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 yokubekezelelana kokwehluleka. 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, inani elilinganiselwe le-MER lingu-23.5dB, futhi ku-256QAM lingu-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 ukhiye. Izidingo zokuphuma kwe-modulation ekupheleni kwesikhombi se-MER: Ku-64/256QAM, isiphetho > 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.
Lapho 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 lomngcele, i-BER izokwehla kakhulu.
Isikhathi sokuthumela: Feb-23-2023