Optical Fiber Transmission muaj ntau yam zoo
Bandwidth
Qhov dav ntawm cov zaus band sawv cev rau qhov loj ntawm lub peev xwm kis tau tus mob. Qhov siab dua ntawm cov cab kuj, qhov loj dua qhov zaus bandwidth uas lub teeb liab yuav kis tau. Hauv VHF zaus band, tus cab kuj zaus yog 48.5MHz-300Mhz. Lub bandwidth yog hais txog 250MHz, uas tsuas yog xa tau 27 pawg ntawm TV teeb thiab kaum ob ntawm FM tshaj tawm. Qhov zaus ntawm lub teeb pom kev nce mus txog 100, 000 GHz, uas yog ntau tshaj li ib lab zaus siab dua VHF zaus band. Txawm hais tias qhov zaus bandwidth cuam tshuam vim qhov sib txawv ntawm cov khoom siv kho qhov muag rau qhov sib txawv ntawm lub teeb, qhov zaus bandwidth hauv thaj tsam poob qis tshaj tuaj yeem ncav cuag 30, 000 GHz. Lub bandwidth ntawm ib lub teeb ci tsuas yog tso rau ib feem me me ntawm nws (qhov zaus ntawm ntau hom fiber ntau yog li ob peb puas megahertz, thiab ib hom fiber ntau zoo tuaj yeem ncav cuag ntau dua 10 GHz). Siv cov kev sib txuas lus kho qhov muag zoo tshaj plaws, 2, 000 optical carriers tuaj yeem npaj nyob rau hauv thaj tsam ntawm 30, 000 GHz. , rau wavelength division multiplexing, uas tuaj yeem ua raws li ntau lab channels.
poob qis
Nyob rau hauv ib lub kaw lus muaj xws li coaxial cables, qhov zoo tshaj plaws cable muaj ib tug poob ntawm ntau tshaj 40dB ib kilometers thaum xa 800MHz signals. Hauv qhov sib piv, qhov poob ntawm optical fiber ntau me dua. Qhov poob ib kilometer tsawg dua 0.35dB thaum kis lub teeb ntawm 1.31um. Qhov ntawd yog 100 lab lub sij hawm tsawg zog poob dua li coaxial cable, cia nws mus deb dua.
Tsis tas li ntawd, muaj ob yam ntxwv ntawm optical fiber ntau kis tau tus mob,
Ib qho yog kom muaj qhov poob zoo ib yam hauv txhua qhov cable TV, thiab nws tsis yog qhov tsim nyog los qhia txog kev sib luag rau kev sib npaug zoo li lub cev cable;
Qhov thib ob yog tias nws qhov poob tsis tshua hloov nrog qhov kub thiab txias, yog li tsis tas yuav txhawj xeeb txog kev hloov pauv hauv cov theem tseem ceeb los ntawm kev hloov pauv ntawm qhov kub thiab txias.
lub teeb nyhav
Vim hais tias cov fiber ntau optical nyias nyias, txoj kab uas hla ntawm ib leeg-hom optical fiber core hlau feem ntau yog 4um txog 10um, thiab sab nraud tsuas yog 125um. Nrog rau qhov sib ntxiv ntawm cov txheej txheem dej tsis zoo, txhawb nqa cov tav, sheath, thiab lwm yam, txoj kab uas hla ntawm cov khoom siv kho qhov muag muaj li ntawm 4 txog 48 fibers optical tsawg dua 13 hli. Nws yog ntau me dua li tus qauv coaxial cable txoj kab uas hla ntawm 47mm. Tsis tas li ntawd, cov fiber ntau optical yog iav fiber ntau thiab muaj qhov tshwj xeeb me me. Nws muaj cov yam ntxwv ntawm txoj kab uas hla me me thiab lub teeb yuag, thiab nws yooj yim heev rau nruab.
