Glossary E-H

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E.I. (Electronic Iris) Shutter

Electronic Iris shuttering is the ability of the camera to compensate for moderate light changes in indoor applications without the use of auto iris lenses.


EIA is the standard monochrome video format used in North America. EIA products are also generally referred to as NTSC because nearly all NTSC products like televisions and VCRs can also handle black and white EIA video.


A device that superimposes electronic signal information on other electronic signals.


The rearrangement of the bit stream of a previously digitally encoded signal in a systematic fashion to make the information unrecognizable until restored on receipt of the necessary authorization key.


A local area network used for connecting computers, printers, workstations, terminals, etc. within the same building.

Ext. Sync (External Sync)

The ability of CCTV equipment, normally cameras, to accept one or more of the standard sync formats so as to align itself to the rest of the system.


Facial Capture

Corner mounted cameras are very effective at capturing overview scene surveillance. In order to obtain facial capture surveillance for positive identification purposes, cameras should be mounted at vertical height conducive for facial capture.

Fiber Optic

The process of transmitting light through a long, flexible fiber such as glass or plastic, for the purpose of transmitting video, audio, or data over long distances.

Field Of View

The maximum viewed image (area covered) a lens "sees." The horizontal or vertical scene size at a given distance from the camera.

Fixed focal length lens

A lens with a predetermined fixed focal length, a focusing control and a choice of iris functions.

Flange Back

The distance from the flange of the lens (beginning of the lens mount) to the focal plane. C-mount lenses have a flange back distance of 17.526mm vs. 12.5mm for CS-mount.

Focal Length

The distance (in millimeters) from the lens to the surface of the image sensor. The shorter the distance, the wider the view; the longer the distance, the narrower (telephoto) the view.


The focal point. An adjustment to the lens optics to improve the clarity of the picture.

Foot Candle (FC)

A measurement of light. 1 lumen per square foot.

Frames per Second (FPS)

Used to describes the number of full video frames displayed or recorded within one second. True real time video consists of 30 frames/sec. for NTSC format and 25 frames / sec. for PAL format. A complete frame of video is compiled of two separate images (or fields), so the number of fields in one second is always twice the number of frames per second.


A term used to indicate the speed of a lens. The smaller the f-number, the greater is the amount of light passing through the lens



Any increase or decrease in strength of an electrical signal. Gain is measured in terms of decibels or number of times of magnification.


A shadowy or weak image in the received picture, offset to either the right or to the left of the primary image.

Gigabyte (GB)

1,024 megabytes or 1 billion characters of information. Also see Megabyte.

Gray Scale

The number of variations from white to gray to black.


An electrical connection point which provides a common electrical reference for all energized devices. A ground wire may or may not be used for operational current.

Ground Loop

Effects video pictures in the form of a black shadow bar across the screen or as tearing in the top corner of a picture. Caused by different earth potentials in a system.


HDDTV - High definition digital television

The upcoming standard of broadcast television with extremely high resolution and aspect ratio of 16:9. It is advancement from the analog high definition, already used experimentally in Japan and Europe. The picture resolution is nearly 2000×1000 pixels, and uses the MPEG-2 standard.

HDTV - High definition television

It usually refers to the analog version of the HDDTV. The SMPTE in the US
and ETA in Japan have proposed a HDTV product standard: 1125 lines at 60 Hz field rate 2:1 interlace; 16: 9 aspect ratio; 30 MHz RGB and luminance bandwidth.


Abbreviation for High Coercivity. HiCo magnetic stripes provide the highest level of immunity to damage by stray magnetic fields. They are more difficult to encode than LoCo magnetic stripes because the encoding requires more power. HiCo magnetic stripe cards are slightly more expensive for this reason.

Head End

Term used to describe a central location for all signal distribution equipment.

Horizontal Resolution

The maximum number of individual picture elements that can be distinguished in a single scanning line.


An improved version of the CCD HAD technology, utilizing on-chip micro-lens technology to provide increased sensitivity without increasing the pixel size.

Hz (Hertz)

Cycles per second.

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