| AC
| |
| | BNC
|
| Alternating Current
| |
| | Standard connector used to connect
|
| ACCESS CONTROL SYSTEM
| |
| | coaxial cables to CCTV equipment or each
|
| Electronic system used to allow, restrict
| |
| | other.
|
| and track the movement of people through
| |
| | BRIDGING SWITCHER
|
| entry/exit points in a site. This is
| |
| | Term for a multi-input sequential video
|
| achieved through the use of electronic
| |
| | switcher, which includes a sequencing
|
| individual codes, keys or cards etc, to
| |
| | output and spot output.
|
| release a locking mechanism.
| |
| | BRIGHTNESS
|
| ACTIVITY DETECTION
| |
| | Term for the intensity of illumination of
|
| A feature built into some multiplexers,
| |
| | a reproduced video picture.
|
| which is used to detect movement within a
| |
| | BRIGHTNESS CONTROL
|
| camera's field of view that is then used
| |
| | Control, which increases or decreases the
|
| to improve camera recording update rate.
| |
| | illumination of phosphors on a monitor
|
| AGC (AUTOMATIC GAIN CONTROL)
| |
| | screen to vary the brightness.
|
| An electronic circuit that is used to
| |
| | BRAID
|
| boost the video signal in a camera in low
| |
| | A group of textile or metallic filaments
|
| light conditions. Use of this feature
| |
| | inter-woven to form a tubular structure,
|
| will usually give a "noisy" or grainy
| |
| | which may be applied over one or more
|
| picture. When comparing camera
| |
| | wires, or flattened to form a strap.
|
| specifications always use data with AGC
| |
| | BYTE
|
| off.
| |
| | A group of eight bits.
|
| ALARM INTERFACE
| |
| | BROADCAST CAMERA
|
| A facility which allows the use of
| |
| | High quality, high-resolution camera used
|
| external alarm equipment such as PIR's,
| |
| | by the professional broadcast industry.
|
| magnetic contacts etc to be connected to
| |
| | CAD
|
| CCTV equipment so that when the alarm is
| |
| | Computer Aided Design. Method of
|
| activated the CCTV equipment will
| |
| | producing complex designs using computer
|
| automatically carry out a pre programmed
| |
| | based software programs.
|
| function such as switching to record a
| |
| | CABLE COMPENSATED AMPLIFIER
|
| given camera.
| |
| | High frequency signals are attenuated
|
| ALC (AUTOMATIC LIGHT CONTROL)
| |
| | when transmitted through cables. A Cable
|
| A feature of an Auto Iris lens used to
| |
| | Compensated Amplifier boosts the high
|
| adjust the between peak and average
| |
| | frequency signals depending on the cable
|
| voltage which will emphasise detail in
| |
| | distance. This ensures the minimum video
|
| bright areas (peak), or shadows
| |
| | loss.
|
| (average).
| |
| | CABLE CORE
|
| ALGORITHMS
| |
| | The central part of the cable, which
|
| Complex mathematical formulae or rules
| |
| | actually carries the video, power and
|
| used to solve complex problems in CCTV
| |
| | control signals. This can be constructed
|
| they are used to achieve digital
| |
| | as a single conductor, or from wire
|
| compression of a video picture.
| |
| | strands.
|
| ALIASING
| |
| | CABLE JACKET
|
| Also known as Moiré patterning. This is
| |
| | The outer protective coating, which
|
| an effect that occurs when an analogue
| |
| | covers the Cable Core.
|
| signal is sampled digitally at a sampling
| |
| | CCIR
|
| frequency less than twice the signal
| |
| | Commitee Consultatif International des
|
| frequency. The effect can be minimised by
| |
| | Radiocommunique. European standardisation
|
| a technique known as optical low-pass
| |
| | body that has set the standards for
|
| filtering.
| |
| | television signals in Europe. 625 lines,
|
| ANALOGUE SIGNAL
| |
| | 25 frames per second.
|
| A signal in which the level is
| |
| | CCTV
|
| represented by a directly proportional
| |
| | Closed Circuit Television. Television
|
| voltage. In video the cameras scene is
| |
| | system intended to be viewed by
|
| represented by varying the voltage in the
| |
| | restricted personnel and with a dedicated
|
| video signal where the voltage is
| |
| | purpose. Pictures from a CCTV system are
|
| directly proportional to the light level.
