Nkhaniyi ikufotokoza za 4 zoyambira zamabwalo a RF kuchokera kuzinthu zinayi: mawonekedwe a RF, chizindikiro chaching'ono choyembekezeredwa, chizindikiro chachikulu chosokoneza, ndi kusokonezedwa ndi mayendedwe oyandikana nawo, ndipo imapereka zinthu zofunika zomwe zimafunikira chidwi chapadera pamapangidwe a PCB.
RF dera kayeseleledwe wa mawonekedwe a RF
Wireless transmitter ndi wolandila mu lingaliro, amatha kugawidwa m'magawo awiri a frequency yayikulu ndi ma frequency radio.Ma frequency ofunikira amakhala ndi kuchuluka kwa ma frequency a siginecha yolowera ya transmitter komanso kuchuluka kwa ma frequency a siginecha ya wolandila.Bandwidth ya ma frequency ofunikira amatsimikizira kuchuluka komwe deta imatha kuyenda mudongosolo.Mafupipafupi ofunikira amagwiritsidwa ntchito kukonza kudalirika kwa kayendedwe ka deta komanso kuchepetsa katundu woperekedwa ndi transmitter pa sing'anga yopatsirana pamlingo woperekedwa.Chifukwa chake, mapangidwe a PCB oyambira pafupipafupi amafunikira kudziwa zambiri zaukadaulo wamasinthidwe.Kuzungulira kwa RF kwa transmitter kumasintha ndikukweza siginecha yokhazikika yokhazikika kunjira yodziwika ndikulowetsa chizindikirochi mu sing'anga yotumizira.Mosiyana ndi izi, RF yozungulira ya wolandila imapeza chizindikiritso kuchokera ku media media ndikuchitembenuza ndikuchitsitsa mpaka pafupipafupi.
Ma transmitter ali ndi zolinga zazikulu ziwiri za mapangidwe a PCB: choyamba ndikuti amayenera kufalitsa mphamvu inayake pomwe akugwiritsa ntchito mphamvu zochepa.Chachiwiri ndi chakuti sangathe kusokoneza ntchito yachibadwa ya transceiver mumayendedwe oyandikana nawo.Pankhani ya wolandira, pali zolinga zazikulu zitatu za mapangidwe a PCB: choyamba, ayenera kubwezeretsa molondola zizindikiro zazing'ono;chachiwiri, ayenera kuchotsa zizindikiro zosokoneza kunja kwa njira yomwe akufuna;mfundo yotsiriza ndi yofanana ndi transmitter, ayenera kudya mphamvu zochepa kwambiri.
RF wozungulira kayeseleledwe wa zizindikiro zazikulu zosokoneza
Olandira ayenera kukhala okhudzidwa ndi zizindikiro zazing'ono, ngakhale pamene zizindikiro zazikulu zosokoneza (blockers) zilipo.Izi zimachitika poyesa kulandira chizindikiro chofooka kapena chakutali ndi chowulutsira champhamvu chowulutsa munjira yoyandikana nayo.Chizindikiro chosokoneza chikhoza kukhala 60 mpaka 70 dB chokulirapo kuposa chizindikiro chomwe chikuyembekezeka ndipo chingalepheretse kulandira chizindikiro chachilendo mu gawo lothandizira la wolandira ndi kuphimba kwakukulu kapena kuchititsa wolandirayo kutulutsa phokoso lambiri mu gawo lolowetsa.Mavuto awiri omwe atchulidwa pamwambapa akhoza kuchitika ngati wolandirayo, mu gawo lolowetsamo, akuthamangitsidwa kudera la nonlinearity ndi gwero la kusokoneza.Kuti mupewe mavutowa, kutsogolo kwa wolandila kuyenera kukhala kozungulira kwambiri.
Chifukwa chake, "mzere" ndiwofunikanso kuganizira popanga PCB yolandila.Monga wolandirayo ndi dera lopapatiza, kotero kusagwirizana ndi kuyeza "kusokoneza intermodulation (intermodulation distortion)" ku ziwerengero.Izi zikuphatikizapo kugwiritsa ntchito mafunde awiri a sine kapena cosine afupipafupi omwe ali pakati pa gulu (mu gulu) kuyendetsa chizindikiro cholowera, ndiyeno kuyeza zomwe zawonongeka kwa intermodulation.Mwambiri, SPICE ndi pulogalamu yoyerekeza nthawi komanso yokwera mtengo chifukwa imayenera kuchita mikombero yambiri isanathe kupeza ma frequency omwe akufunidwa kuti amvetsetse kupotozako.
