Apha, iimpawu ezine ezisisiseko zeesekethe zamaza kanomathotholo ziya kutolikwa kwimiba emine: ujongano lwerediyo frequency, isiginali enqwenelekayo encinci, isiginali enkulu yokuphazamiseka, kunye nokuphazamiseka kwesitishi esikufutshane, kunye nezinto ezibalulekileyo ezifuna ingqwalasela eyodwa kwinkqubo yoyilo lwePCB inikwe.
Ujongano lwerediyo yerediyo yokulinganisa isekethe yerediyo
Isidluliseli esingenazingcingo kunye nomamkeli zahlulwe ngokwengqiqo zibe ngamacandelo amabini: isiseko frequency kunye frequency radio.I-frequency esisiseko ibandakanya uluhlu lwamaza omthamo wesiginali yegalelo le-transmitter kunye noluhlu lwama frequency ophawu oluphumayo lomamkeli.I-bandwidth ye-frequency esisiseko inquma izinga elisisiseko apho idatha inokuhamba khona kwinkqubo.I-frequency yesiseko isetyenziselwa ukuphucula ukuthembeka kwedatha yedatha kunye nokunciphisa umthwalo obekwe ngumthumeli kwi-transmitter medium phantsi kwezinga elithile lokudluliselwa kwedatha.Ke ngoko, ulwazi oluninzi lokusetyenzwa kobunjineli luyafuneka xa kuyilwa isekethe esisiseko ye-frequency kwi-PCB.Isekethe yerediyo yerediyo ye-transmitter inokuguqula kwaye inyuse-ukuguqula isignali ye-baseband esetyenzisiweyo kwitshaneli echongiweyo, kwaye ifake lo mqondiso kwindawo yokuhambisa.Ngokuchasene noko, isekethe yerediyo yerediyo yomamkeli inokufumana isiginali kwindawo yothumelo, kwaye iguqule kwaye inciphise ukuphindaphinda ukuya kwisiseko.
Umthumeli uneenjongo ezimbini eziphambili zoyilo lwePCB: Eyokuqala kukuba kufuneka bagqithise amandla athile ngelixa besebenzisa amandla amancinci anokwenzeka.Okwesibini kukuba abanako ukuphazamisa ukusebenza okuqhelekileyo kwee-transceivers kumajelo akufutshane.Ngokubhekiselele kumamkeli, kukho iinjongo ezintathu eziphambili zoyilo lwePCB: okokuqala, kufuneka babuyisele ngokuchanekileyo iimpawu ezincinci;okwesibini, kufuneka bakwazi ukususa imiqondiso ephazamisayo ngaphandle kwejelo elifunwayo;kwaye okokugqibela, njenge-transmitter, kufuneka badle amandla amancinci kakhulu.
Isiginali yokuphazamiseka okukhulu yokulinganisa isekethe yerediyo
Umamkeli kufuneka abe novelwano kakhulu kwimiqondiso emincinci, nokuba kukho imiqondiso emikhulu yokuphazamiseka (izithintelo).Le meko yenzeka xa uzama ukufumana isignali ebuthathaka okanye ekude, kwaye isidluliseli esinamandla esikufutshane sisasaza kumjelo osecaleni.Isignali ephazamisayo ingaba yi-60 ukuya kwi-70 dB enkulu kunomqondiso olindelekileyo, kwaye inokugqunywa kwisixa esikhulu ngexesha lesigaba sokufaka ummkeli, okanye umamkeli unokuvelisa ingxolo egqithisileyo ngexesha lesigaba sokufaka ukuvala ukwamkelwa kweempawu eziqhelekileyo. .Ukuba umamkeli uqhutyelwa kummandla ongeyena umgca ngumthombo wokuphazamiseka ngexesha lokufaka igalelo, iingxaki ezimbini ezingentla ziya kwenzeka.Ukunqanda ezi ngxaki, isiphelo sangaphambili somamkeli kufuneka sibe simgca kakhulu.
Ke ngoko, "umgca" ikwayingqwalasela ebalulekileyo kuyilo lwePCB yomamkeli.Ekubeni ummkeli yisekethe ye-narrowband, i-nonlinearity ilinganiswa ngokulinganisa "i-intermodulation distortion".Oku kubandakanya ukusebenzisa amaza e-sine amabini okanye amaza e-cosine anamaza afanayo kwaye abekwe kwibhendi esembindini ukuqhuba isiginali yokufakwayo, kwaye emva koko kumeta imveliso yokunqunyulwa kwayo.Ngokuqhelekileyo, i-SPICE yinkqubo yokulinganisa ixesha kunye neendleko eziphezulu, kuba kufuneka yenze izibalo ezininzi ze-loop ukufumana isisombululo esifunekayo ukuze siqonde ukugqwetheka.
