Inyaniso, ibhodi yesekethe eprintiweyo (I-PCB) zenziwe ngezinto zombane ezihamba ngombane, okt impedance yazo kufuneka ihlale ihleli. Ke kutheni le nto iPBB izisa ukungahambelani kumqondiso? Impendulo kukuba ubeko lwePCB “yindawo engeyiyo eyomda” xa kuthelekiswa nalapho kuhamba khona ngoku.

Nokuba i-amplifier ifumana okwangoku ukusuka komnye umthombo okanye enye kuxhomekeke kubuninzi beempawu zomqondiso kumthwalo. Ukuhamba ngoku kuvela kunikezelo lwamandla, ngokudlula kwi-capacitor, ngokusebenzisa i-amplifier kumthwalo. Okwangoku kuhamba ukusuka kwisiphelo somhlaba wokulayisha (okanye ukukhusela isinxibelelanisi semveliso sePCB) ukubuyela kumhlaba wenqwelomoya, nge-bypass capacitor, kwaye ubuyele kumthombo owawunikezela ngoku okhoyo ngoku.

Umxholo wobuncinane bendlela yangoku ngokungahambelani ayilunganga. Isixa sangoku kuzo zonke iindlela ezahlukeneyo zempembelelo ziyalingana nokuqhutywa kwayo. Kwindiza yasemhlabeni, kuhlala kukho ngaphezulu kwendlela enye ye-impedance ephantsi apho indawo enkulu yokuhamba komhlaba ngoku: indlela enye iqhagamshele ngqo kwi-bypass capacitor; Enye into iyonwabisa kwi-resistor yegalelo ide ifikelele kwi-capacitor yokugqitha. Umzobo 1 ubonisa ezi ndlela zimbini. Ukuhamba kwakhona kwangoku yeyona nto ibangela ingxaki.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

Xa ii-capacitors zokudlula zibekwe kwiindawo ezahlukeneyo kwi-PCB, umhlaba okhoyo ngoku uhamba ngeendlela ezahlukeneyo usiya kwii-capacitors ezihamba ngokudlula, okuyintsingiselo “yokungahambelani kwendawo”. Ukuba isahlulo esibalulekileyo secandelo le-polar yomhlaba wangoku uqukuqela kumhlaba wesekethe yokufaka, kuphela lelo candelo lomqondiso liphazamisekile. Ukuba obunye ubume bomhlaba wangoku abuphazanyiswa, umbane wokufaka umbane utshintsha ngendlela engeyoyomgca. Xa elinye icandelo lokungaguquki litshintshiwe kodwa elinye ukungabikho, ukuphambuka kuyenzeka kwaye kubonakaliswe njengokugqwetha kwesibini komqondiso wesiphumo. Umzobo 2 ubonakalisa isiphumo sokugqwetha kwifomu ebaxiweyo.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

Xa inye kuphela into ye-polar ye-sine wave ephazanyisiweyo, ifom ye-wave evelayo ayisasebenzi njenge-sine wave. Ukulinganisa isikhulisi esifanelekileyo esinomthwalo we-100-and kunye nokudibanisa umthwalo okhoyo ngoku ngokuchasene ne-1-ω yokuxhathisa kumbane wevolthi kumhlaba omnye kuphela kumqondiso, iziphumo kumzobo 3.Iinguqu ezine zeFourier zibonisa ukuba ifomathi yokugqwetha ephantse ibe yiyo yonke i-harmonics yesibini kwi-68 DBC. Kwizinga eliphezulu, eli nqanaba lokudibanisa lenziwa ngokulula kwi-PCB, elinokuthi litshabalalise iimpawu ezichasayo zokuchasana nesandisi-lizwi ngaphandle kokubhenela kwiziphumo ezikhethekileyo ezingezizo ezomda zePCB. Xa imveliso yesikhulisi esinye sokusebenza sigqwetha ngenxa yendlela yangoku yomhlaba, ukuhamba komhlaba ngoku kunokuhlengahlengiswa ngokulungiswa kwakhona kwendlela yokudlula kunye nokugcina umgama kwisixhobo sokufaka, njengoko kubonisiwe kumfanekiso 4.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

