Kochwepheshe abambalwa bezokuxhumana, imiqondo efana 'nokubambezeleka kokusabalalisa' kanye 'nokubambezeleka kwe-skew' kukhumbuza izinkumbulo ezibuhlungu zekilasi lesikole samabanga aphezulu.Eqinisweni, imiphumela yokubambezeleka nokubambezeleka i-skew ekudluliselweni kwesignali ichazwa kalula futhi iqondwe.
Ukubambezeleka kuyimpahla eyaziwa ukuthi ikhona kuzo zonke izinhlobo zemidiya yokudlulisela.Ukubambezeleka kokusabalalisa kulingana nenani lesikhathi esidlulayo phakathi kokuthi isignali idluliswa nalapho itholwa ngakolunye uhlangothi lwesiteshi sekhebula.Umphumela ufana nokubambezeleka kwesikhathi phakathi kwalapho umbani ushaya futhi ukuduma kwezulu kuzwakala-ngaphandle kokuthi amasignali kagesi ahamba ngokushesha kakhulu kunomsindo.Inani langempela lokulibaziseka lekhebula elisontekile liwumsebenzi wesivinini esilinganiselwe sokusakazeka (NVP), ubude kanye nemvamisa.
I-NVP iyahlukahluka kuye ngezinto ze-dielectric ezisetshenziswa kukhebuli futhi ivezwa njengephesenti lejubane lokukhanya.Isibonelo, ukwakhiwa okuningi kwesigaba 5 se-polyethylene (FRPE) kunobubanzi be-NVP obusuka ku-0.65cto0.70c (lapho u-“c” umele isivinini sokukhanya ~3 x108 m/s) uma kulinganiswa kukhebuli eqediwe.Ukwakhiwa kwekhebula le-Teflon (FEP) kusuka ku-0.69cto0.73c, kuyilapho izintambo ezenziwe nge-PVC ziku-0.60cto0.64crange.
Amanani aphansi e-NVP azofaka isandla ekubambezelekeni okwengeziwe kobude obunikeziwe bekhebula, njengoba nje ukwanda kobude bekhebula ngasemaphethelweni kuzobangela ukukhuphuka okulinganayo kokulibaziseka kokuphela ukuya ekupheleni.Njengamanye amapharamitha wokudlulisela, amanani okulibaziseka ancike emvamisa.
Uma amapheya amaningi kukhebula efanayo abonisa ukusebenza kokulibaziseka okuhlukile, umphumela uba ukulibaziseka kwe-skew.Ukubambezeleka kwe-skew kunqunywa ngokulinganisa umehluko phakathi kokubhanqwa ngokulibaziseka okuncane kanye nokubhangqa okunokubambezeleka okukhulu.Izinto ezithinta ukusebenza kwe-skew ukubambezeleka zifaka phakathi ukukhethwa kwezinto, ezifana nokufakwa kwe-conductor, nokwakheka komzimba, okufana nomehluko kuzilinganiso zokusonta ukusuka kokubhanqwa kokubhanqwa.
Ukubambezeleka Kokusakazwa Kwekhebula
Nakuba zonke izintambo ezisontekile zibonisa ukubambezeleka kokuhlehla ngezinga elithile, izintambo eziklanywe unembeza ukuvumela ukuhluka kwe-NVP kanye nomehluko wobude bokubhangqwana kokupheya azoba nokuhlehla kokulibaziseka okwamukelekayo ekucushweni kwesiteshi esivundlile okuthobelana okujwayelekile.Ezinye zezici ezingase zibe nomthelela omubi ekusebenzeni kwe-skew yokulibaziseka zifaka amakhebuli anezakhiwo ze-dielectric eziklanywe kabi kanye nalezo ezinomehluko omkhulu kuzilinganiso zokusonta kokupheya.
Ukulibaziseka kokusabalalisa nokusebenza kokuhlehla kokulibaziseka kucaciswa izindinganiso ezithile zenethiwekhi yendawo (i-LAN) esimweni esibi kakhulu sokulungiselelwa kwe-mchannel100 ukuqinisekisa ukudluliswa kwesignali okufanele.Izinkinga zokudlulisela ezihambisana nokubambezeleka okukhulu nokulibaziseka kwe-skew zifaka phakathi ukukhuphuka kwe-jitter namazinga wephutha elincane.Ngokusekelwe kuzicaciso ze-LAN yochungechunge lwe-IEEE 802, ukulibaziseka okukhulu kokusakazeka okungu-570 ns/100mat 1 MHz kanye nokuhlehla kokulibaziseka okukhulu okungu-45ns/100mup kuya ku-100 MHz kucatshangelwa i-TIA ngezintambo zesigaba 3, 4 kanye no-5, amapheya angu-4.I-TIA Working Group TR41.8.1 futhi icubungula ukuthuthukiswa kwezimfuneko zokuhlola ukubambezeleka kokusabalalisa kanye nokulibaziseka kwe-skew yezixhumanisi ezivundlile eziyi-100 ohm namashaneli akhiwe ngokuvumelana ne-ANSI/TIA/EIA-568-A.Njengomphumela wekomidi le-TIA elithi “Letter Ballot” TR-41:94-4 (PN-3772) kwanqunywa phakathi nomhlangano wangoSepthemba 1996 ukuthi kukhishwe “i-Industry Ballot” kuhlaka olubuyekeziwe ngaphambi kokukhululwa.Okusaxazululiwe yindaba yokuthi ukuqokwa kwesigaba kuzoshintsha noma cha (isb, isigaba 5.1), ukuze kubonakale umehluko phakathi kwamakhebuli ahlolelwa izimfuneko zokulibaziseka ezengeziwe/zokulibaziseka kwe-skew, nalezo ezingashintshile.