RF yozungulira kayeseleledwe ka chizindikiro chaching'ono chomwe mukufuna
Wolandirayo ayenera kukhala watcheru kwambiri kuti azindikire zizindikiro zazing'ono zolowetsa.Nthawi zambiri, mphamvu yolowera ya wolandila imatha kukhala yaying'ono ngati 1 μV.kukhudzika kwa wolandila kumachepetsedwa ndi phokoso lopangidwa ndi gawo lake lolowera.Chifukwa chake, phokoso ndilofunika kwambiri popanga cholandila cha PCB.Komanso, kukhala ndi luso lodziwiratu phokoso pogwiritsa ntchito zida zofananira ndikofunikira.Chithunzi 1 ndi wolandila superheterodyne (superheterodyne).Chizindikiro cholandilidwa chimasefedwa koyamba kenako chizindikiro cholowera chimakulitsidwa ndi amplifier yaphokoso lotsika (LNA).Oscillator woyamba wamba (LO) ndiye amagwiritsidwa ntchito kusakaniza ndi chizindikiro ichi kuti asinthe chizindikirochi kukhala ma frequency apakati (IF).Kutsogolo-kumapeto (kutsogolo-kumapeto) phokoso phokoso la dera limadalira makamaka LNA, chosakanizira (mixer) ndi LO.ngakhale kugwiritsa ntchito kusanthula kwaphokoso kwa SPICE, mutha kuyang'ana phokoso la LNA, koma kwa chosakanizira ndi LO, ndizopanda pake, chifukwa phokoso la midadada iyi, lidzakhala chizindikiro chachikulu kwambiri cha LO chokhudzidwa kwambiri.
Chizindikiro chaching'ono cholowetsa chimafuna kuti wolandirayo akwezedwe kwambiri, nthawi zambiri amafuna kupindula mpaka 120 dB.Pakupindula kwakukulu kotere, chizindikiro chilichonse chophatikizidwa kuchokera pazotulutsa (maanja) kubwereranso ku zomwe zalowetsedwera kumatha kuyambitsa mavuto.Chifukwa chofunikira chogwiritsira ntchito zomangamanga za super outlier receiver ndikuti zimalola kuti phindu ligawidwe pama frequency angapo kuti muchepetse mwayi wolumikizana.Izi zimapangitsanso kuti ma frequency a LO ayambe kukhala osiyana ndi ma frequency olowera, amatha kuletsa chizindikiro chachikulu chosokoneza "kuipitsa" ku siginecha yaying'ono yolowera.
Pazifukwa zosiyanasiyana, m'makina ena olumikizirana opanda zingwe, kutembenuka kwachindunji (kutembenuka kwachindunji) kapena kusiyanasiyana kwamkati (homodyne) zomangamanga zimatha kulowa m'malo mwazomangamanga zakutali kwambiri.Pamapangidwe awa, chizindikiro cholowera cha RF chimasinthidwa mwachindunji kukhala pafupipafupi pagawo limodzi, kotero kuti phindu lalikulu limakhala pafupipafupi komanso LO limakhala pafupipafupi ngati siginecha yolowera.Pachifukwa ichi, zotsatira za kugwirizanitsa pang'ono ziyenera kumveka ndipo chitsanzo chatsatanetsatane cha "njira yowonongeka" chiyenera kukhazikitsidwa, monga: kugwirizanitsa kupyolera mu gawo lapansi, kugwirizana pakati pa phazi la phukusi ndi mzere wa solder (bondwire) , ndi kugwirizana kupyolera mu chingwe cha magetsi.
RF Circuit Simulation of Adjacent Channel Interference
Kupotoza kumagwiranso ntchito yofunika kwambiri pa transmitter.Kusagwirizana komwe kumapangidwa ndi transmitter mu gawo lotulutsa kungayambitse kuchuluka kwa ma frequency a siginecha yopatsirana kufalikira panjira zoyandikana.Chodabwitsa ichi chimatchedwa "spectral regrowth".Chizindikiro chisanafike pamagetsi amplifier ya transmitter (PA), bandwidth yake ndi yochepa;komabe, "kusokoneza kwa intermodulation" mu PA kumapangitsa kuti bandwidth ionjezerenso.Ngati bandwidth ikuchulukirachulukira, wotumizirayo sangathe kukwaniritsa zofunikira zamphamvu zamakina oyandikana nawo.Mukatumiza chizindikiro chosinthira digito, ndizosatheka kulosera za kukulanso kwa sipekitiramu ndi SPICE.Chifukwa pafupifupi zizindikiro za digito za 1000 (chizindikiro) cha ntchito yopatsirana ziyenera kufananizidwa kuti zipeze mawonekedwe oyimira, komanso ziyenera kuphatikiza chonyamulira cha pafupipafupi, izi zipangitsa kuti kusanthula kwakanthawi kwa SPICE kukhala kosatheka.
Nthawi yotumiza: Mar-31-2022