Akai A 5181 Service Manual

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Terminology & Abbreviations Terminology & Abbreviations AC-3 The former name of the Dolby Digital audio-coding system . AC-3 followed AC-1 and AC-2. Still used in some standards documents. Angle In DVD-video, a specific view of a s cene, usually recorded from a certain camera angle. Different angles can be chosen while viewing the scene. CD Short for compact disc, an optical disc storage format developed by Philips and Sony. CD-DA Compact disc digital audio. The original music CD format, storing audio information as digital PCM data. Defined by the Red Book standard. CD+G Compact disc plus graphi cs. A variation of CD which embeds graphical data in with the audio data, allowing video pictures to be displayed periodically as music is played. Primarily used for karaoke. CD-R An extension of the CD format allowing data to be recorded once on a disc by using dye-sublimation technology. Defined by the Orange Book standard. Channel A part of an audio track. Typically there is one channel allocated for each loudspeaker. Chapter In DVD-Video, a division of a title. Technically called a part of title (PTT). Closed Caption Text captions for video whic h are not normally visible, as opposed to open captions, which are a permanent part of the pi cture. In the United States, the official NTSC Closed Caption standard requires th at all TVs larger than 13 inches include circuitry to decode and display caption in formation stored on line 21 of the video signal. DVD-Video can provide closed capti on data, but the subpicture format is preferred for its versatility. Component Video A video system containing three separate color component signals, either red/green/blue (RGB) or chroma/color diff erence (YGbCr, YPbPr, YUV), in analog or digital form. The MPEG-2 encodi ng system used by DVD is based on color-difference component digital video. Very few televisions have component video inputs. Composite Video An analog vi deo signal in which the luma and chroma components are combined (by frequency multiplexing), along with sync and burst. Also called CVBS. Most televisions and VCRs have compos ite video connectors, which are usually colored yellow. CD-i Compact disc interactive. An extens ion of the CD format designed around a set-top computer that connects to a TV to provide in teractive home entertainment, including digital audio and video, video games, and software applications. Defined by the Green Book standard. CD-i Assn. 1-1

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Terminology & Abbreviations Dolby Digital A perceptual coding system for audio, developed by Dolby Laboratories and accepted as an international standard. Dol by Digital is the most common means of encoding audio for DVD-Video and is the mandatory audio compression system for 525/60 (NTSC) discs. Dolby Surround The standard for matrix en coding surround-sound channels in a stereo signal by applying a set of defined mathem atical functions when combining center and surround channels with left and right channels. The center and surround channels can then be extracted by a decoder such as a Dolby Pro Logic circuit which applies the inverse of the mathematical func tions. A Dolby Surround decoder extracts surround channels, while a Dolby Pro Logic de coder uses tially independent of the recording or transmission format. Both Dolby Digital and MPEG audio compression systems are compatible with Dolby Surround audio. 1-1 DTS Digital Theater Sound. A perceptual audi o-coding system developed for theaters. A competitor to Dolby Digital and an optional audio track format for DVD-Video. DVCD Stands for Double Video CD -- pretty popular format in mainland China. Format itself is nothing new really, its just a regular VideoCD overburned to include 90 to 99mins per CD, compared to regular 74mi ns per CD in standard VideoCD format. DVD An acronym that officially stands for nothing, but is often expa nded as Digital Video Disc or Digital Versatile Disc. The audio/ video/data storage system based on 12-and 8-cm optical discs. 1-1 DVD+R DVD+Recordable defines a standard for recordable DVD drives and media defined by the DVDRW Alliance. Often called "plus R" , the format is write once (compared to DVD+RW wich can be erased and rewrit ten). The single sided discs can hold 4,700,000,000 bytes (4.38 Gigabytes at 1024 bytes to the kilobyte) with double sided discs holding twice as much. There are no dual layer single sided record able discs. This format competes with the DVD Forum DVD-R specification. DVDRhelp DVDR information JPEG Joint Photographic Experts Group. The international committee which created its namesake standard for compressing still images. Karaoke Literally empty orchestra. The social sensation from Japan where sufficiently inebriated people embarrass themselves in public by singing along to a music track. Karaoke was largely responsible for the succe ss of laserdisc in Japan, thus supporting it elsewhere. Kodak Picture CD Kodak Picture CD is a CD that contains your pictures in JPEG format(.jpg) along with software that lets you view, enhance, share, and print your pictures from your computer. Some standalone DVD Player s supports this format also, but then only for viewing. This format will also work on DVD Players that supports "JPEG file viewing" but you may lose some Kodak Picture CD specific features. Kodak Picture CD. Macrovision An antitaping process that modifi es a signal so that it appears unchanged on most televisions but is distorted and unwatch able when played back from a videotape recording. Macrovision takes advantage of ch aracteristics of AGC circuits and burst decoder circuits in VCRs to interfere with the recording process. 1-2