Chiyambi cha PAM4 Technology

Musanamvetsetse ukadaulo wa PAM4, ukadaulo wa modulation ndi chiyani? Tekinoloje ya Modulation ndi njira yosinthira ma sign a baseband (ma siginecha amagetsi aiwisi) kukhala ma siginecha otumizira. Pofuna kuwonetsetsa kuti kuyankhulana kukuyenda bwino komanso kuthana ndi mavuto pamayendedwe akutali, ndikofunikira kusamutsa sipekitiramu yamagetsi kupita kunjira yothamanga kwambiri kudzera mukusintha kwapaulendo.

PAM4 ndi njira yachinayi yosinthira ma pulse amplitude modulation (PAM).

Chizindikiro cha PAM ndiukadaulo wodziwika bwino wotumizira ma siginecha pambuyo pa NRZ (Non Return to Zero).

Chizindikiro cha NRZ chimagwiritsa ntchito milingo iwiri yazizindikiro, yapamwamba ndi yotsika, kuyimira 1 ndi 0 ya chizindikiro cha digito, ndipo imatha kutumiza chidziwitso cha 1 pang'ono pa wotchi iliyonse.

Chizindikiro cha PAM4 chimagwiritsa ntchito ma siginecha 4 osiyanasiyana potumiza ma siginecha, ndipo wotchi iliyonse imatha kutumiza zidziwitso za 2, zomwe ndi 00, 01, 10, ndi 11.
Chifukwa chake, pansi pazikhalidwe zomwezo za baud, kuchuluka kwa chizindikiro cha PAM4 ndi kawiri kuposa chizindikiro cha NRZ, chomwe chimachulukitsa kufalikira ndikuchepetsa bwino ndalama.

Tekinoloje ya PAM4 yakhala ikugwiritsidwa ntchito kwambiri polumikizana ndi ma signal othamanga kwambiri. Pakalipano, pali 400G optical transceiver module yochokera pa PAM4 modulation technology for data center ndi 50G optical transceiver module yochokera PAM4 modulation technology for 5G interconnection network.

Kukonzekera kwa 400G DML optical transceiver module yochokera ku PAM4 modulation ndi motere: potumiza zizindikiro za unit, njira zolandirira 16 za 25G NRZ zamagetsi zamagetsi zimalowetsedwa kuchokera kumagetsi opangira magetsi, okonzedweratu ndi pulosesa ya DSP, PAM4 modulated, ndi kutulutsa 8 njira za 25G PAM4 zamagetsi zamagetsi, zomwe zimayikidwa pa chip dalaivala. Zizindikiro zamagetsi zothamanga kwambiri zimasinthidwa kukhala mayendedwe a 8 a 50Gbps othamanga kwambiri kudzera mumayendedwe a 8 a lasers, ophatikizidwa ndi ma wavelength division multiplexer, ndipo amapangidwa mu 1 njira ya 400G yotulutsa mawonekedwe othamanga kwambiri. Mukalandira zizindikiro zamagulu, chizindikiro cha 1-channel 400G chothamanga kwambiri chimalowetsedwa kudzera mu optical interface unit, kusinthidwa kukhala 8-channel 50Gbps high-speed optical signal kupyolera mu demultiplexer, yolandiridwa ndi optical receiver, ndi kusinthidwa kukhala magetsi. chizindikiro. Pambuyo pa kuchira kwa wotchi, kukulitsa, kufanana, ndi kuchotsedwa kwa PAM4 ndi chipangizo chopangira DSP, chizindikiro chamagetsi chimasinthidwa kukhala mayendedwe a 16 a 25G NRZ chizindikiro chamagetsi.

Gwiritsani ntchito ukadaulo wa PAM4 ku ma module a 400Gb/s. The 400Gb / s optical module yochokera ku PAM4 modulation ingachepetse chiwerengero cha ma lasers ofunikira pamapeto otumizira ndipo mofananamo kuchepetsa chiwerengero cha olandira oyenerera pamapeto olandira chifukwa chogwiritsa ntchito njira zamakono zosinthira poyerekeza ndi NRZ. PAM4 modulation amachepetsa chiwerengero cha optical components mu optical module, zomwe zingabweretse ubwino monga mtengo wotsika wa msonkhano, kuchepetsa mphamvu yamagetsi, ndi kukula kwapang'onopang'ono.

Pali kufunikira kwa 50Gbit / s optical modules mu 5G transmission and backhaul networks, ndipo yankho lochokera ku 25G optical zipangizo ndi kuwonjezeredwa ndi PAM4 pulse amplitude modulation format amavomerezedwa kuti akwaniritse zofunikira zotsika mtengo komanso zapamwamba za bandwidth.

Pofotokozera zizindikiro za PAM-4, ndikofunika kumvetsera kusiyana pakati pa mlingo wa baud ndi bitrate. Pazizindikiro zachikhalidwe za NRZ, popeza chizindikiro chimodzi chimatumiza kachidutswa kakang'ono ka data, kutsika pang'ono ndi kuchuluka kwa baud ndizofanana. Mwachitsanzo, mu 100G Ethernet, pogwiritsa ntchito zizindikiro zinayi za 25.78125GBaud zotumizira, mlingo wochepa pa chizindikiro chilichonse ndi 25.78125Gbps, ndipo zizindikiro zinayi zimakwaniritsa kutumizira kwa 100Gbps; Kwa zizindikiro za PAM-4, popeza chizindikiro chimodzi chimatumiza 2 bits ya deta, mlingo wochepa womwe ungathe kufalitsidwa ndi wowirikiza kawiri mlingo wa baud. Mwachitsanzo, pogwiritsa ntchito njira za 4 za zizindikiro za 26.5625GBaud zotumizira ku 200G Ethernet, mlingo wochepa pa njira iliyonse ndi 53.125Gbps, ndipo 4 njira zowonetsera zimatha kukwaniritsa 200Gbps kufalitsa chizindikiro. Kwa 400G Ethernet, ikhoza kupezedwa ndi njira za 8 za zizindikiro za 26.5625GBaud.