Sadarwar dijital mara waya: ƙa'idar aiki na daidaitawar IQ

Sadarwar dijital mara waya: ƙa'idar aiki naFarashin IQ
IQ modulation shine tushe na manyan hanyoyin daidaitawa masu girma dabam-dabam da ake amfani da su a cikin filayen LTE da WiFi, kamar BPSK, QPSK, QAM16, QAM64, QAM256, da dai sauransu Fahimtar ka'idar aiki na daidaitawar IQ yana da mahimmanci don ƙarin fahimtar tushen tsarin aiwatar da OFDM a cikin LTE da WiFi. Saboda hanyoyin daidaitawa da aka yi amfani da su akan kowane mai ɗaukar kaya na OFDM har yanzu dabaru ne daban-daban na QAM na daidaitawa dangane da tsarin IQ, kuma da gaske, aiwatar da OFDM shine babban matsayi na ƙirar IQ akan masu ɗaukar kaya masu yawa na orthogonal.
Ma'anar I da Q a cikin daidaitawar IQ sun dace da taƙaitaccen kalmomin Ingilishi guda biyu: A cikin Mataki da Quadrature, bi da bi. Kawai magana daga ma'anar zahiri, sunayen I da Q siginoni ba su da ma'ana. Menene a cikin lokaci? Menene orthogonality? Wace sigina ake amfani dashi azaman tunani don tantance ciki-lokacida qudrature? A cikin aiwatarwa, ana amfani da saitin cosine da raƙuman ruwa na mitoci iri ɗaya azaman siginar I da Q. Saboda haka, siginar cosine da aka yi amfani da shi azaman siginar I shine ainihin siginar tunani, wanda ba shakka siginar In Phase ne. Siginar cosine wanda ke da digiri 90 daga lokaci tare da siginar I shine siginar Quadrature ta halitta. Don haka mafi sauƙin fahimtar siginar daidaitawa na IQ shine la'akari da siginar I azaman siginar jigilar cosine, da siginar Q azaman sigina mai ɗaukar nauyi tare da bambancin mitar digiri na 90 daga siginar I.

Abin da ake kira IQ modulation shine yin amfani da siginar I, wato siginar cosine, da siginar Q, wato siginar sine (tare da bambancin lokaci na digiri 90 da kothogonal ga juna) na mitar iri ɗaya kamar masu ɗaukar kaya, don daidaita siginar tushe guda biyu zuwa ga dillalan biyu, sa'an nan kuma ɗaukaka siginar biyu tare da canza su ta hanyar sigina na RF. Bayan karɓar siginar mitar rediyo, ƙarshen karɓa yana aikiFarashin IQ. A lokacin IQ demodulation, saboda masu ɗaukar kaya guda biyu suna daidai da juna, ana iya raba siginar tushe guda biyu daga sigina mai gauraya dangane da siginar jigilar I da Q da aka yi amfani da su a cikin tsarin daidaitawa na baya kuma an lalata su daban. Domin duka siginar I da Q da IQ suka daidaita, haɓaka girman dangi na gefe ɗaya ba kawai yana ƙara girman siginar da aka daidaita ba, har ma yana haifar da lokacin siginar da aka daidaita don matsawa zuwa gefe tare da ƙara girman girma. Don haka da gaske, IQ modulation shine amplitude modulation da aka yi akan siginar I da siginar Q, amma sakamakon daidaitawar ba wai kawai yana rinjayar girman siginar da aka daidaita ba, har ma da canjin lokaci. Wannan shine ainihin ƙa'idar aiki na IQ modulation da demodulation.