1) AMI code
Cikakken sunan lambar AMI (Alternative Mark Inversion) shine madaidaicin lambar juyar da alamar.blank) zama baya canzawa.Misali:
Lambar saƙo: 0 1 1 0 0 0 0 0 0 0 1 1 0 0 1 1…
Lambar AMI: 0 -1 +1 0 0 0 0 0 0 0 -1 +1 0 0 -1 +1…
Siffar igiyar igiyar ruwa wacce ta dace da lambar AMI jerin bugun jini ne mai inganci, mara kyau, da matakan sifili.Ana iya ɗaukarsa azaman nakasar ƙaƙƙarfan igiyar ruwa ta unipolar, wato, “0″ har yanzu yana daidai da matakin sifili, yayin da “1” yayi daidai da matakan inganci da mara kyau a madadin.
Amfanin lambar AMI shine cewa babu wani ɓangaren DC, akwai ƴan ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙima, kuma makamashin yana mai da hankali akan saurin lambar 1/2.
(Hoto 6-4);Da'irar codec yana da sauƙi, kuma ana iya amfani da polarity code don lura da yanayin kuskure;idan nau'in igiyar igiyar ruwa ce ta AMI-RZ, ana iya canza shi zuwa unipolar muddun ya zama cikakkiyar gyare-gyare bayan karɓa.RZ waveform daga abin da za a iya fitar da abubuwan abubuwan lokaci na bit.Saboda fa'idodin da ke sama, lambar AMI ta zama ɗaya daga cikin nau'ikan lambar watsawa da aka fi amfani da ita.
Lalacewar lambar AMI: Lokacin da lambar asali tana da dogon jerin “0″, matakin siginar baya tsalle na dogon lokaci, wanda ke sa da wahala cire siginar lokaci.Ɗaya daga cikin ingantattun hanyoyin magance matsalar ko da “0″ code shine amfani da lambar HDB3.
(2) HDB3 code
Cikakken sunan lambar HDB3 shine lambar bipolar mai girma mai girma na uku.Yana da ingantaccen nau'in lambar AMI.Manufar haɓakawa ita ce kiyaye fa'idodin lambar AMI da shawo kan gazawarsa ta yadda adadin "0" a jere bai wuce uku ba.Ka'idojin shigar da shi sune kamar haka:
Da farko duba adadin "0" a jere a cikin lambar saƙon.Lokacin da adadin “0″s jere bai kai ko daidai da 3 ba, daidai yake da ƙa'idar shigar da lambar AMI.Lokacin da adadin "0" a jere ya wuce 3, kowanne daga cikin "0" guda 4 a jere za a canza shi zuwa sashe kuma a maye gurbinsa da "000V".V (darajar +1 ko -1) yakamata ya kasance yana da polarity iri ɗaya kamar yadda yake gabatowa kusa da bugun bugun jini mara-”0″ (saboda wannan ya karya ka'idar canjin polarity, don haka ana kiran V bugun bugun jini mai lalacewa).Matsakaicin lambobi V-code dole ne su canza.Lokacin da ƙimar lambar V zata iya cika buƙatun a cikin (2) amma ba zata iya cika wannan buƙatun ba, sannan maye gurbin "0000" da "B00V".Darajar B yayi daidai da bugun bugun V mai zuwa don magance wannan matsalar.Saboda haka, B ana kiransa bugun bugun jini.Hakanan ya kamata a canza polarity na lambar watsawa bayan lambar V.
Baya ga fa'idodin lambar AMI, lambar HDB3 ta kuma iyakance adadin lambobin "0" a jere zuwa ƙasa da 3, ta yadda za'a iya ba da garantin cire bayanan lokaci yayin liyafar.Saboda haka, lambar HDB3 ita ce nau'in lambar da aka fi amfani da ita a cikin ƙasata da Turai, kuma nau'ikan lambar mu'amala da ke ƙasa da rukunin A-law PCM quaternary duk lambobin HDB3 ne.