Isignali encinci elindelekileyo kukulinganisa kweesekethe zeRF
Umamkeli kufuneka abe novakalelo kakhulu ekubhaqeni imiqondiso emincinci yegalelo.Ngokuqhelekileyo, amandla egalelo lomamkeli angancinci njenge-1 μV.Uvakalelo lomamkeli lukhawulelwe yingxolo eyenziwa yisekethe yegalelo layo.Ke ngoko, ingxolo yingqwalasela ebalulekileyo kuyilo lwePCB yomamkeli.Ngaphezu koko, ukukwazi ukuqikelela ingxolo ngezixhobo zokulinganisa kubalulekile.Umzobo 1 ngumamkeli oqhelekileyo we-superheterodyne.Isignali efunyenweyo ihluzwa kuqala, kwaye emva koko isignali yegalelo ikhuliswe ngesandisi sesandi esisezantsi (LNA).Emva koko sebenzisa i-oscillator yendawo yokuqala (LO) ukudibanisa nalo mqondiso ukuguqula lo mqondiso kwi-frequency intermediate (IF).Ukusebenza kwengxolo yesekethe yangaphambili ixhomekeke ikakhulu kwi-LNA, i-mixer kunye ne-LO.Nangona uhlalutyo lwendabuko lwe-SPICE lwengxolo lunokufumana ingxolo ye-LNA, ayinamsebenzi kumxube kunye ne-LO, kuba ingxolo kulezi zibhloko iya kuchaphazeleka kakhulu ngumqondiso omkhulu weLO.
Isignali encinci yegalelo ifuna ukuba umamkeli abe nomsebenzi omkhulu wokukhulisa, kwaye ngokuqhelekileyo ufuna inzuzo ye-120 dB.Ngenzuzo ephezulu ngolo hlobo, naluphi na umqondiso oludityaniswe ukusuka ekupheleni kwemveliso ubuyela kwisiphelo sogalelo lunokubangela iingxaki.Isizathu esibalulekileyo sokusebenzisa i-architecture ye-superheterodyne receiver kukuba inokusasaza inzuzo kwiifrikhwensi ezininzi zokunciphisa ithuba lokudibanisa.Oku kwenza ukuba i-frequency ye-LO yokuqala ihluke kwi-frequency ye-input signal, enokuthi ithintele izibonakaliso ezinkulu zokuphazamiseka ukuba "zingcoliswe" kwiimpawu ezincinci zokufaka.
Ngezizathu ezahlukeneyo, kwezinye iinkqubo zonxibelelwano ezingenazintambo, ukuguqulwa ngokuthe ngqo okanye i-homodyne architecture inokutshintsha indawo ye-superheterodyne architecture.Kolu lwakhiwo, umqondiso we-RF wegalelo uguqulelwa ngokuthe ngqo kwi-frequency esisiseko kwinyathelo elinye.Ngoko ke, ininzi yenzuzo kwi-frequency esisiseko, kwaye i-frequency ye-LO kunye ne-input signal iyafana.Kule meko, impembelelo encinci yokudibanisa kufuneka iqondwe, kwaye imodeli eneenkcukacha "yendlela yesignali elahlekileyo" kufuneka isungulwe, njengale: ukudibanisa nge-substrate, izikhonkwane zephakheji, kunye neentambo zokudibanisa (Bondwire) phakathi kwe-substrate. ukudibanisa, kunye nokudityaniswa ngentambo yombane.
Ukuphazamiseka kwetshaneli ekufutshane kukulinganisa isekethe yerediyo
Ukugqwetheka kukwadlala indima ebalulekileyo kwi-transmitter.I-non-linearity eyenziwa yi-transmitter kwi-circuit output inokusasaza i-bandwidth yesignali edlulisiweyo kumajelo akufutshane.Le nto ibizwa ngokuba "yi-spectral regrowth".Ngaphambi kokuba umqondiso ufikelele kwi-amplifier yamandla yokudlulisa (PA), i-bandwidth yayo ilinganiselwe;kodwa "ukuphazamiseka kwe-intermodulation" kwi-PA kuya kubangela ukuba i-bandwidth inyuke kwakhona.Ukuba i-bandwidth inyuswe kakhulu, i-transmitter ayiyi kukwazi ukuhlangabezana neemfuno zamandla eziteshi zayo ezikufutshane.Xa usasaza iisignali ezimodareyithwe ngokwedijithali, enyanisweni, i-SPICE ayinakusetyenziselwa ukuqikelela ukukhula okuthe kratya kwespectrum.Ngenxa yokuba ukuhanjiswa kweesimboli ezimalunga ne-1,000 (uphawu) kufuneka kufaniswe ukuze kufumaneke i-spectrum emele, kwaye amaza okuthwala amaza aphezulu kufuneka adityaniswe, nto leyo eya kwenza ukuba uhlalutyo lwexeshana lwe-SPICE lungasebenzi.