CD yog digital optical disc rau khaws cov ntaub ntawv hauv ib hom kev sib koom ua ke tsim los ntawm Philips thiab Sony, uas tau tso tawm xyoo 1982. Nws yog Ameslikas tsim los khaws cia thiab ua si suab kaw, tab sis tom qab ntawd nws tau hloov kho los sau ntau yam ntaub ntawv. Ob peb lwm hom tau dhau los ua derivatives ntawm lawv, suav nrog cov ntaub ntawv audio-ib zaug thiab cov ntaub ntawv khaws cia (CD), rov sau tau ntawv xov xwm (RW), video disc (VCD), super video disc (lossis SVCD), PictureCD, thiab lwm yam. Ua ntej muag khoom CDP -101 audio CD player tau tso tawm thaum Lub Kaum Hli 1982 hauv Nyij Pooj.
Standard CDs yog 120mm nyob rau hauv txoj kab uas hla thiab tuaj yeem tuav txog li 80 feeb ntawm lub suab tsis muaj suab lossis txog 700MB ntawm cov ntaub ntawv. Mini CD tuaj nyob rau hauv ntau txoj kab uas hla (xws li 60 mus rau 80 millimeters). Qee zaum lawv siv rau CD singles raws li lawv tuaj yeem tuav tau txog 24 feeb ntawm lub suab, lossis rau kev kaw cov tsav tsheb.
Tshuaj muaj koob meej
Thaum lub sijhawm thev naus laus zis tau tshaj tawm, xyoo 1982, CD tuaj yeem khaws cov ntaub ntawv ntau dua li lub hard drive ntawm tus kheej.computer, uas feem ntau tsis loj dua 10 MB. Los ntawm 2010, hard drives feem ntau muaj qhov chaw cia ntau npaum li ib txhiab CDs, thaum lawv cov nqi tau nqis mus rau theem qis. Xyoo 2004, audio CDs, CD-ROMs thiab CD-Rs tau muag ib ncig 30 billions luam thoob ntiaj teb. Los ntawm 2007, 200 billion CDs tau muag thoob ntiaj teb.
Txij li thaum xyoo 2000s, CDs tau hloov zuj zus los ntawm lwm hom kev khaws cia thiab kev faib tawm, nrog rau qhov tshwm sim los ntawm 2010 lawv cov lej tau poob li ntawm 50% ntawm lawv qhov siab, tab sis lawv tseem yog ib qho ntawm cov xov xwm tseem ceeb. nyob rau hauv kev lag luam suab paj nruag. kev lag luam.
History of Appearance
American inventor James Russell tau txais txiaj ntsig los ntawm kev tsim thawj lub kaw lus rau kev sau cov ntaub ntawv digital ntawm optical transparency zaj duab xis uas tawm lub teeb vim lub zog siab ntawm cov teeb halogen. Nws patent tau xub sau npe rov qab rau xyoo 1966. Tom qab kev sib hais plaub, Sony thiab Philips tau ntawv tso cai Russell's patents hauv xyoo 1980s.
Cov CD yog cov khoom lag luam ntawm cov evolution ntawm laser discs. Qhov no yog ib qho kev siv tshuab uas siv lub teeb tsom teeb laser los muab cov ntaub ntawv siab ceev uas xav tau rau cov suab zoo digital. Prototypes tau tsim los ntawm Philips thiab Sony ntawm nws tus kheej hauv xyoo 1970s. Xyoo 1979, kev sib koom ua haujlwm ntawm cov kws ua haujlwm tau tsim los tsim cov xov xwm digital tshiab. Tom qab ib xyoos ntawm kev sim thiab kev sib tham,Phau Ntawv ntawm Suab Standards tau luam tawm nyob rau hauv 1980. Tom qab thawj zaug luam tawm hauv xyoo 1982, CDs thiab lwm yam players tau nrov heev. Txawm hais tias tus nqi siab, ntau tshaj 400,000 units tau muag hauv Asmeskas ib leeg hauv xyoo 1983 thiab 1984. Los ntawm 1988, kev muag khoom tau tshaj tawm qhov kev thov rau cov ntaub ntawv yas, thiab los ntawm 1992, audio cassettes. Qhov kev vam meej hauv kev nthuav tawm CD thev naus laus zis yog qhov tshwm sim los ntawm kev sib koom tes zoo ntawm Philips thiab Sony, uas tau pom zoo thiab tsim kho khoom siv sib xws. Kev sib koom ua ke CD tsim tau tso cai rau cov neeg siv khoom mus yuav lub turntable lossis player los ntawm ib lub tuam txhab.
thev naus laus zis hloov zuj zus li cas?
