Core of RF Signal to Fiber Transmission: Kev piav qhia ua tiav ntawm lub hauv paus ntsiab lus ntawm Analog Signal rau Fiber Hloov
Nyob rau hauv RF (Xov tooj cua zaus) teeb liab kis tau tus mob, koj puas muaj teeb meem los ntawm cov teeb meem no: cov teeb liab loj attenuation tom qab ntev - kis tau tus mob, teeb liab distortion los ntawm electromagnetic cuam tshuam, thiab loj thiab kim cable thaiv? Txawm hais tias nws yog kev sib txuas lus hauv paus chaw nres tsheb, cov khoom siv xov tooj cua astronomy, kev tswj hwm kev lag luam, lossis xov tooj cua thiab TV, kev ruaj khov ntawm RF cov cim qhia yog qhov xav tau tseem ceeb - thiab RF teeb liab rau fiber ntau optic kis tau tus mob yog tus yuam sij los daws cov teeb meem no. Niaj hnub no, peb yuav nyiam ua txhaum cov ntsiab lus tseem ceeb: yuav ua li cas analog RF signals hloov mus rau hauv fiber ntau optic teeb liab kom ua tiav kev cuam tshuam - dawb, ntev - nrug, thiab siab - kev sib kis ncaj ncees.
Ua ntej, nws yog ib qho tsim nyog los qhia meej txog qhov tseem ceeb: fiber ntau optic kis tau tus mob optical signals, thaum peb RF signals yog analog hluav taws xob cov teeb liab, thiab ob qho tib si tsis ncaj qha. Yog li ntawd, lub ntsiab lus ntawm cov teeb liab analog rau fiber ntau hloov dua siab tshiab yog ua kom tiav ob qhov kev hloov pauv: "analog hluav taws xob teeb liab → optical teeb liab → analog hluav taws xob teeb liab", thiab tom qab ntawd paub txog cov teeb liab tau txais txiaj ntsig los ntawm qhov qis - poob thiab tiv thaiv - cuam tshuam cov yam ntxwv ntawm optical fiber- uas yog qhov tseem ceeb ua haujlwm ntawm peb RF teeb liab rau fiber ntau cov khoom. Tag nrho cov txheej txheem feem ntau yog muab faib ua 5 cov kauj ruam tseem ceeb, txhua tus txiav txim siab qhov zoo ntawm cov teeb liab kis tau tus mob. Peb yuav piav qhia lawv hauv kev nthuav dav ua ke nrog cov qauv tsim ntawm cov khoom.
Kauj Ruam 1: Analog RF Signal Preprocessing - Tshem tawm kev cuam tshuam thiab ua kom zoo teeb liab zoo
Thawj analog RF signals (xws li xov tooj cua zaus signals los ntawm lub hauv paus chaw nres tsheb thiab nrhiav pom cov teeb liab los ntawm radars) yog feem ntau tov nrog suab nrov thiab cuam tshuam. Kev hloov pauv ncaj qha yuav ua rau muaj kev cuam tshuam ntawm cov teeb liab kho qhov muag thiab cuam tshuam rau kev sib kis. Yog li ntawd, ua ntej nkag mus rau qhov kev sib txuas ntawm kev hloov pauv, peb cov khoom yuav ua ntej ua ntej cov cim RF analog, uas tseem yog lub hauv paus rau kev ua kom muaj kev sib kis ncaj ncees.
Preprocessing feem ntau suav nrog ob txoj haujlwm tseem ceeb: ua ntej, teeb liab amplification, uas ua kom lub zog tsis muaj zog RF rau lub zog tsim nyog rau kev hloov dua siab tshiab los ntawm lub siab -precision amplifier kom tsis txhob hloov dua siab tshiab vim tsis muaj zog; thib ob, lim thiab lim dej, uas siv cov kev lim dej lim dej los lim tawm cov suab nrov tsis cuam tshuam thiab cuam tshuam cov teeb liab thiab khaws cov txiaj ntsig zoo RF. Peb cov khoom txais yuav customized filtering technology, uas yuav raug hloov mus rau RF teeb liab zaus band ntawm 5MHz mus rau 6GHz, kom ntseeg tau lub purity ntawm preprocessed teeb liab thiab npaj rau tom ntej conversion.
