Extron electronic 68-388-01 manual Glossary of terms

Reference • Appendix B

Glossary of terms

Following is a list of terms taken from Extron’s Glossary.

AC Reset –

Refers to status that changes when power is removed from a device. Many electronic devices have live power inside, even after “Power off” has been initiated from a panel or remote control device. This is not the same as “AC Reset”, when power is removed at the AC cord.

Attenuation –

The decrease in magnitude (of a signal).

Audio follow –

A term used when audio is tied to other signals, such as video, and they are switched together. (The opposite of Breakaway)

Balanced Audio –

A method that uses three conductors for one audio signal. They are plus (+), minus (-) and ground. The ground conductor is strictly for shielding, and does not carry any signal. Also differential audio.

Bandwidth –

A frequency range, or “band” of frequencies, within which a device operates. In audio and video, it is the band of frequencies that can pass through a device without significant loss or distortion. The higher the bandwidth, the sharper the picture; low bandwidth can cause a “fuzzy” picture.

Breakaway –

The ability to separate signals for the purpose of switching them independently. For example: an audio and video signal from the same source may be “broken away” and switched to different destinations. The opposite of the term “follow”.

Buffer –

Generally referred to as a unity gain amplifier used to isolate the signal source from the load. This is for both digital and analog signals.

Chroma –

The color information (hue and saturation), independent of luma intensity. Black, gray, and white objects do not have chroma characteristics.

Chroma Signal –

Part of a television signal containing the color information. Abbreviated as “C”.

Clip, Clipping –

The level at which a signal excursion begins to exceed limits of the circuit and flattens out, distorting the signal. When setting audio attenuation, the clip level can be defined as a level short of the distortion point, thus allowing “headroom” and maintaining the signal’s fidelity.

Composite Sync –

A signal consisting of horizontal sync pulses, vertical sync pulses, and equalizing pulses only, with no signal reference level. Also referred to as RGBS.

Composite Video –

A combined signal which includes luma black and white, chroma (color), blanking

Differential Audio –

See Balanced Audio.

DLP –

Digital Light Processing – Also DMD (Digital Micro-mirror Device). Uses an array of mirrors that move independently, reflecting light to compose the picture.

Gain –

A term used to denote an increase in signal power or voltage produced by an amplifier in transmitting a signal from one point to another. The amount of gain is usually expressed in decibels above a reference level. Opposite of Attenuation.

Headroom –

The margin between a nominal operating signal level and peak clipping (distortion) level. See Clipping.

High Impedance

(Hi Z/High Z) – This is typically 10k ohms or greater. In video, when the signal is not terminated locally, there may be a switch for Hi Z or some termination value (75 ohms). Hi Z is used if termination is provided by another device.

IR Learning –

The ability of a device to receive and store infrared commands for other devices, such as the projector. With Extron’s System 5, each command is assigned to a system operation (such as selecting an input). When an operation is executed,

B-3 Extron • System 5cr Switcher • User’s Manual