General mfundo za machitidwe a ADC

Tiyeni tione osiyanasiyana waukulu wa nkhani zimene akhoza zimachitika mfundo za analogi ndi digito converters (ADCs) a mitundu yosiyanasiyana. Yotsatana nkhani, motsatizana kugwirizanitsa - chimene chinapangitsa mawu awa? mfundo ntchito ya ADC wa microcontroller ndi chiyani? nkhani zina izi ndi ayankhidwa mu chimango nkhaniyo. The atatu oyambirira kukhala zoyenera chiphunzitso ambiri, ndi subtitle wachinai udzakhala kuphunzira mmene ntchito. Mungathe kukumana mabuku ADC ndi DAC maunso. Mfundo ntchito zipangizozi kusiyana pang'ono, kotero sizikusokonezani iwo. Choncho, nkhani tidzakambirana kutembenuka kwa chizindikiro kwa analogi kwa digito, pamene DAC ntchito mu iwowo.

tanthauzo

Mukuganizira mfundo ya ADC, tiyeni tipeze chimene chipangizo ndi. Analogi kuti converters digito ndi zipangizo kuti kuchuluka thupi n'kukhala lolingana chifaniziro M'ndandanda. The chizindikiro koyamba akhoza kuchita chilichonse - panopa, voteji, capacitance, kukana, kasinthasintha wa kutsinde, ndi mtima umagunda mofulumira ndi zina zotero. Koma kuti Otsimikiza, tidzayesetsa kugwira ntchito ndi kutembenuka chimodzi chokha. Izi "kachidindo voteji". Kusankha mtundu uwu ntchito si mwangozi. Pambuyo ADC (mfundo ya ntchito chipangizo izi) ndi mbali zake kwakukulukulu amadalira wotani mfundo muyeso ntchito. Amenewa amanena za ndondomeko choyerekezera mtengo wina ndi muyezo poyamba kukhazikitsidwa.

makhalidwe ADC

Pokha waukulu angatchedwe, ndi mlingo kutembenuka. Koyamba mu Akamva, ndipo chachiwiri - mu zitsanzo chachiwiri. Modern converters analogi ndi digito mwina 24-bit kapena kutembenuka liwiro, yomwe ibwela GSPS mayunitsi. Onani kuti ADC akhoza imodzi imakupatsani ndi ntchito imodzi yokha ya makhalidwe ake. Kwakukulu ntchito yawo, kovuta kugwira ntchito ndi chipangizo, ndipo ndi okwera mtengo kwambiri yokha. Koma phindu mwina kupeza zofunika pang'ono mozama ntchito ndi nsembe liwiro chida cha.

mitundu ADC

Mfundo ntchito zimasiyanasiyana mwa magulu osiyana zipangizo. Tikambirana mitundu zotsatirazi:

1. Atakhala mwachindunji.
2. Ndi chiyerekezo motsatizana.
3. Ndi kusinthika yomweyi.
4. Analogi ndi digito Converter ndi mlandu kugwirizanitsa (ankadziwana-Sigma).
5. Kaphatikizidwe ADC.

Pali mitundu ina ya conveyor ndipo zimagwira amene makhalidwe awo wapadera wa zomangamanga osiyana. Koma anthu zitsanzo, limene tidzakambirana mu chimango cha nkhani ndi chidwi chifukwa mbali chitsanzo chabwino zipangizo zake kagawo kakang'ono ngati kulunjika. Choncho tiyeni tione mfundo ya ADC, komanso ngati kudalira ake pa chipangizo thupi.

Direct analogi kuti converters digito

Achita otchuka kwambiri mu 60-70-ntchentche Mu zaka zapitazo. Mu mawonekedwe a madera Integrated amapangidwa ndi 80s. Ndi yosavuta, ngakhale wosazindikira zipangizo kuti sangathe kudzitama wa kanjedza kwambiri. chawo ndi amangoona 6-8 Akamva, ndi liwiro la kawirikawiri kuposa 1 GSPS.

Mfundo ntchito mtundu wa ADC ndi pa zolowetsa kuphatikiza a comparators athandizira mbendera imodzi. Pa zoipa osachiritsika voteji ndi phindu zina. Ndiyeno chipangizo Mzimuyo kugwira ntchito. Izi zachitika chifukwa cha voteji pakuyenerera. Tiyeni tinene kuti tili chipangizo kumene 8 comparators. Pamene kudyetsa ½ wa voteji Buku ndikoyambitsidwa 4 yekha wa iwo. Kutsogoza encoder anapanga malamulo bayinare, amene ali linanena bungwe m'kaundula ndi latches. Wachibale mphamvu ndi zofooka tinganene kuti mfundo ya ntchito limakupatsani kulenga zipangizo mkulu-liwiro. Komatu kuti tilandire zinafunika mawu kutalika ali ndi thukuta kwambiri.

