Siemens TFT - Manual (Page 205)

Glossary
16-3 © Siemens Building Technologies Group
Cable Compensated Amplifier
High frequency video signals are attenuated when transmitted
through cables. A cable compensated amplifier boosts the high fre-
quency signals depending upon the cable distance. This ensures
minimum video loss.
Cable Core
Is the central part of the cable which actually carries the video, con-
trol or power signals. It can be made up of a single conductor (solid
core) or a number of electrical wires.
Cable Jacket
Is the outer protective coating which covers the core of the cable.
Cable Tray
Is a long tray installed in many sites which allows cables to be eco-
nomically laid out.
Camera
Is an electronic device which converts light into an electrical signal.
Camera Controller
Controls the different functions of a pan & tilt head and the zoom
lens. It is also known as the PTZ controller.
Candela
Is a new unit which replaces the candle and is a measurement of
luminous intensity.
Cathode Ray Tube (CRT)
Is a tube in the monitor containing a heated cathode which emits a
beam of electrons focused on a phosphor coated surface. The sur-
face glows depending upon the intensity of the beam. The deflection
circuitry in the tube controls the movement of the beam.
CCD
Charge Coupled Device is a solid state device in a camera that con-
verts light falling on it into an electrical signal.
CCD Iris
Is a feature in modern CCD cameras by which the iris function is per-
formed by the CCD chip itself. This eliminates the need for an auto
iris lens. The CCD iris can handle minor light fluctuations only and
therefore is not recommended for most outdoor applications.
CCIR
International Radio Consultative Committee recommends a format
of 625 lines per frame and a transmission speed of 25 frames per
second.
CCTV
Closed circuit television
Channel Separation
When signals are multiplexed at different frequencies for transmis-
sion, then the separation between these frequencies is called chan-
nel separation. Poor separation can lead to cross talk.
Chassis
Is used as a carrier for a certain number of slide-in modules. A power
supply in the chassis ensures power for the modules. The CCTV chas-
sis fit the industry 19” standard.
Chromatic Aberration
Is an error in lenses which causes the focal point to be scattered. This
occurs because different wavelengths of light bend differently
through a lens. A combination of lenses are required to minimise this
error.
Chrominance Signal
Is that part of the video signal which contains the colour information.
In S-VHS, this signal is transmitted along a separate cable. In a com-
posite video signal, the chrominance signal is multiplexed at a higher
frequency and sent along the same cable.
Colour Stripe Filter
This type of filter is placed in front of a colour CCD chip. It breaks up
light into the basic colours - red, green and blue which are then
directed to separate pixels in the CCD chip.
Common Sync
Is a device used to synchronise cameras. It generates synchronizing
pulses that are sent to all cameras connected to it by coaxial cable.
Generator
Composite video is a standard signal format in CCTV which contains
the video signal, the horizontal and vertical sync pulses and the
blanking pulses.
Concave
Is a type of optical lens in which the light rays passing through it are
made to diverge by the inward bulge of the glass surface.
Conduit
Is a plastic or metallic tube which is used to conceal, protect or
secure cables.
Connector
Is a device used to interconnect cables or connect cables to various
equipment.
Contrast
Is the difference in the intensity between the black parts and white
parts of the picture on the monitor.
Contrast Control
Is a control in the monitor which changes the contrast by increasing
or decreasing the amplitude of the video signal.
Covert
Is a mode of CCTV surveillance in which the camera and lens are hid-
den and cannot be seen.
Convex
Is a type of optical lens in which the light rays passing through it are
made to converge by the outward bulge of the glass surface.