C Details

links page
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

C

Cable modem

Computer modem connected to cable TV coax able to transport data at very high speeds (up to 30Mbps).

A device that connects between your computer and your cable-TV source, able to transmit data quickly to an Internet service provider also on the system

Cache.

A small amount of extremely fast RAM used to provide frequently-needed data for the processor. A processor stores recently of frequently used instructions in small chunks of very fast memory called level 1 and 2 caches.
Cache Principles
Purpose: to give memory speed approaching that of the fastest memories available, and provide large memory size inexpensively
Small amount of fast memory
Sits between normal main memory and CPU
May be located on CPU chip or module
Cache Operation
CPU requests contents of memory location
Check cache for this data
If present, get from cache (fast)
If not present, read required block from main memory to cache
Then deliver from cache to CPU
Cache includes tags to identify which block of main memory is in each cache slot
Level 1 Cache
fast on-chip memory
access speed is equal to CPU clock speed
often split into two parts:
instruction cache
data cache
large data cache improves multimedia performance
Level 2 Cache.
on-chip cache currently restricted to at most 512K - often much less.
still want to speed up memory access.
use secondary, off-chip cache based on fast-access memory (SRAM).
traditionally, Level 2 cache was situated on the motherboard.
new CPUs bundle cache into processor module.

Calibration.
Setting up or otherwise getting ready a piece of electronic equipment; primarily used in regard to calibrating or properly adjusting video displays and audio equalizers.

Camcorder.
Combination of camera and video tape recorder in one device. Camcorders permit easy and rapid photography and recording simultaneously. Camcorders are available in most home video formats: 8mm*, Hi-8*, VHS*, VHS-C*, S-VHS*, etc

Camera adapter
Box of electronics that a portable camera can plug into (instead of directly into a VCR) that powers the camera and distributes the camera's video and other signals via standardized outputs. Camera supply Most video cameras use an external DC voltage supply which is derived either from a battery belt worn by the camera operator, from a battery within the video recorder itself, or from the mains power supply (after voltage conversion).

Candlepower.
The unit measure of incident light.

Capacitance.
The ability of an electronic device, a capacitor, to hold and store an electric charge.

Capacitors.
Electric devices that store a charge.

Capstan.
Round tube-like object in a cassette player that rotates against the tape thus pulling the tape through the player (similar to a car tire rotating on the road to provide motion).

Captioning encoder.
Device that changes text data into the codes that go on line 21 of the video signal passing through it, essentially making closed (or open) captioned video.

Captioning Service.
Company that encodes closed (or open) captions into your TV production, either live or off-line.

Capture.
Digitize a stretch of videotape on a non-linear editor, or digitize the first and last image of a scene and store the time codes on an analog non-linear editor.

Capture Ratio.
Radio tuner specification describing a tuner's ability to lock in on and play information from one channel versus another based on the strength of the channel when both channels are on the same frequency.

Carousel Changer.
Type of optical disc player/transport (namely CD) that holds multiple discs on a rotating platter enabling the component to play numerous discs without the user needing to manually switch discs.

Cartridge (Phono Cartridge).
Device used with record players that holds the stylus or needle and attaches to the tonearm of the record player converting signals from the record grooves into electrical energy that can be played on an audio system.

CATV.
Cable television; video and audio signals transmitted through coaxial cables terminated with F-connectors to television tuners enabling the television to display a large number of channels with little distortion and no antenna.

CAV (Constant Angular Velocity).
Laserdisc format in which the disc spins at a constant, unchanging number of revolutions per second resulting in less information being held compared to a CLV disc (30 minutes per side versus 60 minutes per side) but allowing the use of special features such as stop motion and slow motion.

CCD (Charge Coupled Device).
A semiconductor device (IC) that converts optical images to electronic signals. CCDs are the most commonly found type of image sensor in consumer camcorders and video cameras.

CCIR (Comite Consulatif International Des Radiocommunications).
A European committee situated in Paris responsible for creating and approving professional standards related to audio and video.

CCTV (Closed Circuit TV).
A video system used in many commercial installations for specific purposes such as security, medical and educational.