Chilinganizo ambiri chiwerengero cha comparators chiri motere: 2 ^ N. Pansi N m'pofunika kuika chiwerengero cha manambala. Ankaona Mwachitsanzo yapita angagwiritsidwe ntchito kachiwiri: 2 ^ 3 = 8. Subtotal kwa kumaliseche lachitatu ayenera kukhala 8 comparators. Izi ndi mfundo ya ADC, amene analengedwa choyamba. Nzosatheka kwambiri, choncho kenako panali zomangamanga zina.

Analogi ndi digito converters, motsatizana chiyerekezo

aligorivimu "weighting" ntchito pano. Kufupikitsa zipangizo zikugwira ntchito pa mwambo umenewo, anangomutchula kuti ADC motsatizana ngongole. Mfundo ntchito chiri motere: chipangizo chimaonekera mwa mbendera athandizira, ndipo ndiye poyerekeza ndi manambala, amene amayambira malinga ndi ndondomeko zina:

1. Akanema wa theka zotheka kutchulidwa voteji.
2. Ngati chizindikiro ukulu malire kuthana ulendo №1, izo poyerekeza ndi nambala lomwe lili Midway pakati pa mtengo otsala. Choncho, mu mlandu wathu zidzakhala ¾ wa voteji pakuyenerera. Ngati chizindikiro Buku silikugwirizana chithunzi ichi, poyerekezera izichitikira ndi gawo lina la imeneyi ndi mfundo zofanana. Muchisanzo chimenechi, ¼ ya voteji pakuyenerera.
3. Gawo 2 ayenera kubwereza nthawi N, amene adzatipatsa N Akamva chotsatira. Ichi ndi chifukwa khalidwe la N Chiwerengero cha m'mafanizo.

mfundo ya zida walola kupeza ndi wachibale mlingo mkulu kutembenuka, amene motsatizana chiyerekezo ADCs. Mfundo opareshoni, monga momwe mukuonera, losavuta komanso ndi zipangizozi abwino zosiyanasiyana zochitika.

Kufanana analogi ndi digito converters

Amagwira ntchito ngati chipangizo siriyo. Yowerengera chilinganizo - (2 ^ n) -1. Pakuti choncho ankaona kale, tiyenera (2 ^ 3) -1 comparators. Ntchito ntchito zosiyanasiyana yeniyeni ya mafoni amenewa, omwe mwina yerekezerani athandizira ndi munthu Buku voteji. Kufanana converters analogi ndi digito ndi mwachilungamo kudya zipangizo. Koma mfundo ya kumanga zipangizozi ndi kuthandiza Mwachangu awo amafuna mphamvu kwambiri. Choncho, ntchito zawo mu batire zoyendetsedwa ndi zosayenera.

Analogi ndi digito Converter ndi kugwirizanitsa motsatizana

Mozama pa njira zofanana chipangizo m'mbuyomu. Choncho, pofuna kufotokoza ntchito motsatizana kugwirizanitsa ADC, mfundo ya opareshoni oyamba tidzakambirana kwenikweni pa zala. Mu zipangizozi zochokera chodabwitsa dichotomy lapansi. M'mawu ena, kufanizitsa siriyo ikuchitika anayeza mtengo ndi mbali zina za kufunika pazipita. Kodi kutenga mfundo ½, 1/8, 1/16 ndi zina zotero. Choncho, analogi ndi digito Converter tikhoza kuchita ndondomeko N iterations (motsatizana mapazi). M'menemo N liri pokha ADC (kuyang'ana mitunduyi kale pamwambapa). Choncho, tili ndi phindu ndithu mu nthawi, ngati ndikofunikira ntchito njira. Ngakhale liwiro ndithu, zipangizozi amagwiritsidwa yodziwika ndi zolakwa otsika malo amodzi.

Analogi ndi digito converters ndi mlandu kugwirizanitsa (ankadziwana-Sigma)

Ndi chidwi kwambiri mtundu wa chipangizo mosalephera chifukwa mfundo zake opaleshoni. Amakhala mu kuti voltages athandizira akuyerekezedwa kuti anapeza integrator. Kodi nyemba athandizira ndi zoipa kapena zabwino polarity (zimatengera pa chifukwa cha machitidwe yapita). Choncho, tingathe kunena kuti zimenezi Converter analogi ndi digito ndi kutsatira dongosolo losavuta. Koma izi monga chitsanzo kuyerekezera, kotero inu mukhoza kumvetsa zimene ankadziwana-Sigma ADC. Mfundo za dongosolo opareshoni, koma ntchito ogwira mtima a Converter analogi ndi digito sikokwanira. Mapeto ndi pakutuluka anthu ndi ziro, ndiwo wakuyenda kudzera digito otsika-chiphaso fyuluta. Iwo amapanga zina pang'ono zinayendera. Kusiyanitsa ADC converters a dongosolo loyamba ndi lachiwiri.

