Additional Information ǀ GLOSSARY OF TERMS
Analog Signal: Representation of data by continuously varying quantities, with respect to time. An analog electrical signal has a different value of volts or amperes, or phases of either, for electrical representation of the original excitement (sound, light) within the dynamic range of the system
Angle of View: The angular range that can be focused within the image size. Small focal lengths give a wide angle of view, and large focal lengths give a narrow field of view.
Aperture: The opening of a lens which controls the amount of light reaching the surface of the pickup device. The size of the aperture is controlled by the iris adjustment. By increasing the F-stop number (f1.4, f1.8, f2.8, etc.) less light is permitted to pass to the pickup device.
Archive: Long-term off-line storage. In digital systems, pictures are generally archived onto some form of hard disc, magnetic tape, floppy disk or DAT cartridge, CDROM or DVD.
Artifacts: Undesirable elements or defects in a video picture. These most commonly occur after an image has been compressed and re-constituted.
Aspect Ratio: The ratio of width to height for the frame of the televised picture. 4:3 for standard systems, 5:4 for 1K x 1K, and 16:9 for HDTV.
Aspherical Lens: A lens designed with a non spherical shape so that it refracts the light passing through it to either lower the lens aperture so that it passes more light or decrease barrel distortion on wide angle lenses.
AGC (Automatic Gain Control): An electronic circuit used by which the gain of a signal is automatically adjusted as a function of its input or other specified parameter.
Automatic Iris Lens: A lens in which the aperture automatically opens or closes to maintain proper light levels on the faceplate of the camera pickup device.
ALC (Automatic Level Control): A feature on Auto Iris lenses (also known as the peak/average control). Adjusting this control allows the Auto Iris circuitry to either take bright spots more into consideration (peak), bringing out detail in bright areas, or less into consideration (average) bringing out detail in shadows.
Auto Terminating: A feature where the equipment (e.g., monitor) automatically selects the correct termination depending on whether the video output BNC is connected.
AWB (Auto White Balance): A feature on color camera that constantly monitors the light and adjusts its color to maintain white areas.
Back-Focus: A procedure of adjusting the physical position of the CCD-chip/lens to achieve the correct focus for all focal length settings (especially critical with zoom lenses).
Balun: This is a transformer used to match or transform an unbalanced coaxial cable to a balanced twisted pair system, or visa versa.
GLOSSARY OF TERMS
Bandwidth: A measure of the carrying capacity of information over a network. Video, for example, takes more bandwidth to transmit over a network than text. Bandwidth is an important issue for network administrators.
Bit Rate: The number of bits per second stored or transmitted by a digital signal. Higher bit rates translate to a better audio or video quality.
Blackburst: A composite color video signal. The signal has composite sync, reference burst and a black video signal.
BLC (Back Light Compensation): A feature on newer CCD cameras which electronically compensates for high background lighting to give detail which would normally be silhouetted.
BNC (Bayonet Fitting Connector): A professional quality cable termination which is used primarily in labs and professional studios as an interconnect. Bayonet Neill-Corcelman.
Brightness: The attribute of visual perception in accordance with which an area appear to emit more or less light. (Luminance is the recommended name for the photoelectric quantity which has also been called brightness.)
Broadband: A transmission medium that has a bandwidth (capacity) capable of carrying numerous voice, video, and data channels simultaneously. Each channel operates on a different frequency. Often the term ‘broadband’ is used to refer to any type of high-speed internet access in the home.
Byte: Is 8 binary bits (ones and zeroes). The greater multiples of bytes are shown below: Kilobyte (1,024 bytes)
Megabyte (1,024 kilobytes, 10488576 bytes) Gigabyte (1,024 megabytes 1073741824 bytes) Terabyte (1,024 gigabytes 1099511627776 bytes)
Camera Format: The approximate size of a camera image pickup device. This measurement is derived from the diagonal line of a chip or the diameter of the tube. Currently there are five format sizes in the CCTV industry: 1", 2/3", 1/2", 1/3" and 1/4".
CCD (Charge-Coupled Device): For imaging devices, a self-scanning semiconductor array that utilizes MOS technology, surface storage, and information transfer by shift register techniques.
C mount/CS mount: CCTV lenses are available in two different lens mounts. C-mount lenses have a flange back distance of 17.5 mm vs. 12.5 mm for CS-mount lenses. Many of today’s cameras can accept either type of lens, but it is important to make sure that camera and lens are compatible and set up properly. C-mount lenses can be used on CS-mount cameras by utilizing a 5mm adapter or adjusting the camera for C-mount lenses. Because of the shorter back focal distance, CS-mount lenses can only be used on CS-mount cameras. Your picture will be out of focus if you use a CS-mount lens on a C-mount camera.
C-mount adaptor: An adaptor used to convert a CS-mount camera to C-mount to accommodate a C-mount lens. It is simply a ring 5 mm thick, with a male thread on one side and a female on the other
side. It has a 1" diameter and 32 threads/inch, as the cameras and lenses. It often comes packaged with the newer type (CS-mount) of cameras.
Coaxial Cable: A particular type of cable capable of passing a wide range of frequencies with very low signal loss. Such a cable in its simplest form consists of a hollow metallic shield with a single wire accurately placed along the center of the shield and isolated from the shield.
Composite Video Signal: The combined picture signal, including vertical and horizontal blanking and synchronizing signals.
Compression: The reduction in gain at one level of a picture signal with respect to the gain at another level of the same signal.
Contrast: The range of light to dark values in a picture or the ratio between the maximum and minimum brightness values.
CRT (Cathode Ray Tube): A large vacuum tube featuring a slightly curved glass surface at one end (the screen) and an emitter of electrons on the other, which focuses and directs a stream of electrons to hit a coating of phosphors on the back side of the screen.
Current: Flow of electricity through a circuit over a period of time; current is measured in amperes.
D/A: Opposite to A/D, i.e., digital-to-analog conversion.
dB (Decibel): A measure of the power ratio of two signals. It is equal to ten times the logarithm of the ratio of the two signals.
DC Type Auto-Iris Lens: An Auto-Iris lens with internal circuit which receives voltage and a video signal from the camera to adjust the iris.
Depth of Field: The front to back zone in a field of view which is in focus in the televised scene. With a greater depth of field, more of the scene, near to far, is in focus. Increasing the f-stop number increases the depth of field of the lens. Therefore, the lens aperture should be set at the highest f-stop number usable with the available lighting. The better the lighting, the greater the depth of field possible. In other words, the depth of field is the area in front of the camera which remains in focus. The larger the f- number the greater is the depth of field.
Distribution Amplifier: A device that provides several isolated outputs from one looping or bridging input, and has a sufficiently high input impedance and input-to-output isolation to prevent loading of the input source.
DSP (Digital Signal Processing): An algorithm within the camera that digitizes data (the image). Examples include automatic compensation for backlight interference, color balance variations and corrections related to aging of electrical components or lighting. Functions such as electronic pan and zoom, image annotation, compression of the video for network transmission, feature extraction and motion compensation can be easily and inexpensively added to the camera feature set.
For ordering information, visit
www.honeywellvideo.com or contact Inside Sales at 1-800-796-2288. 137
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