Thaum pib, ntseeg tau tias CD yog qhov ua tiav ntawm cov ntaub ntawv yas rau kev ua suab paj nruag, thiab tsis yog qhov nruab nrab cia. Txawm li cas los xij, txij li nws tau qhia ua suab paj nruag hom, CDs tau txais los ntawm lwm cov ntawv thov.
Nyob rau xyoo 1983, thawj qhov kev sim nrog cov CD tshem tawm tau ua. Thaum Lub Rau Hli 1985, thawj zaug, CD nyeem ntawv tau ua hauv lub computer, thiab xyoo 1990, cov ntawv sau rov qab siv tau rov qab tau tshwm sim ntawm kev muag khoom. Lawv tau dhau los ua lwm txoj hauv kev rau kev kaw suab paj nruag thiab luam tawm suab paj nruag albums yam tsis muaj qhov tsis xws luag vim yog compression siv hauv lwm txoj hauv kev kaw suab. Yog li, cov suab paj nruag CD zoo li yog cov xov xwm yooj yim tshaj plaws piv rau cov kab xev thiab cov ntaub ntawv.
Los ntawm 2000s thaum ntxov, CD player tau hloov pauv ntau daim kab xev,nrog rau cov xov tooj cua raws li cov khoom siv hauv cov tsheb tshiab.
Meanwhile, nrog rau kev nce ntxiv hauv kev faib cov ntaub ntawv hauv compressed audio formats (xws li MP3), CD muag pib poob rau xyoo 2000s. Piv txwv li, nyob nruab nrab ntawm 2000 thiab 2008, txawm tias tag nrho cov khoom muag suab paj nruag, CD muag poob los ntawm tag nrho 20%. Txawm hais tias qhov kev thov poob qis dua rau xyoo dhau los, cov thev naus laus zis tseem nyob rau qee lub sijhawm.
CD qauv
Txhua CD yog 1.2mm tuab thiab ua los ntawm polycarbonate yas. Txhua tus neeg nqa khoom hnyav 15-20 grams. Nws cov qauv yog txhais los ntawm qhov chaw sab nraud, nws cov ntsiab lus yog:
- center ntawm spindle qhov (15mm);
- thawj qhov chaw hloov pauv (clamping nplhaib);
- clamping bracket;
- thib ob hloov chaw (daim iav stripe);
- software cheeb tsam (ntawm 25 txog 58 mm);
- rim.
Ib txheej nyias ntawm txhuas lossis tsawg dua kub yog siv rau saum npoo ntawm disc, ua rau nws muaj kev cuam tshuam. Cov hlau yog tiv thaiv los ntawm ib zaj duab xis ntawm lacquer, feem ntau yog siv ncaj qha mus rau lub reflective txheej. Daim ntawv lo yog luam tawm rau saum cov kua roj vanish, feem ntau yog silkscreen lossis offset printing.
CD cov ntaub ntawv yog sawv cev raws li cov ntaub ntawv me me, hu ua "tracks", encoded nyob rau hauv cov kab sib txuas tso tawm rau saum txheej txheej polycarbonate. CD player mechanism tig lub disc rau ib qho scan ntawm qhov nrawm ntawm 1.2 txog 1.4 m / s (qhov nrawm nrawm), uas yog sib npaug li 500 rpm ntawm sab hauv ntawm lub disc, thiabtxog 200 rpm - sab nraud. Lub disc ua si txij thaum pib mus txog thaum xaus qeeb qeeb thaum ua si.
Cov ntaub ntawv rov qab li cas?
Thaj chaw program muaj thaj tsam li ntawm 86.05 cm2, thiab qhov ntev ntawm cov kaw kaw yog 5.38 km. Thaum lub scan ceev ntawm 1.2 m / s, lub sij hawm playback yog 74 feeb, los yog 650 MB ntawm cov ntaub ntawv ib CD-ROM. Cov ntaub ntawv denser me ntsis tuaj yeem ua si los ntawm cov neeg ua si feem ntau (txawm tias qee cov qauv qub tsis txhawb hom ntawv no).
Ib daim CD tau nyeem siv lub laser infrared semiconductor tso rau hauv CD player los ntawm txheej ntawm polycarbonate. Ib qho kev hloov hauv qhov siab ntawm lem ua rau qhov sib txawv ntawm lub teeb pom kev. Nws yog los ntawm kev ntsuas qhov kev siv ntawm kev hloov pauv los ntawm photodiode uas cov ntaub ntawv tuaj yeem nyeem tau los ntawm kev tshaj tawm.
