Isignali ye-baseband yedijithali iwuhlelo lwamaza kagesi olumelela ulwazi lwedijithali, olungamelwa amazinga ahlukene noma ama-pulses. Kunezinhlobo eziningi zamasignali e-baseband yedijithali (ngemuva kwalokhu okubizwa ngokuthi amasignali e-baseband). Umfanekiso 6-1 ubonisa amagagasi ambalwa ayisisekelo esignali ye-baseband, futhi sizosebenzisa i-pulse engunxande njengesibonelo.
1. Unipolar waveform
Njengoba kukhonjisiwe kuMfanekiso 6-1(a), lena i-waveform yesignali ye-baseband elula kakhulu. Isebenzisa ileveli ephozithivu neziziro ukuze imele izinombolo kanambambili "1" kanye "no-0," noma isebenzisa ubukhona noma ukungabikho kwama-pulses ukumela u-"1" kanye "no-"0" ngesikhathi sophawu.Izici zalolu hlobo lwamagagasi ukuthi asikho isikhawu phakathi kwama-pulses kagesi, i-polarity iyodwa, futhi yenziwa kalula ngamasekhethi e-TTL kanye ne-CMOS. Ingathunyelwa ngaphakathi kwekhompyutha noma phakathi kwezinto ezisondelene kakhulu, njengebhodi lesifunda eliphrintiwe kanye ne-chassis.
2. I-bipolar waveform
Isebenzisa ama-pulses eleveli ephozithivu nenegethivu ukuze imele amadijithi kanambambili “1″ kanye “no-0,” njengoba kuboniswe kuMfanekiso 6-1(b).Ngenxa yokuthi amaleveli aphozithivu nenegethivu anama-amplitudes alinganayo nokuphambene, ayikho ingxenye ye-DC uma amathuba okuthi “1″ kanye no-“0” avele, avumela ukudluliswa kwesiteshi, futhi izinga lesinqumo lokubuyisela isignali ekupheleni kokwamukela linguziro, Ngakho-ke, alithintwa ukushintsha kwezici zesiteshi, futhi ikhono lokulwa nokugxambukela nalo linamandla. I-interface standard ye-ITU-T's V.24 kanye nezinga lokusebenzisana le-American Electrotechnical Association's (EIA) RS-232C zombili zisebenzisa amagagasi e-bipolar.
3. I-unipolar yokubuyela ku-zero waveform
Ububanzi be-pulse obusebenzayo befomu legagasi lokubuyela-ku-zero (RZ) bungaphansi kobubanzi bophawu T, okusho ukuthi ugesi wesiginali uhlala ubuyela kuqanda ngaphambi kwesikhathi sokunqanyulwa sophawu, njengoba kuboniswe kuMfanekiso 6-1(c). ).bonisa. Ngokuvamile, i-return-to-zero waveform isebenzisa ikhodi ye-half-duty, okungukuthi, umjikelezo womsebenzi (T/TB) ungama-50%, futhi ulwazi lwesikhathi lungakhishwa ngokuqondile ku-unipolar waveform ye-RZ. inguquko waveform.
elihambisana ne-waveform yokubuyela ku-zero. Amagagasi e-unipolar kanye ne-bipolar ngenhla ayingxenye yamagagasi angabuyeli ku-zero (NRZ) anomjikelezo wemfanelo wokuthi.
4.I-bipolar return-to-zero waveform
Kuyindlela yokubuyela ku-zero ye-bipolar waveform, njengoba kuboniswe kuMfanekiso 6-1(d). Ihlanganisa izici ze-bipolar kanye ne-return-to-zero waveforms. Ngenxa yokuthi kunesikhawu esingaba nguziro phakathi kwama-pulses aseduze, umamukeli angakwazi ukubona kalula izikhathi zokuqala nezokugcina zophawu ngalunye, ukuze umthumeli nomamukeli bakwazi ukugcina ukuvumelanisa kancane kancane. Le nzuzo yenza i-bipolar nulling waveforms isebenziseke.
5. Umehluko we-waveform
Lolu hlobo lwe-waveform luveza umlayezo ngokushintsha kanye noshintsho lwezinga lophawu oluseduze, kungakhathaliseki amandla noma ukuhlukahluka kophawu ngokwalo, njengoba kuboniswe kuMfanekiso 6-1(e). Emfanekisweni, "1" imelwe ukweqa izinga, futhi "0" imelwe ileveli engashintshiwe. Yiqiniso, lezi zinhlinzeko ezingenhla nazo zingahlehliswa. Njengoba i-waveform ehlukile imelela umlayezo ngoshintsho oluhlobene lwamazinga e-pulse aseduze, ibizwa nangokuthi i-waveform yekhodi ehlobene futhi ngokuhambisanayo, i-unipolar waveform eyanduleleyo noma i-bipolar waveform ibizwa ngokuthi i-absolute code waveform. Ukusebenzisa amagagasi ahlukene ukudlulisa imilayezo kungaqeda umthelela wesimo sokuqala sedivayisi, ikakhulukazi ezinhlelweni zokuguquguquka kwesigaba. Ingasetshenziselwa ukuxazulula inkinga yokungaqondakali kwesigaba senkampani yenethiwekhi.
6. Multi-level waveform
Kunamazinga amabili kuphela wamagagasi angenhla, okungukuthi, uphawu olulodwa kanambambili luhambisana nokushaya kwenhliziyo okukodwa. Ukuze kuthuthukiswe ukusetshenziswa kwebhendi, i-waveform enamazinga amaningi noma i-waveform enamanani amaningi ingasetshenziswa. Umfanekiso 6-1(f) ubonisa ukuma kwegagasi okunezinga eliphezulu okungu-2B1Q (amabhithi amabili amelwe elinye lamazinga amane), lapho u-11 umele u-+3E, u-10 umele u-+E, u-00 umele -E, futhi u-01 umele -3E.The I-waveform enamazinga amaningi isetshenziswa ezinhlelweni zokudlulisa idatha ezinesivinini esikhulu ezinamabhendi alinganiselwe. Njengoba i-pulse eyodwa ye-waveform enamazinga amaningi ihambisana namakhodi kanambambili amaningi, izinga lebhithi liyakhuphuka ngaphansi kwesimo sezinga elifanayo le-baud (umkhawulokudonsa wokudlulisela ofanayo). Isetshenziswe kabanzi.
Kufanele kuqashelwe ukuthi i-waveform ye-pulse eyodwa emele uphawu lolwazi ayikona ngempela unxande. Ngokwezidingo zangempela nezimo zesiteshi, amanye amafomu afana ne-Gaussian pulse, i-cosine pulse ephakanyisiwe, njll. angasetshenziswa. Kodwa kungakhathaliseki ukuthi yiluphi uhlobo lwe-waveform olusetshenziswayo, isignali ye-baseband yedijithali ingamelwa ngokwezibalo. Uma ama-waveform amelela izimpawu ezifanayo kodwa amanani eleveli ahlukile.
Lesi "Isingeniso Se-Digital Baseband Signal Waveforms" esilethwe kuwe yi-Shenzhen HDV Phoelectron Technology Co., Ltd., ngithemba ukuthi lesi sihloko singakusiza ukukhulisa ulwazi lwakho. Ngaphandle kwalesi sihloko uma ufuna inkampani enhle yabakhiqizi bemishini yokuxhumana ye-fiber ongase uyicabangeleMayelana NATHI.
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