CCU or camera control unit.
Box of electronic circuits which can remotely adjust the operation of a camera as well as provide power and signals to it.

CSS Cascading Style Sheets.
Style Rules Terminology
Selector { Property : Value}
Selector
The element which is affected by the style - typically HTML elements, user-defined classes, user-defined IDs or pseudoclasses such as anchors.
Property
The characteristic of the selector that you wish to style (e.g. font-family or background-color).
Value.
The precise style specification of the property (e.g. monospace or red).

CCS Information at www.w3.org.

CD (Compact Disc).
A digitally encoded disc capable of containing more than one hour of music at a sampling frequency of 44.1 khz. The data is read by a laser beam. (Sound)

Compression.
The reduction of a span of amplitudes done for the purpose of limiting the reproduction of those amplitudes. (Post Production)

CD Changer.
Type of compact disc player that holds more than one disc internally and that can swap discs to play various discs without the need for the user to physically swap discs or add discs.

CD-I.
Compact Disc Interactive, a disc (or player) able to play interactively, up to 74 minutes of limited motion MPEG-1 compressed audio and video.

CD-R.
Compact Disc-Recordable.(also CD - Writable) Form of compact disc consumers can record on using special CD "burners" or CD recorders.

CD-ROM.
Compact disc read only memory; CD that cannot be written to or recorded making it useful only for data retrieval.

CD-ROM XA .
CD-ROM Extended Architecture, plays music CDs and CD-ROM data on one multisession disc. Discs can be recordable.

Center Channel.
Third front audio channel (in addition to main stereo left and right channels) found in surround sound audio systems with the primary task of reproducing movie dialogue thus locking the voices to the screen for all listeners.

Center Channel Speaker
Speaker used to output information from the center channel in a surround sound audio format.

CG
Character Generator operator, person who locates titles and text and has it ready to key into the program along with any transitions or movement.

CGI
Common Gateway Interface. A set of rules that describe how a Web Server communicates with another piece of software on the same machine and how the other piece of software (the CGI program) talks to the web server. Any piece of software can be a CGI program if it handles input and output according to the CGI standard. Usually a CGI program is a small program that takes data from a web server and does something with it, like putting the content of a form into an e-mail message, or turning the data into a database query.

CGMS or Copy Generation Management System.
Method of making DVDs uncopyable. Character generation Device that electronically generates text which can be superimposed* over a video signal. Text is usually entered via a keyboard, allowing selection of various fonts, sizes, colours, styles and background colours, then stored as multiple pages for retrieval

Channel.
Discrete, single grouping of audio information played through a sound system resulting in a steady flow of sound from one single source; for example a stereo system with two speakers has two channels, one left channel and one right channel.

Channel Leakage.
Audio signal that travels from one channel to another where it is not intended to be thus creating distortion; bleeding of audio information between channels.

Channel Separation.
Measurement in decibels of the amount of channel leakage that occurs; higher figures are preferable meaning that there is little channel leakage (see Channel Leakage).

Chapter.
One section of a level 2 videodisc program, like a chapter of a book.

Chapter stop.
A code, embedded in the level 1 videodisc flags where each new chapter or section begins. While scanning fast forward, the player will sense the code and will still-frame at this point. This feature speeds the process of locating segments on the disc.

Character generator or CG.
Typewriter keyboard that electronically displays letters, numbers, and symbols on a TV screen.

Chip.
Miniature electronic circuit consisting of thousands of transistors.

Circular polarizer.
Polarizing lens attachment designed to work with cameras having mirrors.

Channels.

One of 16 different data paths that are available to carry messages in MIDI.

Channel Message.

A type of MIDI message that carries specific channel information.

Chroma.
The colour information contained in a video signal, consisting of hue (phase angle) and saturation (amplitude) of the colour subcarrier signal.

Chroma corrector.
A device used to correct problems related to the chroma of the video signal, as well as colour balance and colour noise.

Chroma gain.
Camera control that boosts the amounts of colour in the picture.

Chroma noise.
Noise which manifests itself in a video picture as coloured snow.

