Constellation yog ib lub tswv yim yooj yim hauv digital modulation. Thaum peb xa cov cim digital, peb feem ntau tsis xa 0 lossis 1 ncaj qha, tab sis ua ntej tsim ib pawg ntawm 0 thiab 1 cov cim (ntsis) raws li ib lossis ob peb. Piv txwv li, txhua ob lub khoom tsim ib pab pawg, uas yog, 00, 01, 10, thiab 11. Muaj plaub lub xeev tag nrho (yog tias tsis muaj peb cov khoom, muaj yim lub xeev, thiab lwm yam). Lub sijhawm no, peb tuaj yeem xaiv QPSK (plaub-theem kev hloov kho, sib haum rau plaub lub xeev ua ntej ntawm 00, 01, 10, thiab 11), Plaub QPSK cov ntsiab lus tsim ib lub hnub qub QPSK. Txhua qhov taw tes yog 90 degrees deb ntawm cov ntsiab lus uas nyob ib sab (qhov amplitude yog tib yam). Ib tug constellation point sib raug rau ib tug modulation cim. Nyob rau hauv txoj kev no, txhua lub cim hloov pauv xa mus yog ob zaug ntau npaum li cov ntaub ntawv xa me ntsis.
QPSK modulation hnub qub
Daim duab constellation ntawm lub teeb liab tau txais
Thaum tau txais thiab demodulating QPSK teeb liab, txiav txim seb lub teeb liab raug xa mus raws li qhov kev ncua deb ntawm lub teeb liab tau txais thiab plaub lub ntsiab lus nyob rau hauv lub hnub qub (feem ntau hu ua European nrug), thiab txiav txim siab seb qhov twg yog qhov ze tshaj plaws rau qhov taw tes rau demodulation.
Yog li, daim duab kos duab feem ntau yog siv rau daim duab qhia thaum lub sijhawm hloov kho (xws li QPSK, 16QAM, 64QAM, thiab lwm yam) thiab txhawm rau txheeb xyuas qhov twg yog xa mus rau lub sijhawm txais tos kom cov ntaub ntawv tuaj yeem demodulated kom raug.
Cov saum toj no yog cov lus piav qhia ntawm Constellation Chart coj los ntawm Shenzhen Haidiwei Optoelectronics Technology Co., Ltd., uas yog cov chaw tsim khoom kho qhov muag thiab tsim kev sib txuas lus.cov khoom.
