MER: Umlinganiselo wemposiso yokumodareyitha, umlinganiselo wexabiso elisebenzayo lobungakanani bevekhtha ukuya kwixabiso elisebenzayo lempazamo yobukhulu kwidayagram yeqela leenkwenkwezi (umyinge wesikwere sobukhulu bevektha obufanelekileyo kwisikwere sobukhulu bevektha yempazamo) .Sesinye sezalathisi eziphambili zokulinganisa umgangatho wemiqondiso yedijithali yeTV.Ibaluleke kakhulu kwiziphumo zomlinganiselo welogarithmic wokugqwethwa okubekwe ngaphezulu kumqondiso womodareyitha wedijithali.Ifana ne-signal-to-noise ratio okanye i-carrier-to-noise ratio esetyenziswe kwinkqubo ye-analog.Yinkqubo yokugweba Inxalenye ebalulekileyo yokusilela ukunyamezela.Ezinye izalathi ezifanayo ezifana ne-BER bit error rate, i-C/N carrier-to-noise ratio, i-power level average power level, i-constellation diagram, njl.
Ixabiso le-MER libonakaliswe kwi-dB, kwaye ixabiso elikhulu le-MER, ngcono umgangatho wesignali.Okukhona umqondiso ungcono, kokukhona iisimboli ezimodulisiweyo zisondele kakhulu kwindawo efanelekileyo, kwaye ngokuphambeneyo.Isiphumo sovavanyo lwe-MER sibonisa amandla omamkeli wedijithali ukubuyisela inombolo yebhinari, kwaye kukho injongo ye-signal-to-noise ratio (S / N) efana neyomqondiso we-baseband.I-QAM-modulated signal iphuma kwi-front end kwaye ingena ekhaya ngokusebenzisa inethiwekhi yokufikelela.Isalathisi se-MER siya kuhla kancinci kancinci.Kwimeko ye-constellation diagram 64QAM, ixabiso lomda we-MER yi-23.5dB, kwaye kwi-256QAM yi-28.5dB (isiphumo sangaphambili kufuneka sibe Ukuba siphezulu kune-34dB, inokuqinisekisa ukuba isignali ingena ekhaya ngokuqhelekileyo. , kodwa ayikhupheli ngaphandle kokungaqhelekanga okubangelwa umgangatho wentambo yokuhambisa okanye i-sub-front end).Ukuba ingaphantsi kweli xabiso, umzobo weenkwenkwezi awuyi kutshixwa.Isalathisi se-MER Iimfuno zesiphumo sokumodareyitha isiphelo sesiphelo sangaphambili: Kwi-64/256QAM, isiphelo sangaphambili> 38dB, isiphelo esisezantsi> 36dB, i-optical node> 34dB, iamplifier> 34dB (yesibini yi-33dB), isiphelo somsebenzisi> 31dB (yesibini yi33dB ), ngaphezulu kwe-5 Indawo engundoqo ye-MER ikwasetyenziswa rhoqo ukufumana iingxaki zentambo ye-TV.
Ukubaluleka kwe-MER MER kuthathwa njengohlobo lomlinganiselo we-SNR, kwaye intsingiselo ye-MER ithi:
①.Ibandakanya iintlobo ezahlukeneyo zomonakalo kwisignali: ingxolo, ukuvuza komthwali, ukungalingani kwe-IQ amplitude, kunye nomsindo wesigaba.
②.Ibonisa amandla emisebenzi yedijithali ukubuyisela amanani okubini;ibonakalisa iqondo lomonakalo kwiisignali zedijithali zeTV emva kokusasazwa kuthungelwano.
③.I-SNR yiparameter ye-baseband, kwaye i-MER yiparamitha yamaza kanomathotholo.
Xa umgangatho wesignali wehla ukuya kwinqanaba elithile, iisimboli ziya kugqitywa ngokungalunganga.Ngeli xesha, elona nqanaba lempazamo encinci BER liyenyuka.I-BER (I-Bit Error Rate): Izinga lempazamo yeBit, lichazwa njengomlinganiselo wenani leempazamo zebits ukuya kwitotali yenani leebits.Kwimiqondiso yokubini yedijithali, njengoko amasuntswana okubini ehanjiswa, izinga lempazamo encinci libizwa ngokuba yi-bit error rate (BER).
I-BER = i-Error Bit Rate / i-Bit Rate.
I-BER ngokuqhelekileyo ibonakaliswe kwi-notation yesayensi, kwaye i-BER ephantsi, ingcono.Xa umgangatho wesignali ulungile kakhulu, ixabiso le-BER ngaphambi nangemva kokulungiswa kwephutha liyafana;kodwa kwimeko yokuphazamiseka okuthile, amaxabiso e-BER ngaphambi nasemva kokulungiswa kwempazamo ahlukile, kwaye emva kokulungiswa kwempazamo Isantya sempazamo encinci sisezantsi.Xa impazamo encinci ingu-2 × 10-4, imosaic engaphelelanga ivela ngamaxesha athile, kodwa isenokujongwa;i-BER ebalulekileyo yi-1 × 10-4, inani elikhulu le-mosaics livela, kunye nokudlala komfanekiso kubonakala kuphakathi;I-BER enkulu kuno-1×10-3 ayinakujongwa kwaphela.jonga.Isalathisi se-BER sixabiso lereferensi kuphela kwaye ayibonakalisi ngokupheleleyo imeko yezixhobo zenethiwekhi yonke.Ngamanye amaxesha kubangelwa kuphela ukwanda ngokukhawuleza ngenxa yokuphazamiseka ngokukhawuleza, ngelixa i-MER ichasene ngokupheleleyo.Yonke inkqubo ingasetyenziswa njengohlalutyo lwempazamo yedatha.Ke ngoko, i-MER inokubonelela ngesilumkiso kwangethuba kwimiqondiso.Xa umgangatho wesignali uyancipha, i-MER iya kuncipha.Ngokunyuka kwengxolo kunye nokuphazamiseka kwinqanaba elithile, i-MER iya kuncipha ngokuthe ngcembe, ngelixa i-BER ihlala ingatshintshi.Kuphela xa uphazamiseko lunyuka ukuya kumlinganiselo othile, i-MER I-BER iqala ukuwohloka xa i-MER ihla ngokuqhubekayo.Xa i-MER yehla kwinqanaba lomgca, i-BER iya kuhla ngokukhawuleza.
Ixesha lokuposa: Feb-23-2023