I-chip ye-Multiamplifier chip

Ingxaki yee-chip zesikhulisi ezininzi (ezimbini, ezintathu, okanye ezine zesikhulisi) zidityaniswa kukungakwazi ukugcina unxibelelwano lomhlaba ngokudlula kwi-capacitor kude kulo lonke igalelo. Oku kuyinyani ngokukodwa kwizikhulisi ezine. Iichips zesikhulisi se-Quad zineetheminali zokufaka kwicala ngalinye, ke akukho gumbi lokudlula kwiisekethe ezithintela ukuphazamiseka kwisitishi sokufaka.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

Umzobo 5 ubonisa indlela elula kulwakhiwo lwe-amplifier ezine. Uninzi lwezixhobo zixhuma ngqo kwipini yesikhulisi se-quad. Umbane wangoku wombane omnye unokuphazamisa ukufakwa kwamandla ombane womhlaba kunye nomhlaba wangoku welinye ijelo lwamandla ombane, okukhokelela kukugqwetha. Umzekelo, i (+ Vs) yokudlula kwi-capacitor kwisitishi se-1 sesikhulisi se-quad singabekwa ngqo kufutshane negalelo laso; I (-Vs) yokudlula kwe-capacitor inokubekwa kwelinye icala lephakheji. Okwangoku (+ Vs) umhlaba okwangoku unokuphazamisa ishaneli 1, ngelixa (-vs) umhlaba wangoku ungenako.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

Ukuthintela le ngxaki, vumela umhlaba okhoyo uphazamise igalelo, kodwa yeka ukuhamba kwe-PCB ngoku kwindawo yomgama. Ukufezekisa oku, i-bypass capacitor inokucwangciswa kwi-PCB ngendlela yokuba (+ Vs) kunye (-Vs) imijelo yomhlaba ihambe ngendlela efanayo. Ukuba umqondiso wokufaka uphazanyiswa ngokulinganayo yimisinga elungileyo nembi, ukuphazamiseka akuyi kwenzeka. Ke ngoko, lungelelanisa ii-capacitors ezimbini zokudlula ecaleni kwenye ukuze babelane ngomhlaba. Ngenxa yokuba amacandelo amabini e-polar omhlaba okhoyo ngoku avela kwindawo enye (isinxibelelanisi sokukhupha imveliso okanye umhlaba olayishayo) kwaye zombini zihamba zibuyelela kwindawo enye (unxibelelwano lomhlaba oluqhelekileyo lwe-bypass capacitor), i-positive / negative current flow through indlela efanayo. Ukuba ukunganyangeki kwejelo kuphazanyiswa yi (+ Vs) yangoku, (-Vs) yangoku kunefuthe elifanayo kuyo. Ngenxa yokuba ukuphazamiseka okubangelwa yinto enye ngaphandle kokuphazamiseka, akukho kugqwetha, kodwa utshintsho oluncinci ekufumaneni ishaneli luya kwenzeka, njengoko kubonisiwe kwi Umzobo 6.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

Ukuqinisekisa oku kungasentla, kusetyenziswa iindlela ezimbini ezahlukeneyo zePCB: uyilo olulula (Umzobo 5) kunye nolungelelwaniso oluphantsi (Umzobo 6). Ukuphazamiseka okuveliswe sisikhulisi sokusebenza se-FHP3450 sisebenzisa i-fairchild semiconductor kubonisiwe kwitafile 1. Ububanzi bebhendi ye-FHP3450 yi-210MHz, ithambeka lingu-1100V / thina, igalelo langoku le-100nA, kunye nokusebenza ngoku kwisitishi ngasinye ngu-3.6 MA. Njengoko kunokubonwa kwiTheyibhile 1, kokukhona kugqwetha ijelo, kokukhona kungcono ukuphucula, ukuze iindlela ezine ziphantse zilingane ngokusebenza.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

