(1) AMI code
AMI (Alternative Mark Inversion) code yog lub npe tag nrho ntawm cov cim hloov pauv hloov pauv, nws txoj cai encoding yog hloov pauv cov lus code "1" (kos) rau "+1" thiab "-1", thaum "0" ( npliag kos npe) tseem tsis hloov. Piv txwv li:
Message code: 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 1 1
AMI code: 0-1 +1 0 0 0 0 0 0 0 0 0 0 0 1 +1 0 0 0 0 1 +1
Lub waveform sib raug rau AMI code yog lub tsheb ciav hlau mem tes nrog qib zoo, tsis zoo thiab xoom. Nws tuaj yeem pom tau tias yog unipolar waveform deformation, uas yog, "0" tseem sib raug rau qib xoom, thiab "1" hloov pauv mus rau qib zoo thiab tsis zoo.
Qhov kom zoo dua ntawm AMI code yog tias tsis muaj DC tivthaiv, thiab cov khoom siv siab thiab qis qis yog me me, thiab lub zog yog concentrated ntawm qhov zaus ntawm 1/2 yard ceev.
(Daim duab 6-4); Lub codec Circuit Court yog qhov yooj yim, thiab qhov yuam kev ntawm code tuaj yeem raug soj ntsuam los ntawm kev siv txoj cai ntawm kev hloov polarity ntawm lub teeb liab. Yog tias nws yog AMI-RZ waveform, tom qab tau txais nws, ntev li ntev raws li kev hloov kho nthwv dej tag nrho, nws tuaj yeem hloov pauv mus rau unipolar RZ waveform, los ntawm lub sijhawm me ntsis tuaj yeem muab rho tawm. Nyob rau hauv kev pom ntawm qhov zoo saum toj no, AMI code tau dhau los ua ib qho ntawm feem ntau siv cov lej sib kis.
Qhov tsis zoo ntawm AMI code: Thaum tus lej thawj muaj "0" txoj hlua ntev, theem ntawm lub teeb liab tsis dhia ntev, ua rau muaj teeb meem hauv kev rho tawm lub sijhawm teeb tsa. Ib txoj hauv kev zoo los daws qhov teeb meem ntawm "0" code yog siv HDB3 code.
(2) HDB3 code
Lub npe tag nrho ntawm HDB3 code yog thib peb-kev txiav txim siab bipolar code. Nws yog ib qho kev txhim kho ntawm AMI code, lub hom phiaj ntawm kev txhim kho yog los tswj qhov zoo ntawm AMI code thiab kov yeej nws qhov tsis txaus, kom tus naj npawb ntawm "0" tsis tshaj peb. Nws cov cai encoding yog raws li nram no:
Txheeb xyuas tus naj npawb ntawm zeros txuas nrog cov kab lus. Thaum tus naj npawb ntawm "0" tsawg dua lossis sib npaug rau 3, txoj cai coding yog tib yam li AMI code. Thaum tus naj npawb ntawm cov xoom sib law liag ntau tshaj peb, txhua qhov ntawm plaub qhov sib law liag tau hloov mus rau hauv ib ntu thiab hloov los ntawm 000V. V (siv tus nqi +1 lossis -1) yuav tsum muaj tib lub polarity li yav dhau los uas nyob ib sab uas tsis yog- "0" mem tes (vim qhov no ua txhaum txoj cai ntawm polarity alternation, V yog hu ua kev puas tsuaj pulse). V-code polarities uas nyob ib sab yuav tsum hloov. Thaum tus nqi ntawm V code tuaj yeem ua tau raws li qhov yuav tsum tau ua hauv (2) tab sis tsis tuaj yeem ua tau raws li qhov yuav tsum tau ua, "0000" yog hloov los ntawm "B00V". Tus nqi ntawm B yog tib yam li V mem tes hauv qab no los daws qhov teeb meem no. Yog li, B yog hu ua regulating mem tes. Lub polarity ntawm tus lej kis tau tus mob tom qab V code yuav tsum tau hloov.
