HDMI 1.0 specification and subsequent updates. CEC is used to provide control for multiple products, connected via HDMI cables, from a single remote control. Alternately, one device, for example a Blu-ray Disc player, can turn on another device, such as a display, when put into Play mode. CEC command sets are proprietary to each manufacturer; Sony CEC commands cannot control devices from Panasonic or Sharp, and vice versa.

Cladding - In fiber optics, the outer layer surrounding the core of a fiber that serves as an optical barrier as well as protection for the core. The index of refraction for the cladding is always lower than that for the core in order to maintain total internal reflection and thus ensure that the light always travels within the core.

Cliff effect - The sudden or discrete loss of signal at a digital receiver due to the degradation of a transmitted signal that has been terminated due to an error rate being exceeded and the received signal being rejected.

Component digital - Digital video using separate color components, such as Y, Cb, Cr. Digital recording formats such as D1 (Sony, BTS/Philips) and D5 (Panasonic) utilize component digital recording technology. Component digital is the digital representation of the component analog signal set, Y, B-Y, R-Y; it is often represented as 4:2:2. The encoding parameters are specified by ITU-R BT.601-2 (formerly known as CCIR 601).

Compression - The art and science of reducing the amount of data required to represent a picture or a stream of pictures and sound before sending or storing it. Compression systems are designed to eliminate redundant or repeated information to the desired data level while allowing the original information to be reproduced to the desired quality.

Compression artifacts - Compacting of a digital signal, particularly when a high compression ratio is used, may result in small errors when the signal is decompressed. These errors are known as artifacts, or unwanted defects. The artifacts may resemble noise (or edge busyness) or may cause parts of the picture, particularly fast moving portions, to be displayed as distorted or incomplete.

Core - The central core of an optical fiber in which the light travels. The core’s index of refraction is always greater than that of the cladding which surrounds it, to maintain total internal reflection and therefore keep the light within the core.

D/A - Digital to analog.

DA - Distribution amplifier. A device that allows connection of one input source to multiple, isolated (buffered) output destinations such as monitors or projectors.

DAC - Digital to analog converter.

DDC - Display Data Channel. A bi-directional communications standard developed by VESA (Video Electronics Standards Association) that defines a universal data transmission standard for the connectivity between display devices and computers.

DDWG - Digital Display Working Group. The DDWG develops standards for digital displays. Developer of the DVI standard.

Deep Color - A very wide color gamut with a bit depth of 30 bits or more, capable of displaying billions of colors.

Digital - A system of data or image values in the form of discrete, non-continuous codes, such as binary. When data is in a digital format, it can be processed, stored (recorded), and reproduced easily while maintaining its original integrity.

DisplayID - Released in December 2007, this second-generation version of VESA EDID – Extended Display Identification Data is intended to replace all previous versions. DisplayID represents a 256-byte data structure that conveys display-related information to attached source devices. It is meant to encompass PC display devices, consumer televisions, and embedded displays such as LCD screens within a laptop without need for multiple extension blocks. Display ID is not directly backward compatible with previous EDID/E-EDID versions.

DisplayPort - The newest digital audio/video interconnect standard, designed primarily for use between a computer and display device. DisplayPort supports data rates up to 10.8 Gbps at a distance of 2 meters for full bandwidth transmissions, and up to 15 meters for reduced bandwidth signals such as 1080p/60, over copper cable. DisplayPort is not directly compatible with DVI or HDMI, but a DisplayPort connector can pass these signals, and the standard does provide an emulation mode for ease of integration with DVI or HDMI equipped products.

Dolby® Digital - A digital audio encoding and decoding technology utilized for DVDs, Blu-ray Discs, video games, and many cable and satellite television services. Also referred to as “AC-3.” Dolby Digital can transmit mono or standard two-channel stereo audio, as well as 5.1 channel surround sound (left front, center front, right front, left rear, right rear, and sub-woofer).

Dolby® Digital Plus - A digital audio compression technology designed as an optional codec for use with Blu-ray Disc. Dolby Digital Plus is an extension of the earlier Dolby Digital format and supports up to 13 audio channels, although Blu-ray Disc is limited to 8 discrete channels. The extra audio channels are often used to support multiple languages.

Dolby® TrueHD - An advanced, lossless multi-channel audio encoder and decoder technology intended primarily for high-definition content and is optional for Blu-ray Disc; support for TrueHD is also optional in the HDMI 1.3 specification. TrueHD supports up to 8 discrete audio channels at 96 kHz sampling, or up to 6 channels at 192 kHz sampling. Since TrueHD is optional for Blu-ray Disc, discs encoded with a TrueHD audio track must also include a separate 2-channel digital audio track.

