C

C-Language - A mid-level programming language designed for structured programming

C-Mount - A lens mounting system for video cameras and 16mm movie cameras, which accepts certain lenses. This standard mount and mounting plate are common on portable and personal video cameras. The C-Mount is 1 in diameter, 16mm, and has 32 threads per inch

Cable Equalization - Altering the frequency response of a video amplifier to compensate for high frequency losses in coaxial cable

CAD - Computer Aided Design: a broad definition that usually applies to mechanical design applications, also known as MCAD, such as physical layout

CAD/CAM - Computer Aided Design/Computer Aided Manufacturing

CADD - Computer Aided Drafting and Design

CAI- Computer Aided Instruction

CAM - Computer Aided Manufacturing; Content Addressable Memory

Cans - Earphones

CAP (Competitive Access Provider) - Companies which offer telecommunication services to bypass the local phone company and tie directly into a long distance carrier

Capacitor - A component in circuitry which stores and releases voltage within the circuit. Also a type of microphone See also MICROPHONES

Capacity - Total amount of information that can be stored in a system or transmitted by that system

Capstan - A rotating shaft or spindle, which moves tape at a constant speed during recording or playback in tape recorders and players. A pressure roller squeezes or pinches the tape tight against the capstan to provide traction

Capture - The effect of a strong FM signal suppressing weaker signals at the receiver.

Card Reader - See MAGNETIC CARD READER

Cardioid Microphone - A unidirectional microphone with moderately wide front pickup (131’), Angle of best rejection is 180~ from the front of the microphone, that is, directly at the rear,

Carrel - Booth or station for individual or small group study

Carriage Return - An end-of-line character not normally seen on the CAT) which moves the cursor or print head to the left end of the Line, often accompanied by a LINE FEED character which advances paper 1 line, or moves the cursor to the next line down

Cartesian - The simplest and most popular screen mapping

Cartridge. Continuous - A container for film or tape in which the end of the material may be spliced to the beginning for self-threading and continuous operation so that rewinding is not needed and usually not possible

CAT - Concatenate, bringing together strings or files into one large one

Cathode Ray Tube (CRT) - The video display tube used in video monitors and receivers, radar displays and video computer terminals. Contains a cathode and heater element at one end which produces electron beams which hit a phosphor coating on the face of the tube and make it glow or hit an oxide coating and produce voltage

CATV Community Antenna Television, usually referred to as cable television

CAV - Component Analog Video; unencoded video signals which can provide greater color resolution. An NTSC encoder must be used to read the signals so they may be recognized by a standard NTSC receiver

CBL - Compute’ Based Learning

back to top

CCD - Charge-Coupled Device, semiconductor devices arrayed so that the electric charge at the output of one provides the input stimulus to the next. More compact and efficient than cathode ray tubes.

CCIR - Comité Consultatif International Radiocommunications, a French standards body

CCTV - Closed Circuit Television

CCU - Camera Control Unit

Cell Animation - Since moving full-screen images requires large amounts of memory and rapid processing, it is more convenient to animate small portions of the image. The smaller components are called cells and can be rapidly changed, giving the effect of movement

CGA - Color Graphics Adaptor

Channel - One program path through a system without interference from another. See DUAL CHANNEL

Character - A letter, digital, or other typographic symbol that requires 1 byte of storage

Character Generator - A device which displays letters and numbers electronically on a video screen for use in video productions- Usually provides multiple screen storage and is capable of background colorization from video display

Chip - Miniscule piece of silicon; an IC or integrated circuit

Chroma - Chrominance

Chromakeying (also Chrome Keying) - A film and video process in which a subject is filmed or taped in front of a blue or green screen. The colored screen is later replaced with another background, either provided on film, tape, or with computer graphics

Chrominance - In video, the hue and saturation of color of an object as differentiated from the brightness value or luminance of that object. Without the chrominance signal, the received video picture would be in black-and-white. Compare with LUMINANCE

CIF (Common Intermediate Format) - A compromise television display format adopted by the TSS CCIU} which is relatively easy to derive from both PAL and NTSC video signals.

CinemaScope - One of the first wide screen movie formats, presenting a 2.35:1 aspect ratio with a 2:1 anamorphic squeeze

back to top

Clamp. Clamping - The circuit or process that restores the DC component of a signal. A video clamp circuit, usually triggered by horizontal synchronizing pulses, re-establishes a fixed DC reference level. Some clamp circuits clamp sync tip to a fixed level while others clamp back porch blanking) to a fixed level

Clipping Level - An electronic limit to avoid overdriving the audio or video portion of the television signal

Clock Cycle - The rate at which a computer executes an operation, something like the RPMs of a car engine

Closed Circuit Television (CCTV) - A distribution system which limits reception of an image to those receivers or monitors which are directly connected to the origination point by coaxial cable or microwave link

Closed Loop - A continuous loop of film or tape for repetitive playing, often in a cartridge

COBOL - Common Business-Oriented Language.

Codec (Coder/Decoder) - A data processing device which converts analog signals to digital form and vice versa. Codecs also compress and decompress data. In videoconferencing, codecs allow real time transmission of video over digital links with 56Kbps to 45Mbps of bandwidth transmission.

Color Bars - SMPTE standard test bars used to match playback with original recording levels. Often accompanied by a 1000Hz audio tone

Color Burst - The portion of the composite video signal, which aligns the color decoder of the display device

Color Cycling - The colors of individual pixels are changed to give the effect of movement

Colorization - Adding color to an originally black-and-white image, often done with old films

Colorplexer (also Color Encoder) - An encoder, which combines the separate red, green and blue signals into one composite video signal.