Nakuba ukubambezeleka kokusabalalisa kanye nokulibaziseka kokulibaziseka kuthola ukunakwa okukhulu, kubalulekile ukuqaphela ukuthi inkinga ebaluleke kakhulu yokusebenza kwekhebula yezinhlelo zokusebenza eziningi ze-LAN isalokhu iwukuncishiswa kwesilinganiso se-crosstalk (ACR).Nakuba amamajini e-ACR ethuthukisa isignali kuzilinganiso zomsindo futhi ngaleyo ndlela ehlisa izehlakalo zamaphutha amancane, ukusebenza kwesistimu akuthintwa ngokuqondile iziteshi zekhebula ezinomkhawulo wokulibaziseka obalulekile we-skew.Isibonelo, i-15 ns yokubambezeleka i-skew yesiteshi sekhebula ngokuvamile ngeke iphumele ekusebenzeni kwenethiwekhi okungcono kuno-45 ns, ohlelweni oluklanyelwe ukubekezelela kufika ku-50 ns wokulibaziseka kwe-skew.
Ngenxa yalesi sizathu, ukusetshenziswa kwamakhebuli ane-skew margins yokulibaziseka okuphawulekayo kubaluleke kakhulu kumshwalense abawunikezayo ngokumelene nezinqubo zokufaka noma ezinye izici ezingase zicindezele ukulibaziseka kokuhle ngaphezu komkhawulo, kunesithembiso sokusebenza okungcono kwesistimu uma kuqhathaniswa nesiteshi. ihlangabezana kuphela nemikhawulo yokubambezeleka kwesistimu ngama-nanosecond ambalwa.
Ngenxa yokuthi izintambo ezisebenzisa izinto ezihlukene ze-dielectric zamabhangqa ahlukene zitholwe zenza izinkinga nge-skew yokulibaziseka, kube khona impikiswano yakamuva mayelana nokusetshenziswa kwezinto ezixubile ze-dielectric ekwakheni ikhebula.Amagama afana nokuthi “2 by 2″ (ikhebula elinamapheya amabili anezinto ze-dielectric “A” namapheya amabili anezinto ezibonakalayo “B”) noma “4 by 0″ (ikhebula elinawo wonke amapheya amane enziwe nganoma iyiphi into engu-A, noma into engu-B ) eziphakamisa kakhulu izingodo kunekhebula, ngezinye izikhathi zisetshenziselwa ukuchaza ukwakhiwa kwe-dielectric.
Naphezu kwe-hype yezohwebo engase idukise umuntu ukuba akholelwe ukuthi kuphela izakhiwo ezinohlobo olulodwa lwempahla ye-dielectric ezizobonisa ukusebenza kokubambezeleka okwamukelekayo, iqiniso liwukuthi izintambo eziklanywe kahle ezinempahla eyodwa ye-dielectric, noma izinto eziningi ze-dielectric ziyakwazi ngokulinganayo ukwanelisa Izimfuneko ezinzima kakhulu zokulibaziseka kwesiteshi ezicaciswe amazinga ezicelo kanye nalezo ezicatshangelwa yi-TIA.
Ngaphansi kwezinye izimo, ukwakhiwa kwe-dielectric okuxubile kungase kusetshenziswe ngisho nokunciphisa ukulibaziseka kwe-skew umehluko owumphumela wamazinga ahlukene okusonta.Amanani 1 kanye no-2 abonisa ukubambezeleka kommeleli kanye namanani e-skew atholwe kusampula yekhebula yamamitha ayi-100 ekhethwe ngokungahleliwe enokwakhiwa kwe-“2 by 2″ (FRPE/FEP).Qaphela ukuthi ukulibaziseka kokusabalalisa okuphezulu nokulibaziseka kwe-skew yale sampuli kungu-511 ns/100mand 34 ns, ngokulandelanayo kububanzi befrikhwensi ukusuka ku-1 MHz ukuya ku-100 MHz.
Isikhathi sokuthumela: Mar-23-2023