I-MER: Isilinganiso sephutha lokushintshwa, okuyisilinganiso senani elisebenzayo le-vector magnitude kunani elisebenzayo lobukhulu bephutha kumdwebo womlaza (isilinganiso sesikwele se-vector magnitude efanelekile kuya kusikwele sobukhulu bevekhtha yephutha) .Ingenye yezinkomba eziyinhloko zokulinganisa ikhwalithi yamasiginali we-TV yedijithali.Ibaluleke kakhulu emiphumeleni yokulinganisa i-logarithmic yokuhlanekezela okubekwe phezulu kusiginali yokushintshashintsha kwedijithali.Iyafana nesilinganiso sesignali-kuya-nomsindo noma isilinganiso senkampani yenethiwekhi ukuya nomsindo esisetshenziswa kusistimu ye-analog.Iwuhlelo lokwahlulela Ingxenye ebucayi yokubekezelela ukwehluleka.Ezinye izinkomba ezifanayo ezifana nesilinganiso sephutha le-BER bit, isilinganiso se-C/N yenkampani yenethiwekhi ukuya kumsindo, amandla amaphakathi wezinga lamandla, umdwebo womlaza, njll.
Inani le-MER livezwa nge-dB, futhi uma likhulu inani le-MER, iba ngcono ikhwalithi yesiginali.Uma isignali ingcono, izimpawu eziguquliwe ziba seduze nendawo ekahle, futhi ngokuphambene nalokho.Umphumela wokuhlola we-MER ubonisa ikhono lesamukeli sedijithali lokubuyisela inombolo kanambambili, futhi kukhona isilinganiso somgomo wesignali-kuya-noise (S/N) esifana nalesi siginali ye-baseband.Isiginali ye-QAM-modulated iphuma ekugcineni futhi ingena ekhaya ngenethiwekhi yokufinyelela.Inkomba ye-MER izowohloka kancane kancane.Endabeni yomdwebo womlaza ongu-64QAM, i-threshold value ye-MER ingu-23.5dB, futhi ku-256QAM ingu-28.5dB (okukhiphayo okungaphambili kufanele kube Uma kungaphezulu kuka-34dB, kungaqinisekisa ukuthi isignali ingena ekhaya ngokujwayelekile. , kodwa akukhiphi ukungavamile okubangelwa ikhwalithi yekhebuli yokudlulisela noma ingemuva elingaphansi).Uma ingaphansi kwaleli nani, umdwebo womlaza ngeke uvaliwe.Izidingo zokuphuma kwe-modulation ekupheleni kwesikhombi se-MER: Ku-64/256QAM, ekupheleni > 38dB, isiphetho esingaphansi > 36dB, inodi yokubona > 34dB, isikhulisi > 34dB (isibili ngu-33dB), ekugcineni komsebenzisi > 31dB (isibili ngu-33dB ), ngenhla 5 Iphuzu elingukhiye le-MER nalo livame ukusetshenziselwa ukuthola izinkinga zomugqa wekhebula le-TV.
Ukubaluleka kwe-MER MER kuthathwa njengohlobo lokulinganisa kwe-SNR, futhi incazelo ye-MER ithi:
①.Kubandakanya izinhlobo ezahlukahlukene zokulimala kusiginali: umsindo, ukuvuza kwenkampani yenethiwekhi, ukungalingani kwe-IQ amplitude, nomsindo wesigaba.
②.Ibonisa ikhono lemisebenzi yedijithali ukubuyisela izinombolo kanambambili;kukhombisa izinga lomonakalo kumasignali we-TV yedijithali ngemva kokudluliselwa ngenethiwekhi.
③.I-SNR ipharamitha ye-baseband, futhi i-MER iyipharamitha yefrikhwensi yomsakazo.
Uma ikhwalithi yesignali yehla ifinyelela ezingeni elithile, izimpawu zizogcina ziqoshwe ngokungalungile.Ngalesi sikhathi, inani langempela lephutha elincane elingu-BER liyakhuphuka.I-BER (Isilinganiso Sephutha Elincane): Izinga lephutha likabhithi, elichazwa njengesilinganiso senani lamabhithi ephutha kwinani eliphelele lamabhithi.Kumasiginali wedijithali kanambambili, njengoba amabhithi kanambambili asakazwa, izinga lephutha elincane libizwa nge-bit error rate (BER).
BER = Iphutha Lebhithi Yesilinganiso/Inani Lebhithi Eliphelele.
I-BER ivame ukuvezwa kumbhalo wesayensi, futhi uma i-BER iphansi, iba ngcono.Uma izinga lesignali lihle kakhulu, amanani e-BER ngaphambi nangemva kokulungiswa kwephutha ayafana;kodwa esimweni sokuphazanyiswa okuthile, amanani e-BER ngaphambi nangemuva kokulungiswa kwephutha ahlukile, futhi ngemva kokulungiswa kwephutha Izinga lephutha elincane liphansi.Uma iphutha elincane lingu-2×10-4, i-mosaic eyingxenye ivela ngezikhathi ezithile, kodwa isengabukwa;i-BER ebalulekile i-1 × 10-4, inani elikhulu lama-mosaics livela, futhi ukudlalwa kwesithombe kubonakala ngezikhathi ezithile;I-BER enkulu kuno-1×10-3 ayikwazi ukubukwa nhlobo.buka.Inkomba ye-BER ingeyereferensi kuphela futhi ayibonisi ngokugcwele isimo sayo yonke imishini yenethiwekhi.Ngezinye izikhathi kubangelwa kuphela ukwanda okungazelelwe ngenxa yokuphazamiseka okusheshayo, kuyilapho i-MER ihluke ngokuphelele.Yonke inqubo ingasetshenziswa njengokuhlaziya iphutha ledatha.Ngakho-ke, i-MER inganikeza isexwayiso sangaphambi kwesikhathi samasignali.Uma ikhwalithi yesiginali yehla, i-MER izokwehla.Ngokukhula komsindo nokuphazamiseka ngezinga elithile, i-MER izokwehla kancane kancane, kuyilapho i-BER ihlala ingashintshile.Kuphela lapho ukuphazamiseka kukhula ngezinga elithile, i-MER I-BER iqala ukonakala lapho i-MER yehla ngokuqhubekayo.Lapho i-MER yehlela ezingeni lomkhawulo, i-BER izokwehla kakhulu.
Isikhathi sokuthumela: Feb-23-2023