Ukuze siqonde umugqa wenyoka, ake sikhulume ngawo PCB umzila kuqala. Lo mqondo awubonakali udinga ukwethulwa. Ngabe unjiniyela wehadiwe akawenzi yini umsebenzi wokufaka izintambo nsuku zonke? Wonke umkhondo ku-PCB ukhishwa ngamunye ngamunye ngunjiniyela wehadiwe. Yini engashiwo? Eqinisweni, lo mzila olula nawo uqukethe amaphuzu amaningi olwazi esivame ukuwashaya indiva. Isibonelo, umqondo we-microstrip line kanye ne-stripline. Kalula nje, umugqa we-microstrip uwumzila ogijima phezu kwebhodi le-PCB, futhi umugqa wokuhluthula uwumzila ogijima engxenyeni engaphakathi ye-PCB. Uyini umehluko phakathi kwale migqa emibili?

Indiza eyireferensi yomugqa we-microstrip iyindiza ephansi yongqimba lwangaphakathi lwe-PCB, kanti olunye uhlangothi lomkhondo luvezwa emoyeni, okubangela ukuthi i-dielectric constant ezungeze umkhondo ingahambisani. Isibonelo, i-dielectric constant ye-substrate yethu evame ukusetshenziswa ye-FR4 i-Around 4.2, i-dielectric constant yomoya ingu-1. Kukhona izindiza eziyisithenjwa kuzo zombili izinhlangothi ezingenhla nezingezansi zomugqa we-strip, wonke umkhondo ushumekwe ku-substrate ye-PCB, futhi i-dielectric constant ezungeze umkhondo iyafana. Lokhu futhi kubangela ukuthi igagasi le-TEM lidluliselwe emugqeni we-strip, kuyilapho igagasi le-quasi-TEM lidluliselwa kulayini we-microstrip. Kungani kuyigagasi le-quasi-TEM? Lokho kungenxa yokungafani kwesigaba kusixhumi esibonakalayo phakathi komoya ne-PCB substrate. Yini i-TEM wave? Uma ujula ngalolu daba, ngeke ukwazi ukuluqeda ezinyangeni eziyishumi nesigamu.

Ukwenza indaba ende ibe mfushane, noma ngabe umugqa we-microstrip noma umugqa ohlutshiwe, indima yabo ayiyona into engaphezu kokuphatha amasignali, noma amasignali edijithali noma amasignali e-analog. Lezi zimpawu zihanjiswa ngendlela yamaza kagesi ukusuka komunye umkhawulo kuya komunye emkhondo. Njengoba kuyigagasi, kufanele kube nesivinini. Siyini isivinini sesiginali ekulandeleleni kwe-PCB? Ngokomehluko ku-dielectric constant, ijubane nalo lihlukile. Ijubane lokusabalalisa lamagagasi kagesi emoyeni yijubane elaziwa kakhulu lokukhanya. Isivinini sokusabalalisa kwenye imidiya kumele sibalwe ngale fomula elandelayo:

V=C/Er0.5

Phakathi kwazo, i-V ijubane lokusabalalisa phakathi nendawo, i-C ijubane lokukhanya, futhi i-Er i-dielectric constant ye-medium. Ngale fomula, singakwazi ukubala kalula isivinini sokudlulisa sesiginali kumkhondo we-PCB. Isibonelo, simane sithathe i-dielectric constant yesisekelo se-FR4 material siyifake kufomula ukuze siyibale, okungukuthi, isivinini sokudlulisela sesiginali kokubalulekile kwesisekelo se-FR4 siwuhhafu wejubane lokukhanya. Kodwa-ke, ngenxa yokuthi uhhafu womugqa we-microstrip olandelelwe phezulu usemoyeni futhi uhhafu usemoyeni, i-dielectric constant izoncishiswa kancane, ngakho isivinini sokudlulisela sizoshesha kancane kunesomugqa we-strip. Idatha ye-empirical evame ukusetshenziswa ukuthi ukubambezeleka komugqa we-microstrip cishe ku-140ps/intshi, futhi ukubambezeleka kokulandela kwe-stripline cishe ku-166ps/inch.

