Extron Glossary of Terms

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A micron

A millionth ($10^{-6}$) of a meter.

10/100Base-T

The Ethernet protocol that uses Unshielded Twisted Pair (UTP Cat 5, etc.) cable, in which the amount of data transmitted between two points in a given amount of time is equal to either 10 Mbps or 100 Mbps.

1080i

Interlaced HDTV transmission standard. Refers to an active pixel rate of 1920×1080 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.

A

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.

Absorption

The attenuation of light as it passes through fiber, similar to the resistive loss of an electrical signal as it passes through cable. Absorption is caused by impurities and defects in the fiber.

B

Backbone

The primary transmission network for telecommunications that connects between key locations and branches off to buildings and other facilities.

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.

C

Cable equalization

The method of altering the frequency response of a video amplifier to compensate for high frequency loss in cables that it feeds.

Capacitance

The ability to store an electrical charge.

D

DA

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

DANTE

Dante is an acronym for Digital Audio Networking though Ethernet, from Audinate. It is a combination of hardware, software and network protocols that delivers uncompressed, high resolution, multi-channel, low-latency digital audio distribution over a standard Ethernet network using standard TCP/IP protocols.

E

EAP

Extensible Authentication Protocol. It is an authentication framework that is often used in network and Internet connections.

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.

F

F connector

A type of plug used for RF video connections, such as those used to connect TV antennas and cable TV to televisions and VCRs.

Feedback

(also known as Larson effect) The phenomenon where the sound from a loudspeaker is picked up by the microphone feeding it, and then reamplified again and again.

G

Gain

(1) A general term for an increase in signal power or voltage produced by an amplifier. The amount of gain is usually expressed in decibels above a reference level. Opposite of attenuation. (2) The amplification of a signal, unit, or system. Expressed in the unit of measurement appropriate to the signal or system.

Genlock

A technique where the video output of one source, or a specific reference signal, is used to synchronize other television picture sources together.

G

Gain

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 960×540 pixels before outputting it.

Genlock

ID bit termination – Used to identify what type of display device is attached to a computer-video output port. ID bit termination involves connecting specific data lines or “pins” to the electrical ground. ID bit termination assures that the correct video signals will be sent to the display device. A computer checks for ID bits during the power-up self diagnosis, and sets the video output frequency and resolution based on how the ID bits are set. Some computers will not send any video signal if they do not sense any ID bits on boot-up, so no picture will be displayed. ID bits are also called “sense lines.”

G

Gain

H.264 (MPEG-4 AVC) – Block-oriented motion-compensation-based codec standard developed by the ITU-T Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG). It is the product of a partnership effort known as the Joint Video Team (JVT). H.264 is used in such applications as Blu-ray Disc, videos from YouTube and the iTunes Store, DVB broadcast, direct-broadcast satellite television service, cable television services, and real-time videoconferencing.

Genlock

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.

G

Gain

Jitter – A deviation in the timing of a digital signal, usually in relevance to a reference clock source. Jitter can occur over long lengths of low quality cable, or through the cumulative effect caused by cascading several digital devices in line between the source and destination. Also used to describe a video problem in which the displayed image is unstable or appears to shake.

Genlock

A technique where the video output of one source, or a specific reference signal, is used to synchronize other television picture sources together.

G

Gain

K – kilo. An abbreviation for 1,000. A kilobyte is 1,000 bytes. Because numbers used in computer RAM sizes are in binary, the closest number is used. When talking about memory size, the numbers are rounded off (e.g. 1 kbyte is really 1,024 bytes). Kell factor – The ratio between the measured number of TV lines and the pixel count of a fixed pixel video device. It equals 0.7. For example, a DVD picture with 720 pixels in the horizontal direction is equivalent to about 500 TV lines (720 x 0.7=500) of resolution. Kelvin – An absolute scale of temperature measurement typically used to describe the color of light, expressed in “degrees Kelvin.” The lower the number, the “warmer” or redder the color of the light; a higher number indicates a “colder”, or bluer, light source. Also see “Color temperature.” Kevlar® – A brand name from DuPont for aramid yarn, used in the construction of cables to provide strength and strain relief. Key – (1) Also called key source or key cut. A signal that can be used to electronically cut a hole in a video picture to allow for insertion of other elements such as text or another video image. The key signal is a switching or gating signal for controlling a video mixer that switches or mixes between the background video and the inserted element. (2) The composite effect created by cutting a hole in one image and inserting another image into the hole.