| |
| | not intended to be broadcast for general
|
| ALKALINE BATTERY
| |
| | viewing.
|
| DC power source with a longer life than a
| |
| | CCVE
|
| standard battery. Cannot be recharged.
| |
| | Closed Circuit Video Equipment.
|
| AMPLITUDE
| |
| | Alternative term for CCTV.
|
| Expression of the strength of a video
| |
| | CFA
|
| signal at a given point. Measured in
| |
| | Colour Filter Array. Optical pixel
|
| Volts.
| |
| | filters used in single chip colour CCD
|
| ANGLE OF VIEW
| |
| | cameras, to produce the colour components
|
| Represents the area of a scene (maximum
| |
| | of a video signal.
|
| horizontal and vertical angle) that can
| |
| | CHANNEL SEPARATION
|
| be seen through a lens. Measured in
| |
| | The term for the separation of signals
|
| degrees.
| |
| | when multiplexed at different frequencies
|
| APERTURE
| |
| | for transmission down a single cable.
|
| The light gathering part of a lens. The
| |
| | CHROMATIC ABERRATION
|
| size of the aperture is controlled by the
| |
| | Optical term, which refers to the
|
| Iris. Aperture size is expressed as an
| |
| | distortion of an image as a result of a
|
| "f" number. The lower the "f" number the
| |
| | scattered focal point caused by a defect
|
| greater the amount of light gathered by
| |
| | in a lens. A combination of lens can be
|
| the lens.
| |
| | used to correct this effect.
|
| ASPECT RATIO
| |
| | CHROMINANCE SIGNAL
|
| The ratio between the width and height of
| |
| | The part of the video signal that
|
| a video picture. The standard Aspect
| |
| | contains the colour information. In
|
| Ratio for CCTV Monitors, NTSC and PAL
| |
| | composite video The chrominance signal is
|
| systems is 4:3.
| |
| | multiplexed at a higher frequency than
|
| ASPHERICAL LENS
| |
| | the signal and transmitted down the same
|
| A type of lens, which has a non-spherical
| |
| | cable. In S-VHS this signal is
|
| shape. It is harder and more expensive to
| |
| | transmitted along a separate cable.
|
| manufacture, but it offers certain
| |
| | CLADDING
|
| advantages over a normal spherical lens.
| |
| | The outer part of a fibre optics cable.
|
| ATTENUATION
| |
| | The cladding is less dense than the
|
| The decrease in magnitude of a signal, as
| |
| | central core, and acts as an optical
|
| it travels through a medium. Used to
| |
| | barrier to prevent the transmitted signal
|
| describe signal loss in a transmission
| |
| | from leaking away from the core.
|
| system. Measured in decibels (dB).
| |
| | C-MOUNT
|
| AUDIBLE DETECTOR
| |
| | Standard lens mounting with a 17.526mm
|
| A device used to detect sound. In CCTV
| |
| | back flange (distance between the lens
|
| system it can be interfaced with a
| |
| | mount and the focal point). Normally used
|
| switcher to switch on a nominated camera
| |
| | on 2/3" and 1" cameras and lenses.
|
| when the detector is activated.
| |
| | COAXIAL CABLE
|
| AUTO BALANCE
| |
| | Term for cable in which two or more
|
| System used in colour cameras to detect
| |
| | conductors share the same axis. Normally
|
| and automatically correct errors in the
| |
| | consists of a single inner core and an
|
| amplitude of colour signals.
| |
| | outer shield. This is the standard cable
|
| AUTO IRIS (AI)
| |
| | used to carry video signals in CCTV
|
| An automatic method of varying the size
| |
| | installations, because it does not
|
| of a lens aperture to allow the correct
| |
| | produce and is not influenced by external
|
| amount of light to fall on the imaging
| |
| | fields.
|
| device. The lens Includes a tiny motor
| |
| | COLOUR STRIPE FILTER
|
| and amplifier, which are used to maintain
| |
| | A filter that is placed in front of a
|
| a one-volt Peak to peak video signal.