Kauj Ruam 2: Electro-Kev hloov kho qhov muag (E/O) - "Hloov" Analog Hluav Taws Xob Hluav Taws Xob rau hauv Optical Signals
Qhov no yog cov kauj ruam tseem ceeb ntawm tag nrho cov txheej txheem hloov dua siab tshiab thiab cov txheej txheem thev naus laus zis ntawm peb cov khoom. Yooj yim muab tso, nws yog los hloov cov analog RF hluav taws xob ua ntej rau hauv cov teeb liab kho qhov muag uas tuaj yeem xa mus rau hauv cov khoom siv kho qhov muag los ntawm electro- kho qhov muag hloov khoom siv- sib npaug los tso "lub tsho tiv no ntawm lub teeb" rau ntawm cov teeb liab hluav taws xob, tso cai rau lawv ua tiav ntev - kis tau tus mob nrog qhov zoo ntawm optical fibers.
Peb cov khoom siv siab -linearity DFB laser diodes raws li cov tub ntxhais electro- kho qhov muag hloov khoom siv, thiab lawv txoj hauv kev ua haujlwm yog ua raws li "Intensity Modulation (IM)" thev naus laus zis: kev tsav tsheb tam sim no ntawm lub laser yog ncaj qha hloov kho los ntawm cov teeb liab hluav taws xob, kom qhov kev siv zog ntawm cov zis hluav taws xob kho qhov muag hloov pauv synchronously nrog lub amplitude ntawm RF ntawm 2 amplitude ntawm lub teeb liab { Lub teeb los simulate qhov siab ntawm lub suab, qhov kev siv ntawm lub teeb hloov tag nrho sib haum mus rau txoj cai hloov pauv ntawm thawj RF teeb liab, paub txog qhov tseeb ntawm "hluav taws xob teeb liab → optical teeb liab". Qhov kom zoo dua ntawm txoj kev hloov kho no yog cov lus teb ceev ceev thiab cov teeb liab me me distortion, uas tuaj yeem ua kom muaj txiaj ntsig zoo tshaj plaws ntawm cov yam ntxwv ntawm analog RF signals, tshwj xeeb tshaj yog tsim rau cov xwm txheej uas yuav tsum muaj siab rau cov teeb liab fidelity, xws li xov tooj cua astronomy thiab satellite kev sib txuas lus.
Nyob rau tib lub sijhawm, peb cov khoom lag luam muaj qhov ua tau zoo - nyob rau hauv qhov kub thiab txias ua haujlwm, uas tuaj yeem cuam tshuam qhov cuam tshuam ntawm qhov kub thiab txias hloov ntawm lub laser, ua kom muaj kev ruaj ntseg ntawm cov teeb liab kho qhov muag. Txawm nyob rau hauv huab cua puag ncig los ntawm -40℃mus rau +70 degree, nws muaj peev xwm stably ua tiav electro-optical conversion.
Kauj ruam 3: Fiber Optic Transmission - Ib qho kev cuam tshuam - Dawb, Tsawg - Poob "Signal Channel"
Tom qab electro- hloov kho qhov muag, lub teeb liab kho qhov muag tau ua ke rau hauv cov tub ntxhais fiber ntau thiab pib ntev - kis tau tus mob. Qhov kom zoo dua ntawm cov kauj ruam no yog cov tub ntxhais ntawm fiber ntau optic kis tau tus mob sib txawv ntawm cov tsoos cable kis tau tus mob: optical fiber siv lub hauv paus ntsiab lus ntawm tag nrho cov kev xav ntawm lub teeb kom txwv lub optical teeb liab mus propagate nyob rau hauv lub fiber core. Lub refractive index ntawm cov tub ntxhais fiber ntau yog me ntsis siab dua li ntawm cov cladding, kom ntseeg tau tias cov teeb liab kho qhov muag yuav tsis xau thiab paub txog kev sib kis tau zoo.
