Chizindikiro cha baseband cha digito ndi mawonekedwe amagetsi omwe amayimira chidziwitso cha digito, chomwe chitha kuyimiridwa ndi magawo osiyanasiyana kapena ma pulses. Pali mitundu yambiri yamasigino amtundu wa digito (omwe amatchedwanso ma sign a baseband). Chithunzi 6-1 chikuwonetsa ma waveform ochepa oyambira, ndipo tigwiritsa ntchito kugunda kwamakona monga chitsanzo.
1. Unipolar waveform
Monga tawonetsera pa Chithunzi 6-1 (a), iyi ndiye mawonekedwe osavuta a baseband. Imagwiritsa ntchito mulingo wabwino ndi zero kuyimira manambala a binary "1" ndi "0," kapena imagwiritsa ntchito kukhalapo kapena kusapezeka kwa ma pulse kuyimira "1" ndi "0" mu nthawi yophiphiritsa.Makhalidwe a mawonekedwe awa ndikuti palibe nthawi pakati pa mphamvu zamagetsi, polarity ndi imodzi, ndipo imapangidwa mosavuta ndi mabwalo a TTL ndi CMOS. Itha kutumizidwa mkati mwa kompyuta kapena pakati pa zinthu zapafupi kwambiri, monga bolodi losindikizidwa ndi chassis.
2. Bipolar waveform
Imagwiritsa ntchito ma pulse abwino ndi olakwika kuyimira manambala a binary "1" ndi "0," monga momwe zasonyezedwera pa Chithunzi 6-1 (b). Chifukwa chakuti milingo yabwino ndi yolakwika ili ndi matalikidwe ofanana ndi ma polarities osiyana, palibe gawo la DC pamene Kuthekera kwa "1" ndi "0" kumawoneka, komwe kumathandizira kufalikira mu tchanelo, ndipo mulingo wamalingaliro obwezeretsanso chizindikiro pamapeto olandila ndi ziro, Chifukwa chake, sichikhudzidwa ndi kusintha kwa mayendedwe, ndipo mphamvu yotsutsa kusokoneza imakhalanso yamphamvu. ITU-T's V.24 interface standard ndi American Electrotechnical Association's (EIA) RS-232C mawonekedwe onse amagwiritsa ntchito mafunde a bipolar.
3. Unipolar kubwerera kwa zero mawonekedwe
Kuthamanga kwamphamvu kwa mawonekedwe obwerera ku zero (RZ) ndikocheperako kuposa chizindikiro m'lifupi T, zomwe zikutanthauza kuti mphamvu yamagetsi nthawi zonse imabwerera ku zero nthawi yomaliza ya chizindikiro isanathe, monga momwe tawonetsera pa Chithunzi 6-1(c). ).kuwonetsa. Kawirikawiri, mawonekedwe obwerera ku zero amagwiritsa ntchito code ya theka la ntchito, ndiko kuti, ntchito yozungulira (T / TB) ndi 50%, ndipo chidziwitso cha nthawi chikhoza kuchotsedwa mwachindunji ku unipolar RZ waveform. kusintha waveform.
zofananira ndi mawonekedwe obwerera ku ziro. Mafunde a unipolar ndi bipolar pamwambawa ndi a non-return-to-zero (NRZ) ma waveform omwe ali ndi ntchito yozungulira.
4.Bipolar kubwerera-to-zero waveform
Ndilo mawonekedwe obwerera ku zero a bipolar waveform, monga momwe tawonetsera pa Chithunzi 6-1 (d). Zimaphatikiza mawonekedwe a bipolar ndi ma waveform obwerera ku zero. Chifukwa pali ziro zomwe zingatheke pakati pa ma pulse oyandikana nawo, wolandirayo amatha kuzindikira mosavuta nthawi yoyambira ndi yomaliza ya chizindikiro chilichonse, kuti wotumiza ndi wolandila athe kusunga kulumikizana koyenera. Ubwinowu umapangitsa ma bipolar nulling waveform kukhala othandiza.
