Hauv kev sib txuas lus digital, tus txais tau txais cov lej ntawm cov teeb liab kis tau tus mob thiab cov suab nrov channel.
Covzoo txais tosntawm cov teeb liab digital raws li "zoo tshaj" cov txheej txheem nrog qhov ua yuam kev tsawg tshaj plaws. Qhov yuam kev uas tau txiav txim siab hauv tshooj no feem ntau yog vim muaj kev txwv tsis pub dawb Gaussian suab nrov. Raws li qhov kev xav no, binary digital modulated teeb liab tau muab faib ua peb hom: cov teeb liab tseeb, theem-nyob ntawm cov teeb liab, thiab cov teeb liab hloov pauv. Qhov tsawg kawg nkaus qhov ua yuam kev yuav raug txheeb xyuas qhov ntau. Tsis tas li ntawd, qhov ua yuam kev tshwm sim tau txais ntau theem baseband teeb liab kuj raug tshuaj xyuas.
CovLub hauv paus ntsiab lus ntawm kev tsom xamyog xav txog tag nrho cov piv txwv qhov tseem ceeb ntawm lub cim tau txais lub cim raws li vector nyob rau hauv k-dimensional tau txais vector qhov chaw thiab faib qhov chaw tau txais vector rau hauv ob cheeb tsam. Seb puas los yog tsis muaj qhov yuam kev tshwm sim yog txiav txim raws li cheeb tsam uas tau txais vector poob rau hauv. Lub hauv paus ntsiab lus thaiv daim duab ntawm qhov zoo tshaj plaws receiver tuaj yeem tau txais thiab qhov yuam kev me ntsis tuaj yeem xam los ntawm qhov kev txiav txim siab. Qhov kev ua yuam kev me ntsis no yog qhov ua tau zoo tshaj plaws - uas yog, qhov tsawg tshaj plaws theoretically ua tau.
Covzoo me ntsis yuam kevtus nqi ntawm binary deterministic teeb liab yog txiav txim siab los ntawm kev sib raug zoo coefficient p ntawm ob lub cim thiab lub teeb liab-rau-nrov piv E / n, tab sis tsis muaj kev sib raug zoo nrog lub teeb liab waveform. Qhov me dua qhov sib txheeb coefficient p, qhov tsawg dua qhov yuam kev me ntsis. Qhov sib txheeb coefficient ntawm 2PSK teeb liab yog qhov tsawg tshaj plaws (p = -1), thiab nws qhov yuam kev me ntsis yog qhov qis tshaj. Lub teeb liab 2FSK tuaj yeem suav tau tias yog lub teeb liab plaub thiab nws qhov sib txuas coefficient yog p = 0.
Rau qhovtheem-raws li lub teeb liabthiab lub teeb liab fluctuating, tsuas yog lubFSK teeb liabyog siv los ua tus neeg sawv cev rau kev tsom xam, vim hais tias nyob rau hauv cov channel no, lub amplitude thiab theem ntawm lub teeb liab hloov randomly vim yog lub suab nrov, yog li FSK teeb liab feem ntau haum rau daim ntawv thov. Txij li thaum cov channel ua rau tsis muaj kev hloov pauv hauv lub teeb liab theem, coherent demodulation tsis tuaj yeem siv. Hloov chaw, tsis yog-coherent demodulation yog txoj hauv kev zoo tshaj plaws kom tau txais lub teeb liab.
Muab piv rau qhov yuam kev me ntsis ntawm tus txais tiag tiag thiab covzoo txais txais, nws tuaj yeem pom tau tias yog lub teeb liab-rau-lub suab nrov zog piv r nyob rau hauv lub receiver tiag tiag yog sib npaug ntawm qhov sib piv ntawm lub cim lub zog rau lub suab nrov lub zog spectral ntom nyob rau hauv qhov zoo tshaj plaws receiver E / n, qhov kev ua yuam kev me ntsis ntawm qhov ob yog tib yam. Txawm li cas los xij, qhov no tsis yog ib txwm ua tau vim cov neeg txais tiag tiag. Yog li, qhov tseeb txais qhov kev ua tau zoo yog ib txwm phem dua li qhov zoo tshaj plaws receiver.
Qhov no yog dab tsi Shenzhen HDV Phoelectron Technology Co., Ltd. coj koj txog "Qhov Zoo Tshaj Plaws Zoo Tshaj Plaws Digital". Kuv vam tias tsab xov xwm no tuaj yeem pab koj nce koj txoj kev paub. Dhau li ntawm tsab xov xwm no yog tias koj tab tom nrhiav rau lub tuam txhab kev sib txuas lus zoo fiber ntau cov khoom lag luam koj tuaj yeem xav txogtxog peb.
Shenzhen HDV photoelectric Technology Co., Ltd.feem ntau yog cov chaw tsim khoom ntawm cov khoom sib txuas lus. Tam sim no, cov cuab yeej tsim tawm npog covONU series, Optical module series, OLT series, thiabtransceiver series. Peb tuaj yeem muab cov kev pabcuam customized rau cov xwm txheej sib txawv. Zoo siab txais tossab laj.