Piv nrog cov tsoos coaxial cables, fiber optic kis tau tus mob muaj peb qhov zoo irreplaceable, uas kuj yog tus yuam sij rau peb cov khoom los daws cov neeg siv cov ntsiab lus mob: ua ntej, tsis tshua muaj poob. Nyob rau hauv 1550nm band, qhov kev sib kis ntawm optical fiber ntau tsuas yog li 0.2dB / km, uas yog qis dua qhov poob ntawm coaxial cables uas feem ntau yog ob peb dB / m. Txawm hais tias kis tau mus rau kaum lossis ntau pua mais, lub teeb liab yuav tsis raug txo kom tsawg; thib ob, muaj zog tiv thaiv - cuam tshuam. Optical fiber ntau yog cov khoom siv dielectric, uas tiv thaiv kev cuam tshuam ntawm electromagnetic cuam tshuam (EMI) thiab xov tooj cua zaus cuam tshuam, tshwj xeeb tshaj yog tsim rau kev cuam tshuam hnyav xws li kev lag luam thiab tub rog; peb, lub teeb yuag. Txoj kab uas hla ntawm ib qho fiber ntau optical tsuas yog 125 microns, uas yog sib zog dua li coaxial cables, zoo heev txo qhov nyuaj thiab tus nqi ntawm kev xaim.
Peb cov khoom tau sib xws nrog SM28 ib leeg- hom kho qhov muag fiber ntau thiab txhawb nqa Wavelength Division Multiplexing (WDM) thev naus laus zis, uas tuaj yeem paub ntau-channel RF teeb liab kis tau tus mob los ntawm ib qho kev kho qhov muag fiber ntau, ntxiv kev txhim kho kev sib kis, txo cov nqi xaim, thiab hloov mus rau ntau -scenario daim ntawv thov xav tau.
Kauj Ruam 4: Photoelectric Conversion (O/E) - "Restore" Optical Signals to Analog Electrical Signals
Thaum lub teeb liab kho qhov muag mus txog qhov kawg tau txais, nws yuav tsum tau hloov rov qab mus rau qhov qub analog RF hluav taws xob teeb liab los ntawm kev hloov pauv photoelectric kom nws tuaj yeem lees paub thiab siv los ntawm cov khoom siv davhlau ya nyob twg (xws li chaw nres tsheb hauv paus, radars, thiab cov lus qhia). Cov kauj ruam no yog cov txheej txheem rov qab ntawm electro- kho qhov muag hloov dua siab tshiab, uas tseem yuav tsum tau siab - cov cuab yeej ua tau zoo los xyuas kom zoo ntawm kev kho kom zoo.
Peb cov khoom siv siab -sensitivity photodetectors (PIN photodiodes lossis avalanche photodiodes APD) ua cov khoom siv hloov pauv tseem ceeb. Lawv lub luag haujlwm yog los hloov qhov kev siv zog hloov ntawm cov teeb liab kho qhov muag rau hauv cov teeb liab hluav taws xob sib txuas (photogenerated tam sim no)- lub zog kho qhov muag muaj zog dua, qhov loj dua qhov tsim tawm tam sim no, uas yog tag nrho raws li cov teeb liab hloov txoj cai ntawm kev xa xov kawg. Lub teeb liab hloov hluav taws xob yuav raug nthuav dav ntxiv los ntawm qhov qis - suab nrov amplifier kom ntseeg tau tias lub teeb liab lub zog ua tau raws li qhov yuav tsum tau muaj ntawm cov khoom siv davhlau ya nyob twg, thiab tib lub sijhawm txwv cov suab nrov cuam tshuam kom tsis txhob cuam tshuam cov teeb liab rov qab.
Kauj Ruam 5: Kev Tshaj Tawm Tshaj Tawm-Kev Ua Haujlwm - Kev Kho Kom Zoo Dua Tshiab kom hloov mus rau qhov xav tau ntawm Terminal
Tom qab photoelectric hloov dua siab tshiab, lub analog RF hluav taws xob teeb liab yuav tsum tau mus txog qhov kawg ncej- ua cov kauj ruam ua ntej nws yuav muab tau tiag tiag siv. Post- kev ua haujlwm feem ntau suav nrog cov teeb liab shaping thiab nce calibration: lub shaping module kho me me distortions uas yuav tshwm sim thaum lub teeb liab kis tau tus mob kom ntseeg tau tias lub teeb liab waveform yog kiag li raws li cov thawj teeb liab; qhov nce calibration module kho cov teeb liab nce mus rau qhov ntau tau yoog rau cov khoom siv davhlau ya nyob twg kom tsis txhob muaj cov khoom siv ua haujlwm tsis zoo los ntawm lub teeb liab ntau dhau lossis tsis txaus.
