Hlanganisa: Isilinganiso sephutha lokushintshashintsha, okuyisilinganiso senani elisebenzayo lesilinganiso esisebenzayo senani elisebenzayo lesilinganiso sephutha kumdwebo we-celtellation (isilinganiso sesikwele sobukhulu be-vector ekahle). Ngenye yezinkomba eziphambili ukukala ikhwalithi yamasiginali we-digital TV. Kubaluleke kakhulu emiphumeleni yokulinganisa ye-logarithmic yokuhlanekezela okuphezulu kakhulu kusiginali yokushintshanisa yedijithali. Kuyafana nesilinganiso se-Signal-to-Noise noma isilinganiso se-carrier-to-umsindo esisetshenziswa ohlelweni lwe-analog. Kuyingxenye yokwahlulela okuyingxenye yokuhluleka ukwehluleka. Ezinye izinkomba ezifanayo ezinjengezinga lephutha le-ber, C / N carrier-to-umsindo, amandla aphakathi nendawo aphakathi nendawo, umdwebo we-collellation, njll.
Inani le-MER livezwa ku-DB, futhi likhudlwana inani le-MER, ikhwalithi yesiginali. Isiginali engcono, izimpawu eziseduze nezimpawu ezilungiselelwe zisesimweni esifanele, futhi okuphambene nalokho. Umphumela wokuhlolwa kwe-MER ukhombisa ikhono lokwamukela kwedijithali ukubuyisela inombolo kanambambili, futhi kukhona isilinganiso se-Injongo-to-Noise Ratio (S / N) okufana nalokho kwesiginali ye-baseband. Isiginali elungisiwe ye-Qam-modulated ingukuphela kokuphela kwangaphambili futhi ingena ekhaya ngenethiwekhi yokufinyelela. Isikhombi se-Mer sizowohloka kancane kancane. Endabeni yomdwebo we-Constellation 64Qam, inani le-Empirical Phreshold of Mer lingu-23.5DB, kanti ku-256AM lingu-28.5DB (okuphumayo okuphelele kufanele kube ngaphezulu kunekhwalithi yekhebula lokuhambisa noma ukuphela kwangaphambili). Uma iphansi kunaleli nani, umdwebo we-collellation ngeke ukhiywe. Izidingo zokukhipha ezingaphambili ze-Mer
Ukubaluleka kwe-Mer Mer kubhekwa njengendlela yokulinganisa kwe-SNR, futhi okushiwo yi-MER yi:
①. Kubandakanya izinhlobo ezahlukahlukene zomonakalo ku-Signal: Umsindo, ukuvuza kwenkampani, ukungalingani okungalingani, nomsindo wesigaba.
②. Ibonisa amandla emisebenzi yedijithali ukubuyisela izinombolo kanambambili; Kubonisa izinga lokulimala kwezimpawu ze-TV ze-Digital TV ngemuva kokudluliselwa kwinethiwekhi.
③. I-SNR iyipharamitha yase-Baseband, futhi i-MER iyinhlangano ye-radio frequency parameter.
Lapho ikhwalithi yesiginali ichaza ezingeni elithile, izimpawu ekugcineni zizodonswa ngokungalungile. Okwamanje, isilinganiso sangempela sephutha lephutha le-ber. I-Ber (Little Iphutha Rate): Izinga lephutha elincane, elichazwa njengesilinganiso senombolo yama-bits wephutha kwinani eliphelele lama-bits. Ngezimpawu zedijithali kanambambili, ngoba kudluliswa ama-bits kanambambili, isilinganiso sephutha elincane sibizwa ngokuthi inani lephutha le-bit (BER).
I-Ber = Iphutha Little Rate / inani le-Bit Little.
UBer uvezwa ngokuvamile embhalweni wezesayensi, kanti ophansi we-BER, okungcono. Lapho ikhwalithi yesiginali ihle kakhulu, amanani we-BER ngaphambi nangemva kokulungiswa kwephutha kuyafana; Kepha esimweni sokuphazanyiswa okuthile, amanani we-BER ngaphambi nangemva kokulungiswa kwamaphutha ahlukile, nangemva kokulungiswa kwamaphutha isilinganiso sephutha sephutha. Lapho iphutha elincane lingu-2 × 10-4, ngokwengxenye kubonakala ngezikhathi ezithile, kepha kusengabukwa; I-BER ebucayi ingu-1 × 10-4, inani elikhulu le-mosaics livela, futhi ukudla okudlalwa kwesithombe kuvela kaningi; I-BER enkulu kune-1 × 10-3 ayinakubukwa nhlobo. Bukela. I-BER Index kuphela yenani lesethenjwa futhi ayikhombisi ngokuphelele isimo semishini yonke yenethiwekhi. Kwesinye isikhathi kubangelwa ukukhuphuka okungazelelwe ngenxa yokuphazanyiswa okusheshayo, ngenkathi u-Her ihlukile ngokuphelele. Yonke inqubo ingasetshenziswa njengokuhlaziywa kwephutha kwedatha. Ngakho-ke, uMer unganikeza isexwayiso sokuqala sezimpawu. Lapho ikhwalithi yesiginali incipha, uMer uzokwehla. Ngokunyuka komsindo nokuphazamiseka ngezinga elithile, uMer uzokwehla kancane kancane, ngenkathi uBer ehlala engashintshiwe. Kuphela lapho ukuphakanyiswa kukhuphuka ngezinga elithile, uMer uBer uqala ukuwohloka lapho uMer ehla ngokuqhubekayo. Lapho uMer wehla esigabeni seThreshold, i-BER izokwehla kakhulu.
Isikhathi sePosi: Feb-23-2023