Color Temperature. The color tint expressed in degrees Kelvin (K) of the light source. The higher the color temperature, the bluer the light: the lower the temperature, the redder the light.

Comb Filter - A filter that improves resolution and reduces objectionable color defects.

Command Driven - Type of a program, which requires the user to issue commands to carry out operations. This usually requires the user to learn a set of codes used by the program. Software of this type is usually more difficult to learn, but is much faster and more efficient than MENU DRIVEN software.

back to top

Compact Cassette - Often called Philips cassette; a 0.15 3.81mm) audiotape attached to 2 hubs inside a plastic container for self-threading. May be operated in fast-forward or rewind modes. The number after “Ca indicates the total running time in minutes on both sides of the tape at the standard speed of 1~ ps as defined in American National Standard 54.8-1975 (EIA RS-399-A-May 1975)

Compander - A two-step noise reduction system consisting of a compressor in the transmitter and an expander in the receiver.

Compatible Color - A video broadcast system which separates the luminance and chrominance signals so that the signal may be received by either a color or black-and-white receiver

Component Analog - An unencoded video signal consisting of three primary color signals (RGB) that together convey all necessary picture information

Component Digital - A digital representation of component analog signal set, most often Y, B-Y, R-Y. The encoding parameters are specified by CCIR 601

Composite Sync - A total sync system with horizontal and vertical scan controls

Composite Video Signals - Single signals with picture (luminance and chrorminance) and sync information

Compression - Reduction of the amount of information to accommodate cost-effective digital transmission. For example, sub-Ti video codecs compress analog signals (roughly equivalent to 90,000Kbps) to digital rates varying from 5 to 1,544Kbps.

Compression Algorithms - Software that allows codecs to reduce the number of bits required for data storage or transmission. Some popular types include: DCE - Discrete Cosine Transform (H.261, CTGX): Vector Quantization (PictureTel) - see algorithm

Compressor - A circuit which reduces the dynamic range of a signal by a fixed ratio, typically 2:1 in a compander system Computer Simulation - Using mathematical algorithms, or sets of rules, to simulate physical processes in a computer program. Computers can often interpret numeric results from a given problem and then display them as a graphic screen image.

Condenser - See MICROPHONES

Condenser Lens - On projectors; one or more lenses between the projection lamp and slide or film aperture to concentrate the light in the film and lens apertures

Configuration - Design of computer system; arrangement by which devices communicate with each other

back to top

Console - In an Electronic Learning Laboratory, a desk or cabinet at the instructor’s position with built-in devices for originating, controlling, distributing and monitoring student stations

Continuous Loop - A loop of film or tape made by splicing the ends together for continuous projection or operation. compatible projector, recorder or playback

Contrast - How much brighter the white areas of an image are than the black areas

Contrast Rang, - The range of grays in a video image, usually a ratio of light to dark

Contrast Ratio - The ratio of brightness of the brightest possible area to the darkest possible area of an image

Control Code - Special (and sometimes odd-looking) characters which have no meaning except to the computer program, often imbedded in text documents to control formatting, printing, etc.

Control Key - Sometimes abbreviated as CURL, the control key is usually pressed in conjunction with another key. When the 2 keys are pressed simultaneously, the meaning of the second key is changed, usually determined by the particular software being used

Controlled Reading Device - A device for progressively disclosing or exposing visual information from left to right at controlled rates

Control Track - The lower portion of a tape where all the sync information is recorded

Convergence - Proper alignment of the vertical and horizontal lines, as in video projection

Coordinates - Approach, using en X axis horizontal) and V axis (vertical). For 3-0 images, a Z axis is specified

Copy Stand - A vertical or horizontal stand with a bracket made to hold a camera for photographing or making a videotape of documents or objects at close range

Coupling - The method of connecting two circuits together. Circuits connected with a wire are directly coupled: circuits connected through a capacitor or a transformer are indirectly (or AC) coupled

CPE (Customer Premises Equipment) - Telephones, terminals, codecs, multiplexers, etc.

CPS - Characters Per Second, used as a measurement of computer output

CPU - Central Processing Unit; the portion of a computer which reads and executes programming

back to top

Crash - System failure; unplanned shutdown

Crawl - The smooth horizontal movement of a line of text across the screen.

Crossfade - To dissolve images

CRT - Cathode Ray Tube, the display on any video or computer monitor

Crystal - See MICROPHONES

CSA - Canadian Standards Association

CSMA - Carrier Sense with Multiple Access

CSU (Channel Service Unit) - A CPE component which terminates a digital circuit such as T1. CSU assures compliance to FCC regulations and performs some line-conditioning functions.

CTS - Communications Technology Specialist

CTX and CTX-Plus - Proprietary DCT compression algorithms used by Rembrandt II series codecs from CLI.

Cue Control - A device for rapidly advancing or rewinding a tape or film to sample the contents or find a desired section

Cursor - A symbol (usually a cross-hair or horizontal bar) which indicates where characters or drawing will next appear on the screen

Curved Screen. A section of the surface of a large sphere. Curved screens have viewing angles less than 180° and gains greater than 1°

Cut - To terminate a program, image or scene abruptly; to make a sudden and complete change from one to another

Cycle Palette - See COLOR CYCLING

Cyclorama Lights Designed to create a smooth lighting effect on a backdrop or cyclorama.

back to top