A cikin tsarin ilmantarwa na ƙirar PCB mai sauri, taɗi mai mahimmanci shine mahimmancin ra'ayi da ke buƙatar ƙwarewa. Ita ce babbar hanyar da za a iya yada kutse ta hanyar lantarki. Layukan sigina masu kamanceceniya, layukan sarrafawa, da tashar jiragen ruwa na I\O. Crosstalk na iya haifar da munanan ayyuka na da'irori ko abubuwan haɗin gwiwa.
Katsalandan
Yana nufin tsoma bakin hayaniyar wutar lantarki da ba a so na layin watsa makusanta saboda hada-hadar lantarki lokacin da siginar ta yaɗu akan layin watsawa. Wannan tsangwama yana faruwa ne ta hanyar inductance na juna da ƙarfin juna tsakanin hanyoyin sadarwa. Ma'auni na Layer na PCB, tazarar layin sigina, halayen lantarki na ƙarshen tuƙi da ƙarshen karɓa, da hanyar ƙarewar layi duk suna da takamaiman tasiri akan hanyar sadarwa.
Babban matakan da za a bi don shawo kan tatsuniyoyi sune:
Ƙara tazara na wayoyi masu kama da juna kuma ku bi ka'idar 3W;
Saka waya keɓewa mai tushe tsakanin wayoyi masu layi daya;
Rage nisa tsakanin layin waya da jirgin ƙasa.
Domin rage yawan magana tsakanin layi, tazarar layin ya kamata ya zama babba. Lokacin da tazarar cibiyar layin bai gaza sau 3 a fadin layin ba, ana iya kiyaye kashi 70% na wutar lantarki ba tare da tsangwama ba, wanda ake kira ka'idar 3W. Idan kuna son cimma kashi 98% na wutar lantarki ba tare da tsangwama da juna ba, zaku iya amfani da tazarar 10W.
Lura: A ainihin ƙirar PCB, ƙa'idar 3W ba zata iya cika buƙatun don guje wa yin magana ba.
Hanyoyi don guje wa yin magana a cikin PCB
Don guje wa yin magana a cikin PCB, injiniyoyi za su iya yin la'akari daga ɓangarori na ƙirar PCB da shimfidawa, kamar:
1. Rarraba jerin na'urorin dabaru bisa ga aiki kuma kiyaye tsarin bas ɗin ƙarƙashin kulawa mai ƙarfi.
2. Rage nisan jiki tsakanin abubuwan da aka gyara.
3. Layukan sigina masu saurin sauri da abubuwan haɗin (irin su crystal oscillators) yakamata su kasance da nisa daga haɗin haɗin I / () da sauran wuraren da ke da alaƙa da kutsewar bayanai da haɗin kai.
4. Samar da madaidaicin ƙarewa don layin mai sauri.
5. A guji alamun nesa masu kama da juna da samar da isasshiyar tazara tsakanin alamomin don rage haɗin gwiwa.
6. Wayoyin da ke kusa da yadudduka (microstrip ko stripline) yakamata su kasance daidai da juna don hana haɗin haɗin gwiwa tsakanin yadudduka.
7. Rage nisa tsakanin siginar da jirgin ƙasa.
8. Rarrabawa da keɓance maɓuɓɓugan iskar hayaniya (agogo, I / O, haɗin kai mai sauri), da sigina daban-daban ana rarraba su a cikin yadudduka daban-daban.
9. Ƙara nisa tsakanin layukan sigina gwargwadon yuwuwa, wanda zai iya rage ƙarfin magana yadda ya kamata.
10. Rage inductance gubar, guje wa yin amfani da manyan abubuwan da ba a iya amfani da su ba da kuma ƙarancin ƙarancin nauyi a cikin da'ira, kuma a yi ƙoƙarin daidaita ma'aunin nauyi na da'irar analog tsakanin loQ da lokQ. Saboda babban nauyin haɓakawa zai ƙara ƙarfin crosstalk na capacitive, lokacin amfani da babban nauyin impedance, saboda mafi girman ƙarfin aiki, ƙarfin wutar lantarki zai karu, kuma lokacin amfani da ƙananan ƙarancin ƙarfin aiki, saboda babban aiki na yanzu, inductive Crosstalk zai yi aiki. karuwa.
11. Shirya sigina mai sauri na lokaci-lokaci akan layin ciki na PCB.
12. Yi amfani da fasaha mai dacewa da impedance don tabbatar da amincin siginar takardar shedar BT da hana overshoot.
13. Lura cewa ga sigina masu tasowa masu saurin tasowa (tr≤3ns), aiwatar da aikin sarrafa giciye kamar nannade ƙasa, kuma shirya wasu layukan sigina waɗanda EFT1B ko ESD suka shiga tsakani kuma ba a tace su a gefen PCB ba. .
14. Yi amfani da jirgin ƙasa gwargwadon iko. Layin siginar da ke amfani da jirgin ƙasa zai sami 15-20dB attenuation idan aka kwatanta da layin siginar da ba ya amfani da jirgin ƙasa.
15. Ana sarrafa siginar siginar sigina da sigina masu mahimmanci tare da ƙasa, kuma yin amfani da fasahar ƙasa a cikin nau'i na biyu zai cimma 10-15dB attenuation.
16. Yi amfani da madaidaitan wayoyi, wayoyi masu kariya ko wayoyi na coaxial.
17. Tace layin siginar hargitsi da layukan masu hankali.
18. Saita yadudduka da wiring da kyau, saita layin waya da tazarar wiring da kyau, rage tsawon sigina daidai gwargwado, rage nisa tsakanin siginar siginar da layin jirgin sama, ƙara tazara na layin sigina, da rage tsayin layi daya. Layukan sigina (a cikin kewayon tsayi mai mahimmanci) , Waɗannan matakan na iya rage yawan magana.