50 Ohm VS. 75 Ohm, Twg yog Qhov Zoo Tshaj Plaws Cable?
Muaj ntau hom tooj liab raws li muaj nyob rau hauv cov tes hauj lwm sib txuas lus, tab sis cov fiber ntau tau dominated. Twinax cable, twisted cable, thiab coaxial cable yog peb feem ntau siv tooj liab cables hauv peb lub neej txhua hnub, thiab peb paub twinax cable, xws li 10G DAC los yog 40G DAC, thiab twisted kab cable, xws li cat5e los yog cat6, txij thaum peb tau qhia lawv ntau zaus ua ntej hauv kuv cov blogs dhau los. Li cas coaxial cable? Coaxial cable raws li qhia hauv qab no yog hom kab hlau txuas uas siv raws li cov kab sib txuas rau cov xov tooj cua ntau zaus. Lub sij hawm "coaxial" los ntawm tus neeg xyuas hluav taws xob sab hauv thiab sab nraud sib koom ib qhov geometric axis. Tam sim no, tsis yog tag nrho cov coaxial cable yog tsim vaj huam sib luag thiab yog qhov chaw uas lub coaxial cable impedance los ua si. Feem ntau, muaj ob hom kab xev fais fab: ib qho yog impedance ntawm 75 Ohm, feem ntau siv cov kev siv video, thiab lwm tus yog nrog impedance ntawm 50 Ohm, feem ntau yog siv cov ntaub ntawv thiab kev sib txuas lus wireless. Qhov twg yog qhov zoo tshaj plaws? Nyeem cov ntawv nram qab no, thiab koj yuav tau txais txoj kev teb.
Ib qho Ohm yog ib qho ua haujlwm ntawm qhov tsis sib haum-uas yog qhov tsis haum rau cov hluav taws xob ntawm lub voj voog. Nyob rau hauv daim ntawv sau npe siv yooj yim tshaj plaws, uas peb tabtom hais txog DC los yog kev siv hluav taws xob tam sim no, xws li ntawm 12-volt roj teeb lub tsheb, peb yog ntsuas qhov ua haujlwm nyob hauv Ohms. Txawm li cas los xij, qhov thib ob peb sim thiab xa AC los yog hloov tam sim no los ntawm Circuit Court, peb tsis muaj kev ntsuas kom ua haujlwm, peb tab tom ntsuas impedance. Feem ntau, lub Ohm, qhov zoo dua qhov ua tau zoo. Li ntawd, 50 Ohm cable tau muab cov txiaj ntsig zoo dua li 75 Ohm ib qho.
Tus qauv ntawm 50 Ohm impedance rov qab mus tsim coaxial cables rau Kilowatt xov tooj cua transmitter hauv lub xyoo 1930. Ua tau, raws li cov kev sim ua los ntawm cov kws paub hauj lwm ua pov thawj tias qhov kev qis qis qis tau tiav los ntawm 77 Ohm, thaum lub zog zoo tshaj plaws muaj tshwm sim ntawm 30 Ohm. Tab sis muaj ob peb dielectric khoom haum rau siv nyob rau hauv ib coaxial cable los txhawb 30 Ohm impedance. Yog li, qhov kev xaiv ntawm 50 Ohm yog ib qho kev sib txuas ntawm kev tuav tswj lub peev xwm thiab ib qho poob ib chav tsev ntev, rau cua dielectric.
Nrog 50 Ohm coaxial cable yog qhov zoo tshaj plaws txoj kev daws teeb meem, suab txhua daim ntawv thov uas xav tau kev siv zog ua tau zoo, zoo li 100 watts los yog ntau dua, yuav siv 50 Ohm coaxial cable. Thawj kev siv ntawm 50 Ohm coaxial cable yog kis tau ntawm ib lub teeb liab cov ntaub ntawv hauv ob txoj kev sib txuas lus. Ib txhia daim ntawv thov rau 50 Ohm coaxial cable yog computer Ethernet backbones, wireless antenna feed cables, GPS (ntiaj teb no positioning satellite) antenna pub cables thiab xov tooj ntawm tes.
Txawm hais tias 50 Ohm nyiam tshaj hauv cov ntawv sau ntau, nws tsis haum rau txhua daim ntawv thov, vim tsis yog txhua txhua rooj plaub ua kom muaj hwj chim ntau. Piv txwv, thaum lub hom phiaj los xyuas kom meej tias qhov teeb liab tau txais los ntawm kev siv kab hauv txoj kev ua tau zoo tshaj plaws, poob me ntsis teeb liab lub zog, peb xav tau 75 Ohm coaxial cable es tsis txhob 50 Ohm.
Technically, 93 Ohm coaxial cable muaj lub peev xwm qis tshaj plaws ntawm txhua yam, tiam sis 93 Ohm coax yog tsawg thiab kim. Yog li, 75 Ohm coaxial cable yog qhov ze tshaj plaws, muab tsis tsuas hnov lub teeb meem tsis hnov lus, tab sis kuj kuj tsis tshua muaj peev xwm. Thawj daim ntawv thov ntawm 75 Ohm cable yog xa ib qhov video teeb liab. Ib qho ntawm cov kev siv raug yog cov ntawv xov xwm hauv TV tshaj cable, qee zaus hu ua teeb meem pub cables. Lwm daim ntawv thov ntawm 75 Ohm coaxial cable yog video teeb tsa ntawm cov cheebtsam, xws li DVD players, VCRs lossis Receivers feem ntau hu ua suab / yees duab (A / V) cables.
50 Ohm thiab 75 Ohm qhov ntsuas tau hais txog qhov impedance ntawm coaxial cable. Qhov sib txawv ntawm qhov ob hom coaxial cable yog lawv daim ntawv sau npe. Thawj daim ntawv thov yog kev sib kis ntawm lub teeb liab video, thiab nyob rau hauv cov ntaub ntawv ntawm 50 Ohm cable, nws yog ib lub teeb liab cov ntaub ntawv uas yog rau feem ntau yog xa mus. Tsuas yog siv, 75 Ohm cable yog rau duab, thaum 50 Ohm cable rau kev qhia. Kev xaiv txoj cai coaxial, koj yuav tsum paub seb koj daim ntawv thov hom twg. Peb tuaj yeem yooj yim qhia qhov sib txawv ntawm qhov ob coaxial cable hom ntawm cov duab nram qab no.
Dhau li ntawd, thaum siv coaxial cable, koj yuav tsum nco ntsoov tias lub impedance ntawm ntau yam khoom txuas nrog raws li tus coaxial cable nws tus kheej yuav tsum match. Piv txwv li, txuas tus 75 Ohm video yees txuas mus rau ib lub chaw soj ntsuam saib, tus kab xev kaw lus yuav tsum yog 75 Ohm thiab tus connectors nyob rau hauv lub coaxial cable yuav tsum yog 75 Ohm nyob rau hauv impedance, lwm yam, ib lub hla sawv yuav loj hlob (kev sau ntawv: yog lub teeb liab uas xav tias yog qhov tseem ceeb nkim). FOCC muab ntau hom tooj liab, nrog rau, khij kab twv, twinax cable, thiab coaxial cable, thiab peb kuj muaj ntau cov khoom siv fiber ntau hauv Tshuag. Yog tias koj muaj tej yam xav tau, thov mus saib FOCC.