Ke kamaʻilio kikohoʻe uila: ʻO ke kumu hana o ka modulation IQ

Ke kamaʻilio kikohoʻe uwea ʻole: Ke kumu hana oIQ modulation
ʻO ka modulation IQ ke kumu o nā ʻano hana modulation kiʻekiʻe i hoʻohana nui ʻia ma nā kahua LTE a me WiFi, e like me BPSK, QPSK, QAM16, QAM64, QAM256, a me nā mea ʻē aʻe. No ka mea, ʻo nā ʻano modulation i hoʻohana ʻia ma kēlā me kēia subcarrier o OFDM he mau ʻano hana modulation QAM e pili ana i ka modulation IQ, a ʻo ka mea nui, ʻo ka hoʻokō ʻana o OFDM ka superposition o ka modulation IQ ma nā subcarriers orthogonal lehulehu.
ʻO nā manaʻo o I a me Q i ka modulation IQ e pili ana i nā pōkole o nā huaʻōlelo Pelekane ʻelua: In Phase a me Quadrature, kēlā me kēia. Ma ka ʻōlelo wale ʻana mai ka manaʻo maoli, ʻaʻohe manaʻo o nā inoa o nā hōʻailona I a me Q. He aha ka in-phase? He aha ka orthogonality? He aha ka hōʻailona i hoʻohana ʻia ma ke ʻano he kuhikuhi e hoʻoholo ai i kapaea me ka quadrature? Ma ka hoʻokō pono, hoʻohana mau ʻia kahi pūʻulu o nā nalu cosine a me nā sine o ka alapine like me nā hōʻailona I a me Q. No laila, ʻo ka hōʻailona cosine i hoʻohana ʻia e like me ka hōʻailona I, ʻo ia ka hōʻailona kuhikuhi, ʻo ia nō ka hōʻailona In Phase. ʻO ka hōʻailona cosine he 90 degere ma waho o ka pae me ka hōʻailona I ʻo ia ka hōʻailona Quadrature. No laila, ʻo ka ʻike maʻalahi o nā hōʻailona modulation IQ, ʻo ia ka noʻonoʻo ʻana i ka hōʻailona I ma ke ʻano he hōʻailona lawe cosine, a ʻo ka hōʻailona Q he hōʻailona lawe sine me ka ʻokoʻa alapine o 90 degere mai ka hōʻailona I.

ʻO ka mea i kapa ʻia ʻo IQ modulation, ʻo ia ka hoʻohana ʻana i kahi pūʻulu o nā hōʻailona I, ʻo ia hoʻi nā hōʻailona cosine, a me nā hōʻailona Q, ʻo ia hoʻi nā hōʻailona sine (me ka ʻokoʻa o ka pae o 90 degere a me ka orthogonal kekahi i kekahi) o ka alapine like me nā mea lawe, e hoʻololi like i nā hōʻailona baseband ʻelua i nā mea lawe ʻelua, a laila e hoʻopili i nā hōʻailona modulated ʻelua i hui pū ʻia a hoʻouna iā lākou ma o kahi kaapuni RF. Ma hope o ka loaʻa ʻana o ka hōʻailona alapinepine radio, hana ka hopena loaʻaIQ demodulation. I ka IQ demodulation, no ka mea, he orthogonal nā mea lawe ʻelua i kekahi i kekahi, hiki ke hoʻokaʻawale ʻia nā hōʻailona baseband ʻelua mai ka hōʻailona hui ʻia e pili ana i nā hōʻailona lawe I a me Q i hoʻohana ʻia i ke kaʻina modulation mua a hoʻokaʻawale ʻia. No nā hōʻailona I a me Q i hoʻololi ʻia e IQ, ʻo ka hoʻonui ʻana i ka amplitude pili o kekahi ʻaoʻao, ʻaʻole ia e hoʻonui i ka amplitude o ka hōʻailona modulated, akā e hoʻoneʻe pū i ka pae o ka hōʻailona modulated i ka ʻaoʻao me ka hoʻonui amplitude. No laila, ʻo ka IQ modulation ka amplitude modulation i hana ʻia ma ka hōʻailona I a me ka hōʻailona Q, akā ʻaʻole pili wale ka hopena modulation i ka amplitude o ka hōʻailona modulated, akā ʻo kona hoʻololi pū kekahi. ʻO kēia ke kumu hana kumu o ka modulation IQ a me ka demodulation.