EVM: abbreviation of Error Vector Magnitude, uas txhais tau hais tias yuam kev vector amplitude.
Cov teeb liab digital zaus kis tau tus mob yog los hloov kho cov teeb liab baseband ntawm qhov kawg xa, xa mus rau kab rau kev sib kis, thiab tom qab ntawd demodulate nws ntawm qhov kawg tau txais kom rov qab tau qhov qub baseband teeb liab. Nyob rau hauv cov txheej txheem no, qhov kev ua yuam kev uas tsim los ntawm lub modulator, qhov zoo ntawm RF cov cuab yeej, theem-xauv lub voj (PLL) suab nrov, PA distortion nyhuv, thermal suab, thiab modulator tsim yuav tag nrho cov ua yuam kev vectors (EVM). EVM yuav muaj kev cuam tshuam zoo rau qhov zoo ntawm cov teeb liab modulated, yog li qhov kev sim ntsuas qhov project yog ib qho tseem ceeb ntawm RF xeem.
EVM tshwj xeeb yog hais txog qhov sib thooj ntawm IQ tivthaiv tsim thaum lub transmitter demodulates lub teeb liab thiab cov teeb liab zoo tagnrho. Nws yog ib qho qhia txog qhov zoo ntawm cov teeb liab modulated. Feem ntau, qhov yuam kev vector yuav tsum tau ua nrog M-ary I / Q cov qauv kev hloov pauv zoo li QPSK, thiab nws feem ntau pom los ntawm I / Q "lub hnub qub" daim duab ntawm cov cim demodulation.
Qhov yuam kev vector amplitude [EVM] yog txhais raws li qhov piv ntawm cov hauv paus ntsiab lus square tus nqi ntawm qhov nruab nrab lub zog ntawm qhov yuam kev vector teeb liab mus rau hauv paus txhais tau tias square tus nqi ntawm qhov nruab nrab lub zog ntawm lub teeb liab zoo tagnrho thiab qhia raws li feem pua. Qhov me me ntawm EVM, qhov teeb meem zoo dua.
Qhov yuam kev vector amplitude yog qhov sib txawv ntawm qhov ntsuas waveform thiab theoretically modulated waveform. Ob lub waveforms muaj bandwidth ntawm 1.28 MHz thiab yob tawm coefficient ntawm 0.22. Ob lub waveforms yog ntxiv modulated los ntawm kev xaiv zaus, meej theem, meej amplitude, thiab nti moos sij hawm kom txo tau qhov yuam kev vector. Lub sij hawm ntsuas yog ib zaug ib zaug. Yam tsawg kawg yuam kev vector amplitude yuav tsum tsis txhob ntau tshaj 17.5%.
Lub hom phiaj ntawm qhov kev xeem yog kom pom tias lub waveform ua los ntawm lub transmitter yog qhov tseeb txaus rau tus neeg txais kev pab kom tau txais kev txais tos kev ua tau zoo uas tau teev tseg.
Qhov no yog kev taw qhia rau EVM los ntawm Shenzhen HDV Optoelectronic Technology Co., Ltd., lub tuam txhab kev sib txuas lus kho qhov muag uas ua rau cov khoom sib txuas lus. Zoo siab txais tossab laj