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Indima yesihluzo se-EMI

Yintoni uphazamiseko lukanomathotholo (RFI)?

I-RFI ibhekisa kumandla ombane we-electromagnetic angafunwayo kuluhlu lwamaza xa eveliswa kunxibelelwano lukanomathotholo.Uluhlu oluphindaphindiweyo lwe-conduction phenomenon luvela kwi-10kHz ukuya kwi-30MHz;uluhlu lwamaza okwenziwa kwemitha luphakathi kwe-30MHz kunye ne-1GHz.

Kutheni kufuneka sinikele ingqalelo kwiRFI?

Kukho izizathu ezibini zokuba i-RFI kufuneka ithathelwe ingqalelo: (1) Iimveliso zabo kufuneka zisebenze ngokuqhelekileyo kwiindawo abasebenza kuzo, kodwa indawo yokusebenza ihlala ihamba ne-RFI enzima.(2) Iimveliso zabo azinakukhanya kwiRFI ukuqinisekisa ukuba aziphazamisi unxibelelwano lweRF olubalulekileyo kwimpilo nakukhuseleko.Umthetho wenze ilungiselelo lonxibelelwano oluthembekileyo lweRF ukuze kuqinisekiswe ulawulo lweRFI kwizixhobo zombane.

Yeyiphi indlela yonxibelelwano lweRFI?

I-RFI isasazwa yi-radiation (amaza ombane kwindawo ekhululekileyo) kwaye ihanjiswa ngomgca wesignali kunye nenkqubo yamandla ye-AC.
Imitha - enye yezona zinto zibalulekileyo kwimithombo ye-RFI yokusasazeka kwezixhobo zombane yintambo yombane ye-AC.Ngenxa yokuba ubude bomgca wamandla we-AC bufikelela kwi-1/4 ye-wavelength ehambelanayo yezixhobo zedijithali kunye nokunikezelwa kwamandla okutshintsha, oku kubandakanya i-eriyali esebenzayo.
Ukuqhuba—I-RFI iqhutywa ngeendlela ezimbini kwinkqubo yonikezelo lwamandla e-AC.Ifilimu eqhelekileyo (i-asymmetric) i-RFI iyenzeka kwiindlela ezimbini: kumgca womgca (LG) kunye nomhlaba ongathathi hlangothi (NG), ngelixa imodi yokwahlukana (i-symmetric) i-RFI ibonakala kumgca wokungathathi hlangothi (LN) ngendlela yombane.

Yintoni isihluzo sokuphazamiseka kwentambo yombane?

Ngophuhliso olukhawulezayo lwehlabathi namhlanje, ngakumbi nangakumbi amandla ombane aphezulu aveliswa.Kwangaxeshanye, ngakumbi nangakumbi amandla aphantsi amandla ombane asetyenziselwa ukuhanjiswa kwedatha kunye nokusetyenzwa, ukuze ivelise impembelelo enkulu kwaye nokuphazamiseka kwengxolo kutshabalalisa izixhobo zombane.Isihluzo sokuphazamiseka kwentambo yombane yenye yeendlela eziphambili zokucoca ezisetyenziswayo ukulawula iRFI esuka kwisixhobo sombane ukuze ingene (ukungasebenzi kakuhle kwesixhobo esinokwenzeka) nokuphuma (uphazamiseko olunokwenzeka kwezinye iinkqubo okanye unxibelelwano lweRF).Ngokulawula i-RFI kwiplagi yamandla, isihluzo somgca wamandla sithintela kakhulu ukusasazeka kwe-RFI.
Isihluzi somgca wamandla licandelo le-multi channel network passive, elicwangciswe ngokuphindwe kabini kwisakhiwo sokucoca isitishi esisezantsi.Inethiwekhi enye isetyenziselwa ukuthomalalisa imo yesiqhelo, kwaye enye yeyemo yokwahlulahlula.Uthungelwano lubonelela ngokuthomalalisa amandla eRF kwi "stop band" (idla ngokuba ngaphezu kwe-10kHz) yesihluzi, ngelixa langoku (50-60Hz) ngokuyimfuneko ayicuthwanga.

Ingaba isihluzo sokuphazamiseka kwentambo yombane sisebenza njani?

Njengothungelwano lwe-passive kunye ne-bilateral network, isihluzo sokuphazamiseka komgca wamandla sinesimo sokutshintsha esintsonkothileyo, esixhomekeke kakhulu kumthombo kunye nokuphazamiseka komthwalo.Uphawu lokuthotywa kwesihluzi luboniswa ngexabiso lophawu loguqulelo.Nangona kunjalo, kwimeko yendawo yombane, umthombo kunye nokuphazamiseka komthwalo akuqinisekanga.Ngoko ke, kukho indlela esemgangathweni yokuqinisekisa ukuhambelana kwesihluzo kwishishini: ukulinganisa inqanaba lokunciphisa kunye ne-50 ohm umthombo ochasayo kunye nokuphela komthwalo.Ixabiso elilinganisiweyo lichazwa njengelahleko yokufaka (IL) yesihluzi:
Ndi..L.= 10 log * (P(l)(Ref)/P(l))
Apha P (L) (Ref) ngamandla aguqulwa ukusuka kumthombo ukuya kumthwalo (ngaphandle kwesihluzi);
I-P (L) ngamandla okuguqula emva kokufaka isihluzo phakathi komthombo kunye nomthwalo.
Ilahleko yokufaka nayo inokubonakaliswa kolu hlobo lombane lulandelayo okanye lwangoku:
IL = 20 log *(V(l)(Ref)/V(l)) IL = 20 log *(I(l)(Ref)/I(l))
Apha V (L) (Ref) kunye ne (L) (Ref) ngamaxabiso alinganisiweyo ngaphandle kwesihluzi,
I-V (L) kunye no-I (L) ngamaxabiso alinganisiweyo ngesihluzo.
Ilahleko yokufakela, ekufanele ukuba iqwalaselwe, ayibonisi ukusebenza kwe-RFI yokuthomalalisa okubonelelwa sisihluzo kwimekobume yombane.Kwimeko-bume yentambo yombane, ixabiso elizalanayo lomthombo kunye nothintelo lomthwalo kufuneka liqikelelwe, kwaye isakhiwo esifanelekileyo sokuhluza sikhethwe ukwenza obona buninzi bokungahambelani kokuphazamiseka kwitheminali nganye.Isihluzi sixhomekeke ekusebenzeni kwe-terminal impedance, esisiseko sombono we "mismatch network".

Uluqhuba njani uvavanyo lokuqhuba?

Uvavanyo lokuqhuba lufuna indawo ezolileyo yeRF - iqokobhe lekhaka - uthungelwano lokuzinzisa komgca, kunye nesixhobo sombane se-RF (njengesamkeli se-FM okanye isihlalutyi se-spectrum).Ubume be-RF yovavanyo kufuneka ubuncinane bube ngaphantsi komda ofunekayo wenkcazo ye-20dB ukuze ufumane iziphumo zovavanyo ezichanekileyo.Uthungelwano lwe-linear impedance stabilization network (LISN) luyafuneka ukuseka i-impedance efunwayo yomthombo wegalelo lombane wombane, eyona nxalenye ibaluleke kakhulu yenkqubo yokuvavanya kuba ukuxhatshazwa kuchaphazela ngokuthe ngqo inqanaba lokulinganisa lemitha.Ukongezelela, umlinganiselo ochanekileyo we-broadband we-receiver kwakhona ipharamitha ephambili yovavanyo.


Ixesha lokuposa: Mar-30-2021