Njengoba ngishilo ngaphambili, kunenhloso eyodwa kuphela, okungukuthi, ukudluliswa kwesignali ku-PCB kubambezelekile! Okusho ukuthi, isignali ayidluliswa kwenye iphinikhodi ngezintambo ngokuphazima kweso ngemva kokuthunyelwa kwephinikhodi eyodwa. Nakuba isivinini sokudlulisa isignali sishesha kakhulu, inqobo nje uma ubude bokulandelela bude ngokwanele, sisazothinta ukudluliswa kwesignali. Isibonelo, kusignali ye-1GHz, isikhathi singu-1ns, futhi isikhathi somkhawulo okhuphukayo noma owehlayo cishe ingxenye eyodwa kweshumi yenkathi, bese kuba ngu-100ps. Uma ubude bokulandelela kwethu budlula intshi engu-1 (cishe u-2.54 cm), khona-ke ukubambezeleka kokudlulisela kuzoba ngaphezu konqenqema olukhuphukayo. Uma umkhondo udlula amasentimitha angu-8 (cishe u-20 cm), khona-ke ukubambezeleka kuyoba umjikelezo ogcwele!

Kuvele ukuthi i-PCB inomthelela omkhulu kangaka, kuvame kakhulu ukuthi amabhodi ethu abe nemikhondo engaphezu kuka-1inch. Ingabe ukubambezeleka kuzoba nomthelela ekusebenzeni okuvamile kwebhodi? Uma ubheka isistimu yangempela, uma kuyisignali nje futhi ungafuni ukucisha ezinye izimpawu, khona-ke ukubambezeleka akubonakali kunomthelela. Nokho, ohlelweni olunesivinini esikhulu, lokhu kubambezeleka kuzoqala ukusebenza. Isibonelo, izinhlayiya zethu zememori evamile zixhunywe ngendlela yebhasi, enemigqa yedatha, imigqa yamakheli, amawashi, nemigqa yokulawula. Bheka isikhombimsebenzisi sethu sevidiyo. Kungakhathaliseki ukuthi zingaki iziteshi ze-HDMI noma i-DVI, izoqukatha amashaneli edatha namashaneli wewashi. Noma amanye amaphrothokholi ebhasi, wonke lawo angukudluliswa okuvumelanayo kwedatha newashi. Bese, ohlelweni lwangempela lwesivinini esikhulu, lawa masiginali wewashi namasignali edatha athunyelwa ngokuhambisanayo esuka ku-chip eyinhloko. Uma idizayini yethu yokulandelela ye-PCB ingeyinhle, ubude besignali yewashi nesiginali yedatha kuhluke kakhulu. Kulula ukubangela ukusampula okungalungile kwedatha, futhi yonke isistimu ngeke isebenze ngokujwayelekile.

Yini okufanele siyenze ukuze sixazulule le nkinga? Ngokwemvelo, singacabanga ukuthi uma imikhondo yobude obufushane inwetshwa ukuze ubude bokulandelela beqembu elifanayo bufane, khona-ke ukubambezeleka kuyoba okufanayo? Indlela yokwandisa i-wiring? Zulazula! Ibhingo! Akulula ukuthi ekugcineni ubuyele endabeni. Lona umsebenzi oyinhloko womugqa wenyoka ohlelweni lwejubane eliphezulu. Ukusonteka, ubude obulinganayo. Kulula kanjalo. Umugqa wenyoka usetshenziselwa ukugoqa ubude obulinganayo. Ngokudweba umugqa wenyoka, singenza iqembu elifanayo lamasignali libe nobude obufanayo, ukuze ngemva kokuba i-chip eyamukelayo ithole isignali, idatha ngeke ibangelwe ukubambezeleka okuhlukile kumkhondo we-PCB. Ukukhetha okungalungile. Umugqa we-serpentine uyafana nokulandela amanye amabhodi e-PCB.

