Nigute washyira imirongo ya RF hamwe na sisitemu ya digitale ku kibaho cya PCB?

Niba umuzunguruko wa analogi (RF) hamwe numuzunguruko wa digitale (microcontroller) ukora neza kugiti cyawe, ariko iyo umaze gushyira byombi kumurongo umwe wumuzunguruko hanyuma ugakoresha amashanyarazi amwe kugirango ukorere hamwe, sisitemu yose irashobora kuba idahindagurika. Ibi biterwa ahanini nuko ibimenyetso bya digitale bigenda bihindagurika hagati yubutaka nogutanga amashanyarazi meza (ingano 3 V), kandi igihe ni gito cyane, akenshi ns urwego. Bitewe na amplitude nini nigihe gito cyo guhinduranya, ibyo bimenyetso bya digitale birimo umubare munini wibice byinshi-byigenga bitigenga guhinduranya inshuro. Mubice bisa, ibimenyetso biva kuri antenne tuning kugeza kubakira igice cyigikoresho kitagira umugozi muri rusange kiri munsi ya 1μV.

Gutandukanya bidahagije kumirongo yoroheje hamwe numurongo wibimenyetso urusaku ni ikibazo gikunze kugaragara. Nkuko byavuzwe haruguru, ibimenyetso bya digitale bifite swing ndende kandi birimo umubare munini wibihuza byinshi. Niba ibimenyetso bya digitale wiring kuri PCB iherekejwe nibimenyetso byoroshye bigereranywa, guhuza imirongo myinshi irashobora guhuzwa kera. Imitsi yunvikana yibikoresho bya RF mubisanzwe ni umuzunguruko wa filteri yumuzunguruko wa feri ifunze (PLL), indege yo hanze igenzurwa na oscillator (VCO) inductor, ibimenyetso byerekana kristu hamwe na antenna, kandi ibyo bice byumuzingi bigomba kuvurwa hamwe n'ubwitonzi budasanzwe.

Kubera ko ibimenyetso byinjira / bisohoka bifite swing ya V nyinshi, imiyoboro ya digitale iremewe mubisanzwe urusaku rwamashanyarazi (munsi ya mV 50). Inzira ya Analog yunvikana urusaku rwamashanyarazi, cyane cyane kuri burr voltage nizindi zihuza cyane. Kubwibyo, umurongo w'amashanyarazi unyura ku kibaho cya PCB urimo imirongo ya RF (cyangwa ibindi bisa) bigomba kwitonda kuruta insinga ziri ku kibaho gisanzwe cy’umuzunguruko, kandi bigomba kwirindwa. Twabibutsa kandi ko microcontroller (cyangwa indi miyoboro ya digitale) izahita yonsa mugice kinini cyigihe gito mugihe gito mugihe cyisaha yimbere, bitewe na CMOS yuburyo bwa microcontrollers igezweho.

Ikibaho cyumuzunguruko wa RF kigomba guhora gifite umurongo wubutaka uhujwe na electrode mbi yo gutanga amashanyarazi, ishobora kubyara ibintu bidasanzwe iyo bidakozwe neza. Ibi birashobora kugora kubishushanyo mbonera bya sisitemu kubyumva, kuberako imiyoboro myinshi ya digitale ikora neza kabone niyo yaba idafite aho ihurira. Muri bande ya RF, niyo insinga ngufi ikora nka inductor. Urebye neza, inductance kuri mm mm z'uburebure ni 1 nH, naho reaction ya inductive y'umurongo wa mm 10 PCB kuri 434 MHz ni 27 Ω. Niba umurongo wubutaka udakoreshejwe, imirongo myinshi yubutaka izaba ndende kandi umuzenguruko ntushobora kwemeza ibishushanyo mbonera.

Ibi bikunze kwirengagizwa mumuzingo urimo radiyo yumurongo nibindi bice. Usibye igice cya RF, mubisanzwe hariho izindi nzitizi zisa kurubaho. Kurugero, microcontrollers nyinshi yubatswe-igereranya-na-digitale (ADCs) kugirango yipime ibyinjira kimwe na voltage ya bateri cyangwa ibindi bipimo. Niba antenne ya transmitter ya RF iherereye hafi (cyangwa kuri) iyi PCB, ibimenyetso byasohotse cyane bishobora kugera kubintu bisa na ADC. Ntiwibagirwe ko umurongo uwo ariwo wose ushobora kohereza cyangwa kwakira ibimenyetso bya RF nka antene. Niba ADC yinjije idakozwe neza, ibimenyetso bya RF birashobora kwishima muri diode ya ESD yinjira muri ADC, bigatera gutandukana kwa ADC.