Muaj zog tiv thaiv kev cuam tshuam
Vim hais tias cov khoom tseem ceeb ntawm optical fiber yog quartz, nws tsuas yog xa lub teeb, tsis muaj hluav taws xob, thiab tsis cuam tshuam los ntawm electromagnetic teb. Lub teeb liab optical kis tau nyob rau hauv nws tsis cuam tshuam los ntawm electromagnetic teb. Yog li ntawd, optical fiber kis tau tus mob muaj zog tiv thaiv electromagnetic cuam tshuam thiab muaj kev cuam tshuam. Vim li no, cov teeb liab kis tau rau hauv qhov muag fiber ntau tsis yooj yim rau kev mloog, yog li nws yog qhov tsim nyog rau kev ceev ntiag tug.
siab fidelity
Vim hais tias fiber ntau kis tau tus mob feem ntau tsis xav tau rov ua kom nrov nrov, tsis muaj qhov hloov pauv tshiab uas tsis yog hauv nruab nrab yuav raug qhia vim yog kev nthuav dav. Ntev npaum li qhov linearity ntawm lub laser yog zoo, TV signals yuav kis tau nrog siab fidelity. Qhov kev ntsuam xyuas tiag tiag qhia tau hais tias cov cab kuj sib xyaw peb qhov sib tw C / CTB ntawm qhov zoo AM fiber ntau yog siab dua 70dB, thiab qhov ntsuas qhov nruab nrab cM kuj tseem siab dua 60dB, uas yog siab dua qhov ntsuas qhov tsis sib xws ntawm cov kab ke dav dav.
Txhim khu kev ua tau zoo
Peb paub tias qhov kev ntseeg siab ntawm ib qho system muaj feem xyuam nrog cov xov tooj ntawm cov khoom siv uas tsim cov kab ke. Cov cuab yeej siv ntau dua, qhov ntau dua qhov ua tsis tiav. Vim hais tias lub fiber optic system muaj ib tug me me ntawm cov khoom siv (tsis xav tau kaum tawm amplifiers zoo li lub cable system), kev ntseeg siab yog ib txwm siab, thiab lub neej ntawm cov khoom siv fiber optic yog ntev heev, nrog rau lub sij hawm tsis muaj teeb meem ua hauj lwm. 500, 000 mus rau 750, 000 teev. Ntawm lawv, lub laser hauv optical transmitter muaj lub neej luv tshaj plaws, thiab qhov tsawg kawg nkaus lifespan kuj yog ntau tshaj 100,000 teev. Yog li ntawd, kev ua haujlwm ntawm kev tsim qauv zoo, raug teeb tsa thiab debugged optical fiber ntau yog qhov txhim khu kev qha.
Tus nqi pheej poob
Ib tug neeg tau thov tsab cai Moore tshiab, tseem hu ua Txoj Cai Kho qhov muag. Txoj cai lij choj hais tias bandwidth ntawm optical fiber ntau kis tau tus mob ob zaug txhua txhua 6 lub hlis, thaum tus nqi txo los ntawm 1 zaug. Txoj kev loj hlob ntawm optical kev sib txuas lus technology tau nteg ib tug zoo heev lub hauv paus rau txoj kev loj hlob ntawm Internet broadband technology. Qhov no tshem tawm qhov teeb meem kawg rau cov kab hluav taws xob loj hauv xov tooj cua los txais yuav kev xa xov fiber ntau. Vim muaj ntau qhov chaw ntawm cov ntaub ntawv (quartz) rau kev ua cov fibers optical, nrog rau kev nce qib ntawm kev siv tshuab, tus nqi yuav raug txo ntxiv; thaum cov khoom siv tooj liab xav tau rau cov cables raug txwv, tus nqi yuav siab dua thiab siab dua. Obviously, optical fiber ntau kis tau tus mob yuav nyob rau hauv lub neej yav tom ntej kom zoo dua, thiab dhau los ua txoj kev kis tau tus mob tseem ceeb tshaj plaws rau kev tsim lub cable TV network nyob rau hauv tag nrho cov xeev thiab txawm lub teb chaws.
