Lub teeb liab kis tau los ntawm cable TV network yog broadband, zaus sib faib spectrum. Cov teeb liab tsis muaj, suav nrog cov zaus thiab cov lej channel hauv Russia tau tswj hwm los ntawm GOST 7845-92 thiab GOST R 52023-2003, tab sis tus neeg teb xov tooj muaj kev ywj pheej xaiv cov ntsiab lus ntawm txhua channel ntawm nws tus kheej txiav txim siab.
Cov ntsiab lus ntawm cov kab lus
- Ntu 2: Cov teeb liab muaj pes tsawg leeg thiab cov duab
- Part 3: Analog Signal Component
- Ntu 4: Cov Khoom Siv Hluav Taws Xob Digital
- Ntu 5: Coaxial faib network
- Ntu 6: RF Signal Amplifiers
- Ntu 7: Optical receivers
- Part 8: Optical backbone network
- Ntu 9: Headend
- Ntu 10: Kev daws teeb meem ntawm CATV network
Cia kuv ceeb toom rau koj tias kuv tsis yog sau phau ntawv, tab sis yog ib qho kev kawm kom nthuav dav kuv lub qab ntug thiab nkag mus rau hauv lub ntiaj teb ntawm cable TV. Yog li ntawd, kuv sim sau cov lus yooj yooj yim, tawm cov ntsiab lus rau cov neeg nyiam thiab tsis nkag mus tob rau hauv cov lus piav qhia ntawm cov thev naus laus zis uas tau piav qhia ntau pua zaus yam tsis muaj kuv.
Peb ntsuas dab tsi?
Peb cov kws tshaj lij feem ntau siv Deviser DS2400T kom tau txais cov ntaub ntawv xov xwm ntawm coaxial cables.
Qhov tseem ceeb, qhov no yog lub xov tooj txais xov tooj cua, tab sis tsis yog cov duab thiab suab, peb pom cov yam ntxwv ntawm qhov ntau thiab zoo ntawm tag nrho cov spectrum thiab tus kheej. Cov duab hauv qab no yog cov screenshots los ntawm cov cuab yeej no.
Qhov Deviser no txawm muaj qhov ua haujlwm tsis txaus ntseeg, tab sis tseem muaj cov khoom siv txias dua: nrog lub vijtsam qhia cov duab hauv TV ncaj qha, tau txais lub teeb liab kho qhov muag thiab, Deviser tsis muaj dab tsi, tau txais DVB-S satellite teeb liab (tab sis qhov ntawd yog ib zaj dab neeg sib txawv kiag li) .
Teeb liab spectrum
Lub spectrum zaub hom tso cai rau koj los ntsuas lub xeev ntawm lub teeb liab "los ntawm qhov muag" sai.
Nyob rau hauv hom no, lub cuab yeej scans raws raws li qhov kev npaj zaus. Rau kev yooj yim, zaus tsis siv nyob rau hauv peb lub network tau raug tshem tawm ntawm tag nrho cov spectrum, yog li cov duab tshwm sim yog lub palisade ntawm cov channel.
Cov channels digital tau qhia hauv xiav, cov channel analogue yog daj. Ib feem ntsuab ntawm cov analog channel yog nws lub suab.
Qhov sib txawv ntawm cov theem ntawm cov channel sib txawv tau pom meej meej: tus neeg tsis sib xws nyob ntawm qhov chaw ntawm cov transponders ntawm lub taub hau, thiab qhov sib txawv ntawm qhov siab thiab qis zaus muaj qee lub ntsiab lus, uas kuv yuav tham hauv qab no.
Nyob rau hauv hom no, muaj zog sib txawv ntawm cov qauv yuav pom meej meej, thiab yog tias muaj teeb meem loj hauv lub network, qhov no yuav pom tam sim ntawd. Piv txwv li, nyob rau hauv cov duab saum toj no koj tuaj yeem pom qhov hla ntawm ob lub xov tooj digital hauv cheeb tsam siab: lawv tsuas yog tam sim no nyob rau hauv daim ntawv luv luv, NW nyuam qhuav mus txog qib 10 dBΒ΅V (qib siv ntawm 80 dBΒ΅V yog qhia ntawm sab saum toj - qhov no yog lub sab sauv txwv ntawm daim duab), uas yog tiag tiag suab nrov uas lub cable tau txais ntawm nws tus kheej raws li ib tug kav hlau txais xov los yog pab los ntawm cov khoom siv. Ob txoj kev no yog cov kev sim thiab raug kaw thaum lub sijhawm sau ntawv.
