A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Aperture Opening (Lens) Controls the amount of light reaching the surface of the camera pick-up device. Aperture size is controlled by the iris. Increasing the f-stop decreases the amount of light reaching the pick-up device.

Aspect Ratio Ratio of picture height to picture width. Standard ratio is 4:3.

Automatic Brightness Control Electronic circuitry, which automatically controls the brightness of video monitors in relation to ambient light.

Automatic Frequency Control (AFC) Circuitry that automatically maintains the desired frequency.

Automatic Gain Control (AGC) Circuitry that automatically adjust the signal to proper strength.

Automatic Light Control Process by which the brightness upon the camera pick-up device is automatically adjusted according to the brightness of the scene.

Auto Pan Automatic back and forth camera motion.

Auto Scan Same as Auto Pan.

Auto Iris Lens Camera lens, which automatically adjusts for proper light levels.

Attenuation A decrease in signal strength.

Bandpass Specific range of frequencies allowed to pass through a device.

Bandpass Filter Filter that passes only a specific band of frequencies.

Bandwidth Range of frequencies in which a specific device will properly operate.

Blooming Defocusing effect that occurs around bright areas of a picture when an increase in brightness occurs.

BNC Most commonly used video cable connector.

Bridging When a high impedance video line is paralleled, usually through a switch, to a source of video.

C-Mount Former industrial standard lens mounting format.

Candlepower Unit measure of incident light.

CCD (Charged Coupled Device) The "chip" in a solid-state camera that replaced the camera tube.

CCTV Closed Circuit Television.

Coaxial Cable Cable commonly used to transmit video signals. It consists of a metallic shield with one or more center conductors, which are isolated from each other and the shield.

Composite Video Video signal that contains the picture signal, and vertical and horizontal blanking and sync pulses.

Compression Reduction in gain at one level of a video signal with respect to the gain at another level of the same signal.

Contrast The range of light and dark values in a picture or the ratio of maximum and minimum brightness.

Crosstalk Undesired signal that interferes with a desired signal.

CS Mount New standard lens mounting format.

DB (decibel) The power ratio of two signals.

Depth of Field Front to back area in the camera view, which is in focus. The better the lighting, the greater the Depth of Field possible.

DSP Digital signal processing.

Duplex (Multiplexer) A multiplexer, which allows viewing of multiple "pictures" during recording.

DVR Digital Video Recorder same as Time Lapses Recorder but all recording is on a computer hard drive and can be networked.

Dwell Length of time a video switcher holds a camera's "picture" before switching to the next camera's "picture".

Distribution Amplifier Device used to send a single video input signal to multiple video output devices EIA US standard, 525 TV lines and 60 fields.

F-Number Indicates the brightness of the image formed by the lens and controlled by the iris. A smaller f-number means a brighter image.

F-Stop Indicates the speed of a lens. The smaller the number, the greater the amount of light that passes through the lens, thus allowing for better low light camera performance.

Fiber Optics Flexible glass fibers used to conduct signals.

Field One of the two equal parts into which a TV frame is divided.

Field Frequency Number of fields transmitted per second in a TV system. The NTSC standard is 60.

Field of View The horizontal or vertical picture size at a given distance from a camera to the subject.

Focal Length The distance from the centerline of the lens to the camera pick-up device. It determines the size of the image and the angle of the field of view as seen by the camera through the lens.

Foot Candle (FC) Unit of measurement of the intensity of light. 1 FC = 10 lux.

Frame One complete TV picture.

Gain The amplification a system provides to a signal.

Gen-Lock Method used to synchronize one or more cameras by external means. Typical methods are composite video, composite sync, and horizontal or vertical sync.

Ground Electrical point that is common to either metal chassis, a terminal, or a ground bus.

Homing Process of displaying a given camera output on a given monitor.

Horizontal Blanking Electrical signal produced at the end of each scanning line.

Hum Electrical disturbance at the power supply frequency or harmonic.

Infra Red (I.R) Frequency of light, invisible to the human eye, used for covert surveillance and low light camera use.

Image Intensifier Electronic device used to provide a brighter output image than the input image.

Impedance Opposition to the flow of electrical current.

Incident Light Amount of light directly over an object.

Insertion Loss Signal strength lost due to the insertion of a piece of equipment in the line.

Looping Term used when a high impedance device is connected in parallel to a video source.

Lux Unit of measurement of the intensity of light. 10 lux = 1 FC.

Matrix Switcher Normally used in larger camera systems, this switcher allows any of the systems cameras to be routed to any of the systems monitors.

Modulate To vary the amplitude or frequency of a signal.

Monochrome Having one color. In CCTV it is Black and White.

Multiplexer Device, which allows the recording/playback of multiple cameras on a single time-lapse recorder with little loss of information.

Noise Random electrical energy or interference.

NTSC National Television Systems Committee. Formulated the standards with the FCC for color television in the U.S.

Pan Horizontal camera movement.

Passive Non-powered element of a system.

Peak-to-Peak Amplitude difference between the most positive and negative points of a signal.

Pinhole lens Lens with a very small front, easily concealed, for use in covert applications.

Quad Device that simultaneously places the pictures from four cameras onto one video monitor.

Resolution Measure of the ability of a CCTV system, or one of itÕs components, to produce detail.

Roll Result of the loss of vertical sync, which causes the picture on a monitor to move up or down.

Saturation (color) The vividness of a color, which is directly related to the amplitude of the chrominance signal.

Scanning Horizontal (panning) camera motion.

Sensitivity (pickup device) The amount of light needed for the pickup device to operate.

Signal to Noise Ratio Ratio between a useful signal and unwanted noise.

Spot Filter A small device used to increase the f-stop range of a lens.

SVHS High resolution video recording format. SYNC Electronic pulses inserted in a video signal for assembling picture information in the proper position.

Time Lapse VCR VCR that can record for extended periods of time on a single videotape by using frequent tape "pausing". The longer the time of recording, the fewer number of "pictures" recorded per second.

Vari-focal Lens Lens with an adjustable focal length, such as 3.5-8mm, 2.6-6mm, and 4.5-10mm.

Vertical Interval The time of the vertical retrace.

Vertical Retrace Return of the electron beam to the top of a TV picture tube or a camera pickup device target at the completion of the field scan.

Zoom Lens A lens that is used as a wide angle, standard, or telephoto lens by varying the lens focal length.