DPCP – DisplayPort Content Protection - DPCP is a content-protection scheme for DisplayPort developed by Advanced Micro Devices. Like HDCP 2.0, DPCP uses AES 128 encryption. To date, DPCP has not been implemented by any manufacturer of source or display devices equipped with DisplayPort. All devices currently on the market use HDCP for digital rights management.

DRM – Digital Rights Management - A generic term for technologies such as content scrambling in cable or satellite television transmission, HDCP, and DPCP that can be used to control the access to, or reproduction of, copyrighted, commercially-available content. DRM is used primarily to prevent piracy, the unauthorized duplication and distribution of copyrighted material. However, DRM often also governs how content can be used. Commercially-available DVDs and Blu-ray Discs, for example, are typically licensed for personal use in a residential environment. Use of such content in a public venue, such as a school or business setting, without express consent or licensing by the copyright holder, is typically in violation of the media’s license.

DTS® Digital Surround - A digital audio encoding and decoding technology from DTS, Inc. that delivers 5.1 channels of surround sound. It is an optional surround sound format for DVDs but is mandatory for Blu-ray Disc. DTS Digital Surround has also been used in some LaserDisc releases as well as CDs, and is also featured in some video games.

DTS-HD High Resolution Audio - An extension to the DTS Digital Surround format that offers up to 7.1 channels at 24-bit resolution and 96 kHz sampling. DTS-HD High Resolution Audio is an optional surround sound format for Blu-ray Disc.

DTS-HD Master Audio - A lossless audio encoder/decoder technology from DTS, Inc. DTS-HD Master Audio allows a bit-for-bit representation of a movie’s original studio master soundtrack and supports up to 8 audio channels. Support for DTS-HD Master Audio is optional in the HDMI 1.3 specification released in 2006, and is also optional for Blu-ray Disc.

Dual-Link DVI - A dual-link DVI output has two TMDS links and twice the bandwidth of single-link DVI, and can therefore support much higher resolutions. With two TMDS links, the number of data channels is doubled, although there is still only one clock signal, so both links are clocked identically. Apples 30 Cinema Display with a native resolution of 2560x1600, is an example of a display requiring dual-link DVI. See also Single-Link DVI. Also see "Single-Link DVI."

Dual-Link HD-SDI - Is a method applying two HDSDI signals 1920x1080 video at 50 or 60Hz as progressive frames, at 12 bit depth or with 4:4:4 color quantization.

DVB/ASI – Digital Video Broadcasting/Asynchronous Serial Interface - A standard for the broadcast of digital television signals. Terrestrial broadcast, primarily seen in Europe, is often stated as DVB-T. In the US, DVB-S is often used for compression and encoding of digital satellite transmission; for terrestrial applications, North America utilizes the ATSC standard.

DVD-Audio - A digital format for delivering high-fidelity audio content on DVD – Digital Video Discs. DVD-Audio is a standalone format intended for audio only and is not used for the audio portion of DVD video content. DVD-Audio is similar in application to SACD, although to maintain compatibility with DVD players, the format is not capable of the very high sampling rates found in SACD. Support for DVD-Audio was added to the HDMI 1.1 specification in 2004.

DVI - Digital Visual Interface. The digital video connectivity standard that was developed by the DDWG – Digital Display Working Group. This connection standard offers two different connectors: one with 24 pins that handles digital video signals only and one with 29 pins that handles both digital and analog video. This standard uses TMDS – Transition Minimized Differential Signal from Silicon Image and DDC – display Data Channel from VESA – Video Electronics Standards Association.

DVI-D - DVI connector that supports digital signals only.

DVI-I - DVI connector that supports both digital and analog signals.

EDID - Extended Display Identification Data - EDID is a data structure used to communicate video display information, including native resolution and vertical interval refresh rate requirements, to a source device. The source device will then output the optimal video format for the display based on the provided EDID data, ensuring proper video image quality. This communication takes place over the DDC – Display Data Channel.

EDID Minder® - A proprietary EDID management process from Extron. EDID Minder® automatically manages the EDID information between a digital display device and one or more input sources. By maintaining continuous EDID communication with all sources, EDID Minder® ensures that digital sources power up properly and maintain their video output, whether or not they are actively connected to the digital display device.

