Amasistimu okugcina anamuhla awagcini nje ngokukhula ezindaweni futhi abe namazinga aphezulu okudlulisa idatha, kodwa futhi adinga amandla amancane futhi athatha indawo encane.Lezi zinhlelo futhi zidinga ukuxhumana okungcono ukuze zinikeze ukuguquguquka okwengeziwe.Abaklami badinga ukuxhumana okuncane ukuze banikeze amanani edatha adingekayo namuhla noma esikhathini esizayo.Futhi okujwayelekile kusukela ekuzalweni kuya ekuthuthukisweni futhi kancane kancane ukuvuthwa kukude nomsebenzi wosuku.Ikakhulukazi embonini ye-IT, noma ibuphi ubuchwepheshe buhlala buthuthuka futhi buzishintsha ngokwawo, njengoba kunjalo nencazelo ye-Serial Attached SCSI (SAS).Njengomlandeli wokuhambisana ne-SCSI, ukucaciswa kwe-SAS sekunesikhathi kukhona.
Eminyakeni i-SAS eye yadlula kuyo, ukucaciswa kwayo kuye kwathuthukiswa, nakuba iphrothokholi eyisisekelo igciniwe, ngokuyisisekelo azikho izinguquko eziningi kakhulu, kodwa imininingwane yesixhumi esibonakalayo sangaphandle senziwe izinguquko eziningi, okuwukulungiswa okwenziwe I-SAS ukuze ijwayelane nesimo semakethe, ngalezi “zinyathelo ezikhuphukayo eziya kumamayela ayinkulungwane” ngokuqhubekayo, imininingwane ye-SAS isikhule ngokukhula.Izixhumi zesikhombimsebenzisi sokucaciswa okuhlukile zibizwa nge-SAS, futhi uguquko olusuka ku-parallel kuya ku-serial, lusuka kubuchwepheshe obufanayo be-SCSI ukuya kubuchwepheshe be-SCSI obuxhumeke kwi-serial exhunywe (i-SAS) lushintshe kakhulu uhlelo lomzila wekhebula.I-SCSI ehambisanayo yangaphambili ingasebenzisa i-single-end noma ihlukanise ngaphezu kweziteshi eziyi-16 ngokufika ku-320Mb/s.Njengamanje, i-interface ye-SAS3.0 evame kakhulu endaweni yokugcina ibhizinisi isasetshenziswa emakethe, kodwa i-bandwidth ishesha kabili kune-SAS3 engakaze ithuthukiswe isikhathi eside, okuyi-24Gbps, mayelana ne-75 % womkhawulokudonsa wedrayivu yesimo esiqinile ye-PCIe3.0×4.Isixhumi sakamuva se-MiniSAS esichazwe ekucacisweni kwe-SAS-4 sincane futhi sivumela ukuminyana okuphezulu.Isixhumi sakamuva se-Mini-SAS siwuhhafu wosayizi wesixhumi sokuqala se-SCSI kanye no-70% wosayizi wesixhumi se-SAS.Ngokungafani nentambo yokuqala ye-SCSI parallel, zombili i-SAS ne-Mini SAS zineziteshi ezine.Kodwa-ke, ngaphezu kwejubane eliphezulu, ukuminyana okuphezulu, nokuguquguquka okwengeziwe, kukhona nokwanda kobunzima.Ngenxa yosayizi omncane wesixhumi, umkhiqizi wekhebula wasekuqaleni, isihlanganisi sekhebula, nomklami wesistimu kufanele anake kakhulu amapharamitha obuqotho besignali kukho konke ukuhlanganisa ikhebula.
Akuwona wonke amakhebula ahlanganisa amakhebula akwazi ukunikeza amasignali ekhwalithi ephezulu ukuze ahlangabezane nezidingo zesignali yobuqotho bezinhlelo zokugcina.Izihlanganisi zekhebula zidinga izixazululo zekhwalithi ephezulu nezingabizi kakhulu kumasistimu okugcina akamuva.Ukuze kukhiqizwe amakhebula aqinile, ahlala isikhathi eside anesivinini esikhulu, izici eziningana zidinga ukucatshangelwa.Ngaphezu kokugcina ikhwalithi yomshini nokucubungula, abaklami badinga ukunaka kakhulu amapharamitha obuqotho besignali enza izintambo zanamuhla zedivayisi yenkumbulo enesivinini esikhulu zibe khona.
Ukucaciswa kobuqotho besignali (Isiphi isignali esiphelele?)
Eminye yemingcele eyinhloko yobuqotho besignali ihlanganisa ukulahlekelwa kokufaka, i-crosstalk eseduze nasekupheleni, ukulahlekelwa ukubuyisela, ukuhlanekezela kwe-skew of the difference pair ngaphakathi, kanye ne-amplitude yemodi yomehluko kumodi evamile.Nakuba lezi zici zihlobene futhi zithonya enye kwenye, singacabangela isici esisodwa ngesikhathi ukuze sifunde umthelela wayo oyinhloko.