Qhov sib txawv ntawm cov lem tsis ncaj qha sawv cev rau xoom thiab ib qho hauv cov ntaub ntawv binary. Hloov chaw, ib qho encoding yog siv uas xav tias tsis rov qab mus rau xoom. Txoj kev encoding no yog Ameslikas tsim rau audio CDs, tab sis txij li thaum tau dhau los ua tus qauv rau yuav luag txhua hom.
Media feature
CDs muaj kev puas tsuaj thaum tuav thiab siv. Cov lem nyob ze ze rau ntawm daim ntawv lo ntawm lub disc, thiab vim li no qhov tsis xws luag thiab cov kab mob ntawm lub pob tshab tsis cuam tshuam rau kev ua si. Yog li ntawd, CDs feem ntau yuav muaj kev puas tsuaj ntawm daim ntawv lo. khawb rausab pob tshab tuaj yeem rov qab los ntawm kev sau lawv nrog cov yas zoo sib xws los yog ua tib zoo polishing lawv. Cov npoo ntawm lub disc yog qee zaum tsis raug kaw tag nrho, tso cai rau cov pa roj thiab cov kua ua kom puas cov xim hlau reflective txheej thiab / los yog cuam tshuam nrog lub laser lub peev xwm los tsim cov ntsiab lus ntawm cov lem. Cov ntaub ntawv digital ntawm CD yog khaws cia thiab ua si ntawm qhov chaw mus rau ntug.
Cov CDs twg muaj muag?
Standard CDs muaj nyob rau hauv ob qhov ntau thiab tsawg. Txog tam sim no cov xov xwm tshaj plaws yog 120 millimeters inch, nrog 74 lossis 80 feeb ntawm lub peev xwm suab, thiab cov ntaub ntawv muaj peev xwm ntawm 650 lossis 700 MB. Kuj tseem muaj cov discs nrog txoj kab uas hla ntawm 80 hli, uas tuaj yeem tuav tau txog 24 feeb ntawm cov suab paj nruag lossis 210 MB ntawm cov ntaub ntawv.
Cov hom phiaj xwm txheej ntawm Audio CD (tseem yog Digital Audio lossis CD-DA) tau piav qhia hauv ib daim ntawv tso tawm xyoo 1980 los ntawm cov tsim qauv, Sony thiab Philips. Nws yog ob-channel 16-ntsis encoding ntawm zaus ntawm 44.1 kHz. Plaub-channel suab yuav tsum yog qhov sib txawv ntawm cov qauv no, tab sis nws yeej tsis tau muab tso rau hauv kev xyaum. Cov no yog cov qauv nkauj CDs feem ntau pom nyob rau hauv khw.
CD + ntawv yog Audio CD txuas ntxiv uas tso cai rau koj khaws cov ntaub ntawv ntxiv (xws li lub npe album, nkauj, npe hu nkauj), tab sis cov xov xwm raug hlawv raws li Audio CD cov qauv. Cov ntaub ntawv yog khaws cia nyob rau hauv qhov chaw ntawm lub disk qhov twg muaj kwv yees li tsib kilobytes ntawm qhov chaw dawb, los yog nyob rau hauv txoj cai khiav, uas yuav khaws cia.txog 31MB ntxiv.
CD + nraaj yog ib lub CD tshwj xeeb uas muaj cov ntaub ntawv nraaj ntxiv rau cov suab. Cov xov xwm no tuaj yeem ua si ntawm tus neeg ua si ib txwm, tab sis thaum ua si ntawm CD + G ntaus ntawv, nws tuaj yeem tso tawm cov duab. Raws li txoj cai, xws li cov neeg uas ua ntawv txuas nrog lub TV lossis tso tawm ntawm lub computer saib. Cov duab no yuav luag txhua zaus siv los tso saib cov nkauj ntawm lub screen rau karaoke.
CD + Advanced Graphics (tseem hu ua CD + EG) yog ib qho kev txhim kho ntawm cov ntaub ntawv duab CD. Zoo li CD + G, CD + EG siv cov haujlwm tseem ceeb ntawm CD-ROM los tso saib cov ntawv nyeem thiab cov ntaub ntawv video ntxiv rau cov suab paj nruag raug ntaus. Cov no yog cov khoos phis tawj CD tsim los ua si nrog lub monitor.