Ntxiv rau qhov zoo ntawm AMI code, HDB3 code kuj txwv tus lej ntawm "0" code rau 3, kom cov ntaub ntawv sijhawm tuaj yeem muab rho tawm thaum tau txais. Yog li ntawd, HDB3 code yog hom code siv dav tshaj plaws nyob rau hauv Suav teb thiab Europe thiab lwm lub tebchaws, thiab kev sib txuas lus hom kev cai lij choj A PCM hauv qab plaub pawg yog HDB3 code.
Nyob rau saum toj no AMI code thiab HDB3 code, txhua binary teeb liab code yog hloov dua siab tshiab rau hauv ib-ntsis peb-theem tus nqi (+1, 0,-1) code, yog li hom code no kuj hu ua 1B1T code. Tsis tas li ntawd, HDBn code tuaj yeem tsim tau kom tus naj npawb ntawm "0" tsis tshaj n.
(3) ob-phase code
Biphasic code tseem hu ua Manchester code. Nws siv qhov zoo thiab tsis zoo symmetric square waves ntawm ib lub sij hawm los sawv cev "0" thiab nws inverting waveform los sawv cev "1". Ib qho ntawm cov kev cai coding yog tias "0" code yog sawv cev los ntawm "01" ob-tus lej code, thiab "1" code yog sawv cev los ntawm "10" ob-tus lej, piv txwv li:
Xov tooj: 1 1 0 0 0 1 0 1
Biphase code: 10 10 01 01 10 01 10
Ib tug bipolar code waveform yog ib tug bipolar NRZ waveform nrog tsuas yog ob theem ntawm opposite polarity. Nws muaj qib dhia hauv qhov chaw nruab nrab ntawm txhua lub cim lub sijhawm, yog li nws muaj cov ntaub ntawv nplua nuj me ntsis sijhawm, thiab tsis muaj DC tivthaiv, thiab cov txheej txheem coding yog yooj yim. Qhov tsis zoo yog tias cov khoom siv bandwidth tau muab faib ua ob npaug, yog li kev siv bandwidth tsawg dua. Biphase code yog tsim rau luv luv kis tau tus mob ntawm cov ntaub ntawv davhlau ya nyob twg cov cuab yeej, thiab nws yog feem ntau siv raws li kis tau tus mob code hom nyob rau hauv lub cheeb tsam network.
(4) Sib txawv biphase code
Txhawm rau daws qhov kev txiav txim siab yuam kev tshwm sim los ntawm polarity thim rov qab hauv cov lej biphasic, lub tswv yim ntawm cov lej sib txawv tuaj yeem raug saws. Biphasic codes yog synchronized thiab sawv cev los ntawm ib theem dhia nyob rau hauv nruab nrab ntawm txhua lub cim lub sij hawm (ib tug dhia ntawm qhov tsis zoo mus rau qhov zoo sawv cev rau ib tug binary "0" thiab ib tug dhia ntawm zoo mus rau qhov tsis zoo sawv cev rau ib tug binary "1"). Nyob rau hauv sib txawv biphase coding, theem dhia nyob rau hauv nruab nrab ntawm txhua lub caij yog siv rau synchronization, thiab seb puas muaj ib tug ntxiv dhia thaum pib ntawm txhua lub caij yog siv los txiav txim lub teeb liab code. Yog hais tias muaj dhia, nws qhia tau hais tias binary "1", thiab yog tias tsis muaj dhia, nws qhia tau tias binary "0". Cov cai no feem ntau siv hauv cov chaw hauv cheeb tsam.
(5) CMI code
CMI code yog luv luv rau cov cim thim rov qab, thiab zoo ib yam li bipolar code, nws kuj yog ib tug bipolar bipolar flat code. Nws txoj cai coding yog: "1" code yog alternated los ntawm "11" thiab "00" ob-tus lej codes; Tus lej 0 yog sawv cev los ntawm 01, thiab nws cov qauv waveform yog qhia hauv daim duab 6-5(c).