Embedded data - Digital technologies such as SDI, HD-SDI, and HDMI, can carry variety of other data along with the primary video data, including audio, control, metadata such as content title or other identifying information, or other ancillary information. These data are said to be embedded, as they travel with the primary signal from the source device to the destination.

End Finish - The endface of an optical fiber at the ferrule, finished or polished to be smooth in order to minimize signal loss or backreflection. PC, SPC, UPC, and APC polishing finishes are available for singlemode connectors.

EQ (Video) - Equalization. Selective amplification (signal restoration) applied to a signal to compensate for high frequency attenuation and other distortions encountered in long lengths of cable.

Error detection and correction - The ability to detect errors caused by interference or other factors during the transmission of a signal, and then reconstruct the received signal so that it is a faithful reproduction of the original signal, without errors. A process known as Forward Error Correction is often used to allow the receiver to detect and correct some errors without having to “ask” the transmitter to send additional data.

Eye Pattern - The representation of a digital signal on an oscilloscope in which a digital data signal is repetitively sampled. Distortion in the signal waveform due to interference and noise appears as closure of the eye pattern. Signals that are poorly synchronized with the system clock (also known as jitter), too high, too low, too noisy, too slow to change, or which have too much undershoot or overshoot, can be observed from the eye pattern. Eye patterns are used to evaluate the quality of digital signals when passed through cables or signal extension devices, switchers, signal processors, and other electronics.

FCC - Federal Communications Commission. The US governmental agency that controls and makes all policy for the use of broadcast airwaves.

Ferrule - A precision tube which centers an optical fiber and provides stabilization and precise alignment. A ferrule may be part of a connector or a mechanical splice.

Fiber - The basic optical transmission element. The components of a fiber include the core, surrounded by the cladding, and then a coating for protection. Specific optical properties of the core and cladding enable light to be contained within the core as it travels along the fiber.

fps - frames per second. A measure of information that is used to store and display motion video. Each frame represents a still image and displaying frames in succession creates the illusion of motion. The more frames per second (fps), the smoother the motion appears.

GHz - Gigahertz. One billion cycles per second.

Giga - The prefix abbreviation for billion. (G) One G-Byte = 1 billion bytes.

H.264 Encoding - A standard for video compression equivalent to MPEG-4 Part 10 or MPEG-4 AVC – Advanced Video Coding. H.264 was created to provide video quality suitable for high definition applications at bit rates lower than that utilized in MPEG-2, the compression standard used in DVD authoring.

HDCP – High-bandwidth Digital Content Protection - A digital rights management scheme developed by Intel to prevent the copying of digital video and audio content. HDCP is mandatory for the HDMI interface, optional for DVI. HDCP defines three basic system components: source, sink, and repeater.

Sources send content to the display. Sources can be set-top boxes, Blu-ray Disc players, computer-graphics cards, and so forth. A source can have only one HDCP transmitter.

Sinks decrypt the content so it can be viewed. Sink is typically used to describe a flat panel display, television, or projector. Sinks can have one or more HDCP receivers.

Repeaters sit between Sources and Sinks. They accept content, decrypt it, then re-encrypt and transmit. Internally, a Repeater may provide signal processing, such as scaling, splitting out audio for use in an analog audio playback system, or splitting the input data stream for simultaneous viewing on multiple displays. Switchers, matrix switchers, and distribution amplifiers are all examples of Repeaters.

HDMI – High-Definition Multimedia Interface - An interface for the digital transmission of uncompressed high definition video, multi-channel audio, and control signals, over a single cable. HDMI is the de facto standard for consumer level video sources and displays.

HDTV - High Definition Television. HDTV refers to a complete product/system with the following minimum performance attributes: a receiver that receives ATSC terrestrial digital transmissions and decodes all ATSC Table 3 video formats; a display scanning format with active vertical scanning lines of 720 progressive (720p), 1080 interlaced (1080i), or higher; aspect ratio capabilities for displaying a 16:9 image; receives and reproduces, and/or outputs Dolby Digital audio.

Hot Plug/Hot Plug Detect - Describes a feature of DVI, HDMI, USB, and other digital technologies which allows a host device, such as a computer, to detect the presence of a new device without intervention by the user. Hot Plug technology allows a new device to be added to a system while it’s still connected to a power source. Once the new device is connected, the Hot Plug Detect circuit, or HPD, senses the new device and tells the rest of the system that the device is ready to either send or receive a data stream.