Peb cov khoom txhawb nqa Automatic Gain Control (AGC), uas tuaj yeem hloov kho qhov nce ntxiv raws li kev sib kis thiab teeb liab lub zog yam tsis muaj kev cuam tshuam los ntawm phau ntawv, txhim kho kev yooj yim ntawm kev siv, thiab ua kom ntev - lub sij hawm ruaj khov thiab sib xws ntawm cov teeb liab.
Vim li cas thiaj xaiv peb RF Signal rau Fiber Optic khoom?
Nkag siab txog lub hauv paus ntsiab lus ntawm analog teeb liab rau kev hloov pauv fiber ntau, nws tsis yog qhov nyuaj kom pom tias txhua kauj ruam ntawm cov txheej txheem hloov dua siab tshiab tso siab rau siab -cov cuab yeej ua tau zoo thiab kev tsim kho kom zoo- thiab qhov no yog qhov tseem ceeb ntawm kev sib tw ntawm peb cov khoom. Hauv cov ntsiab lus, peb qhov zoo tau tshwm sim hauv peb yam:
Siab -Kev Ncaj Ncees: Kev siv siab-linearity lasers thiab photodetectors, ua ke nrog kev lim dej thiab nce kev tswj hwm, qhov spurious - dawb dynamic ntau yam tuaj yeem ncav cuag 100dBm / H2 / 3, ua kom zoo tshaj qhov khaws cia ntawm cov yam ntxwv qub ntawm analog RF signals thiab tsis txhob cuam tshuam;
Kev ruaj ntseg thiab kev ntseeg tau: Ua tau- nyob rau hauv qhov kub thiab txias kev tswj hwm kev ua haujlwm, hloov mus rau qhov kub thiab txias ib puag ncig, txhawb nqa ntev - kis tau tus mob mus txog 20km yam tsis muaj rov ua dua, nrog kev poob qis dua 0.4dB / km, ua tau raws li qhov xav tau hnyav ntawm ntau yam xwm txheej xws li kev lag luam, kev sib txuas lus, thiab tub rog;
Kev hloov pauv tau yooj yim: Npog ntau zaus ntawm 5MHz txog 6GHz, txhawb nqa ib zaug - hom optical fiber ntau thiab WDM thev naus laus zis, thiab muab cov kev daws teeb meem raws li cov neeg siv khoom xav tau, hloov mus rau ntau yam kev thov xws li 5G hauv paus chaw nres tsheb, xov tooj cua telescopes, xov tooj cua thiab TV, thiab radars.
Txawm hais tias koj yuav tsum tau daws qhov teeb meem ntawm RF teeb liab kis tau tus mob attenuation nyob ntev los yog tshem tawm cov teeb meem ntawm electromagnetic cuam tshuam, analog teeb liab rau fiber optic tshuab yog qhov kev daws teeb meem zoo tshaj plaws -thiab peb cov teeb liab RF rau fiber optic cov khoom yog cov paub daws teeb meem uas siv txoj cai no, pab koj ua tiav cov txiaj ntsig zoo, ruaj khov, thiab qis - nqi teeb liab kis tau tus mob.
Yog tias koj qhov project tab tom ntsib teeb meem kev sib kis ntawm RF thiab koj xav paub seb peb cov khoom tuaj yeem hloov kho li cas rau koj cov kev xav tau tshwj xeeb, thov hu rau peb kom tau txais cov ncauj lus kom ntxaws cov kev daws teeb meem thiab cov khoom lag luam, thiab cia peb siv cov thev naus laus zis thev naus laus zis los coj koj cov teeb liab kis.
