1) AMI code
Lub npe tag nrho ntawm AMI (Alternative Mark Inversion) code yog tus lej cim hloov pauv. blank) nyob twj ywm tsis hloov. Piv txwv li:
Message code: 0 1 1 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 -1 +1 0 0 -1 +1…
Lub waveform sib raug rau AMI code yog ib theem mem tes nrog qhov zoo, tsis zoo, thiab xoom. Nws tuaj yeem suav tau tias yog qhov deformation ntawm unipolar waveform, uas yog, "0" tseem sib raug mus rau qib xoom, thaum "1" sib raug rau qib zoo thiab tsis zoo hloov pauv.
Qhov kom zoo dua ntawm AMI code yog tias tsis muaj DC tivthaiv, muaj ob peb lub siab thiab qis zaus, thiab lub zog yog concentrated ntawm zaus ntawm 1/2 code ceev.
(Daim duab 6–4); Lub codec Circuit Court yog qhov yooj yim, thiab tus lej polarity tuaj yeem siv los soj ntsuam qhov teeb meem yuam kev; Yog tias nws yog AMI-RZ waveform, nws tuaj yeem hloov mus rau unipolar ntev npaum li nws tau kho tag nrho-yoj tom qab tau txais. RZ waveform los ntawm cov khoom me ntsis sij hawm tuaj yeem muab rho tawm. Vim yog qhov zoo saum toj no, AMI code tau dhau los ua ib qho ntawm ntau hom kev sib kis kab mob.
Qhov tsis zoo ntawm AMI code: Thaum tus thawj code muaj qhov ntev ntawm "0", theem ntawm lub teeb liab tsis dhia mus ntev, uas ua rau nws nyuaj rau rho tawm lub sijhawm teeb liab. Ib txoj hauv kev zoo los daws qhov teeb meem txawm tias "0" code yog siv HDB3 code.
(2) HDB3 code
Lub npe tag nrho ntawm HDB3 code yog qhov thib peb-txiav txim siab siab bipolar code. Nws yog hom kev txhim kho ntawm AMI code. Lub hom phiaj ntawm kev txhim kho yog kom tswj tau qhov zoo ntawm AMI code thiab kov yeej nws qhov tsis txaus kom tus naj npawb sib law liag "0" tsis tshaj peb. Nws cov cai encoding yog raws li nram no:
Ua ntej kos tus naj npawb sib law liag "0"s hauv cov lus code. Thaum tus naj npawb sib law liag "0"s tsawg dua lossis sib npaug rau 3, nws yog tib yam li txoj cai encoding ntawm AMI code. Thaum tus naj npawb ntawm qhov sib law liag “0″s tshaj 3, txhua qhov 4 sib law liag “0″s yuav raug hloov mus rau ib ntu thiab hloov nrog “000V”. V (tus nqi +1 lossis -1) yuav tsum muaj tib lub polarity raws li nws tam sim ntawd ua ntej uas nyob ib sab uas tsis yog "0" mem tes (vim qhov no ua txhaum txoj cai polarity alternation, yog li V 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, ces hloov "0000" nrog "B00V". Tus nqi ntawm B yog raws li V pulse hauv qab no los daws qhov teeb meem no. Yog li, B yog hu ua modulation mem tes. Lub polarity ntawm tus lej kis tau tus mob tom qab V code yuav tsum tau hloov pauv.
Ntxiv rau qhov zoo ntawm AMI code, HDB3 code tseem txwv cov lej sib law liag "0" kom tsawg dua 3, kom cov ntaub ntawv rho tawm sijhawm tuaj yeem lav tau thaum txais tos. Yog li, HDB3 code yog hom code siv dav tshaj plaws hauv kuv lub tebchaws thiab Europe, thiab cov lej sib cuam tshuam hauv qab A-txoj cai PCM quaternary pawg yog tag nrho HDB3 cov lej.