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Ihuza ryose ryubutaka rigomba kuba rigufi rishoboka, kandi ubutaka buciye mu mwobo bugomba gushyirwa (cyangwa hafi cyane) padi yibigize. Ntuzigere wemerera ibimenyetso bibiri byubutaka gusangira ubutaka unyuze mu mwobo, bushobora gutera umuhanda hagati yamakariso yombi kubera guhuza imiyoboro. Ubushobozi bwa decoupling capacitor bugomba gushyirwa hafi ya pin ishoboka, kandi gusohora capacitor bigomba gukoreshwa kuri buri pin igomba gukuramo. Ukoresheje ubushobozi bwo hejuru bwa ceramic capacator, ubwoko bwa dielectric ni "NPO", "X7R" nabwo bukora neza mubisabwa byinshi. Agaciro keza ka capacitance yatoranijwe igomba kuba nkiyi seriveri yayo resonance ingana na signal inshuro.

Kurugero, kuri 434 MHz, SMD yashyizwemo 100 pF capacitor izakora neza, kuriyi nshuro, reaction ya capacitif ya capacitor igera kuri 4 and, kandi reaction ya inductive yu mwobo iri murwego rumwe. Ubushobozi hamwe nu mwobo murukurikirane bikora akayunguruzo kerekana ibimenyetso byinshyi, bikemerera gucibwa neza. Kuri 868 MHz, ubushobozi bwa 33 p F ni amahitamo meza. Usibye RF yagabanije ubushobozi buke bwa capacitor, capacitor nini nini igomba no gushyirwa kumurongo wamashanyarazi kugirango ikureho inshuro nke, irashobora guhitamo ceramic ya 2.2 μF cyangwa 10μF ya tantalum.

Inyenyeri yo kwinika ni tekinike izwi muburyo bwo kugereranya ibizunguruka. Inyenyeri - Buri module kurubaho ifite umurongo wamashanyarazi kuva aho amashanyarazi asanzwe. Muri iki gihe, insinga yinyenyeri bivuze ko ibice bya digitale na RF byumuzunguruko bigomba kugira imirongo yabyo, kandi iyi mashanyarazi igomba gucibwa ukwe hafi ya IC. Uku gutandukana numubare

Uburyo bwiza bwo gutanga urusaku rwamashanyarazi nigice cya RF. Niba module ifite urusaku rukomeye ishyizwe ku kibaho kimwe, inductor (isaro ya magnetique) cyangwa imbaraga nke zo kurwanya (10 Ω) irashobora guhuzwa mukurikirane hagati yumurongo wamashanyarazi na module, hamwe na capacitori ya tantalum byibura 10 μF bigomba gukoreshwa nkumuriro w'amashanyarazi ugabanuka. Module nkiyi ni RS 232 abashoferi cyangwa guhinduranya amashanyarazi.

Kugirango ugabanye intambamyi ziva mu rusaku hamwe nigice gikikije igice, imiterere ya buri cyiciro cyumuzingi ku kibaho ni ngombwa. Modules yunvikana (ibice bya RF na antene) bigomba guhora byitaruye module yuzuye urusaku (microcontrollers na RS 232) kugirango birinde kwivanga. Nkuko byavuzwe haruguru, ibimenyetso bya RF birashobora gutera intambamyi izindi moderi zisa zingana na ADC mugihe zoherejwe. Ibibazo byinshi bibaho mumikorere yo hasi (nka 27 MHz) kimwe nimbaraga nyinshi zisohoka. Nuburyo bwiza bwo gushushanya gukuramo ingingo zoroshye hamwe na capacitori ya RF (100p F) ihujwe nubutaka.

Niba ukoresha insinga kugirango uhuze ikibaho cya RF numuyoboro wa sisitemu yo hanze, koresha insinga zigoretse. Buri cyuma cyerekana ibimenyetso kigomba guhuzwa numuyoboro wa GND (DIN / GND, DOUT / GND, CS / GND, PWR _ UP / GND). Wibuke guhuza ikibaho cyumuzunguruko wa RF hamwe nububiko bwa sisitemu ya sisitemu ya sisitemu hamwe na kabili ya GND ya kabili yahinduwe, kandi uburebure bwa kabili bugomba kuba bugufi bushoboka. Amashanyarazi aha imbaraga ubuyobozi bwa RF agomba no kugoreka-hamwe na GND (VDD / GND).

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