DEPTH OF FIELD
The distance between the furthest and nearest points at the same level of definition within a certain view.
DIGITAL VIDEO
A video storage media using 5:1 compression method.
DWELL TIME
Amount of time that a sequential switcher allows between the viewing of the different cameras connected to it.
EXWAVEHAD
Trademark of latest Sony Hole Accumulated Diode charge coupled device.
ELECTRONIC SHUTTER
CCD iris which eliminates the need for an auto iris lens. The CCD iris automatically controls the light intensity by adjusting the electronic shutter speed.
FRAME
A single television or film image. In European television, 25 frames per second is used to give an illusion of continuous movement. Each frame in TV is normally two fields.
FOCAL LENGTH
Distance from the optical centre of a lens to the focal plane. Generally referred to in millimetres.
FOCAL POINT
Point at which light passing through a lens is concentrated.
F STOP
Figure given of the ratio between a lens aperture and its length.
GAMMA
Unit of measurement for one amount of contrast in an image.
GENLOCK
A means of locking a video source to a second video source or reference signal.
GROUNDLOOP
A condition that occurs when two or more grounded points in an electrical system develop a conductive loop between them.
Basic CCTV Terminology
HAD SENSOR
An improved type of
HDR
Hard Disk Recorder. A device which captures images to hard disk.
HSR
Hybrid Surveillance Recording. A combination of hard disk and Digital Video in one recording machine which greatly increase the storage capacity over HDR.
HYPER HAD
An improved version of the Sony HAD sensor, using
IMAGE INTENSIFIER
Device which uses photo multiplier technology to amplify the available light to increase the sensitivity of a camera.
ISDN
Integrated Services Digital Network. Digital phone line with transmission speeds of up to 128Kb per second. Used with PMS video transmission systems.
INFRA-RED
A range of frequencies just below the visible spectrum. Can be used for the transmission of information or for providing additional illumination for cameras.
INTERLACE 2:1
Scanning process for reducing the image flicker consisting of successively scanned lines which adjacent lines belong to different fields.
LINE FED CAMERA
See Triple Multiplex.
LINE LOCK
Method of synchronising AC powered cameras.
LUX
Metric unit of measurement of light.
MEGASTREAM
A network (normally fibre optic) allowing
the transmission of data at 1Mbits per second or faster.
For more information contact the Sony Business Information Centre: 01932 816340
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