Ukuxhumana kwedijithali okungenantambo: Umgomo wokusebenza wokuguquguquka kwe-IQ

Ukuxhumana kwedijithali okungenantambo: Umgomo wokusebenza weUkushintsha kwe-IQ
Ukushintshashintsha kwe-IQ kuyisisekelo sezindlela ezihlukahlukene zokuhleleka okuphezulu ezisetshenziswa kabanzi ezinkambini ze-LTE ne-WiFi, njenge-BPSK, QPSK, QAM16, QAM64, QAM256, njll. Ukuqonda isimiso sokusebenza sokushintshwa kwe-IQ kubalulekile ukuze kuqondwe kangcono indlela eyisisekelo yokusebenzisa i-OFDM ku-LTE ne-WiFi. Ngenxa yokuthi izindlela zokuguquguqula ezisetshenziswa kusithwali ngasinye esingaphansi se-OFDM zisangamaqhinga ahlukahlukene e-QAM asekelwe ekushintshashintshashintshashintshayo kwe-IQ, futhi empeleni, ukuqaliswa kwe-OFDM kuwukugxila okuphezulu kokuguquguquka kwe-IQ kuma-subcarrier amaningi we-orthogonal.
Imiqondo ka-I no-Q ekuguquguqukeni kwe-IQ ihambisana nezifinyezo zamagama amabili esiNgisi: Esigabeni kanye ne-Quadrature, ngokulandelana. Ukukhuluma nje kusuka encazelweni engokoqobo, amagama amasiginali we-I kanye no-Q awanayo incazelo. Kuyini ngesigaba? Iyini i-orthogonality? Isiphi isignali esisetshenziswa njengereferensi yokunquma ku-isigabakanye ne-quadrature? Ekusetshenzisweni okungokoqobo, isethi yamagagasi e-cosine kanye ne-sine yefrikhwensi efanayo ngokuvamile asetshenziswa njengezimpawu ze-I ne-Q. Ngakho-ke, isignali ye-cosine esetshenziswa njengesignali ye-I empeleni iyisiginali yereferensi, okuyisignali ye-In Phase. Isignali ye-cosine engaphandle kwesigaba esingu-90 degrees ngesignali ye-I ngokwemvelo iyisiginali yayo yeQuadrature. Ngakho-ke ukuqonda okulula kakhulu kwamasiginali wokuguquguquka kwe-IQ ukucabangela isiginali ye-I njengesignali yenkampani ye-cosine, kanye nesignali ye-Q njengesiginali yenkampani yenethiwekhi ene-ine nomehluko wemvamisa wama-degree angu-90 ukusuka kusiginali ye-I.

Okubizwa ngokuthi i-IQ modulation ukusebenzisa isethi yamasignali e-I, okuyizimpawu ze-cosine, namasiginali we-Q, okuyizimpawu ze-sine (ezinomehluko wesigaba samadigri angama-90 kanye ne-orthogonal komunye nomunye) wemvamisa efanayo nabathwali, ukuze ngesikhathi esisodwa ukulinganisa amasiginali amabili e-baseband kubathwali ababili, bese ubeka phezulu amasekhethi amabili bese uwahumusha nge-RF. Ngemva kokuthola isignali yefrikhwensi yomsakazo, indawo eyamukelayo iyasebenzaUkushintsha kwe-IQ. Ngesikhathi sokwehliswa kwe-IQ, ngenxa yokuthi abathwali ababili bangama-orthogonal komunye nomunye, amasiginali amabili e-baseband angahlukaniswa kusiginali exubile ngokusekelwe kumasiginali yenkampani yenethiwekhi ye-I ne-Q esetshenziswe kunqubo yangaphambilini yokushintshashintsha futhi yehliswe ngokuhlukana. Kuwo womabili amasiginali we-I kanye ne-Q ahlelwe yi-IQ, ukukhulisa ubukhulu obuhlobene bohlangothi olulodwa akukhulisi nje kuphela i-amplitude yesiginali eshintshiwe, kodwa futhi kubangela ukuthi isigaba sesignali eshintshiwe sigudluke siye ohlangothini ngokukhuphuka kwe-amplitude. Ngakho-ke, ukuguquguquka kwe-IQ ukuguquguquka kwe-amplitude okwenziwa kusiginali ye-I kanye nesignali ye-Q, kodwa umphumela wokuguquguquka awuthinti nje kuphela ubukhulu besiginali eshintshiwe, kodwa futhi noshintsho lwesigaba salo. Lona umgomo oyisisekelo wokusebenza wokuguquguquka kwe-IQ nokudilizwa.