| |
| | colour CCD chip to break up the light
|
| AUTO PAN
| |
| | into the basic colours (Red, Green, and
|
| A feature of a pan and tilt head or dome,
| |
| | Blue) The individual colours are then
|
| which allows the camera to pan
| |
| | directed at different pixels on the chip.
|
| continually between two preset points.
| |
| | COMMON SYNC
|
| AVERAGE VIDEO SIGNAL
| |
| | Device used to synchronise cameras by
|
| Represents the average light level of a
| |
| | generating a synchronising pulse that is
|
| picture and is used to open or the iris
| |
| | sent to all cameras connected to it.
|
| in an Auto Iris lens.
| |
| | COMPOSITE VIDEO
|
| BACK-FOCUS
| |
| | The complete video signal, comprising
|
| A fine mechanical adjustment in a camera
| |
| | both the video and sync information.
|
| that is used to adjust the imaging device
| |
| | CONCAVE LENS
|
| relative to the lens to ensure that it is
| |
| | Type of lens in which the light rays
|
| at the exact focal point for the lens
| |
| | passing through it are made to diverge by
|
| fitted. This adjustment is especially
| |
| | the inward curve of the glass surface.
|
| important when fitting a zoom lens.
| |
| | CONDUIT
|
| BACKLASH
| |
| | Plastic or metallic pipe, which is used
|
| An effect noticed in Pan and Tilt units,
| |
| | to conceal and protect cables and wiring.
|
| whereby the unit does not come to a
| |
| | CONTRAST
|
| smooth stop at the end of the pan
| |
| | The difference in intensity between the
|
| movement. This is usually caused by play
| |
| | darkest and the brightest parts of an
|
| in the mechanical components of the unit
| |
| | image.
|
| or by attempting to bring the unit to an
| |
| | CONTRAST CONTROL
|
| instant stop.
| |
| | The control on a monitor used to change
|
| BALANCED SIGNAL
| |
| | the contrast by varying the amplitude of
|
| This is a video signal that has been
| |
| | the video signal.
|
| converted to enable it to be transmitted
| |
| | CONVEX LENS
|
| along 'twisted pair' cables. Usually used
| |
| | Type of lens in which the light rays
|
| where the signal has to be transmitted
| |
| | passing through it are made to converge
|
| over long distances, which would produce
| |
| | by the outward curve of the glass
|
| unacceptably high losses in Coaxial
| |
| | surface.
|
| cable.
| |
| | COVERT CAMERA
|
| BANDWIDTH
| |
| | Type of CCTV camera, which is concealed
|
| The frequency range required to carry an
| |
| | to allow video recordings to be made
|
| electronic signal without attenuation or
| |
| | without the knowledge of the subjects.
|
| loss.
| |
| | CPU
|
| BARREL DISTORTION
| |
| | Central Processing Unit. The heart of a
|
| A distortion in a monitor due to non
| |
| | computer or computer based device.
|
| uniform scanning which causes the image
| |
| | CRIMPING
|
| to appear to bulge outward like a barrel.
| |
| | Term used to describe the process of
|
| BAUD
| |
| | joining a cable to a connector without
|
| Data transfer rate, named after Maurice
| |
| | screwing or soldering. Requires a special
|
| Emile Baud, Equal to 1bit per second.
| |
| | crimping tool to ensure a proper
|
| BIT
| |
| | connection.
|
| Acronym formed from "binary digit". The
| |
| | CRO
|
| basic unit of information in a computer
| |
| | Cathode Ray Oscilloscope (see
|
| or digital system Either 1 or 0.
| |
| | Oscilloscope).
|
| BLACK LEVEL
| |
| | CROSSTALK
|
| Part of the video signal, just above the
| |
| | Noise generated by the interference
|
| sync level corresponding to 0.3v This is
| |
| | between adjacent video, audio or data
|
| where black parts of an image are
| |
| | signals in a multiplexed signal.
|
| electronically represents.
| |
| | CS-MOUNT
|
| BLANKING PULSE
| |
| | Standard lens mounting with a 12.5mm back
|
| A black pulse added to a monitor signal
| |
| | flange (the distance between the lens
|
| during the fly back period to make the
| |
| | mount and the focal point) Normally used
|
| return trace video signal invisible on
| |
| | on modern ¼", 1/3", and ½" cameras and
|
| the screen.
| |
| | lenses.
|
