Chizindikiro chomwe chimaperekedwa pa netiweki ya kanema wawayilesi ndi burodibandi, wogawanika pafupipafupi. Zigawo za siginecha, kuphatikiza ma frequency ndi manambala amakanema ku Russia zimayendetsedwa ndi GOST 7845-92 ndi GOST R 52023-2003, koma woyendetsa ali ndi ufulu wosankha zomwe zili panjira iliyonse mwakufuna kwake.

Zamkatimu zankhani

• Gawo 1: Zomangamanga zonse za netiweki ya CATV
• Gawo 2: Mapangidwe ndi mawonekedwe a wave
• Gawo 3: Chigawo cha analogi cha chizindikiro
• Gawo 4: Digital gawo la chizindikiro
• Gawo 5: Coaxial Distribution Network
• Gawo 6: RF Amplifiers
• Gawo 7: Optical Receivers
• Gawo 8: Optical backbone network
• Gawo 9: Mutu
• Gawo 10: Troubleshooting pa chingwe TV maukonde

Ndiroleni ndikukumbutseni kuti sindikulemba buku, koma pulogalamu yophunzitsira yokulitsa malingaliro anga ndikulowa dziko la TV TV. Chifukwa chake, ndimayesetsa kulemba chilankhulo chosavuta, ndikusiya mawu osakira kwa iwo omwe ali ndi chidwi komanso osapita mozama pakufotokozera zaukadaulo zomwe zafotokozedwa bwino mazana ambiri popanda ine.

Kodi timayezera chiyani?

Akatswiri athu makamaka amagwiritsa ntchito Deviser DS2400T kuti apeze zidziwitso zamazingwe a coaxial.


Kwenikweni ichi ndi cholandirira pawailesi yakanema, koma m'malo mwa chithunzi ndi mawu, timawona kuchuluka kwake komanso mawonekedwe amitundu yonse komanso njira iliyonse. Zithunzi zotsatirazi ndizithunzi zochokera ku chipangizochi.

Deviser iyi imakhala ndi magwiridwe antchito pang'ono, koma pali zida zoziziritsa kukhosi: zokhala ndi chinsalu chowonetsa chithunzi cha TV mwachindunji, kulandira chizindikiro chowonekera komanso, zomwe Deviser amasowa, kulandira chizindikiro cha satellite ya DVB-S (koma ndi nkhani yosiyana kwambiri) .

Sipekitiramu yamagetsi

Mawonekedwe a sipekitiramu amakulolani kuti muwone mwachangu momwe chizindikirocho chilili "ndi diso"

Munjira iyi, chipangizochi chimayang'ana machanelo molingana ndi dongosolo lomwe latchulidwa pafupipafupi. Kuti zitheke, ma frequency osagwiritsidwa ntchito pamanetiweki athu achotsedwa pachiwonetsero chonse, kotero chithunzi chomwe chimabwera ndi ma tchanelo.

Makanema a digito amawonetsedwa mumtundu wa buluu, ma analogi ali achikasu. Gawo lobiriwira la njira ya analogi ndi gawo lake lomvera.

Kusiyana kwa milingo yamayendedwe osiyanasiyana kumawonekera momveka bwino: kusagwirizana kwapayekha kumadalira makonda a transponders pamutu, ndipo kusiyana kwakukulu pakati pa ma frequency apamwamba ndi apansi kumakhala ndi tanthauzo lina, lomwe ndikambirana pansipa.

Munjira iyi, zopotoka zamphamvu kuchokera pachizoloŵezi zidzawonekera bwino, ndipo ngati pali mavuto aakulu pa intaneti, izi zidzawonekera nthawi yomweyo. Mwachitsanzo, pachithunzi pamwambapa mutha kuwona kudumpha kwa ma tchanelo awiri a digito pagawo lothamanga kwambiri: amapezeka ngati mikwingwirima yaifupi, osafika pamlingo wa 10 dBµV (chiwonetsero cha 80 dBµV chikuwonetsedwa. pamwamba - ichi ndi malire apamwamba a graph), yomwe kwenikweni ndi phokoso limene chingwe chimadzilandira chokha ngati mlongoti kapena chothandizidwa ndi zipangizo zogwira ntchito. Njira ziwirizi ndi njira zoyesera ndipo zidazimitsidwa panthawi yolemba.

Kugawidwa kosagwirizana kwa njira za digito ndi analogi kungayambitse chisokonezo. Izi, ndithudi, sizolondola ndipo zinachitika chifukwa cha kusinthika kwa maukonde: njira zowonjezera zinangowonjezeredwa ku ndondomeko yafupipafupi mu gawo laulere la sipekitiramu. Popanga dongosolo lafupipafupi kuyambira pachiyambi, zingakhale zolondola kuyika analogi yonse kumapeto kwa sipekitiramu. Kuphatikiza apo, zida zamasiteshoni zomwe zidapangidwa kuti zipangitse chizindikiro kumayiko aku Europe zili ndi zoletsa kugwiritsa ntchito ma frequency akuwulutsa chizindikiro cha digito ndipo, ngakhale kulibe zoletsa zotere m'dziko lathu, kugwiritsa ntchito zida zotere ndikofunikira kuyika njira zama digito pamawonekedwe. , mosiyana ndi kulingalira.

Waveform

Monga momwe zimadziwikira kuchokera ku physics yoyambira, kuchulukira kwa mafunde kumachulukirachulukira, kutsika kwake kumakulirakulira pamene ikufalikira. Potumiza chizindikiro cha burodibandi chotere monga chomwe chikupezeka mu netiweki ya CATV, kuchepa kwa maukonde ogawa kumatha kufika makumi a decibel pa mkono, ndipo m'munsi mwa sipekitiramu kudzakhala kuchepera kangapo. Chifukwa chake, potumiza chizindikiro chokhazikika kwa chokwera kuchokera pansi, pansanja ya 25 tiwona zinthu monga izi:

Mulingo wa ma frequency apamwamba ndi otsika kwambiri kuposa otsika. M’zochitika zenizeni, TV, mosaimvetsetsa, ingalingalire matchanelo opanda mphamvu chabe ndi kuwasefa. Ndipo ngati amplifier waikidwa m'nyumba, ndiye kuti mukamayesa kukonza kuti mulandire njira zapamwamba kuchokera kumtunda wamtundu, kumtunda kudzachitika kumunsi. Miyezo imasonyeza kusiyana kwa kusapitirira 15 dBµV pamtundu wonsewo.

Kuti mupewe izi, pokonzekera zida zogwira ntchito, mlingo wapamwamba umayikidwa poyamba pazigawo zapamwamba kwambiri. Izi zimatchedwa "kupendekera molunjika", kapena kungoti "kupendekera". Ndipo zomwe zikuwonetsedwa pachithunzichi ndi "kupendekera kumbuyo", ndipo chithunzi choterocho chachitika kale mwangozi. Kapena, osachepera, chisonyezero chakuti pali vuto ndi chingwe kumalo oyezera.

Zosiyanazi zimachitikanso, pamene ma frequency otsika sakhala, ndipo apamwamba samalowa pamwamba pa phokoso:

Izi zimatiuzanso za kuwonongeka kwa chingwe, chomwe ndi pachimake chake chapakati: kumtunda kwafupipafupi, kufupi ndi m'mphepete mwa waveguide yomwe imafalikira (khungu mu chingwe coaxial). Chifukwa chake, tikuwona njira zokhazo zomwe zimagawidwa pama frequency apamwamba, koma, monga lamulo, ma TV sangathenso kuwalandira pamlingo uwu.

Source: www.habr.com