A cikin lambar AMI da aka ambata a sama da lambar HDB3, kowace lambar binary ana canza su zuwa lamba tare da ƙimar matakin 1-bit uku (+1, 0, -1), don haka irin wannan lambar kuma ana kiranta lambar 1B1T.Bugu da kari, yana yiwuwa kuma a tsara lambar HDBn wanda adadin “0″s bai wuce n.
(3) Lambobin Biphase
Hakanan ana kiran lambar Biphase azaman lambar Manchester.Yana amfani da lokacin raƙuman murabba'i mai inganci da mara kyau don wakiltar "0" da juzu'in raƙuman sa don wakiltar "1".Ɗaya daga cikin ƙa'idodin ɓoye shine cewa "0" lambar tana wakilta ta "01" lambar lambobi biyu, kuma "lambar" 1" tana wakilta ta "10" lambar lambobi biyu.Misali,
Lambar saƙo: 1 1 0 0 1 0 1
Lambar Biphase: 10 10 01 01 10 01 10
A biphasic code waveform ne mai bipolar NRZ waveform tare da matakai biyu kawai na kishiyar polarity.Yana da matakan tsalle-tsalle a tsakiyar kowane tazara ta alama, don haka yana ƙunshe da wadataccen bayanan lokaci.Babu bangaren DC, kuma tsarin ɓoye ma yana da sauƙi.Rashin hasara shi ne cewa bandwidth da aka mamaye yana ninka sau biyu, wanda ke rage yawan amfani da rukunin mitar.Lambar bi-phase yana da kyau don aika kayan aikin tashar bayanai akan ɗan gajeren nesa, kuma galibi ana amfani dashi azaman nau'in lambar watsawa a cibiyar sadarwar yanki.
(4) Lambar banbance-banbance na lokaci biyu
Domin warware kuskuren yanke hukunci da aka samu ta hanyar juyar da lambobi na lamba biyu, ana iya amfani da manufar lambar banbanta.Lambar Biphase tana amfani da mizanin matakin a tsakiyar tsawon lokacin kowace alama don aiki tare da wakilcin lambar sigina (matsayi daga korau zuwa tabbatacce yana wakiltar binary “0″, kuma sauyawa daga tabbatacce zuwa korau yana wakiltar binary “1″).A bambance-bambancen lambar lambar biphase, ana amfani da canjin matakin a tsakiyar kowace alama don aiki tare, kuma ko akwai ƙarin canji a farkon kowace alama ana amfani da shi don tantance lambar siginar.Idan akwai sauyi, yana nufin binary “1″, kuma idan babu canji, yana nufin binary “0″.Ana yawan amfani da wannan lambar a cibiyoyin sadarwar yanki.
Lambar CMI
Lambar CMI ita ce taqaitaccen lambar "lambar inversion.Kamar lambar bi-phase, ita ma lambar matakin mataki biyu ce.Ka'idar coding ita ce: “1″ code ana wakilta ta hanyar “11″ da “00″ lambar lambobi biyu;lambar “0″ tana wakilta sosai da “01″, kuma ana nuna sifarta a hoto 6-5(c).
Lambobin CMI suna da sauƙin aiwatarwa kuma suna ƙunshe da wadatattun bayanan lokaci.Bugu da kari, tun da 10 haramun rukuni ne na lamba, ba za a sami lambobi sama da uku a jere ba, kuma ana iya amfani da wannan doka don gano kuskuren macroscopic.ITU-T ce ta ba da shawarar wannan lambar azaman nau'in lambar mu'amala ta PCM quartet kuma wani lokaci ana amfani da ita a tsarin watsa kebul na gani tare da ƙimar ƙasa da 8.448Mb/s.