SACD format
Super Audio CD (SACD) yog qhov kev daws teeb meem siab, nyeem nkaus xwb audio format. Cov optical discs no tau tsim los muab kev ncaj ncees digital audio reproduction. Cov hom ntawv tau tshaj tawm hauv xyoo 1999, tau tsim los ntawm Sony thiab Philips. SACDs pib tshwm sim hauv DVD audio formats, tab sis tsis hloov tus qauv Audio CDs.
Raws li lub npe SACD, kuj tseem muaj cov hybrid discs uas muaj SACD thiab cov kwj suab, nrog rau cov txheej txheem CD suab uas yuav ua si ntawm cov txheej txheem CD. Qhov no tau ua los xyuas kom meejcompatibility.
Lwm hom ntawv
Rau thawj ob peb xyoos ntawm nws lub neej, CD yog qhov nruab nrab siv tshwj xeeb rau lub suab. Txawm li cas los xij, xyoo 1988 tus qauv no tau txhais tias tsis yog-volatile optical cia li. Yog li ntawd muaj CDs nrog cov kev pab cuam, yeeb yaj duab thiab hais txog. Cais, nws tsim nyog qhia cov hom hauv qab no.
Video CD (VCD) yog tus qauv digital rau khaws cov yeeb yaj kiab. Cov xov xwm no tuaj yeem ua si rau ntawm VCD cov neeg ua si, feem ntau niaj hnub DVD players, tus kheej lub computer, thiab qee qhov game consoles.
Feem ntau, cov duab zoo yuav tsum tau muab piv rau VHS video. Cov yeeb yaj kiab VCD tsis zoo tuaj yeem qee zaum qis dua, tab sis hom ntawv no khaws cov ntaub ntawv hauv cov chunks ntau dua li cov suab nrov analog uas ua rau tsis zoo rau txhua qhov kev siv (piv rau daim kab xev kaw).
Super Video CD (Super Video Compact Disc lossis SVCD) yog hom siv los khaws cov yeeb yaj kiab ntawm cov qauv CDs. SVCD tau xeeb los ua tus neeg txuas ntxiv rau VCD thiab lwm txoj hauv kev rau DVD-Video. Raws li nws cov yam ntxwv, nws yog qhov chaw nruab nrab ntawm cov qauv saum toj no, ob qho tib si ntawm kev muaj peev xwm thiab cov duab zoo.
Ib daim CD-R tuaj yeem tuav txog 60 feeb ntawm tus qauv zoo SVCD video. Thaum tsis muaj kev txwv tshwj xeeb rau qhov ntev ntawm SVCD cov yeeb yaj kiab, tus nqi me ntsis thiab yog li qhov zoo yuav tsum raug txo kom haum rau ntev heev.cov ntaub ntawv. Vim li no, nws yog ib qho teeb meem kom haum rau ntau tshaj 100 feeb ntawm video ntawm ib SVCD yam tsis muaj kev poob zoo, thiab ntau tus neeg siv kho vajtse tsis tuaj yeem ua si cov ntaub ntawv ntawm qhov ceev qis dua 300-600 kilobits ib ob.
Cov khoom siv pov tseg thiab rov siv tau dua
CD-R kaw yog npaj rau kev siv mus tas li. Sij hawm dhau mus, cov yam ntxwv ntawm lub cev ntawm cov xov xwm tuaj yeem hloov pauv, ua rau kev nyeem ntawv tsis raug thiab cov ntaub ntawv poob kom txog thaum tus nyeem ntawv tuaj yeem rov qab tau lawv siv cov txheej txheem kho qhov yuam kev. Lawv lub neej kev pab cuam yog los ntawm 20 mus rau 100 xyoo, nyob ntawm seb lawv qhov zoo, cov ntaub ntawv nws tus kheej thiab qhov chaw cia ntawm CD. Txawm li cas los xij, cov kev ntsuam xyuas tau rov ua dua qhov tsis zoo rau cov discs feem ntau tom qab li ntawm 18 lub hlis nyob rau hauv ib txwm khaws cia thiab siv tsis tu ncua.
CD-RW yog cov ntaub ntawv kaw lus uas siv cov hlau tsis muaj xim. Kev sau ntawv laser nyob rau hauv rooj plaub no yog siv los ua kom sov thiab hloov cov khoom ntawm cov hlau thiab yog li ntawd hloov qhov kev xav. CD-RW yog vim li cas thiaj li muaj qhov cuam tshuam tsawg dua. Hom CD no tuaj yeem sau tau ntau zaus. Tab sis vim qhov txawv ntawm hom, tsis yog txhua tus players tuaj yeem nyeem cov ntaub ntawv los ntawm cov xov xwm no.
