Umqondiso ogqithiselwa kwinethiwekhi yentambo kamabonakude yibroadband, i-spectrum eyahlulwe ngamaza. Iimpawu zomqondiso, kubandakanywa ama-frequencies kunye neenombolo zetshaneli eRashiya zilawulwa yiGOST 7845-92 kunye neGOST R 52023-2003, kodwa umqhubi ukhululekile ukukhetha umxholo wetshaneli nganye ngokubona kwakhe.
Iziqulatho zoluhlu lwamanqaku
- Icandelo 2: Ukuqulunqwa komqondiso kunye nokumila
- Icandelo 3: Icandelo leSiginali ye-Analog
- Icandelo 4: ICandelo loMqondiso weDijithali
- Icandelo 5: Inethiwekhi yokusabalalisa i-coaxial
- Icandelo 6: I-RF Signal Amplifiers
- Icandelo 7: Abamkeli bamehlo
- Icandelo 8: Inethiwekhi ye-Optical backbone
- Icandelo 9: Intloko
- Icandelo 10: Ukulungisa inethiwekhi yeCATV
Makhe ndikukhumbuze ukuba andibhali incwadi yesifundo, kodwa inkqubo yemfundo yokwandisa i-horizons yam kwaye ndingene kwihlabathi le-cable TV. Ngoko ke, ndizama ukubhala ngolwimi olulula, ndishiya amagama angundoqo kulabo abanomdla kwaye bangangeni nzulu kwinkcazo yezobuchwepheshe ezichazwe ngokugqibeleleyo ngamakhulu amaxesha ngaphandle kwam.
Silinganisa ntoni?
Iingcali zethu ngokuyintloko zisebenzisa i-Deviser DS2400T ukufumana ulwazi lwesignali kwiintambo ze-coaxial.
Ngokusisiseko lo ngumamkeli kamabonwakude, kodwa endaweni yomfanekiso kunye nesandi, sibona iimpawu zobungakanani kunye nekhwalithi yazo zombini i-spectrum kunye netshaneli nganye. Le mifanekiso ilandelayo zii-screenshots kwesi sixhobo.
Lo Mcebisi ude ube nomsebenzi ongafunekiyo, kodwa kukho izixhobo ezipholileyo: kunye nesikrini esibonisa umfanekiso weTV ngokuthe ngqo, ukufumana isignali yokubona kwaye, into enqongopheleyo uMcebisi, ifumana umqondiso wesathelayithi yeDVB-S (kodwa libali elahluke ngokupheleleyo) .
Isibonisi somqondiso
Imowudi yokubonisa i-spectrum ikuvumela ukuba uhlole ngokukhawuleza imeko yesignali "ngeso"
Kule mowudi, isixhobo siskena amajelo ngokuhambelana nesicwangciso sefrikhwensi esixeliweyo. Ukuze kube lula, ii-frequencies ezingasetyenziswanga kuthungelwano lwethu zisusiwe kwi-spectrum epheleleyo, ngoko umfanekiso obangelwa yi-palisade yamajelo.
Imijelo yedijithali ibonakaliswe ngebhlowu, itshaneli ze-analogue zityheli. Inxalenye eluhlaza yeshaneli ye-analog yinxalenye yayo yomsindo.
Umahluko kumanqanaba amajelo ahlukeneyo ubonakala ngokucacileyo: ukungalingani komntu ngamnye kuxhomekeke kwizicwangciso ze-transponders kwi-headend, kwaye umehluko oqhelekileyo phakathi kwee-frequencies eziphezulu kunye nezantsi zinentsingiselo ethile, endiya kuxubusha ngayo ngezantsi.
Kule modi, ukuphambuka okunamandla kwisiqhelo kuya kubonakala ngokucacileyo, kwaye ukuba kukho iingxaki ezinzulu kwinethiwekhi, oku kuya kubonakala ngokukhawuleza. Umzekelo, kulo mfanekiso ungasentla ungabona ukutsitywa kweetshaneli ezimbini zedijithali kwindawo enefrikhwensi ephezulu: zikhona kuphela ngokohlobo lwemigca emifutshane, engafikeleli kwinqanaba le-10 dBΒ΅V (inqanaba lesalathiso lika-80 dBΒ΅V libonisiwe. phezulu - lo ngumda ophezulu wegrafu), eneneni ingxolo efunyanwa yintambo ngokwayo njenge-eriyali okanye igalelo lezixhobo ezisebenzayo. Ezi tshaneli zimbini zizijelo zovavanyo kwaye zaye zacinywa ngexesha lokubhala.
