Ekusakazweni kwe-FM, ikhwalithi yomsindo ibalulekile. Abantu bahlale belwela ukuthuthukisa ubuchwepheshe obusha ukuze banciphise izimpawu zomsindo ekudluliseni ukuze bathuthukise amasignali omsindo kanye nolwazi lokulalela. Okubili kobuchwepheshe ukugcizelela kwangaphambili kanye nokungagcizeleli. Ingabe uyawaqonda? Lesi sabelo sizokwethula incazelo kanye nokusetshenziswa kokugcizelela kwangaphambili kanye nokungagcizeleli kuwe.
Ukwabelana Kuyanakekela!
Okuqukethwe
Kuyini Ukugcizelela?
Empeleni, Ukugcizelela ngaphambilini kanye Nokwehliswa ukugcizelela kungabizwa ukugcizelela ndawonye. Kodwa kungani ihlukaniswe yaba Pre-emphasis kanye De-emphasis? Ukuze siphendule lo mbuzo, sidinga ukuqonda okuyisisekelo kokugcizelela kwangaphambili kanye nokugcizelela.
Incazelo Yokugcizelela Ngaphambili
Ukugcizelelwa kwangaphambili umqondo osetshenziswa ekudluliseni okokusebenza njengama-transmitters e-FM. Kusho ukuthi ngaphambi kwenqubo ethile, njengamasiginali amanje asakazwa ngekhebula, uhla oluthile lwefrikhwensi yokufaka luzothuthukiswa noma i-amplitude izokwandiswa. Ngamagama alula, ivolumu yomsindo ebangeni elithile iyaphakanyiswa.
Incazelo Yokungagcizelelwa
Kunalokho, ukugcizelela umqondo osetshenziswa ekutholeni amathuluzi afana nemisakazo ye-FM. Kusho ukuthi ngaphambi kokuthi amasiginali omsindo aguqulwe abe umsindo futhi adlalwe, ububanzi obufanayo befrikhwensi buzosebenza ukuguqulwa okuphambene nokugcizelela kwangaphambili. Lokho kusho ukuthi, ivolumu yomsindo ebangeni elithile izokwehliswa.
Umehluko Wokugcizelela Ngaphambili kanye Nokungagcizelelwa
Sengiphetha, Ukugcizelelwa kwangaphambili kanye Nokwehliswa kokugcizelela kuyafana komunye nomunye, kodwa kusetshenziswa emishinini ehlukene futhi kusebenza ngokuphambene. Kodwa basebenzela inhloso efanayo - ukuthuthukisa amasignali alalelwayo.
Kusebenza Kanjani Ukugcizelela?
Ukugcizelela ngaphambilini kanye Nokwehliswa kokugcizelela kusebenza ndawonye ukuze kuthuthukiswe amasignali omsindo. Kodwa bayifeza kanjani le njongo?
Umsindo Kuzimpawu Zomsindo
Amasignali kumafrikhwensi aphezulu anamandla okumelana nesignali ephakeme, kodwa anamandla amabi kakhulu wokuphazamisa umsindo ngenxa yokuthi amasignali kumafrikhwensi aphezulu anamandla amancane kunalawo angaphansi kwefrikhwensi. Ngakho-ke ekusakazeni komsakazo, ukususa uthando lomsindo kumafrikhwensi aphezulu kubalulekile. Futhi Ukugcizelelwa kwangaphambili kanye Nokugcizelelwa kuxazulule inkinga ngokwenza ngcono i-SNR yamasignali.
Ukuqedwa komsindo
Ake sibone ukuthi Ukugcizelela Ngaphambili kanye Nokwehliswa kokugcizelela kusebenza kanjani ndawonye ukuze kuthuthukiswe i-SNR yamasignali.
Nquma Imvamisa - Ukugcizelela ngaphambili kukhulisa izingxenye zefrikhwensi ephezulu ngokusebenzisa isekethe yokugcizelela kwangaphambili. Nawu umbuzo, unganquma kanjani ukuthi yiluphi uhla lwemvamisa okufanele lukhuliswe? Uzobona kunesikhawu sesikhathi ngaphambi kokuthi amasignali akhuliswe. Sibiza isikhawu sesikhathi ngokuthi ngokungaguquki. Ibalwa ngefomula ethi T=RC, lapho u-R emele ukumelana nesekethe futhi u-C umele ukuphakelwa kwamandla kusekethe. Ngokujwayelekile, ama-25μs, 50μs, kanye nama-75μs lezi zimo ezihlala izikhathi ezintathu ziyatholakala, futhi amazwe ahlukene athatha izikhathi ezishintshashintshayo njengezijwayelekile. Isibonelo, eNyakatho Melika naseNingizimu Korea, kusetshenziswa ama-75μs, futhi eYurophu, kusetshenziswa ama-50μs.