Kaphatikizidwe analogi ndi digito Converter

Iyi ndi nkhani wapadera wa iwowa, umene kutengedwa ngati mbali imodzi ya nkhani. Kenako, ife pofotokoza ntchito mafoni amenewa, koma pa mlingo ambiri. ADC Izi analogi ndi digito Converter ndi Kankhani-Chikoka kusakanikirana. Kukumana chipangizo otere akhale ndi multimeter yadigito. Ndipo zimenezi si zodabwitsa, chifukwa iwo kupereka mkulu molondola ndi pa nthawi yomweyo bwino kubisa kusokonezedwa.

Tsopano tiyeni tione mfundo zake ntchito. Iwo kwagona kuti athandizira capacitor wapatsidwa kwa nthawi yoikika. Childs, nthawi imeneyi ndi imodzi mwa mains pafupipafupi imene mafumuwa chipangizo (50 Hz kapena 60 Hz). Zingakhalenso angapo. Choncho, phokoso mkulu-pafupipafupi ndi kuponderezedwa. Imodzi angaimbidwenso chikoka wosakhazikika voteji mphamvu zoyendetsera magetsi pa lolondola zinachitika.

Pamene mlandu nthawi ikutha analogi-digito Converter, ndi capacitor akuyamba zimatulutsa ndi makamaka amodzi liwiro. Internal kauntala chipangizo amawerengedwa chiwerengero cha nyemba wotchi imene amayambira pa ndondomeko iyi. Choncho, yaitali nthawi imeneyi, wamkulu ntchito.

ADC twostroke kusakanikirana ndi lolondola mkulu ndi kusamvana. Chifukwa ichi, komanso kumanga dongosolo osavuta, iwo ziperekedwa monga Chip a. The drawback yaikulu Motero, ntchito - malingana ndi maukonde ntchito. Kumbukirani kuti mphamvu zake tamangirizidwa ku nthawi za nthawi pafupipafupi mphamvu okwanira.

Apa ndi momwe ADC awiri kusakanikirana. Mfundo ntchito chipangizo ngakhale ndi zovuta kwambiri, koma amapereka zizindikiro khalidwe. Nthawi zina, izi ndi chabe chofunika kwambiri.

Sankhani APC ife ndi mfundo kofunika

Tiyeni tinene, takumana ndi ntchito yeniyeni. Amene kusankha chipangizo moti akhoza kukumana ndi zosowa zathu? Choyamba, tiyeni tikambirane za kusamvana ndi olondola. Nthawi zambiri iwo ali osokonezeka, ngakhale mchitidwe iwo ali kwambiri ofooka amadalira munthu wachiwiri. Onani kuti 12-bit analogi ndi digito Converter zochepa molondola kuposa 8-bit. Pankhaniyi, kuthetsa - ndi muyeso wa kuchuluka kwa zigawo akhoza allocated kwa mpandawo chizindikiro athandizira osiyanasiyana. Choncho, 8-bit ADC adzalandira August ² = 256 mayunitsi amenewa.

Zowona - ndi okwana kutembenuka chifukwa analandira zopatuka makhalidwe abwino, amene ayenera kukhala pa anapatsidwa athandizira voteji. Ndiko kuti, chizindikiro choyamba amadziwika amaona kuti ali ADC, ndi yachiwiri ikusonyeza zimene tili kuchita. Choncho, tiyenera kupita apo ndi mtundu wosavuta (mwachitsanzo, mwachindunji analogi ndi digito converters), umene akwaniritsa zofunikira chifukwa molondola mkulu.

Kukhala ndi lingaliro la zimene zimafunika kuti ayamba kuwerengera magawo thupi ndi kupanga chilinganizo masamu a mogwirizana. Zofunika ndi zolakwa malo amodzi ndi zazikulu, chifukwa pamene ntchito zosiyanasiyana zigawo zikuluzikulu ndi mfundo za yomanga chipangizo iwo adzakhala ndi amadza osiyana pa ntchito yake. More mudziwe angapezeke mu zolembedwa luso anapereka Mlengi wa chilichonse chipangizo yeniyeni.

Mwachitsanzo

Tiyeni tiyang'ane pa ADC SC9711. Mfundo zikugwira ntchito chipangizo izi ndi zovuta chifukwa cha kukula kwake ndi mphamvu. Ponena za iwowa, tisaiwale kuti alidi osiyanasiyana. Choncho Mwachitsanzo, n'zotheka ntchito pafupipafupi zimasiyanasiyana 10 Hz 10 MHz. M'mawu ena, zimakhala zitsanzo 10 miliyoni pa wachiwiri! Ndipo chipangizo pakokha chinthu cholimba, ndipo ali ndi kumanga yodziyimira payokha dongosolo la. Koma kawirikawiri ntchito mafomu zovuta kumene mukufuna kugwira ntchito ndi chiwerengero chachikulu cha chizindikiro.

Pomaliza

Monga mukuonera, ADCs tinabadwa ndi mfundo zosiyana za ntchito. Zimenezi zimatithandiza kusankha chipangizo umene zosoŵa akuwuka ndi kum'patsa ntchito oyenera pa zinthu zomwe zilipo.