Tech Terms Glossary
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C mount/CS mount: CCTV lenses are available in two different lens mounts. "C-mount" lenses have a flange back distance of 17.5mm vs. 12.5mm 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.
CATV (Community-Antenna Television): Also called cable TV. Broadcasting method that uses a central antenna to feed off-air broadcast programming to an entire community through a hard-wired network.
Cardioid: Heart-shaped pick-up pattern of a microphone. (This means that the microphone can "hear" sounds coming from directly in front of and to the sides of the microphone head, but not behind it.) Useful in isolating sounds in loud environments and avoiding sound-system feedback.
Candlepower: The unit measure of an incident (direct) light.
Cantilever: The part of a cartridge that transmits vibrations, first picked up by the stylus tip from a record, to the electromagnetic generating unit.
Cartridge: A transducer that converts the mechanical vibrations caused by the record groove undulations into an electric signal.
Cat 5 (Category 5) or Cat 3 (Category 3): refers to specific building regulations for structural and fire safety to which the materials (usually wire and cable) conform.
CCD (Charged Coupled Device): A chip that is the pick up devise on a camera, performing a similar function as a camera tube.
CCTV: The common abbreviation for Closed Circuit Television. Video signals that are generated and viewed in the same area. Many times corporations use this type of system for training and other information within their facilities. Home security video monitoring systems can also be considered CCTV.
Cell: A single-unit, self-contained, voltage/current source. Has positive connectors for use with electrical or electronic devices, alone or along with other cells. Examples of cells: AA, AAA, C, D, button cells and many others.
Chrominance Subcarrier: Frequency used to establish a reference for demodulating the chrominance signal.
Cms: The mechanical compliance of a speaker driver's suspension (surround, cone and spider). Measured in inches per pound or millimeters per Newton.
Coatings: Light is lost by reflection from optical surfaces that are intended to be refractors only. This loss is effectively reduced by very thin coatings on the lens surfaces. This can be seen as a blue or violet hue on the lens surface.
Coaxial: Circles that share the same center-point (axis). Used to describe cable and speakers.
Coaxial cable: Consists of center signal-carrying conductors and outer shielding conductors that share the same center axis. The outer shield prevents interference of outside noise and signals from distorting or weakening the signal traveling across the center conductors.
Coaxial speakers: Consists of woofers and tweeters that are mounted together such that they share the same center axis. The theory here is that sounds coming from speakers that share the same centerpoint are supposed to sound as though they are coming from one source as opposed to separate drivers.
Comb Filter: Circuitry that electronically separates the color (chrominance) from the picture (luminance) signal, to enhance fine detail with minimal color spill or picture "noise" (distortion).
Combiner: Used to combine similar signals into one cable. Used for UHF/VHF and CATV signals.
Composite Video: The combined video signal that includes the picture signal, the vertical and horizontal blanking and synchronizing pulses. Examples of composite video sources: "Video Out" connection points, usually RCA jacks, on VCRs, DVDs, satellite receivers, home video cameras, surveillance cameras, "web-cam" cameras, etc.
Compression-type Connector: A connector that is attached to a wire or cable such that when the connector is assembled, it's parts grip into the wire to which they are attached.
Conditional Refresh: A technique used in slow and fast scan transmission equipment, where only small screen changes are transmitted. Up to a certain percentage of the on-screen picture can be updated before a full picture is required.
Crosstalk: An undesired signal that interferes with the desired signal.
Crossover: Splits an audio signal into different frequency ranges (low, middle and high) for use with different types of speaker drivers (woofers, midranges and tweeters) or to be routed to different amplifiers in a multi-amp system.
Current: The organized migration of electrons through a circuit or conductive material, as the result of an applied voltage and the presence of resistance.
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