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Glossary

G
GAIN

Amplification of an input signal versus its output (ratio). The gain is usually in decibels (dB). Unity Gain: 0dB.

GAMMA

Function that gives the non-linearity response of a CRT Display.

GATEWAY

A gateway is a point of entry or exit at which a gate may be hung. A network device that allows or controls access to another computer or network.

GENLOCK

Synchronization method used in video equipment such as Scan Converters. It consists of using an external Master Signal (the Black Burst generator is a TV/Studio video genlock source). It enables several video sources to be cut, faded and mixed together.

GHOSTING

In video, a “ghost” or “refections” are a replica of the transmitted image, offset in position, that is super-imposed on top of the main image on an analogue broadcast.

GROUND

Electrical connection of a circuit to a point designated as having zero potential. Ground or earth may be the reference point in an electrical circuit from which other voltages are measured.

GROUND LOOP

Common noise problem found in signal management caused by different ground potentials when an item is connected to several others.

H
H SYNC.

see HORIZONTAL SYNC.

HD +

High Definition Plus – Standard computer format consisting of 1600 x 900 pixels. The aspect ratio is 16:9.

HD BLACK

see HD GENLOCK.

HD CONNECTOR

High Density Connector, usually used for the video display of RGB signals on Personal Computers (an HD 15 connector has 3 rows of 5 pins).

HDCP

(High-Bandwith Digital Content Production). A system for the protection of copyright on digital audio and video contents to avoid misuse. HDCP encrypts the digital signal from the source and allows playback only on approved devices with which keys have been exchanged. It operates on DVI, HDMI or DisplayPort. The specification is proprietary, and implementing HDCP requires a license.

HD GENLOCK

There are 2 common types : Analog HD Black with 3 levels Sync., and Black HDSDI serial stream with 10 bits H&V word flags. See also GENLOCK.

HDMI

High Definition Digital Interface: thin non-locking connector & SERIAL data for Computer, Video(15Khz),HDTV & Audio. It is backwards compatible with DVI. The electronic transmission is also differential. Often foundComing in High-Tech Consumer and Professional display.

HD-SDI

High Definition Serial Digital Interface. For Broadcast Television. YUV-4:2:2 8 or 10 bits multiplexed High Speed component (about 1,5 gb/s to 3 gb/s, depending on the standard). Non compressed.

HDTV

High Definition Television, video technology giving an improved resolution at least twice as high as in the NTSC, PAL, SECAM standards (e.g. 720 p means 720 progressive lines, 1080 i means 1080 interlaced lines). Up to 30 HDTV formats have been proposed, since the beginning, by worldwide manufacturers and working groups. Only a few of them have been retained (principally the 720p, 1080i, 1080 sF, 1035i). Full HDTV format consists of 1920 x 1080 pixels. The aspect ratio is 16:9.

HERTZ (Hz)

Frequency Measurement unit (1 cycle per second).

HHXGA

Hex Hex eXtended Graphics Array - Standard computer format consisting of 16384 x 12288 pixels. The aspect ratio is 4:3.

HIGH IMPEDANCE (Hi-Z)

Term used for a High input or output load. Most of Analog Way's converters are fitted with a Hi-Z / 75 Ohms switch on their RGB input/output loopthrough.

HORIZONTAL FREQUENCY

Also called Line Frequency, it is the number of horizontal lines per second that a video signal generates (Hz) - see Line Frequency.

HORIZONTAL RATE

Horizontal scanning frequency. The number of complete horizontal lines (trace and retrace) scanned per second. Measured in kHz, the PAL standard is 15.625 kHz line rate.

HORIZONTAL RESOLUTION

Can either be the number of vertical lines that can be seen on the screen of a TV device (from left to right) or the number of pixels contained in a line, for a computer display.

HORIZONTAL SYNC.

Portion of a video waveform that indicates to the display where the beginning of a non-visible part of the picture is (from left to right axis). The horizontal sync. abbreviation marked on the products is H Sync. or H.

HUE

Picture's color tint adjustment. The hue is active only on NTSC video sources. It acts directly on the Red, Green and Blue by changing their UV color balance.

HUM BARS

Image interference, caused by ground loops, that looks like horizontal bars which scroll vertically on the screen. They can be eliminated by some HUM suppressor.

HUXGA

Hex Ultra eXtended Graphics Array - Standard computer format consisting of 6400 x 4800 pixels. The aspect ratio is 4:3.

H&V SEPARATED SYNC.

Signal in which the horizontal sync. and the vertical sync. are transmitted separately (2 wires, commonly found in Computer Sync. displays).

Hz

see Hertz

I
ICIA

International Communication Industry Association. Official Audio & Video industry association (NAVA issued) TV.

IEC CONNECTOR

International Electrotechnical Committee. Standard AC power cable and connector used to power scan converters, interfaces, projectors and most electronic equipments.

IEEE

Institute of Electrical & Electronics Engineers.

IMAGE NOISE

Image noise is the random variation of brightness or color information in images produced by the sensor and circuitry of a scanner or digital camera.

IMPEDANCE

Load signal, measured in Ohms. The impedance of a video signal is 75 Ohms (low impedance) and it has to be matched to the cable impedance to avoid echo on the picture.

INTERFACE

Device or program that creates a link between 2 different products or protocols. In Video, the interface usually adapts the computer unit (CPU) to different displays. It acts only on the synchronization but not on the scanning rate (see Scan Converter). Powerful interfaces are fully automatic and with no Dip Switches.

INTERLACED (i)

Method of line interleaving that scans the image into 2 fields (1 image = 1 frame = 2 fields). TV video standards (PAL, SECAM, NTSC) use the interlaced method. PAL/SECAM is equivalent to 625 lines per frame which is equivalent to 2 x {312.5 lines per field}. NTSC is equivalent to 525 lines per frame which is equivalent to 2 x {262.5 lines per field}. However, computer sources usually use Non Interlaced or Progressive scanning methods (1 image = 1 frame = 1 field).

IP

Internet Protocol (also Intellectual Property).

IP Address

The unique identifier given to a device to allow communication on a network.

ISO

International Standard Organization.

ITU

International Telecommunication Union. Committee that sets Digital Broadcast Video Standards (successor to CCIR).