Ulwabiwo olungalinganiyo lwedijithali kunye nejelo le-analog kunokubangela ukudideka. Oku, ngokuqinisekileyo, akuchanekanga kwaye kwenzeke ngenxa yophuhliso lothungelwano lwendalo: iziteshi ezongezelelweyo zongezwa nje kwiplani yefrikhwensi kwindawo yasimahla yespectrum. Xa usenza isicwangciso sokuphindaphinda ukusuka ekuqaleni, kuya kuba kuchanekile ukubeka yonke i-analog kwisiphelo esisezantsi sespectrum. Ukongeza, izixhobo zesikhululo ezenzelwe ukuvelisa umqondiso kumazwe aseYurophu zinezithintelo zokusetyenziswa kwamaza okusasaza umqondiso wedijithali kwaye, nangona kungekho zithintelo ezinjalo kwilizwe lethu, ukusebenzisa izixhobo ezinjalo kuyimfuneko ukubeka iziteshi zedijithali kwi-spectrum. , ngokuchaseneyo nengqiqo.
Ifom yamaza
Njengoko kusaziwa kwifiziksi esisiseko, kokukhona inyuka isantya samaza, kokukhona inamandla okunciphisa njengoko isasazeka. Xa uhambisa umqondiso we-broadband onjalo okhoyo kwinethiwekhi ye-CATV, ukutshatyalaliswa kwinethiwekhi yokusabalalisa kunokufikelela amashumi e-decibels ngengalo nganye, kwaye kwindawo engezantsi ye-spectrum iya kuba ngamaxesha amaninzi ngaphantsi. Ke ngoko, emva kokuthumela umqondiso ozinzileyo kwisinyusi ukusuka kumgangatho ongaphantsi, kumgangatho wama-25 siya kubona into enje ilandelayo:
Inqanaba lee-frequencies eziphezulu libonakala liphantsi kunelo lisezantsi. Kwimeko yokwenyani, umabonwakude, engayiqondi, unokuwaqwalasela amajelo abuthathaka nje ngengxolo aze awahluze. Kwaye ukuba i-amplifier ifakwe kwigumbi, ngoko xa uzama ukuyiqwalasela umgangatho ophezulu wokufumana amajelo ukusuka kwindawo ephezulu yoluhlu, ukukhulisa ngaphezulu kuya kwenzeka kwindawo engezantsi. Imigangatho ichaza umahluko ongekho ngaphezulu kwe-15 dBΒ΅V kuluhlu lulonke.
Ukuze ugweme oku, xa uqwalasela izixhobo ezisebenzayo, inqanaba eliphezulu libekwe ekuqaleni kwindawo ephezulu. Oku kubizwa ngokuba "yithambeka ethe ngqo", okanye ngokulula "ithambeka". Kwaye oko kuboniswe kumfanekiso "ku-reverse tilt", kwaye umfanekiso onjalo sele uyingozi. Okanye, ubuncinci, isibonakaliso sokuba kukho ingxaki ngekhebula kwindawo yokulinganisa.
Imeko echaseneyo nayo iyenzeka, xa ii-frequencies ezisezantsi zingekho, kwaye ezingaphezulu zingena lula ngaphezu kwenqanaba lengxolo:
Oku kukwasixelela ngomonakalo wentambo, oko kukuthi umbindi wayo ophakathi: i-frequency ephezulu, isondele kumda we-waveguide isasaza (impembelelo yesikhumba kwintambo ye-coaxial). Ngoko ke, sibona kuphela ezo ziteshi ezihanjiswa kwiifrikhwensi eziphezulu, kodwa, njengomthetho, iTV ayiyi kuphinda ikwazi ukuyifumana kweli nqanaba.
umthombo: www.habr.com