ICT – Image Constraint Token - Part of AACS, the Blu-ray Disc digital rights management system, the Image Constraint Token can cause the output of a Blu-ray Disc player to be down-converted to low-resolution video, similar in quality to a DVD. AACS requires that all components in the display chain, from the source to the display device, to be secured through HDCP or DPCP content protection. If the ICT flag is set and the Blu-ray player is connected to a device that does not support HDCP, for example an analog television or video recorder, the player automatically reduces the high-definition video quality to a maximum of 960x540 pixels before outputting it.

IP Link® - Extron’s high performance IP integration technology specifically engineered to meet the needs of professional A/V environments.

ITU - International Telecommunication Union. Formerly known as the CCIR (Comité Consultatif International des Radiocommunications) or International Radio Consultative Committee. A global organization responsible for establishing television standards.

ITU-R BT.601 - Formerly known as CCIR 601. A serial digital form of component video developed by the International Telecommunication Union for the digitization of color video signals. ITU-R BT.601 is the digital equivalent to Y, R-Y, B-Y, component analog video, and is transmitted on one coax cable instead of three. It is also called 4:2:2, which refers to the number of samples taken from each of the video channels: for every four samples of the Y (luminance) channel, the two color difference channels, R-Y and B-Y, are sampled twice.

Jitter - A video problem in which the displayed image is unstable or appears to shake.

Keys - See "KSV – Key Selection Vector."

KSV – Key Selection Vector - A unique numerical key used in content protection or digital rights management schemes such as HDCP. Keys are used to authenticate devices connected to one another, to ensure that a source is connected to a display and not a digital recording device.

Laser - Light Amplification by Stimulated Emission of Radiation. An optical source that generates coherent light within a narrow band of wavelengths.

Laser-Optimized Multimode Fiber - A multimode fiber with higher bandwidth than legacy multimode fiber, designed for transmission with laser based sources such as VCSEL.

Loss Budget - A specified, maximum tolerable loss of optical power, or attenuation of light, as it passes through a fiber optic system.

LPCM - Linear PCM - A specific method of pulse code modulation that is used to represent an analog waveform as a sequence of amplitude values. LPCM has been defined as part of the DVD and Blu-ray Disc standards, and is also used by HDMI. Also see "PCM – Pulse Code Modulation."

Macrobending - A term that describes a macroscopic deviation of an optical fiber’s axis from a straight line due to bending, to the extent that optical loss occurs.

Matrix switcher - A means of selecting an input source and connecting it to one or more outputs. Like a regular switcher, but with multiple inputs and multiple outputs.

Mechanical splice - A splice between optical fibers accomplished by using a mechanical fixture and an index gel, rather than by thermal fusion.

MHz - Megahertz. One million hertz (cycles per second). Video bandwidth is measured in megahertz.

Microbend - A localized defect in an optical fiber at the core-cladding boundary, caused by mechanical stress that results in sharp, microscopic curvatures in the fiber.

Mode - A path for light within an optical fiber. Singlemode fiber comprises a single path, while in multimode fiber, there are multiple light paths.

MPEG-4 - A patented collection of methods defining compression of audio and visual (AV) digital data. Uses of MPEG-4 include compression of AV data for web (streaming media) and CD distribution, voice (telephone, videophone) and broadcast television applications. MPEG-4 absorbs many of the features of MPEG-1 and MPEG-2 and other related standards, adding new features such as (extended) VRML support for 3D rendering, object-oriented composite files (including audio, video and VRML objects), support for externally-specified Digital Rights Management and various types of interactivity.

Multimode Fiber – MMF - An optical fiber that allows for the propagation of more than one mode or light path. It is commonly used with LED light sources for shorter distance links.

Multi-Rate SDI - the capability to support multiple SMPTE serial digital interface standards, including SMPTE 424M (2.97 Gbps 3G-SDI), SMPTE 292M (1.485 Gbps HD-SDI), and SMPTE 259M (270 Mbps SDI).

Native Resolution - Refers to the single fixed resolution of an LCD, plasma, or other fixed matrix display. An image said to match the native resolution of a display is one where pixels between the image source and display are perfectly aligned and require no additional scaling or other signal processing.

Non-blocking matrix switchers - These are true matrix switchers allowing any input to switch to any or all outputs. They have no switching limitations contingent on hardware or software. Extron builds only true matrix switchers with all switching paths available at all times; there is no blocking.