5. Kusiyana kwa mawonekedwe
Mtundu woterewu umasonyeza uthengawo ndi kusintha ndi kusintha kwa mlingo wa chizindikiro choyandikana, mosasamala kanthu za kuthekera kapena polarity ya chizindikirocho, monga momwe tawonetsera pa Chithunzi 6-1 (e). Pachithunzichi, "1" imayimiridwa ndi kudumpha, ndipo "0" imayimiridwa ndi mlingo wosasinthika. Inde, zomwe tafotokozazi zingathenso kusinthidwa. Popeza mawonekedwe osiyana siyana amayimira uthenga ndi kusintha kwapang'onopang'ono kwa ma pulse oyandikana nawo, amatchedwanso wachibale wa waveform ndipo mofananamo, mawonekedwe a unipolar kapena bipolar waveform amatchedwa absolute code waveform. Kugwiritsa ntchito ma waveform osiyanitsa kufalitsa mauthenga kumatha kuthetsa momwe chipangizocho chimayambira, makamaka pamakina osinthira magawo. Ikhoza kugwiritsidwa ntchito kuthetsa vuto la kusamvetsetsana kwa gawo lonyamulira.
6. Multi-level waveform
Pali magawo awiri okha a mawonekedwe apamwambawa, ndiye kuti, chizindikiro chimodzi cha binary chimafanana ndi kugunda kumodzi. Kuti muwongolere ma frequency band magwiritsidwe, mawonekedwe amitundu yambiri kapena mawonekedwe amitundu yambiri angagwiritsidwe ntchito. Chithunzi 6-1 (f) chikuwonetsa mawonekedwe a magawo anayi a 2B1Q (magawo awiri amaimiridwa ndi imodzi mwa magawo anayi), pomwe 11 imayimira + 3E, 10 imayimira + E, 00 imayimira -E, ndipo 01 imayimira -3E. ma waveform amitundu yambiri amagwiritsidwa ntchito mumayendedwe othamanga kwambiri otumizira ma data okhala ndi magulu ocheperako pafupipafupi. Popeza kugunda kumodzi kwa mawonekedwe amitundu yambiri kumafanana ndi ma code angapo a binary, kutsika pang'ono kumachulukitsidwa pansi pamlingo womwewo wa baud (kutumiza komweko). Lakhala likugwiritsidwa ntchito kwambiri.
Zindikirani kuti mawonekedwe a mafunde amtundu umodzi woyimira chizindikiro cha chidziwitso sikuti amakhala amakona anayi. Malingana ndi zosowa zenizeni ndi zochitika zamakina, mitundu ina monga Gaussian pulse, kukweza kwa cosine pulse, etc. ingagwiritsidwenso ntchito. Koma ziribe kanthu kuti mawonekedwe a waveform amagwiritsidwa ntchito bwanji, chizindikiro cha digito cha baseband chikhoza kuimiridwa ndi masamu. Ngati ma waveform omwe akuyimira zizindikilo ali ofanana koma milingo ndi yosiyana.
Ichi ndi "Mawu Oyamba a Digital Baseband Signal Waveforms" omwe abweretsedwa kwa inu ndi Shenzhen HDV Phoelectron Technology Co., Ltd., ndikuyembekeza kuti nkhaniyi ingakuthandizeni kuonjezera chidziwitso chanu. Kupatula nkhaniyi ngati mukuyang'ana kampani yabwino yopanga zida zoyankhulirana zama fiber zomwe mungaganizirezambiri zaife.
Shenzhen HDV photoelectric Technology Co., Ltd. ndiyomwe imapanga zinthu zolumikizirana. Pakadali pano, zida zomwe zimapangidwa zimakwiriraZithunzi za ONU, Optical module mndandanda, Zithunzi za OLT,nditransceiver mndandanda. Titha kupereka ntchito makonda pazochitika zosiyanasiyana. Mwalandiridwafunsani.
