Kafin fahimtar fasahar PAM4, menene fasahar daidaitawa? Fasahar gyare-gyare ita ce dabarar juyar da siginar tushe (siginonin lantarki masu asali) zuwa siginonin watsawa. Don tabbatar da ingancin sadarwa da shawo kan matsaloli a cikin watsa sigina mai nisa, ya zama dole don canja wurin siginar siginar zuwa tashar mai girma ta hanyar daidaitawa don watsawa.
PAM4 shine tsari na huɗu na odar bugun bugun jini (PAM) dabarar daidaitawa.
Siginar PAM sanannen fasahar watsa sigina ce bayan NRZ (Ba Komawa zuwa Sifili ba).
Siginar NRZ tana amfani da matakan sigina guda biyu, babba da ƙasa, don wakiltar 1 da 0 na siginar dabaru na dijital, kuma yana iya watsa 1 bit na bayanan dabaru a kowane zagaye na agogo.
Siginar PAM4 tana amfani da matakan sigina daban-daban guda 4 don watsa sigina, kuma kowane zagayowar agogo zai iya watsa rago biyu na bayanan dabaru, wato 00, 01, 10, da 11.
Sabili da haka, a ƙarƙashin yanayin ƙimar baud iri ɗaya, ƙimar bit na siginar PAM4 ya ninka na siginar NRZ sau biyu, wanda ke ninka ingantaccen watsawa kuma yana rage farashin yadda ya kamata.
An yi amfani da fasahar PAM4 sosai a fagen haɗin haɗin sigina mai sauri. A halin yanzu, akwai na'urar transceiver na gani na 400G dangane da fasahar daidaitawa ta PAM4 don cibiyar bayanai da kuma 50G na'urar transceiver na gani dangane da fasahar daidaitawa ta PAM4 don hanyar sadarwar haɗin gwiwar 5G.
Tsarin aiwatarwa na 400G DML na gani mai ɗaukar hoto dangane da tsarin PAM4 shine kamar haka: lokacin da ake watsa siginar naúrar, tashoshi 16 da aka karɓa na siginar lantarki na 25G NRZ ana shigar da su daga naúrar keɓancewar lantarki, wanda mai sarrafa DSP, PAM4 ya daidaita, da fitarwa tashoshi 8 na siginar lantarki na 25G PAM4, waɗanda aka ɗora akan guntun direba. Ana canza siginar wutar lantarki mai sauri zuwa tashoshi 8 na 50Gbps manyan sigina masu saurin gani ta hanyar tashoshi 8 na lasers, hade da madaidaicin raƙuman raƙuman raƙuman ruwa, kuma an haɗa su cikin tashar 1 na 400G mai saurin fitowar siginar gani mai sauri. Lokacin karɓar siginar naúrar, siginar gani mai sauri na 1-tashar 400G da aka karɓa ana shigar da ita ta hanyar naúrar keɓancewar gani, wanda aka canza zuwa tashar 8-tashar 50Gbps babban siginar gani mai saurin gani ta hanyar demultiplexer, mai karɓar gani ya karɓa, kuma ya canza zuwa na'urar lantarki. sigina. Bayan dawo da agogo, haɓakawa, daidaitawa, da lalata PAM4 ta guntu mai sarrafa DSP, ana canza siginar lantarki zuwa tashoshi 16 na siginar lantarki na 25G NRZ.
Aiwatar da fasahar daidaitawa ta PAM4 zuwa 400Gb/s na gani na gani. 400Gb / s na gani na gani wanda ya dogara da tsarin PAM4 na iya rage yawan adadin laser da ake buƙata a ƙarshen watsawa kuma daidai da rage yawan masu karɓa da ake buƙata a ƙarshen karɓa saboda amfani da fasaha na gyaran fuska mafi girma idan aka kwatanta da NRZ. Modulation PAM4 yana rage adadin abubuwan da aka gyara a cikin na'urar gani, wanda zai iya kawo fa'ida kamar ƙananan farashin taro, rage yawan amfani da wutar lantarki, da ƙaramin marufi.
Akwai buƙatar 50Gbit / s na kayan gani na gani a cikin watsawar 5G da cibiyoyin sadarwa na baya, da kuma mafita dangane da na'urorin gani na 25G da ƙari ta hanyar PAM4 pulse amplitude modulation format ana karɓar don cimma ƙarancin farashi da buƙatun bandwidth mai girma.
Lokacin kwatanta siginar PAM-4, yana da mahimmanci a kula da bambanci tsakanin ƙimar baud da ƙimar bit. Don siginar NRZ na al'ada, tun da alama ɗaya tana watsa bayanai guda ɗaya, ƙimar bit da ƙimar baud iri ɗaya ne. Misali, a cikin 100G Ethernet, ta amfani da siginar 25.78125GBaud guda huɗu don watsawa, ƙimar bit akan kowane siginar shima 25.78125Gbps ne, kuma sigina huɗu suna samun isar da siginar 100Gbps; Don siginar PAM-4, tunda alama ɗaya tana watsa bayanai guda 2, ƙimar bit ɗin da za'a iya watsawa shine sau biyu ƙimar baud. Misali, ta amfani da tashoshi 4 na sigina na 26.5625GBaud don watsawa a cikin 200G Ethernet, ƙimar bit akan kowane tashoshi shine 53.125Gbps, kuma tashoshi 4 na sigina na iya samun isar da siginar 200Gbps. Don 400G Ethernet, ana iya samun shi tare da tashoshi 8 na siginar 26.5625GBaud.
Lokacin aikawa: Janairu-02-2025