Toshe rikodin
Don inganta aikin coding na layi, ana buƙatar wasu nau'in sakewa don tabbatar da aiki tare da ƙirar ƙira da gano kuskure.Gabatarwar toshe codeing na iya cimma waɗannan dalilai guda biyu zuwa wani ɗan lokaci.Sigar block codeing shine lambar nBmB, lambar nBmT da sauransu.
nBmB code wani nau'i ne na block codeing, wanda ke raba n-bit binary code na ainihin bayanan rafi zuwa rukuni kuma ya maye gurbinsa da sabon code group na m-bit binary code, inda m>n.Tun m>n, sabon rukunin lambar na iya kasancewa Akwai haɗin 2^m, don haka akwai ƙarin haɗin (2^m-2^n).Daga cikin haɗe-haɗe na 2 ″, an zaɓi ƙungiyar lambar da ta dace ta wata hanya azaman rukunin lambar da aka ba da izini, sauran kuma ana amfani da su azaman rukunin lambar haramun don samun kyakkyawan aikin coding.Misali, a cikin lambar 4B5B, ana amfani da lambar 5-bit maimakon lambar 4-bit.Coding, don 4-bit grouping, akwai kawai 2^4=16 haduwa daban-daban, kuma ga 5-bit grouping, akwai 2^5=32 daban-daban haduwa.Domin samun aiki tare, ba za mu iya bin ba fiye da ɗaya jagora “0″ da ƙari biyu “0″ ana amfani da su don zaɓar ƙungiyoyin lamba, sauran kuma ƙungiyoyin lambar nakasassu ne.Ta wannan hanyar, idan rukunin lambar nakasassu ya bayyana a ƙarshen karɓar, yana nufin cewa akwai kuskure a cikin tsarin watsawa, don haka inganta iya gano kuskuren tsarin.Duk lambobin biyu-lokaci da lambobin CMI ana iya ɗaukar su azaman lambobin 1B2B.
A cikin tsarin sadarwar fiber na gani, ana yawan zaɓar m=n+1, kuma ana ɗaukar lambar 1B2B, lambar 2B3B, lambar 3B4B da lambar 5B6B.Daga cikin su, an yi amfani da tsarin lambar 5B6B a zahiri azaman tsarin lambar watsa layi don rukuni na uku da rukuni na huɗu ko fiye.
Lambar nBmB tana ba da kyakkyawan aiki tare da ayyukan gano kuskure, amma kuma yana biyan takamaiman farashi, wato, bandwidth ɗin da ake buƙata yana ƙaruwa daidai.
Tunanin ƙirar lambar nBmT shine canza n lambobin binary zuwa sabon rukuni na lambobin m ternary, da m.Misali, lambar 4B3T, wacce ke canza lambobin binary 4 zuwa lambobin ternary 3.Babu shakka, a ƙarƙashin ƙimar lambar guda ɗaya, ƙarfin bayanin lambar lambar 4B3T ya fi na 1B1T, wanda zai iya inganta ƙimar amfani da mitar.4B3T code, 8B6T code, da dai sauransu sun dace da mafi girma kudi tsarin watsa bayanai, kamar high-oda coaxial na USB watsa tsarin.
Abin da ke sama shine bayanin abubuwan ilimi na "Nau'in Code na yau da kullum don Baseband Transmission" wanda Shenzhen Hi-Diwei Optoelectronics Technology Co., Ltd. ya kawo muku, Ina fatan wannan labarin zai iya taimaka muku wajen haɓaka ilimin ku.Bayan wannan labarin idan kuna neman ingantaccen kamfanin kera kayan sadarwa na fiber optic za ku iya la'akari da sugame da mu.
Shenzhen HDV photoelectric Technology Co., Ltd. shine yafi masana'anta na samfuran sadarwa.A halin yanzu, kayan aikin da aka samar sun rufejerin ONU, na gani module jerin, Hanyoyin ciniki na OLT, kumatransceiver jerin.Za mu iya samar da ayyuka na musamman don yanayi daban-daban.Barka da zuwatuntuba.