Chroma key.
The process of overlaying one video signal over another by replacing a range of colours with the second signal. Typically, the first (foreground) picture is photographed with a person or object against a special, single- colour background (the key- colour). The second picture is inserted in place of the key- colour. The most common example is in broadcast weather segments where pictures of weather maps are inserted "behind" the talent.

Chrominance & Chrominance level.
The colour portion of a video signal separate from the luminance component, representing the saturation and tint at a particular point of the image. Black, gray and white have no chrominance, but any coloured signal has both chrominance and luminance. The higher the chrominance level, the stronger the colour (e.g., a strong signal produces red, and a weak signal, pink). colour saturation level can be changed using a colour processor.

Chorusing.
A doubling effect commonly found on a synthesizer or sampler that makes a single sound appear to sound like an entire ensemble. The initial signal is split and appears at a slightly altered pitch from the original, or at a slightly later point in time. This time and pitch level are often controllable by a low frequency oscillator (LFO).

Class.
Describes the method used by an electronic component's output devices to amplify signals; common classes are Class A, Class B, and Class AB.

Class A.
Type of amplifier (amplifier class) in which both the negative and positive polarity output devices conduct at all times so that a current is always flowing through them.

Class AB.
A combination amplifier design using the concept of continuous current in both the positive and negative polarity output devices found in class A designs coupled with class B's turn-off of unused output devices with the result being an amplifier that only allows very minimal current flow through output devices when signals of the opposite polarity are being created.

Class B.
The exact opposite of a class A amplifier, the class B amplifier completely shuts off its output devices when not needed (the positive polarity output is off when the signal is negative and the negative polarity output is off when the signal is positive).

Clip.

A digitized audio sample. It could be a sound effect or a whole song or speech.

A video and/or audio scene or shot, usually of raw footage. Non-linear editors will digitize the clip so it may be trimmed and added to the timeline.

ClipLink.
Sony DVCAM mechanism for marking in/out points of raw footage while it's in the camera. Thumbnail images and time code numbers may then be quickly downloaded to the non-linear editor, possibly guiding the editor in digitizing only the "good" shots.

Clipping.
Amplifier distortion occurring when a high energy wave form (a very loud sound resulting in a large output) is input into an amplifier and the amplifier is unable to fully reproduce it due to power supply limitations or amplifier design limitations resulting in the audio output waves being cut off (the rounded tops sliced off resulting in short waves with flat tops).

Clock Speed.
Clock speed is a measure of how many times a processor 'cycles' every second. Measured in millions of cycles per second, or MHz.

Closed caption decoder.
Circuit in a TV set that extracts closed caption data from the video signal and displays it on the screen. Closed caption submaster tape Copy of your master tape with closed captions encoded into line 21 of the video. Closed captions Signals invisibly encoded in the picture of some TV shows can be deciphered by a caption decoder and turned into text appearing over the TV image, mostly for the benefit of the hearing impaired.

CLV (Constant Linear Velocity).
Laserdisc format in which the disc is spun at varying speeds or revolutions per second to allow the laser to maintain a constant speed over the surface of the disc resulting in the ability to maximize data storage (compared to a CAV disc).

Coarticulation.
The phenomenon of transitions between individual speech elements.

Coaxial Cable.
Specific type of cable design with two conductors, one running through the center of the cable surrounded by some form of non-conductive insulator with a second braided conductor wrapped around the insulation material and serving double-duty as a shield against interference.

Co-axial Speaker.
Type of speaker driver in which a high frequency driver (a tweeter in most cases) is placed inside a low or mid frequency driver in the place of the dust cap.

Co-channel interference.
Wavy lines or other interference appearing on the TV screen caused when a TV set receives more than one signal at a time on the same channel (i.e., two channel 3s at once).

Codec.
Coder/decoder, device to convert video and audio into digits transportable via phone lines, then convert the digits back to audio/video for the recipient. Codecs may also employ digital compression.

Colour bars.
An electronically generated video pattern consisting of eight equal width colours, used to establish a proper colour reference before recording and playback and for adjustment purposes.

