Wireless digital kev sib txuas lus: Txoj cai ua haujlwm ntawmIQ Modulation
IQ kev hloov kho yog lub hauv paus ntawm ntau yam kev txiav txim siab hloov kho uas tau siv dav hauv LTE thiab WiFi thaj chaw, xws li BPSK, QPSK, QAM16, QAM64, QAM256, thiab lwm yam. Kev nkag siab txog kev ua haujlwm ntawm IQ kev hloov kho yog qhov tseem ceeb rau kev nkag siab zoo dua ntawm kev siv OFDM hauv LTE thiab WiFi. Vim hais tias cov kev hloov kho siv rau txhua tus subcarrier ntawm OFDM tseem yog ntau yam QAM modulation cov tswv yim raws li IQ kev hloov kho, thiab qhov tseem ceeb, kev siv ntawm OFDM yog qhov superposition ntawm IQ modulation ntawm ntau yam orthogonal subcarriers.
Cov ntsiab lus ntawm kuv thiab Q hauv IQ kev hloov pauv sib haum rau cov ntawv luv ntawm ob lo lus Askiv: Hauv Phase thiab Quadrature, feem. Tsuas yog hais los ntawm lub ntsiab lus, cov npe ntawm kuv thiab Q cov cim tsis muaj lub ntsiab lus. Dab tsi yog hauv-theem? Dab tsi yog orthogonality? Lub teeb liab dab tsi yog siv los txiav txim siab hauv-theemthiab quadrature? Hauv kev siv tswv yim, txheej cosine thiab sine waves ntawm tib zaus feem ntau yog siv raws li cov cim I thiab Q. Yog li ntawd, lub teeb liab cosine siv raws li kuv lub teeb liab yog qhov siv tau, uas yog qhov tseeb hauv Phase teeb liab. Lub teeb liab cosine uas yog 90 degrees tawm ntawm theem nrog I teeb liab yog lawm nws lub teeb liab Quadrature. Yog li qhov kev nkag siab yooj yim tshaj plaws ntawm IQ modulation signals yog xav txog qhov I teeb liab ua lub teeb liab cosine, thiab Q teeb liab ua lub teeb liab sine carrier teeb liab nrog qhov sib txawv ntawm 90 degrees los ntawm I teeb liab.
Lub npe hu ua IQ kev hloov kho yog siv cov teeb liab kuv, uas yog cosine signals, thiab Q signals, uas yog sine signals (nrog rau theem sib txawv ntawm 90 degrees thiab orthogonal rau ib leeg) ntawm tib zaus raws li cov neeg nqa khoom, mus rau tib lub sijhawm modulate ob lub teeb liab baseband rau ob tus neeg nqa khoom, thiab tom qab ntawd hloov cov teeb liab ua ke los ntawm ob qho tib si thiab RF. Tom qab tau txais xov tooj cua zaus teeb liab, qhov kawg tau txais ua tiavIQ demodulation. Thaum lub sij hawm IQ demodulation, vim hais tias ob lub cab kuj yog orthogonal rau ib leeg, ob lub baseband signals tuaj yeem sib cais los ntawm cov teeb liab sib xyaw raws li I thiab Q cov teeb liab siv hauv cov txheej txheem kev hloov pauv dhau los thiab demodulated nyias. Rau ob qho tib si I thiab Q teeb liab modulated los ntawm IQ, nce tus txheeb ze amplitude ntawm ib sab tsis tsuas yog nce lub amplitude ntawm lub teeb liab modulated, tab sis kuj ua rau theem ntawm lub teeb liab modulated hloov mus rau sab nrog nce amplitude. Yog li qhov tseem ceeb, IQ modulation yog amplitude modulation ua rau ntawm I teeb liab thiab Q teeb liab, tab sis qhov kev hloov pauv tsis tsuas yog cuam tshuam rau lub amplitude ntawm lub teeb liab modulated, tab sis kuj nws cov theem hloov. Qhov no yog lub hauv paus ntsiab lus ntawm kev ua haujlwm ntawm IQ kev hloov pauv thiab kev hloov pauv.
Post lub sij hawm: Mar-05-2025