FAQs: A Glossary of common Digital AV terms

Like any type of technology the AV industry has its own vocabulary, one that can become a little confusing if you are not used to it. This Digital AV glossary from Extron is a great place to figure out the meaning of various terms used when referring to digital AV.

Here are few of the terms which you are more likely to come across:

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

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

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.

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.

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.

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

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.

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.

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.

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.

(Image Credit: Extron)

AV Solutions, Audio Visual Consultants at Actis Technologies India