Kev Teeb Liab Modulation thiab Demodulation
Kev hloov kho thiab kev demodulation yog ob lub tswv yim tseem ceeb hauv kev sib txuas lus uas ua rau muaj kev xa cov ntaub ntawv mus deb ntawm cov xov xwm. Hauv tsab xov xwm no, peb yuav tham txog qhov kev hloov kho thiab kev demodulation yog dab tsi, lawv hom, thiab lawv qhov tseem ceeb thiab kev siv hauv lub neej txhua hnub.
Kev Hloov Kho yog dab tsi?
Kev hloov kho yog ib qho txheej txheem uas cov ntaub ntawv yuav tsum tau xa mus rau hauv lub teeb liab nqa khoom. Cov ntaub ntawv no tuaj yeem ua rau hauv daim ntawv ntawm lub teeb liab analog, xws li lub suab lossis suab paj nruag, lossis lub teeb liab digital, xws li cov ntaub ntawv hauv computer. Cov txheej txheem hloov kho yog qhov tsim nyog vim tias cov teeb liab cov ntaub ntawv feem ntau tsis haum rau kev xa ncaj qha los ntawm ib qho nruab nrab, txawm tias huab cua (rau kev sib txuas lus wireless ) lossis cable (rau kev sib txuas lus wired).
Lub teeb liab ntawm tus neeg nqa khoom muaj qhov ruaj khov nruab nrab mus rau qhov siab thiab tuaj yeem mus deb heev. Nrog kev hloov kho, cov ntaub ntawv tuaj yeem xa tau zoo dua thiab zoo dua. Muaj ntau hom kev hloov kho uas siv ntau:
Kev Hloov Pauv Amplitude (AM)
Hauv kev hloov kho qhov loj me, qhov loj ntawm lub teeb liab nqa khoom raug hloov pauv kom phim qhov loj ntawm lub teeb liab cov ntaub ntawv. Qhov kev hloov kho no ua rau lub teeb liab nqa khoom "muaj npe" nrog cov ntaub ntawv xa mus. Txawm hais tias yooj yim rau kev siv, qhov loj me hloov kho yog qhov yooj yim rau kev cuam tshuam thiab suab nrov, tshwj xeeb tshaj yog los ntawm hluav taws xob lossis huab cua.
Kev Hloov Zaus (FM)
Kev hloov pauv zaus hloov qhov zaus ntawm lub teeb liab raws li lub teeb liab cov ntaub ntawv. Cov txheej txheem no paub zoo rau nws txoj kev tiv thaiv suab nrov thiab kev cuam tshuam, ua rau nws zoo tagnrho rau cov ntawv thov xws li kev tshaj tawm suab paj nruag hauv xov tooj cua.
Kev Hloov Kho Theem (PM)
Hauv kev hloov kho theem, theem ntawm lub teeb liab nqa khoom raug hloov pauv raws li lub teeb liab cov ntaub ntawv. Kev hloov kho theem feem ntau siv ua ke nrog kev hloov kho zaus ua ib feem ntawm lub kaw lus nyuaj dua, xws li hauv kev hloov kho digital.
Kev Hloov Kho Digital
Kev hloov kho digital hloov cov teeb liab los sawv cev rau cov ntaub ntawv digital. Cov hom kev hloov kho digital suav nrog Binary Phase Shift Keying (BPSK), Quadrature Amplitude Modulation (QAM), thiab Frequency Shift Keying (FSK). Kev hloov kho digital yog qhov tseem ceeb hauv cov kab ke sib txuas lus niaj hnub xws li cov tes hauj lwm cellular thiab Wi-Fi.
Demodulation yog dab tsi?
Demodulation yog cov txheej txheem rov qab ntawm kev hloov kho, rho tawm cov ntaub ntawv teeb liab los ntawm cov teeb liab nqa khoom modulated. Thaum cov teeb liab modulated mus txog lub receiver, cov ntaub ntawv uas tau ntxig ua ntej yuav tsum tau rho tawm. Lub cuab yeej siv rau cov txheej txheem no hu ua demodulator.
Cov Txheej Txheem Demodulation
Feem ntau, cov txheej txheem demodulation muaj cov kauj ruam hauv qab no:
1. Kev Txais Txais Lub Teeb Liab ntawm Tus Neeg Nqa Khoom: Lub teeb liab ntawm tus neeg nqa khoom uas tau hloov kho tau txais thiab ua kom nrov dua.
2. Kev Rov Qab Tau Cov Lus Qhia Txog Lub Teeb Liab: Cov ntsiab lus ntawm lub teeb liab raug rho tawm ntawm lub teeb liab ntawm tus neeg nqa khoom siv ntau txoj kev sib txawv raws li hom kev hloov kho uas siv.
3. Kev Ua Ntxiv: Cov teeb liab uas tau rho tawm lawm ces raug ua ntxiv thiab hloov mus ua daim ntawv kawg uas siv tau, txawm yog suab, video, lossis cov ntaub ntawv digital.
Hom Demodulator
AM Demodulator: Cov cuab yeej no ntes tau qhov kev hloov pauv ntawm qhov loj me hauv lub teeb liab nqa khoom kom rov qab tau cov teeb liab cov ntaub ntawv.
