GLOSSARY in Software

Encode Denso QR Bar Code in Software GLOSSARY

Asynchronous Transfer Mode (ATM) A high speed data transmission and switching technique that uses fixed-size cells to transmit voice, data, and video, which greatly increases the capacity of transmission paths, both wired and wireless Backbone A fat pipe within a network The term is relative to the size of network it serves Backchannel Term commonly used to describe the action of sending data back to a host server over a phone wire or cable pipe Bandwidth 1 (Broadcast) The range of frequencies available for signaling The difference expressed in cycles per second (Hertz) between the highest and lowest frequency of a band (James Martin, 1971) 2 (Data wire) Analog telephone lines measure capacity in Hertz (the difference in the highest and lowest frequency in the channel) Digital channels measure capacity in bits per second A T3 connection is approximately 30 times as fast as a T1 connection, which is 50 times as fast as a 288 modem, which is twice as fast as a 144 modem Broadcast: 6 MHz analog Cable: 450 MHz analog signal Cable Modems: up to 27 mps downstream shared Internet data: 144k 26 MBPS with VDSL VBI: 4 Mbps Digital Signal: 192 Mbps Bezel The frame that covers the edge of the picture tube in some TV sets and can therefore hide edge information transmitted in an ATV system (such as ACTV I) not meant for the viewer to see See also Overscanning Bit Error Rate Similar to signal-to-noise ratio (SNR) for a digital signal Bit Rate The digital equivalent of bandwidth The rate at which the compressed bit stream is delivered from the channel to the input of the decoder

Bit Rate Reduction Schemes for compressing high bit-rate signals into channels with much lower bit rates Blur A state of reduced resolution Blur can be a picture defect, as when a photograph is indistinct because it was shot out of focus or the camera was moved during exposure Blur can also be a picture improvement, as when an unnaturally jagged-edged diagonal line or jerky motion is blurred to smoothness Broadband A network capable of delivering high bandwidth Broadband networks are used by Internet and cable television providers For cable, they range from 550 MHz to 1GHz A single regularly broadcast TV channel requires 6MHz, for example In the Internet domain, bandwidth is measured in bits-per-second (BPS) See Digital Subscriber Line (DSL) Broadcast Television Conventional terrestrial television broadcasting, the most technically constrained delivery mechanism for ATV, faced with federal regulations and such potential problems as multipath distortion and cochannel interference Burn An image or pattern appearing so regularly on the screen of a picture tube that it ages the phosphors and remains as a ghost image even when other images are supposed to be shown On computer terminals, the areas occupied by characters are frequently burned, particularly in the upper left corner In television transmission centers, color bars are sometimes burned onto monitors There is some concern that some ATV schemes will burn a widescreen pattern on ordinary TV sets because of increased vertical blanking or will burn a non-widescreen pattern on ATV sets because of reception of non-ATV signals In production, burn refers to long-term or permanent image retention of camera pickup tubes when subjected to excessive highlights C Chrominance Also Compatible Cable Modem A device that permits one-way or two-way high speed data communication over a cable television sys-

tem for purposes such as Internet access at speeds of around 15 MBPS Download rate is 27 Mbps Cable Plant The central equipment and broadcasting headquarters of a cable operator All initial broadcasts from the content providers are sent to the cable plant, aggregated, re-encoded, and broadcast to its set-top box network Cable Television The system network for the distribution of the television signal and now digital data by cable (coaxial, twisted pair, or fiber optic) Carrier An electromagnetic wave modulated with information to be recorded or transmitted; also a term used for such organizations as telephone companies, who carry signals from place to place See also Modulation CATV Community Antenna Television or cable television; a delivery mechanism for ATV not necessarily as technically constrained as broadcast television CAV Component Analog Video; refers to the handling of unencoded color signals (separate components), a form of signal recording and distribution not subject to cross-color and cross-luminance artifacts and offering potentially greater chroma resolution When used to ultimately feed NTSC receivers, CAV signals must pass through an NTSC encoder; but, because that might be the only encoder used in production or postproduction, it can be an advanced encoder CD Compact Disc The audio quality some ATV proponents feel is the minimum performance level acceptable for ATV Others feel CD quality might be excessive Channel Stuffing Technique for adding information to an NTSC channel without increasing its bandwidth or eliminating its receiver compatibility Characteristic An aspect or a parameter of a particular television system that is different from another system s, but is not necessarily a defect Characteristics include aspect ratio, colorimetry, resolution, and sound bandwidth