To use the glossary, simply click below on the first letter of the term of interest:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

G

G.711

An ITU-T recommendation about a 3.4-KHz bandwidth PCM audio coding algorithm working over the range of 32- to 64-Kbps. It forms a part of the ITU-T codec and telephony requirements. This algorithm produces telephone grade audio, especially useful in videoconferencing at aggregate bit rates above 128 Kbps.

Appendix I to G.711 adds low complexity packet loss concealment, useful for good quality audio transmission within a suite of VoIP applications.

G.720

ITU-T recommendation characterizing low bit rate digital voice codec performance using non-voice signals, useful for testing VoIP coders, transcoders, gateways and terminal devices.

G.722

An ITU-T recommendation detailing a 7-KHz bandwidth audio coding algorithm working at 64-Kbps. It forms a part of the H.320 codec requirements. G.722 produces good quality audio but is generally not recommended at aggregate bit rates below 256 Kbps.

G.722.1

An ITU-T recommendation detailing 7-KHz and 14-KHz bandwidth audio coding algorithms working at 24- and 32-Kbps. It forms part of the H.320 and H.323 codec requirements. May be licensed from Polycom who acquired PictureTel Corp. IP assets. G.722.1 also includes testing and packetizing considerations.

G.723.1

An ITU-T recommendation for a Dual Rate Speech Coder for Multimedia Communications Transmitting at 5.3- and 6.3-Kbps.

G.726

ITU-T recommendation for ADPCM (adaptive differential pulse code modulation) coding at 16-, 24-, 32- and 40-Kbps. Includes useful annexes.

G.727

ITU-T recommendation using ADPCM (adaptive differential pulse code modulation) with 2- to 5-bits/sample. Includes useful annexes with test sequences.

G.728

An ITU-T recommendation detailing a 16-Kbps 3.4-KHz bandwidth audio coding algorithm known as LD-CELP or low-delay code excited linear prediction. Part of the H.320 and H.323 codec recommendations. Produces good speech intelligibility and is a good choice for videoconferencing operating at 112- or 128-Kbps aggregate transmission rates.

Appendix I includes frame- or packet-loss concealment methods for VoIP and similar applications.

G.729

ITU-T recommendation about an 8-Kbps speech coder using the CS-ACELP or, conjugate-structure algebraic-code-excited linear prediction speech coder. Annexes provide algorithms at 6.4- and 11.8-Kbps, C code and test verification suites.

G/T

The figure of merit or carrier-to-noise ratio, of a satellite receive earth station where G is gain and T is noise temperature. The value includes contributions of factors including antenna gain, noise temperature of the low-noise amplifier and other aspects. A typical value for a modern earth station might be 25db°K

G

Green. The green video signal, part of an RGB component video signal. G may also include synchronization information.

Gateway

Hardware or software that converts between algorithms, protocols or standards. May also act as a means of access from one network to another.

GCC

Generic Conference Control

Genlock

The synchronization of a piece of video equipment to another using an external video or similar signal. In broadcasting and videoconferencing systems, all picture sources should be genlocked together or made synchronous.

GFSK

Gaussian filtered Frequency Shift Keying; a data modulation method used by Bluetooth (which see) wireless systems. Gaussian filtering reduces the instantaneous transmission bandwidth required.

GSO

GeoStationary Orbit; a satellite in an equatorial orbit and at an altitude that matches the rotation of the Earth. To a fixed observer on the Earth, the satellite position appears stationary.

GUI

Graphical User Interface; a human - machine interface based on a graphical and iconic metaphor techniques, to simplify or clarify operation of a device and to provide visual feedback to the operator about the state of the system.

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