FM Demodulator: Nws yog siv los ntes cov kev hloov pauv ntawm qhov zaus ntawm lub teeb liab thiab rho tawm cov ntaub ntawv.
PM Demodulator: Cov cuab yeej no ntes tau qhov kev hloov pauv theem kom tau txais cov ntaub ntawv qhia.
Digital Demodulator: Muaj nuj nqi los hloov cov teeb liab digital uas tau hloov kho mus rau hauv cov bits ntawm cov ntaub ntawv.
Cov Ntawv Thov Modulation thiab Demodulation
Kev hloov kho thiab kev tshem tawm muaj ntau yam kev siv hauv ntau qhov chaw sib txuas lus . Nov yog qee qhov piv txwv tseem ceeb:
Xov Tooj Cua Tshaj Tawm
Xov tooj cua tshaj tawm yog ib qho ntawm cov ntawv thov thaum ub thiab tseem siv dav ntawm kev hloov kho thiab demodulation. Kev tshaj tawm AM yog siv los xa cov ntaub ntawv ntawm cov zaus qis, thaum FM yog siv rau kev xa cov suab zoo.
Kev Sib Txuas Lus Hauv Xov Tooj Ntawm Tes
Cov thev naus laus zis niaj hnub no, xws li 4G thiab 5G tes hauj lwm, vam khom kev hloov kho digital los xa thiab txais cov ntaub ntawv. Cov txheej txheem xws li Quadrature Amplitude Modulation (QAM) thiab Orthogonal Frequency Division Multiplexing (OFDM) feem ntau siv.
Kev Tshaj Tawm Hauv TV
Kev tshaj tawm hauv TV kuj siv cov txheej txheem modulation thiab demodulation. Analog TV siv frequency modulation rau cov teeb liab suab thiab amplitude modulation rau cov teeb liab video. Hauv digital TV, cov txheej txheem zoo dua xws li QAM raug siv.
Kev Sib Txuas Lus Txog Cov Ntaub Ntawv
Kev hloov kho thiab kev tshem tawm yog qhov tseem ceeb heev hauv kev sib txuas lus ntawm cov ntaub ntawv hauv computer. Piv txwv li, lub modem (modulator-demodulator) yog siv los hloov cov teeb liab digital los ntawm lub computer mus rau hauv cov teeb liab analog uas tuaj yeem xa mus rau cov xov tooj, thiab rov qab los.
Kev Taw Qhia thiab Radar
Cov txheej txheem navigation, xws li GPS, thiab radar systems kuj siv ntau yam txheej txheem modulation los xa cov ntaub ntawv hla kev deb thiab nrhiav cov khoom.
Cov Teeb Meem hauv Kev Hloov Kho thiab Kev Demodulation
Txawm hais tias cov txheej txheem modulation thiab demodulation tau paub tab heev, tseem muaj ntau yam teeb meem uas tseem yuav tsum kov yeej:
Kos Npe-txog-Tsis Paub Zoo (SNR)
Qhov muaj suab nrov ntau dua hauv lub teeb liab, qhov nyuaj dua rau demodulate lub teeb liab cov ntaub ntawv nrog qhov tseeb siab. Qhov no yog qhov nyuaj tshwj xeeb hauv kev sib txuas lus wireless hauv cov chaw uas muaj kev cuam tshuam siab.
bandwidth
Txhua txoj kev siv modulation muaj cov kev xav tau bandwidth sib txawv. Kev siv bandwidth zoo yog qhov tseem ceeb, tshwj xeeb tshaj yog hauv kev sib txuas lus ntawm tes thiab qhov twg cov spectrum xov tooj cua muaj tsawg.
Kev cuam tshuam thiab kev cuam tshuam
Kev cuam tshuam los ntawm cov kab xa xov thiab kev cuam tshuam los ntawm lwm cov teeb liab tuaj yeem cuam tshuam cov txheej txheem modulation thiab demodulation. Cov txheej txheem ua cov teeb liab zoo dua tau raug tsim los txo cov teeb meem no.
Qhov Nyuaj ntawm Lub System
Cov txheej txheem modulation thiab demodulation siab dua, tshwj xeeb tshaj yog cov uas siv hauv kev sib txuas lus digital, feem ntau nyuaj thiab xav tau cov khoom siv kho vajtse thiab software zoo heev kom ua haujlwm tau zoo.
Xaus
Kev hloov kho thiab kev tshem tawm yog cov khoom tseem ceeb ntawm kev siv tshuab sib txuas lus niaj hnub no. Raws li lub sijhawm dhau mus, cov thev naus laus zis no txuas ntxiv hloov zuj zus kom tau raws li qhov xav tau kev sib txuas lus uas nyuaj thiab dav dua. Kev nkag siab zoo txog kev hloov kho thiab kev tshem tawm ua haujlwm li cas yog qhov tseem ceeb rau txhua tus neeg koom nrog kev sib txuas lus, hluav taws xob, thiab ntau yam kev qhuab qhia engineering. Thaum thev naus laus zis txuas ntxiv mus, peb tuaj yeem cia siab tias yuav muaj kev tsim kho tshiab ntxiv uas yuav qhia txog cov txheej txheem hloov kho thiab kev tshem tawm zoo dua, uas tso cai rau peb xa thiab tau txais cov ntaub ntawv zoo dua thiab zoo dua.