Zisetshenziselwa ukuxhuma amasignali, kodwa zinde futhi azinayo. Ngakho-ke umugqa wenyoka awujulile futhi awunzima kakhulu. Njengoba ifana nezinye izintambo, eminye imithetho yezintambo ezivame ukusetshenziswa nayo iyasebenza emigqeni yenyoka. Ngesikhathi esifanayo, ngenxa yesakhiwo esikhethekile semigqa yenyoka, kufanele uyinake lapho ufaka izintambo. Isibonelo, zama ukugcina imigqa yenyoka ihambisana komunye nomunye kude. Okufushane, okungukuthi, zungeza ijika elikhulu njengoba kusho isisho, ungahambi kakhulu futhi ube mncane kakhulu endaweni encane.

Konke lokhu kusiza ukunciphisa ukuphazamiseka kwesignali. Ulayini wenyoka uzoba nethonya elibi esignali ngenxa yokwanda okwenziwayo kobude bomugqa, inqobo nje uma ukwazi ukuhlangabezana nezidingo zesikhathi ohlelweni, ungawusebenzisi. Abanye onjiniyela basebenzisa i-DDR noma amasignali anesivinini esikhulu ukwenza iqembu lonke lilingane ngobude. Imigqa yenyoka indiza kulo lonke ibhodi. Kubonakala sengathi lena i-wiring engcono. Eqinisweni, lokhu kuwubuvila futhi akunasibopho. Izindawo eziningi ezingadingi kulimala ziyizilonda, okumosha indawo yebhodi, futhi kunciphisa ikhwalithi yesignali. Kufanele sibale ukuhlehliswa kokulibaziseka ngokwezidingo zangempela zesivinini sesignali, ukuze sinqume imithetho yezintambo zebhodi.

Ngaphezu komsebenzi wobude obulinganayo, eminye imisebenzi eminingana yomugqa wenyoka ivame ukushiwo ezihlokweni ze-Intanethi, ngakho ngizobuye ngikhulume kafushane ngakho lapha.

1. Elinye lamagama engivame ukuwabona yindima yokufanisa i-impedance. Lesi sitatimende siyamangaza kakhulu. I-impedance ye-PCB trace ihlobene nobubanzi bomugqa, i-dielectric constant, kanye nebanga lendiza yereferensi. Ihlobene nini nomugqa wenyoka? Ukuma komkhondo kuthinta nini i-impedance? Angazi ukuthi iqhamukaphi le nkulumo.

2. kuthiwa futhi kuyindima yokuhlunga. Lo msebenzi ngeke kuthiwe awukho, kodwa akumele kube nomsebenzi wokuhlunga kumasekhethi edijithali noma asikho isidingo sokusebenzisa lo msebenzi kumasekhethi edijithali. Kumjikelezo wefrikhwensi yomsakazo, umkhondo wenyoka ungakha isekethe ye-LC. Uma inomthelela wokuhlunga kusiginali ethile yefrikhwensi, kuseyisikhathi esedlule.

3. Ukwamukela uthi. Lokhu kungaba. Lo mphumela singawubona kwamanye amaselula noma imisakazo. Amanye ama-antenna enziwe nge-PCB traces.

4. Inductance. Lokhu kungaba. Yonke imikhondo ku-PCB ekuqaleni ine-parasitic inductance. Kuyafezeka ukwenza amanye ama-PCB inductors.

5. Fuse. Lo mphumela ungenza ngidideke. Ingabe ucingo olufushane noluncane lwenyoka lusebenza kanjani njengefuse? Uyasha uma umsinga uphezulu? Ibhodi alilahliwe, intengo yale fuse iphezulu kakhulu, angazi ngempela ukuthi izosetshenziswa ngaluphi uhlobo lwesicelo.

Ngesethulo esingenhla, singacacisa ukuthi kumasekhethi e-analog noma omsakazo, imigqa yenyoka inemisebenzi ethile ekhethekile, enqunywa izici zemigqa ye-microstrip. Ekwakhiweni kwesekethe yedijithali, umugqa wenyoka usetshenziselwa ubude obulinganayo ukuze kuzuzwe ukufanisa isikhathi. Ngaphezu kwalokho, umugqa wenyoka uzothinta ikhwalithi yesignali, ngakho-ke izidingo zesistimu kufanele zicaciswe ohlelweni, ukuphindaphinda kwesistimu kufanele kubalwe ngokuvumelana nezidingo zangempela, futhi umugqa wenyoka kufanele usetshenziswe ngokuqapha.