PanelLink® - Silicon Image’s TMDS (Transition Minimized Differential Signaling) all-digital video transmission standard. PanelLink technology was designed to provide the bandwidth necessary to support digital displays.

PCM – Pulse Code Modulation - The digital representation of an analog audio signal. PCM is the standard form of digital audio in computers and the compact disc (CD) “red book” format, as well as the standard used for the audio portion of digital video recording.

Propagation delay - The amount of time that passes between when a signal is transmitted and when it is received at the opposite end of a processor, amplifier, or cable.

Rec. 2020 - See "BT.2020."

Rec. 709 - See "BT.709."

Reclocking - Reclocking is a process that is used to restore the amplitude, rise and fall times, and clock rate attributes of a digital signal. Reclocking can add a small amount of time delay to the signal.

Repeater - See "HDCP – High-bandwidth Digital Content Protection."

Resolution - The density of lines or dots that make up an image. Resolution determines the detail and quality in the image. A measure of the ability of a camera or video system to reproduce detail, or the amount of detail that can be seen in an image. Resolution is often expressed as a number of pixels, but more correctly, it is the bandwidth. A sharp, clear picture has high resolution. Also see "Resolution (horizontal)" and "Resolution (vertical)."

Resolution (horizontal) - The amount of detail in a horizontal direction in a video image. It is expressed as the number of distinct vertical lines, alternately black and white, that can be seen in the width of the picture. This information is usually derived from observation of the vertical wedge of the test pattern. Horizontal resolution depends on the high frequency amplitude and phase response of the pick-up equipment, as well as the transmission medium and the monitor itself.

Resolution (vertical) - The amount of resolvable detail in a vertical direction in a video image. It is expressed as the number of distinct horizontal lines, alternately black and white, that can be seen in a test pattern. Vertical resolution is primarily determined by the number of horizontal scanning lines in a frame.

RS-232 - An Electronic Industries Association (EIA) serial digital interface standard specifying the characteristics of the communication path between two devices using either DB-9 or DB-25 connectors. This standard is used for relatively short-range communications and does not specify balanced control lines. RS-232 is a serial control standard with a set number of conductors, data rate, word length, and type of connector to be used. The standard specifies component connection standards with regard to the computer interface. It is also called RS-232-C, which is the third version of the RS-232 standard, and is functionally identical to the CCITT V.24 standard.

S/PDIF – Sony/Philips Digital Interconnect Format - A data protocol for compressed or uncompressed digital audio co-developed by Sony and Philips Electronics and now part of the larger AES/EBU audio standard. S/PDIF is often misconstrued as a connection type; however, S/PDIF audio can be found in products using either a 75 ohm coaxial connection or a TOSLINK fiber optic connection. S/PDIF is commonly found in Compact Disc and DVD players.

SACD – Super Audio Compact Disc - A very high fidelity, read-only optical disc format for both two-channel stereo and 5.0 (no sub-woofer) or 5.1 surround sound audio. SACD can store up to 10 times as much data as a standard audio CD, up to 7.95 GB. Support for SACD audio was added to the HDMI 1.2 specification in 2005.

Scaling - A conversion of a video or computer graphic signal from a starting resolution to a new resolution. Scaling from one resolution to another is typically done to optimize the signal for input to an image processor, transmission path or to improve its quality when presented on a particular display.

SDI - Serial Digital Interface. Standard definition video is carried on this 270 Mbps data transfer rate. Video pixels are characterized with a 10-bit depth and 4:2:2 color quantization. Ancillary data is included on this interface and typically includes audio or other metadata. Up to sixteen audio channels can be transmitted. Audio is organised into blocks of 4 stereo pairs.

Single-Link DVI - The electrical signaling used to transmit data over DVI is known as transition minimized differential signaling, or TMDS. A single TMDS link carries three data channels and one clock signal, with a maximum video frequency of 165MHz, capable of standard resolutions up to 1920x 1200 pixels. See also “Dual-Link DVI.” Also see "Dual-Link DVI."

Single-Link HD-SDI - See "SMPTE 292M."

Singlemode Fiber – SMF - An optical fiber with a small core, through which only a single mode can propagate.

Sink - See "HDCP – High-bandwidth Digital Content Protection."

SMPTE - Society of Motion Picture and Television Engineers. A global organization, based in the United States, that sets standards for baseband visual communications. This includes film as well as video and television standards.