Nyob rau hauv cov lus saum toj no-hais AMI code thiab HDB3 code, txhua binary code yog hloov dua siab tshiab rau hauv ib tug code nrog ib tug 1-ntsis peb-theem tus nqi (+1, 0, -1), ces hom code no kuj hu ua 1B1T code. Tsis tas li ntawd, nws tseem tuaj yeem tsim tus lej HDBn uas tus lej ntawm "0" tsis tshaj n.
(3) Txoj Cai Biphase
Lub Biphase code tseem hu ua Manchester code. Nws siv lub sijhawm zoo thiab tsis zoo symmetrical square nthwv dej los sawv cev "0" thiab nws qhov hloov pauv hloov pauv los sawv cev "1". Ib qho ntawm cov kev cai encoding 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 code. Piv txwv li,
Xov tooj: 1 1 0 0 1 0 1
Biphase code: 10 10 01 01 10 01 10
Ib tug biphasic code waveform yog ib tug bipolar NRZ waveform nrog tsuas yog ob theem ntawm opposite polarity. Nws muaj qib dhia ntawm qhov chaw nruab nrab ntawm txhua lub cim lub sijhawm, yog li nws muaj cov ntaub ntawv nplua nuj me ntsis sijhawm. Tsis muaj DC tivthaiv, thiab cov txheej txheem encoding kuj yooj yim. Qhov tsis zoo yog tias qhov chaw nyob bandwidth yog ob npaug, uas txo qhov kev siv ntawm cov zaus band. Tus lej bi-theem yog qhov zoo rau kev xa cov ntaub ntawv davhlau ya nyob twg cov cuab yeej siv sijhawm luv luv, thiab nws feem ntau yog siv los ua hom kis kab mob hauv ib cheeb tsam network.
(4) Ob-theem sib txawv code
Yuav kom daws tau qhov kev txiav txim siab yuam kev tshwm sim los ntawm polarity reversal ntawm bi-theem code, lub tswv yim ntawm kev sib txawv code tuaj yeem siv tau. Biphase code siv cov kev hloov pauv nyob rau hauv nruab nrab ntawm lub sijhawm ntawm txhua lub cim rau synchronization thiab cov cim code sawv cev (qhov kev hloov ntawm qhov tsis zoo mus rau qhov zoo sawv cev rau binary "0", thiab kev hloov ntawm qhov zoo mus rau qhov tsis zoo sawv cev rau binary "1"). Nyob rau hauv sib txawv biphase code coding, theem kev hloov nyob rau hauv nruab nrab ntawm txhua lub cim yog siv rau synchronization, thiab seb puas muaj ib tug ntxiv hloov nyob rau hauv lub pib ntawm txhua lub cim yog siv los txiav txim lub teeb liab code. Yog tias muaj kev hloov pauv, nws txhais tau tias binary "1", thiab yog tias tsis muaj kev hloov pauv, nws txhais tau tias binary "0". Cov cai no feem ntau siv hauv cov chaw hauv cheeb tsam.
CMI code
CMI code yog lub ntsiab lus ntawm "kos npe inversion code. Zoo li bi-theem code, nws kuj yog bipolar ob-theem code. Txoj cai coding yog: "1" code yog alternated los ntawm "11" thiab "00" ob-tus lej code; tus "0" code yog tsau sawv cev los ntawm "01", thiab nws waveform yog qhia nyob rau hauv daim duab 6-5(c).
CMI cov lis dej num yog ib qho yooj yim rau kev siv thiab muaj cov ntaub ntawv ntau lub sijhawm. Tsis tas li ntawd, txij li thaum 10 yog ib pawg cai txwv tsis pub muaj, yuav tsis muaj ntau tshaj peb cov lej sib law liag, thiab txoj cai no tuaj yeem siv rau kev tshawb nrhiav qhov yuam kev macroscopic. Cov cai no tau pom zoo los ntawm ITU-T raws li qhov sib txuas code hom ntawm PCM quartet thiab qee zaum siv rau hauv cov kab hluav taws xob xa hluav taws xob nrog tus nqi qis dua 8.448Mb / s.