CMI code yog ib qho yooj yim rau kev siv thiab muaj cov ntaub ntawv ntau lub sijhawm. Tsis tas li ntawd, txij li 10 yog pab pawg neeg xiam oob qhab, ntau tshaj peb cov lej yuav tsis tshwm sim, thiab txoj cai no tuaj yeem siv rau kev tshawb nrhiav qhov yuam kev macro. Cov cai no tau pom zoo los ntawm ITU-T raws li PCM quad-group interface code hom, thiab qee zaum siv rau hauv cov kab hluav taws xob xa hluav taws xob nrog cov nqi qis dua 8.448Mb / s.
(6) Thaiv coding
Txhawm rau txhim kho qhov kev ua tau zoo ntawm kab coding, qee yam kev rov ua dua yog xav tau los xyuas kom meej qhov synchronization thiab kev ua yuam kev muaj peev xwm ntawm cov qauv code. Kev taw qhia txog kev thaiv coding tuaj yeem ua tiav ob lub hom phiaj rau qee qhov. Daim ntawv thaiv coding muaj nBmB code, nBmT code thiab lwm yam.
nBmB code yog ib hom kev thaiv coding, uas faib cov n-ntsis binary code ntawm thawj cov ntaub ntawv ntws mus rau hauv ib pab pawg, thiab hloov nws mus rau ib pawg tshiab code ntawm M-ntsis binary code, qhov twg m>n. Vim tias m>n, cov txheej txheem tshiab yuav muaj 2^m ua ke, yog li muaj ntau (2^m-2^n) ua ke. Hauv 2 "kev sib xyaw ua ke, cov pab pawg pom zoo tau raug xaiv los ua pawg code tso cai nyob rau hauv qee txoj kev, thiab tus so yog siv los ua pab pawg neeg xiam oob qhab kom tau txais txiaj ntsig zoo coding. Piv txwv li, hauv 4B5B encoding, hloov 4-ntsis encoding nrog 5-ntsis encoding, tsuas muaj 2^4 = 16 sib txawv ua ke rau 4-ntsis pab pawg, thiab 2^5 = 32 sib txawv ua ke rau 5- me ntsis pab pawg. Txhawm rau kom ua tiav synchronization, peb tuaj yeem xaiv cov pab pawg hauv qhov tsis pub ntau tshaj ib qho "0" thiab ob lub ntsiab lus "0", thiab tus so yog pab pawg neeg xiam oob qhab. Nyob rau hauv txoj kev no, yog hais tias muaj ib tug neeg xiam oob qhab code teem rau ntawm qhov kawg tau txais, nws qhia tau hais tias muaj ib tug code yuam kev nyob rau hauv cov txheej txheem kis tau tus mob, yog li txhim kho qhov yuam kev nrhiav kom tau lub peev xwm ntawm lub system. Cov lej biphase thiab CMI cov lej tau piav qhia ua ntej tuaj yeem suav tau tias yog 1B2B cov lej.
Hauv kev sib txuas lus kho qhov muag fiber ntau, m = n + 1 feem ntau xaiv, thiab 1B2B code, 2B3B code, 3B4B code thiab 5B6B code raug coj mus. Ntawm lawv, 5B6B code tau siv rau hauv kev xyaum ua kab kis kab mob rau cov pawg cubic thiab ntau tshaj plaub pawg.
Lub nBmB code muab kev sib txuas zoo thiab tshawb pom qhov yuam kev, tab sis nws los ntawm tus nqi, uas yog, qhov yuav tsum tau muaj bandwidth nce.
Lub tswv yim tsim ntawm nBmT code yog hloov n binary codes rau hauv m ternary codes, thiab m
Cov saum toj no yog Shenzhen HDV phoelectron Technology Ltd. los coj koj txog "baseband kis tau tus mob hom code hom" kev paub, vam tias yuav pab tau koj, Shenzhen HDV phoelectron Technology Ltd. ntxiv rauONUseries, transceiver series,OLTseries, tab sis kuj tsim module series, xws li: Kev sib txuas lus kho qhov muag module, optical kev sib txuas lus module, network kho qhov muag module, kev sib txuas lus optical module, optical fiber module, Ethernet optical fiber module, thiab lwm yam., tuaj yeem muab cov kev pabcuam zoo sib xws rau cov neeg siv khoom sib txawv. , txais tos koj tuaj xyuas.