Kev faib tawm tsis sib xws ntawm digital thiab analog channel tuaj yeem ua rau tsis meej pem. Qhov no, ntawm chav kawm, tsis yog thiab tshwm sim vim kev hloov pauv ntawm lub network: cov channel ntxiv tau yooj yim ntxiv rau cov phiaj xwm zaus hauv qhov dawb ntawm spectrum. Thaum tsim ib lub tswv yim zaus los ntawm kos, nws yuav raug muab tso rau tag nrho cov analog ntawm qhov qis kawg ntawm cov spectrum. Tsis tas li ntawd, cov khoom siv hauv chaw nres tsheb tsim los tsim cov teeb liab rau cov tebchaws nyob sab Europe muaj kev txwv rau kev siv ntau zaus rau kev tshaj tawm cov teeb liab digital thiab, txawm hais tias tsis muaj kev txwv zoo li no hauv peb lub tebchaws, kev siv cov cuab yeej zoo li no yuav tsum tso cov channel digital hauv spectrum. , tawm tsam logic.
Waveform
Raws li paub los ntawm lub hauv paus physics, qhov siab dua qhov zaus ntawm nthwv dej, qhov muaj zog nws qhov attenuation thaum nws propagates. Thaum xa cov teeb liab broadband xws li muaj nyob rau hauv CATV network, qhov attenuation nyob rau hauv lub network faib yuav ncav cuag kaum tawm decibels ib sab caj npab, thiab nyob rau hauv qis ib feem ntawm lub spectrum nws yuav yog ob peb zaug tsawg dua. Yog li ntawd, tau xa cov teeb liab tsis tu ncua mus rau lub riser los ntawm hauv qab daus, nyob rau hauv pem teb 25 peb yuav pom ib yam dab tsi zoo li hauv qab no:
Cov theem ntawm cov frequencies sab sauv yog pom tau tias qis dua qhov qis dua. Hauv qhov xwm txheej tiag tiag, TV, tsis nkag siab nws, yuav xav txog cov channel tsis muaj suab nrov thiab lim lawv tawm. Thiab yog hais tias ib tug amplifier yog ntsia nyob rau hauv lub tsev, ces thaum koj sim configure nws rau high-zoo txais tos ntawm cov channel los ntawm lub sab sauv ntawm qhov ntau, over-amplification yuav tshwm sim nyob rau hauv qis qis. Cov qauv qhia qhov sib txawv ntawm tsis pub ntau tshaj 15 dBΒ΅V rau tag nrho cov ntau yam.
Txhawm rau zam qhov no, thaum teeb tsa cov khoom siv nquag, qib siab dua yog pib teeb tsa hauv cheeb tsam siab. Qhov no yog hu ua "ncaj qaij", lossis tsuas yog "tilt". Thiab qhov uas tau pom hauv daim duab yog "rov qab qaij", thiab cov duab zoo li no twb muaj xwm txheej. Los yog, ntawm qhov tsawg kawg nkaus, qhov qhia tau tias muaj teeb meem nrog lub cable mus rau qhov ntsuas ntsuas.
Qhov xwm txheej tsis sib xws kuj tshwm sim, thaum cov zaus tsawg zaus tsis tuaj, thiab cov sab saud tsis tshua nkag mus rau saum lub suab nrov:
Qhov no kuj qhia peb txog kev puas tsuaj rau lub cable, uas yog nws lub hauv paus tseem ceeb: qhov siab dua qhov zaus, ze rau ntawm ntug ntawm lub waveguide nws propagates (cov nyhuv ntawm daim tawv nqaij nyob rau hauv ib coaxial cable). Yog li ntawd, peb pom tsuas yog cov channel uas tau muab faib ua ntau zaus, tab sis, raws li txoj cai, TV yuav tsis tuaj yeem tau txais lawv nyob rau theem no.
Tau qhov twg los: www.hab.com