Colour Burst.
The portion of a colour video signal which contains a short sample of the colour subcarrier used to add colour to a signal. It is used as a colour synchronization signal to establish a reference for the colour information following it and is used by a colour monitor to decode the colour portion of a video signal. The colour burst acts as both amplitude and phase reference for colour hue and intensity. The colour oscillator of a colour television receiver is phase locked to the colour burst.

Colour corrector.
Electronic device that dissects the colours of a video signal and allows them to be individually adjusted (i.e., the blues could be changed to aquas without changing anything else). Colour difference signals Component video signals which represent colour parts of the picture. R-Y and B-Y are colour difference signals.

Colour correction
A process in which the colouring in a television image is altered or corrected by electronic means.

Colour decoder.
A device which divides a video signal into its basic colour components. In TV and video, colour decoding is used to derive signals required by a video monitor from the composite or Y/C signals.

Colour Temperature.
Means of measuring the hue (tint or shade of colour) of white light in relation to the temperature of a glowing "black body" (piece of heated carbon).

Colouration.
The distortion or imperfect reproduction of an audio signal when played back over an audio system.

Colour phase.
The phase of the chroma signal as compared to the colour burst, is one of the factors that determines a video signal's colour balance.

Colour processing.
A way to alter a video signal to affect the colours.

Colour subcarrier.
The 3.58 MHz/NTSC (4.43 MHz/PAL) signal added to a black and white television signal to add colour information. The subcarrier frequency is too high to be detected by black and white televisions ensuring compatibility. colour sets employ special circuitry which detects and decodes the colour component for display.

Colourization.
Special effect (also called paint) which colours a monochrome or colour image with artificial colours.

Comb Filter.
Video display device that separates the chrominance (colour) and luminance (brightness) portions of a composite video signal.

Communication protocol.
A specific software based protocol or language for linking several devices together. Communication protocols are used between computers and VCRs or edit controllers to allow bi-directional "conversation" between the units.

Compact Disc (CD).
Thin, round, reflective disc that stores digital data in the form of microscopic pits and lands and that can be read by a laser.

Compand.
Compress/expand, a technique of squeezing the dynamic range of a wireless microphone, then expanding that range at the receiver end to restore normal sound.

Companding.
Compression/expanding, a technique used by audio devices such as wireless microphones whereby audio signals are compressed prior to recording or transmission, and expanded back to normal just before use. The technique increases the audio dynamic range.

Component.
An individual piece of equipment in an audio or audio/video system.

Component switcher.
Video switcher which switches and mixes component (i.e., RGB, or Y/U/V, or Y/R-Y/B-Y) video signals.

Component Video.
Method of transferring video information using multiple, individual signals such as red, green and blue (RGB) or luminance, luminance minus blue, and luminance minus red (Y-Y/B-Y/R or Y-Pb-Pr) resulting in the highest quality signal transfer and lowest distortion.

Component video recorder.
Professional VCR that records separately the distinct colour video signals from a camera, offering a high-quality image.

Component video.
Separate colour video signals that have not yet been combined into a single video signal. Y/R-Y/B-Y, video is an example of component video signals.

Composite.
A picture made of layers or the act of making such a picture.

Composite sync.
A signal consisting of horizontal sync pulses, vertical sync pulses and equalizing pulses only.

Composite Video.
A video signal in which the luminance (brightness), chrominance (colour), blanking pulses, sync pulses and colour burst information have been combined using one of the coding standards.

Compression.

The process of electronically processing a video picture to make it use less storage or to allow more video or audio to be sent down a transmission channel.

The process of removing picture data to decrease the size of a video image.

Compressor.
Audio device able to reduce the audio signal when it exceeds a set amount.

Computer
A computer is a machine that can be programmed to accept data (input), process it into useful information (output) and store it away (in a secondary storage device) for safekeeping or later reuse. Processing is directed by software but performed by hardware

Cone.
A type of speaker driver resembling an ice cream cone, with its largest diameter at the front of the speaker enclosure becoming smaller deeper within the enclosure.

Continuous Controller.

A type of MIDI message that is generated by the movement of a continuous control.

