Ua ntej nkag siab txog PAM4 thev naus laus zis, modulation technology yog dab tsi? Modulation technology yog cov txheej txheem ntawm kev hloov cov teeb liab baseband (raw electrical signals) mus rau hauv cov teeb liab kis. Yuav kom ntseeg tau tias kev sib txuas lus zoo thiab kov yeej cov teeb meem hauv kev xa cov teeb liab ntev, nws yog qhov tsim nyog los hloov cov teeb liab spectrum mus rau ib qho channel siab los ntawm modulation rau kev xa.
PAM4 yog ib qho txheej txheem modulation modulation plaub theem (PAM) plaub.
PAM teeb liab yog ib qho thev naus laus zis kis tau teeb liab nrov tom qab NRZ (Tsis Rov Qab Mus Rau Xoom).
Lub teeb liab NRZ siv ob theem teeb liab, siab thiab qis, los sawv cev rau 1 thiab 0 ntawm lub teeb liab digital logic, thiab tuaj yeem xa 1 ntsis ntawm cov ntaub ntawv logic ib lub voj voog moos.
PAM4 teeb liab siv 4 qib teeb liab sib txawv rau kev xa teeb liab, thiab txhua lub voj voog moos tuaj yeem xa 2 ntsis ntawm cov ntaub ntawv logic, uas yog 00, 01, 10, thiab 11.
Yog li ntawd, nyob rau hauv tib lub baud rate conditions, lub bit rate ntawm PAM4 teeb liab yog ob npaug ntawm NRZ teeb liab, uas ob npaug ntawm kev sib kis tau zoo thiab txo cov nqi.
PAM4 thev naus laus zis tau siv dav hauv kev sib txuas lus ceev ceev. Tam sim no, muaj 400G optical transceiver module raws li PAM4 modulation technology rau chaw khaws ntaub ntawv thiab 50G optical transceiver module raws li PAM4 modulation technology rau 5G interconnection network.
Cov txheej txheem siv ntawm 400G DML optical transceiver module raws li PAM4 modulation yog raws li nram no: thaum xa cov cim qhia chav tsev, 16 txoj kab ntawm 25G NRZ hluav taws xob tau txais yog cov tswv yim los ntawm chav tsev sib txuas hluav taws xob, ua ntej los ntawm DSP processor, PAM4 modulated, thiab tso tawm 8 txoj kab ntawm 25G PAM4 hluav taws xob teeb liab, uas tau thauj mus rau ntawm tus tsav tsheb chip. Cov teeb liab hluav taws xob ceev ceev tau hloov mus rau hauv 8 txoj kab ntawm 50Gbps high-speed optical teeb liab los ntawm 8 txoj kab ntawm lasers, ua ke los ntawm wavelength division multiplexer, thiab synthesized rau hauv 1 txoj kab ntawm 400G high-speed optical teeb liab tso zis. Thaum tau txais cov cim qhia chav tsev, 1-channel 400G high-speed optical teeb liab tau txais yog cov tswv yim los ntawm chav tsev sib txuas optical, hloov mus rau hauv 8-channel 50Gbps high-speed optical teeb liab los ntawm demultiplexer, tau txais los ntawm lub optical receiver, thiab hloov mus rau hauv lub teeb liab hluav taws xob. Tom qab lub moos rov qab, amplification, equalization, thiab PAM4 demodulation los ntawm DSP processing chip, lub teeb liab hluav taws xob raug hloov mus rau hauv 16 channel ntawm 25G NRZ hluav taws xob teeb liab.
Siv cov thev naus laus zis PAM4 modulation rau 400Gb/s optical modules. Lub 400Gb/s optical module raws li PAM4 modulation tuaj yeem txo cov lasers xav tau ntawm qhov kawg xa thiab txo cov receivers xav tau ntawm qhov kawg txais vim yog siv cov txheej txheem modulation siab dua piv rau NRZ. PAM4 modulation txo cov khoom siv optical hauv optical module, uas tuaj yeem coj cov txiaj ntsig xws li cov nqi sib dhos qis dua, txo kev siv hluav taws xob, thiab qhov loj me me dua.
Muaj kev xav tau 50Gbit / s optical modules hauv 5G kis thiab backhaul networks, thiab kev daws teeb meem raws li 25G optical khoom siv thiab ntxiv los ntawm PAM4 pulse amplitude modulation hom ntawv tau txais yuav los ua tiav cov kev xav tau bandwidth qis thiab siab.
Thaum piav qhia txog PAM-4 cov cim, nws yog ib qho tseem ceeb uas yuav tsum tau them sai sai rau qhov sib txawv ntawm baud rate thiab bit rate. Rau cov cim NRZ ib txwm muaj, vim tias ib lub cim xa ib qho me me ntawm cov ntaub ntawv, qhov bit rate thiab baud rate yog tib yam. Piv txwv li, hauv 100G Ethernet, siv plaub lub cim 25.78125GBaud rau kev xa, qhov bit rate ntawm txhua lub cim kuj yog 25.78125Gbps, thiab plaub lub cim ua tiav qhov xa teeb liab 100Gbps; Rau cov cim PAM-4, vim tias ib lub cim xa 2 bits ntawm cov ntaub ntawv, qhov bit rate uas tuaj yeem xa tau yog ob npaug ntawm baud rate. Piv txwv li, siv 4 txoj kab ntawm 26.5625GBaud cov cim rau kev xa hauv 200G Ethernet, qhov bit rate ntawm txhua txoj kab yog 53.125Gbps, thiab 4 txoj kab ntawm cov cim tuaj yeem ua tiav qhov xa teeb liab 200Gbps. Rau 400G Ethernet, nws tuaj yeem ua tiav nrog 8 txoj kab ntawm 26.5625GBaud cov cim.
Lub sijhawm tshaj tawm: Lub Ib Hlis-02-2025