Automatic Gain Control. When enabled, the camera's sensitivity is automatically increased when the level of ambient light drops. Automatic Gain Control. A circuit for automatically controlling amplifier gain in order to maintain a constant output voltage with a varying input voltage within a predetermined range of input-to-output variation.
Auto-tracking White Balance. This is a white balance feature that accepts many types of lighting conditions by using an automatic tracking system that automatically controls the color temperature range from 2,400K to 10,000K. ATW mode ensures reliable color reproduction when lighting conditions change frequently.
Automatic method of varying the size of the lens aperture in response to changes in light. This is a function of the lens or the camera.
Preset White Balance. AWC is suitable where a lot of white objects appear in the scene. Also it is suitable for situations where the object merges into the scene with a similar color shade..
A system for detecting errors in color balance in white and black areas of the picture and automatically adjusting the white and black levels of both the red and blue signals as needed for correction.
Automatic Brightness Control:
In display devices, the self-acting mechanism which controls brightness of the device as a function of ambient light..
Automatic Iris Lens:
A lens that automatically adjusts the amount of light reaching the imager.
A facility which allows the use of external alarm equipment such as PIR's, magnetic contacts etc to be connected to CCTV equipment so that when the alarm is activated the CCTV equipment will automatically carry out a pre programmed function such as switching to record a given camera.
Also known as Moiré patterning. This is an effect that occurs when an analogue signal is sampled digitally at a sampling frequency less than twice the signal frequency. The effect can be minimised by a technique known as optical low-pass filtering.
Angle of view:
Represents the area of a scene (maximum horizontal and vertical angle) that can be seen through a lens. Measured in degrees.
The light gathering part of a lens. The size of the aperture is controlled by the Iris. Aperture size is expressed as an "f" number. The lower the "f" number the greater the amount of light gathered by the lens.
A type of lens, which has a non-spherical shape. It is harder and more expensive to manufacture, but it offers certain advantages over a normal spherical lens..
Audible Detector: :
A device used to detect sound. In CCTV system it can be interfaced with a switcher to switch on a nominated camera when the detector is activated..
Asymmetrical Digital Subscriber Line (ADSL):
A method for moving data over regular phone lines. An ADSL circuit is much faster than a regular phone connection, and the wires used are the same wires used for regular phone service. ADSL supports data rates of from 1.5 to 9 Mbps when receiving data (known as the downstream rate) and from 16 to 640 Kbps when sending data (known as the upstream rate). ADSL requires a special ADSL modem.
Audio/Video Interleave (AVI):
An AVI file is a sound and motion picture file that conforms to the Microsoft Windows Resource Interchange File Format (RIFF) specification. AVI files (which end with an .avi extension) require a special player that may be included with your web browser.
A decrease or loss in a signal, usually measured in decibels.
Automatically select the correct termination depending on whether the video output is connected.