Khulisa Amafrikhwensi - Uma ama-75μs esetshenziswa njengesikhathi esingaguquki, isekethe yokugcizelela ngaphambili izothuthukisa amafrikhwensi ngaphezu kuka-2123 Hz ngesilinganiso esingu-6 dB/octave, futhi I-6 dB isho izikhathi ezine. Ngemva kokuthuthukisa amaza, i-SNR izothuthukiswa ngoba ingxenye ekhulisiwe yamafrikhwensi izovala umsindo kumasiginali.
Buyisa Amafrikhwensi - Ukuze ube nokuphendula kwefrikhwensi evamile, isekethe yokungagxili kufanele kwengezwe kumamukeli womsakazo. Ngokufana nje nesekhethi ye-Pre-emphasis, inesikhawu sesikhathi ngemva kokuthola amaza omsakazo, futhi iyafana naleyo ye-Pre-emphasis circuit. Isibonelo, u-75μs usetshenziswa ku-De-ephasis, bese izonciphisa amafrikhwensi aphezulu kuno-2123Hz ngesilinganiso esingu-6dB/octave.
Izicelo Zokugcizelela
Ekusakazweni komsakazo, ukugcizelela kwangaphambili kanye nokungagcizelelwa kwamukelwa ezinhlelweni eziningi, njengokusakazwa kwe-FM. Ngoba I-FM inaso isici yemvamisa ephezulu, kulula ukuthintwa umsindo. Ukugcizelelwa kwangaphambili kanye Nokugcizelelwa kungathuthukisa i-SNR kumasiginali ngempumelelo. Ngaphezu kokudluliswa kwesignali ye-analog, ukudluliswa kwedijithali kusebenzisa Ukugcizelela futhi. Ngokufana nokudluliswa kwe-analogi, ukudluliswa kwedijithali kusetshenziswa Ukugcizelela ukulungisa ukuhlanekezela ekudluliseni amasignali ngamanani aphezulu wedatha.
imibuzo ejwayelekile ukubuzwa
1. Umbuzo: Kuyini Ukugcizelelwa ku-FM?
IMP: Kuyinqubo lapho isiginali ishintshwa ngandlela thize futhi ibuyiselwe kokujwayelekile ekugcineni.
Enqubweni yokurekhoda nokusakaza, ukuze kuthuthukiswe ikhwalithi yesiginali, okugcizelelwa ukuthi isignali iyashintshwa ngandlela thize ngaphambi kokurekhoda noma ukudlulisa, kanye nenqubo elandelayo ngakolunye uhlangothi ebuyisela isignali esimweni sayo esivamile. Isibonelo esivame kakhulu ekurekhodweni komsindo ukuncishiswa komsindo.
2. Umbuzo: Kungani Kusetshenziswa Ukugcizelela Ngaphambili Ku-FM Transmitter?
A: Ngoba isetshenziselwa ukuthuthukisa i-SNR nokunciphisa ukuthandwa komsindo.
Enqubweni yokuthola isignali eshintshwa imvamisa, umamukeli angakhiqiza isibonisi somsindo esikhuphukayo. Ukugcizelela ngaphambilini kukhulisa i-amplitude yamafrikhwensi amasignali aphezulu, ngaleyo ndlela kuthuthukisa i-SNR futhi kwehlise ukuthandwa komsindo. I ama-transmitters e-FM athengiswa kakhulu abavela ku-FMUSER bahlonyiswe ngobuchwepheshe bakamuva bokugcizelelwa, uma unentshisekelo kubo, buhlole.
3. Umbuzo: Ayini amasiginali we-FM?
A: Amasiginali afaka ulwazi ngokushintsha imvamisa esheshayo yegagasi.
Izimpawu ze-FM zisetshenziswa kakhulu kukhompyutha, ezokuxhumana kanye nasekucubunguleni amasignali. Baphethe ulwazi ngendlela ye- izinguquko zemvamisa esheshayo yegagasi.
4. Umbuzo: Lungakanani uhla lwamasiginali we-FM?
A: 87.5 -108.0 MHz, 76.0 - 95.0 MHz, 65.8 - 74.0 MHz.
87.5 - 108.0 MHz iwububanzi befrikhwensi esetshenziswa kakhulu emhlabeni wonke. Futhi i-76.0 - 95.0 MHz isetshenziswa eJapane, i-65.8 - 74.0 MHz isetshenziswa kakhulu emazweni asentshonalanga yeYurophu.
Isiphetho
Uma sikhuluma nje, siyazi ukuthi Ukugcizelelwa ubuchwepheshe obusebenzayo ekusakazeni komsakazo, buthuthukisa ngempumelelo amasignali omsakazo ekudluliseni. U-FMUSER ungumhlinzeki wezinto zokusakaza zomsakazo oqeqeshiwe, ungathenga ama-transmitters ekhwalithi ephezulu e-FM ngamanani agculisayo. Ngicela, uma udinga ukuthenga ama-transmitters omsakazo we-FM ngokugcizelela kuqala zizwe ukhululekile xhumana ne-FMUSER.
Funda futhi