Thaiv encoding
Txhawm rau txhim kho kab coding kev ua tau zoo, qee yam kev rov ua dua yuav tsum tau ua kom ntseeg tau cov qauv synchronization thiab tshawb pom qhov yuam kev. Kev taw qhia txog kev thaiv coding tuaj yeem ua tiav ob lub hom phiaj no rau qee qhov. Daim ntawv thaiv coding yog nBmB code, nBmT code thiab lwm yam.
nBmB code yog ib hom kev thaiv coding, uas faib cov n-ntsis binary code ntawm cov ntaub ntawv thawj kwj rau hauv ib pab pawg thiab hloov nws nrog ib pab pawg tshiab ntawm m-ntsis binary code, qhov twg m>n. Txij li thaum m>n, pawg cai tshiab tej zaum yuav muaj 2^m ua ke, yog li muaj ntau (2^m-2^n) ua ke. Ntawm 2 "kev sib xyaw ua ke, cov pab pawg pom zoo tau raug xaiv nyob rau hauv qee txoj kev raws li pawg cai tso cai, thiab tus so yog siv los ua pawg txwv code kom tau txais txiaj ntsig zoo coding. Piv txwv li, hauv 4B5B coding, 5-ntsis code yog siv los ntawm 4-ntsis code. Coding, rau 4-ntsis pab pawg, tsuas muaj 2^4 = 16 sib txawv ua ke, thiab rau 5-ntsis pab pawg, muaj 2^5 = 32 sib txawv ua ke. Txhawm rau kom ua tiav synchronization, peb tuaj yeem ua raws li tsis pub ntau tshaj ib qho "0" thiab Ob lub ntsiab lus "0" yog siv los xaiv pawg code, thiab tus so yog pab pawg neeg xiam oob qhab. Nyob rau hauv txoj kev no, yog tias ib pab pawg neeg xiam oob qhab tshwm nyob rau ntawm qhov kawg tau txais, nws txhais tau hais tias muaj kev ua yuam kev hauv cov txheej txheem sib kis, yog li kev txhim kho qhov kev ua yuam kev ntawm qhov system. Ob lub lis piam bi-theem thiab CMI cov lej tuaj yeem suav tias yog 1B2B cov lej.
Hauv kev sib txuas lus fiber ntau optical, m = n + 1 feem ntau xaiv, thiab 1B2B code, 2B3B code, 3B4B code thiab 5B6B code raug coj mus. Ntawm lawv, 5B6B code qauv tau xyaum siv raws li kab sib kis tus lej qauv rau pawg thib peb thiab pawg plaub lossis ntau dua.
Lub nBmB code muab kev sib txuas zoo thiab kev ua haujlwm tsis raug, tab sis nws kuj them tus nqi, uas yog, qhov xav tau bandwidth nce raws li.
Lub tswv yim tsim ntawm nBmT code yog hloov n binary codes rau hauv ib pawg tshiab code ntawm m ternary codes, thiab m
Cov saum toj no yog ib qho kev piav qhia ntawm cov ntsiab lus kev paub ntawm "Common Code Types for Baseband Transmission" coj los rau koj los ntawm Shenzhen Hi-Diwei Optoelectronics Technology Co., Ltd., Kuv vam tias tsab xov xwm no tuaj yeem pab koj kom koj paub ntau ntxiv. Dhau li ntawm tsab xov xwm no yog tias koj tab tom nrhiav rau lub tuam txhab kev sib txuas lus zoo fiber ntau cov khoom lag luam koj tuaj yeem xav txogtxog peb.
Shenzhen HDV photoelectric Technology Co., Ltd. yog lub chaw tsim khoom ntawm cov khoom sib txuas lus. Tam sim no, cov cuab yeej tsim tawm npog covONU series, Optical module series, OLT series, thiabtransceiver series. Peb tuaj yeem muab cov kev pabcuam customized rau cov xwm txheej sib txawv. Zoo siab txais tossab laj.