Ukulahlekelwa kokufaka (Imingcele yefrikhwensi ephezulu Okuyisisekelo 01- imingcele yokunciphisa)
Ukulahlekelwa kokufaka ukulahlekelwa kokuphakama kwesignali kusukela ekugcineni kokudlulisela kwekhebula kuya ekugcineni kokwamukela, okuhambisana ngokuqondile nobuningi.Ukulahlekelwa kokufaka kuncike futhi enombolweni yocingo, njengoba kukhonjisiwe kumdwebo wokunciphisa ngezansi.Ezingxenyeni zangaphakathi zebanga elifushane lekhebuli engu-30 noma engu-28-AWG, ikhebuli yekhwalithi enhle kufanele ibe nokuncipha okungaphansi kuka-2dB/m kokuthi 1.5GHz.Ku-6Gb/s SAS yangaphandle esebenzisa izintambo ezingu-10m, kunconywa ikhebula elinegeji yomugqa omaphakathi wama-24, ene-13dB attenuation kuphela ku-3GHz.Uma ufuna imajini yesiginali eyengeziwe ngamanani aphezulu edatha, cacisa ikhebula elincipha kancane kumaza aphezulu kumakhebuli amade.
I-Crosstalk (Amapharamitha aphezulu we-High Frequency Parameters 03- amapharamitha e-Crosstalk)
Inani lamandla adluliswa ukusuka kusignali eyodwa noma ukupheya komehluko kuye kwenye.Kuzintambo ze-SAS, uma i-close-end crosstalk (NEXT) ingencane ngokwanele, izodala izinkinga eziningi zesixhumanisi.Isilinganiso se-NEXT senziwa endaweni eyodwa kuphela yekhebula, futhi inani lamandla adluliswa lisuka epheya yesignali yokudlulisa ephumayo liye kumapheya amukela okokufaka.I-Far-end crosstalk (FEXT) ilinganiswa ngokujova isignali yepheya yokudlulisela kwelinye icala lekhebula nokuqaphela ukuthi angakanani amandla asele kusiginali yokudlulisela kwenye indawo yekhebula.
OKULANDELAYO ekuhlanganiseni kwekhebula nesixhumi kuvame ukubangelwa ukungahlukaniswa kahle kwamapheya okuhlukanisa isignali, okungase kubangelwe izitolo namapulaki, ukubeka phansi okungaphelele, noma ukuphathwa kabi kwendawo yokunqamula ikhebula.Umklami wesistimu udinga ukuqinisekisa ukuthi isihlanganisi sekhebula sibhekane nalezi zinkinga ezintathu.
Amajika okulahlekelwa amakhebuli avamile angu-100Ω angu-24, 26, kanye nama-28
Ukuhlanganisa ikhebula lekhwalithi enhle ngokuvumelana ne-“SFF-8410-Specifications for HSS Copper Testing and Performance Izidingo” okukalwe OKULANDELAYO kufanele kube ngaphansi kuka-3%.Mayelana nepharamitha ye-s, i-NEXT kufanele ibe nkulu kuno-28dB.
Ukulahlekelwa Kokubuyisela (Izisekelo Zepharamitha Ephakeme Kakhulu 06- Ukulahlekelwa Ukubuyisela)
Ukulahlekelwa kokubuyisela kulinganisa inani lamandla avela kusistimu noma ikhebuli lapho isignali ijovwa.Lawa mandla abonisiwe angabangela ukwehla kwe-amplitude yesiginali ekupheleni kokwamukela kwekhebula futhi angabangela izinkinga zesignali yobuqotho ekupheleni kokudlulisela, okungabangela izinkinga zokuphazanyiswa kozibuthe kagesi kusistimu nabaklami bohlelo.
Lokhu kulahlekelwa okubuyayo kubangelwa ukungafani kwe-impedance ekuhlanganiseni kwekhebula.Kuphela ngokuphatha le nkinga ngokucophelela okukhulu lapho i-impedance yesignali ingashintshi lapho idlula isokhethi, ipulaki kanye ne-wire terminal, ukuze ushintsho lwe-impedance luncishiswe.Izinga lamanje le-SAS-4 libuyekezelwa kunani le-impedance elingu-±3Ω uma liqhathaniswa ne-±10Ω ye-SAS-2, futhi izimfuneko zamakhebuli ekhwalithi enhle kufanele zigcinwe ngaphakathi kokubekezelela okulinganiselwe okungu-85 noma 100±3Ω.
Skew ukuhlanekezela
Ezintamboni ze-SAS, kukhona ukuhlanekezela okubili: phakathi kwamapheya ahlukene nangaphakathi kwamapheya ahlukene (isiginali yomehluko wetiyori yesiginali yobuqotho).Ngokombono, uma amasiginali amaningi efakwe ekugcineni kwekhebula, kufanele afike komunye umkhawulo kanye kanye.Uma lezi zimpawu zingafiki ngesikhathi esifanayo, lesi simo sibizwa ngokuthi ukuhlanekezela kwe-skew kwekhebula, noma ukuhlanekezela okubambezeleka.Ngamapheya ahlukene, ukuhlanekezela kwe-skew ngaphakathi kokupheya komehluko ukubambezeleka phakathi kwezintambo ezimbili zokupheya komehluko, futhi ukuhlanekezela kwe-skew phakathi kwamapheya ahlukene ukubambezeleka phakathi kwamasethi amabili ahlukene.Ukuhlanekezela okukhulu kwe-skew kwepheya ehlukile kuzolimaza ibhalansi yomehluko wesignali edlulisiwe, kunciphise i-amplitude yesiginali, kukhuphule i-jitter yesikhathi futhi kubangele izinkinga zokuphazanyiswa nguzibuthe.Umehluko wekhebula lekhwalithi enhle ekuhlanekezeni kwe-skew yangaphakathi kufanele ube ngaphansi kuka-10ps
Isikhathi sokuthumela: Nov-30-2023
