Basic CCTV Terminology
APC
Adaptive Picture Control. VCR function which automatically detects the condition of the recording head and the video tape and then sets the optimum record head current to prevent
AGC
Automatic Gain control. Usually a switchable circuit that allows the camera to provide a ‘useable’ picture during low light levels. You can generally tell when the circuit is operating because the picture appears to be ‘grainy’.
AMBIENT LIGHT
Lighting level that is normal for a certain area. It generally does not alter. It also can mean the background light level of a certain area.
APERTURE CORRECTION
Switchable correction circuit which sharpens the image of a picture electronically.
AUTO IRIS
Causes the aperture of a lens to automatically adjust to varying light levels, thus providing a constant picture.
BNC
Commonly used video connector for composite video.
BALANCING LINE
A circuit for transmission of video signals which are equal in voltage, but of opposite polarity.
BANDWIDTH
A value which expresses the difference between the upper and lower limits through a range of frequencies.
BLACK LEVEL
A measurement of a video signal that matches a specified maximum limit for black peaks in the picture.
CCD
Charge Coupled Device. The latest technology for imaging devices. There are two main types: Interline transfer and Interframe transfer.
CCTV
A Closed Circuit Television System which is for private purposes only, and not for public or general broadcasting.
CODEC
Short for coder/decoder. An ISDN transmission system designed to the international teleconferencing standard, H.320.
CONTINUOUS STRIPE PHOSPHORS
Method employed within Trinitron monitors to increase brightness and resolution over conventional dot pattern CRTs.
C MOUNT
The industry standard type of screw threaded lens mount.
CS MOUNT
Same thread as
COMPOSITE VIDEO
1.A video signal in which the luminance and chrominance components have been combined (encoded) as in NTSC, PAL or SECAM.
2.A video signal obtained by combining parts of at least two video signals, for example by keying or matting.
CROSS TALK
Electrical interference caused by electromagnetic or electrostatic couplings from nearby conductors or external sources. It can also refer to interference between two or more signals in close proximity within a bandpass.
CRT
Cathode Ray Tube. Means by which the picture is displayed on a monitor.
dB
Decibel, a ration of input power. It is also a measurement of sound levels.
DARK CURRENT
Leakage signal from a CCD sensor in the absence of incident light.
DARK NOISE
Noise caused by the random nature of the dark current.
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The Sony Guide to CCTV . Issue 3
