Intangiriro ku ikoranabuhanga rya PAM4

Mbere yo gusobanukirwa ikoranabuhanga rya PAM4, ikoranabuhanga rya modulation ni iki? Ikoranabuhanga rya modulation ni uburyo bwo guhindura ibimenyetso bya baseband (ibimenyetso by'amashanyarazi bitaraboneka) mo ibimenyetso byo kohereza ubutumwa. Kugira ngo itumanaho rirusheho kugira akamaro no gukemura ibibazo byo kohereza ubutumwa kure, ni ngombwa kwimura spectrum y'ibimenyetso ku muyoboro w'amajwi ukoresheje modulation kugira ngo byoherezwe ubutumwa.

PAM4 ni uburyo bwa kane bwo guhindura pulse amplitude modulation (PAM).

Ikimenyetso cya PAM ni ikoranabuhanga rikunzwe cyane ryo kohereza ibimenyetso nyuma ya NRZ (Non Return to Zero).

Ikimenyetso cya NRZ gikoresha urwego rw'ibimenyetso bibiri, hejuru n'aho hasi, kugira ngo gigaragaze 1 na 0 by'ikimenyetso cya digitale logic, kandi gishobora kohereza amakuru ya logic 1 kuri buri saha.

Ibimenyetso bya PAM4 bikoresha urwego 4 rw'ibimenyetso bitandukanye mu kohereza ibimenyetso, kandi buri saha ishobora kohereza amakuru 2 ya logique, ari yo 00, 01, 10, na 11.
Bityo rero, mu gihe cy’ikigereranyo kimwe cya baud, igipimo cya biti cya PAM4 kiba inshuro ebyiri cy’ikimenyetso cya NRZ, bikuba kabiri imikorere myiza yo kohereza no kugabanya ikiguzi.

Ikoranabuhanga rya PAM4 ryakoreshejwe cyane mu bijyanye no guhuza ibimenyetso byihuse. Kuri ubu, hari module ya transceiver y'urumuri ya 400G ishingiye ku ikoranabuhanga rya PAM4 modulation technology ku kigo cy'amakuru n'agace ka transceiver y'urumuri ya 50G ishingiye ku ikoranabuhanga rya modulation ya PAM4 ku muyoboro wa 5G.

Ishyirwa mu bikorwa rya module ya transceiver y’amashanyarazi ya 400G DML ishingiye ku ihindagurika rya PAM4 ni iri rikurikira: iyo wohereza ibimenyetso by’amashanyarazi, imiyoboro 16 yakiriwe y’ibimenyetso by’amashanyarazi bya 25G NRZ yinjizwa mu gice cy’amashanyarazi, igatunganywa na poroseseri ya DSP, PAM4 igahindurwa, hanyuma igasohora imiyoboro 8 y’ibimenyetso by’amashanyarazi bya 25G PAM4, bishyirwa kuri chip y’umushoferi. Ibimenyetso by’amashanyarazi byihuta bihindurwamo imiyoboro 8 y’ibimenyetso by’amashanyarazi byihuta bya 50Gbps binyuze mu miyoboro 8 ya laser, bihuzwa na multiplexer yo kugabanya ubunini bw’uburebure, hanyuma bigashyirwa mu muyoboro 1 w’ibimenyetso by’amashanyarazi byihuta bya 400G. Iyo wakira ibimenyetso by’ibikoresho, ikimenyetso cy’amashanyarazi cyihuta cya 1-channel 400G cyakiriwe cyinjizwa binyuze mu gice cy’ikoranabuhanga, kigahindurwamo ikimenyetso cy’amashanyarazi cyihuta cya 8-channel 50Gbps binyuze muri demultiplexer, cyakirwa n’icyuma gikira urumuri, maze kigahindurwamo ikimenyetso cy’amashanyarazi. Nyuma yo kongera igihe, kongera imbaraga, kuringaniza, no gukuraho PAM4 hakoreshejwe chip ya DSP, ikimenyetso cy'amashanyarazi gihindurwamo imiyoboro 16 y'ikimenyetso cy'amashanyarazi cya 25G NRZ.

Koresha ikoranabuhanga rya PAM4 modules kuri 400Gb/s optique modules. Module ya 400Gb/s optique ishingiye kuri PAM4 module ishobora kugabanya umubare wa lasers zikenewe ku mpera yo kohereza no kugabanya umubare w'abakira bakenewe ku mpera yo kwakira bitewe no gukoresha tekiniki zo mu rwego rwo hejuru ugereranije na NRZ. Module ya PAM4 igabanya umubare w'ibice by'urumuri muri module ya optique, bishobora kuzana inyungu nko kugabanuka kw'ibiciro byo guteranya, kugabanuka kw'ikoreshwa ry'ingufu, no kuba ingano nto yo gupakira.

Hari icyifuzo cya modules za optique za 50Gbit/s muri 5G transmission na backhaul networks, kandi igisubizo gishingiye ku bikoresho bya optique bya 25G kandi cyiyongereyeho PAM4 pulse amplitude modulation format kirakoreshwa kugira ngo hagerwe ku giciro gito kandi gihanitse cy’umuyoboro wa interineti.

Mu gusobanura ibimenyetso bya PAM-4, ni ngombwa kwita ku itandukaniro riri hagati y’igipimo cya baud n’igipimo cya biti. Ku bimenyetso bisanzwe bya NRZ, kubera ko ikimenyetso kimwe cyohereza amakuru make, igipimo cya biti n’igipimo cya baud ni bimwe. Urugero, muri 100G Ethernet, hakoreshejwe ibimenyetso bine bya 25.78125GBaud mu kohereza, igipimo cya biti kuri buri kimenyetso nacyo ni 25.78125Gbps, kandi ibimenyetso bine bigeraho kohereza ibimenyetso bya 100Gbps; Ku bimenyetso bya PAM-4, kubera ko ikimenyetso kimwe cyohereza amakuru make, igipimo cya biti gishobora koherezwa ni kabiri igipimo cya baud. Urugero, hakoreshejwe imiyoboro 4 ya 26.5625GBaud mu kohereza muri 200G Ethernet, igipimo cya biti kuri buri muyoboro ni 53.125Gbps, kandi imiyoboro 4 ya signal ishobora kohereza ibimenyetso bya 200Gbps. Kuri 400G Ethernet, ishobora kugerwaho hakoreshejwe imiyoboro 8 ya 26.5625GBaud.