Contrast.

The degree to which the various luminance values in a picture are mapped to very dark and very light values. A high-contrast picture is dominated by black and white and few values between. A low contrast picture has a lot of middle tones without many very dark or very light areas.

A control on a television or monitor which adjusts the white level of the picture.

CONTROL-L
Sony's wired edit control protocol, also called LANC (Local Application Control), which allows two-way communication between a camcorder or VCR and an edit controller such as the Thumbs Up.Control-L allows the controller to control the deck (fast forward, play, etc.) and also allows the controller to read the tape position (tape counter) information from the deck.

CONTROL-M.
Panasonic's wired edit control protocol. Similar to Control-L in function but not compatible. Also called Panasonic 5-pin edit control.

CONTROL-S.
Sony wired transport control protocol which duplicates a VCR's infra-red remote transport control (play, stop, pause, fast forward and rewind). Unlike Control-L, Control-S does not allow the controller to read tape counter information.

CONTROL-T.
Similar to Control-L but allows multiple units to be controlled. Not used in current equipment.

CONTROL TRACK.
The magnetized portion along the length of a videotape on which sync control information is placed. The control track contains a pulse for each video field and is used to synchronize the tape and the video signal.

Controllers.

Various sliders, levers, knobs, or wheels typically found on a MIDI controller. Used to send continuous (as opposed to discrete) data to control some aspect of a sound.

Convergence.

On a three-tube video projector, focusing and aiming the three coloured pictures so that they overlap, producing all colours accurately, without ridges along edges of objects.

The precise overlapping of a colour TV's three primary coloured pictures to make one multi-coloured picture.

Convergence Error.
When the colours used to make up a video display do not properly come together on the screen.

Converter.
Electronic device which translates one channel number (one frequency) into another (another frequency). Often rented from cable TV companies, a converter (or decoder) box connects to your TV and does the tuning instead of your TV tuner. The box usually puts out channel 3, and your TV remains tuned to channel 3.

Cookie.
Message sent by a web server to a browser and stored in a text file.

Copy protected.
A signal recorded on a video tape renders the tape uncopyable.

Copyguard Macrovision.
Antipiracy techniques employed by prerecorded tape producers to thwart tape copying.

CPU Central Processing Unit
The heart of a computer, a single circuit chip with millions of transistors programmed to interpret and carry out commands. The microprocessor (also known as a Central Processing Unit or CPU) is a complete computation engine built on a single chip (dye) and is at the heart of the computer.

The CPU controls the running of the system, directing the operation of all other components.

The CPU is an integrated circuit combining processing units.

The chip contains chips contain millions of transistors etched onto the silicon substrate

An integrated circuit combining processing units, memory stores and additional functions on a single chip

CPU Operation
System Interconnection (Buses)
Interconnection Structures
The collection of paths which connect the various modules is called the interconnection structure Interconnection structure must support the following 5 types of transfer:

Memory - Processor
Processor - Memory
I/O - Processor
Processor - I/O
I/O to/from Memory

Crossfade.
The audio equivalent of the video dissolve where one sound track is gradually faded out while a second sound track simultaneously replaces the original one.

Crossover.

The crossover splits up the frequency spectrum into pieces, which are then handed over to various speaker drivers.

Crossover Point.

The frequency at which a crossover splits the audio signal.

Cross platform.
The ability for software to work on either PC or MacIntosh (or some other type) computers (platforms).

Crosstalk

Audio distortion resulting from information in one audio channel leaking into the signal of another channel.

The interference between two audio or two video signals caused by unwanted stray signals. In video, crosstalk between input channels can be classified into two basic categories: luminance/sync crosstalk; and colour (chroma) crosstalk. When video crosstalk is too high, ghost images from one source appear over the other. In audio, signal leakage, typically between left and right channels or between different inputs, can be caused by poor grounding connections or improperly shielded cables.

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.

CYMK
C c-cyan, Y y-yellow, M m-magenta and K K - Key. Subtractive colour system.
Colour for printing the printing industry is broken into four reflective components.
Theoretically cyan, magenta, and yellow make black.

top