Ngaphandle kwesikhulisi esifanelekileyo se-quad kwi-PCB, ukulinganisa iziphumo zesitishi esinye sokukhulisa kunokuba nzima. Ngokucacileyo, i-amplifier yejelo elinikiweyo aliphazamisi igalelo lalo kuphela, kodwa negalelo lezinye iziteshi ngokunjalo. Umhlaba okhoyo ngoku uqukuqela kuwo onke amagalelo eendlela ezahlukeneyo kwaye uvelise iziphumo ezahlukeneyo, kodwa uphenjelelwa yimveliso nganye enokulinganiswa.

Itheyibhile 2 ibonisa ii-harmonics ezilinganiswe kwezinye iindlela ezingafakwanga ndawo xa kuqhutywa ishaneli enye kuphela. Ijelo elingafakwanga libonisa umqondiso omncinci (i-crosstalk) kwisiseko esisezantsi, kodwa ikwavelisa ukuphazamiseka ngokuthe ngqo okwaziswa ngumhlaba wangoku ngokungabikho komqondiso osisiseko obalulekileyo. Uyilo olugqwethekileyo olusezantsi kuMzobo 6 lubonisa ukuba ulungelelwaniso lwesibini lweharmonic kunye neempawu zokugqwetha ngokupheleleyo (THD) ziphuculwe kakhulu ngenxa yokupheliswa komhlaba okwangoku.

Indlela yokunciphisa ukugqwetha kweHarmonic kuyilo lwePCB

Esi sishwankathelo senqaku

Ukubeka nje, kwi-PCB, ukuhamba kwangoku kuhamba ngokuhamba ngokudlula kwee-capacitors (zonikezelo lwamandla ahlukeneyo) kunye nokunikezelwa kwamandla ngokwawo, okuhambelana nokuqhutywa kwawo. Umqondiso wamaza aphakamileyo ohamba umva ubuyela kwi-capacitor encinci yokudlula. Imisinga yamaza asezantsi, njengaleyo yeempawu zomsindo, inokuhamba ikakhulu ngokudlula kwii-capacitors ezinkulu. Nokuba isantya esisezantsi esisezantsi sinokuthi “singahoyi” amandla apheleleyo okudlula kwaye siphume ngqo sibuyele kumkhombandlela wamandla. Isicelo esithile siya kumisela ukuba yeyiphi indlela yangoku ebaluleke kakhulu. Ngethamsanqa, kulula ukukhusela wonke umhlaba okhoyo ngoku ngokusebenzisa indawo efanayo kunye nomhlaba odlula indawo kwicala lokuphuma.

Umgaqo wegolide wolwakhiwo lwe-HF PCB kukugcina i-HF ngokudlula kwi-capacitor kufutshane nepini yamandla epakishiweyo, kodwa uthelekiso loMzobo 5 kunye noMzobo 6 ibonisa ukuba ukuguqula lo mthetho ukuphucula iimpawu zokugqwetha akuwenzi mahluko. Iimpawu zokugqwetha eziphuculweyo zeza ngeendleko zokongeza malunga ne-intshi ye-0.15 ye-frequency ephezulu yokugqitha i-wiring ye-capacitor, kodwa oku kube nempembelelo encinci ekusebenzeni kwempendulo ye-AC ye-FHP3450. Uyilo lwePCB lubalulekile ekwandiseni ukusebenza kwesikhulisi esikumgangatho ophezulu, kwaye imiba ekuxoxwa ngayo apha ayikhawulelwanga kwii-hf amplifiers. Iimpawu ezisezantsi zamaza ombane ezinje ngesandi zinemfuno engqongqo yokugqwetha. Iziphumo zomhlaba zangoku zincinci kumaza asezantsi, kodwa isenokuba yingxaki ebalulekileyo ukuba isalathiso sokugqwetha esifunekayo siphuculwe ngokufanelekileyo.