SMPTE 259M - Defines the SDI serial digital interface common to most standard definition digital video products. SMPTE 259M includes several data rates, including 143 Mbps (NTSC composite digital), 177 Mbps (PAL composite digital), 270 Mpbs (4:2:2 component digital, 4:3 standard video aspect), and 360 Mbps (4:2:2 component digital, 16:9 widescreen video aspect). Of the group, 270 Mbps and 360 Mbps are the most common data rates.

SMPTE 292M - Defines the HD-SDI high definition serial digital interface. SMPTE 292M has data rate of 1.485 Gbps for 4:2:2 component digital in 16:9 widescreen video aspect. Full bandwidth HD-SDI can be transmitted 300 feet (100 m) on standard RG6 coaxial cable, and more than 60 miles (100 km) using fiber optic technology. SMTPTE 292M is considered a single link HD-SDI signal, in that only one coaxial cable is required to transmit the data.

SMPTE 310 - A broadcast standard for transmitting one or more DTV – digital television channels, and ancillary content, as part of a single data stream.

SMPTE 372M - Defines a full bandwidth, 4:4:4 RGB color space and bandwidth up to 2.97 Gbps, which is sufficient for 1080/60p and 1080/24Psf video streams. SMPTE 372M is most commonly associated with dual-link HD-SDI, wherein two coaxial cables are used to carry alternate pixels, thus doubling the data rate and available resolution. The “Super2k” format in digital cinema, 2048x1080, progressive scan, 4:4:4 RGB color space, is the highest data rate possible with one dual-link HD-SDI connection.

SMPTE 424M - Defines a full bandwidth, 4:4:4 RGB color space and bandwidth up to 2.97 Gbps on a single coaxial cable. SMPTE 424M is colloquially known as 3G-SDI, a term used to describe 2.970 Gigabits per second digital video over a single-link coaxial cable. 3G-SDI is capable of supporting HDTV 1080p video at 50 or 60 frames per second. Most 3G-SDI terminal equipment, such as Extron 3G-SDI matrix switchers, simple switchers, distribution amplifiers, cable equalizers, and fiber optic extenders, is capable of supporting standard SDI data rates from 270 Mbps to 2.970 Gbps.

SMPTE/DCI P3 - A color space defined within the Digital Cinema Initiatives - DCI specification for digital cinema systems. SMPTE/DCI P3 offers a color gamut wider than the ITU-R Recommendation BT.709 or sRGB color spaces, but less than ITU-R Recommendation BT.2020.

Source - The optical source in a fiber optic system, usually an LED or laser diode.

Splice - A permanent connection between the ends of two optical fibers by mechanically joining them together, or heating to fuse them together.

sRGB - A color space widely used in computers, monitors, and the Internet, as well as consumer digital cameras, printers, and scanners. sRGB incorporates the same color space primaries as defined in ITU-R Recommendation BT.709, the international standard for high-definition video.

TMDS - Transition Minimized Differential Signaling. An all-digital video transmission standard developed by Silicon Image, Inc. TMDS is the core technology used in DVI - Digital Visual Interface and HDMI - High Definition Multi-media Interface.

TOSLINK - An optical fiber connection standard for digital audio developed by Toshiba. TOSLINK is very commonly used for audio output from Compact Disc and DVD players, as well as some game consoles. A generic name, “EIAJ optical,” is sometimes used to describe this standard.

Tri-level sync - A sync level scheme developed for HDTV in which the sync line first goes low, then transitions high while going through the reference voltage level, and then drops back down to the reference voltage. The transition of the positive-going sync signal through the reference voltage is the sync trigger.

VCSEL - Vertical Cavity Surface Emission Laser. A high speed, low cost laser diode that emits perpendicular to the surface of the chip, rather than from an edge.

xvYCC - Extended-gamut YCC color space. xVYCC can be used in the electronics of televisions and other video displays to improve the image quality of high-definition video signals.

Y Cr Cb - Used to describe the color space for interlaced component video. Also see "Y, R-Y, B-Y."

Y, R-Y, B-Y - Color difference signal designation. Y corresponds to the luminance signal; R-Y corresponds to the red minus luminance signal, and B-Y corresponds to the blue minus luminance signal. After luminance is subtracted from red and blue, the remainder is considered to be the green portion of the RGB video signal. These signals are derived as follows: Y = 0.3 red + 0.59 green + .11 blue; R-Y = 0.7 red - 0.59 green - 0.11 blue; B-Y = 0.89 blue - 0.59 green - 0.3 red