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Coaxial cable tsis tuaj yeem tsis quav ntsej

2021-03-05

Coaxial cabletuaj yeemyuav tsis quav ntsej

 

Txog kev sim tooj liab tooj liab, peb tau tham txog ntau yam sib npaug ntawm cov sib txig sib xyaw tooj liab tooj liab cabling ntsig txog cov ntsiab lus, xws li Pawg 6 (CAT 6), Pawg 6 (CAT 6A) thiab qeb 8 (CAT 8). Txawm hais tias hom cabling no tau dav siv los txhawb Ethernet kis ntawm lub suab, cov ntaub ntawv, thiab video, nws tsis txhais tau tias nws tsuas yog hom tooj liab cabling uas koj yuav pom.

Coaxial cable ("coax" in English) has long been used to transmit data and video signals. It is one of the first media to support 10BASE2 and 10BASE5 Ethernet, which tuaj yeem achieve 10 Mb up to 185 meters or 500 meters, respectively. /s transfer. The term "coaxial" means that the central conductor of the cable and its shield have the same axis or center point. Some coaxial cables may have multiple shielding layers, such as a four-shielded coaxial cable. The cable contains two layers of shielding, and each layer of shielding is composed of aluminum foil wrapped with wire mesh. The shielding characteristics of coaxial cable make it have strong anti-electromagnetic interference ability and tuaj yeem transmit high-frequency signals over long distances.

Although we usually think that coaxial cable is only used in broadband video and cable television (CATV) home applications, but in the commercial enterprise environment, from closed circuit television (CCTV), audio and video to radio frequency antennas, and even some network connections, you tuaj yeem find Its figure. Therefore, it is very necessary to understand this cable medium and how to test it.

Lub ntsiab

Muaj ntau yam sib txawv ntawm cov coaxial cables uas pab txhawb nqa ntau hom kev tshaj lij, xws li kev sib txuas lus satellite, kev lag luam, kev siv tub rog, thiab cov ntawv thov marine. Peb hom kev siv hluav taws xob tsis zoo tshaj plaws yog cov RG6, RG11, thiab RG59, uas RG6 feem ntau siv hauv cov ntawv thov xws li CCTV thiab CATV hauv cov chaw ib puag ncig. Qhov nruab nrab ntawm tus neeg xyuas pib ntawm RG11 yog tuab dua RG6, uas txhais tau hais tias nws cov nkag ntxig qis dua thiab qhov teeb liab sib kis tau ntev dua. Txawm li cas los xij, cov xov tooj tuab dua RG11 raug nqi ntau dua thiab nyuaj heev rau khoov, uas ua rau lawv tsis tsim nyog rau kev xa tawm hauv cov ntawv thov sab hauv tsev, tab sis zoo dua rau kev sib txuas sab nraud ntev lossis kev sib txuas ncaj qha sab nraub qaum. RG59 yog yoog raws li RG6, tab sis nws qhov kev poob ntau dua. Nws tsis tshua muaj siv nyob rau hauv lwm daim ntawv thov tshwj tsis yog cov bandwidth tsawg, tsawg zaus siv yees duab video (cov koob yees duab tom qab saib hauv lub tsheb) nrog cov kev ncua luv thiab qhov chaw siv tau tsawg.

 

Coaxial xaim hluav taws xobkuj tseem muaj ntau qhov sib txawv-feem ntau 50, 75, thiab 93ΩCov. 50.Ω coaxial cables muaj lub zog loj tswj kev ua haujlwm thiab feem ntau yog siv hauv xov tooj cua tshaj tawm xov tooj cua xws li cov khoom siv xov tooj cua nyiam, suab nkauj hauv xov tooj cua (CB) thiab walkie-talkies. 75Ω cables tuaj yeem maintain signal strength well and are mainly used to connect various types of receiving equipment, such as cable television (CATV) receivers, high-definition televisions and digital video recorders. 93 Ω coaxial cable tau siv rau hauv IBM mainframe tes hauj lwm hauv xyoo 1970 thiab thaum 1980s, nrog rau cov ntawv thov tsawg heev thiab kim heev. Txawm hais tias tus 75Ω coaxial cable impedance feem ntau ntsib nyob rau hauv feem ntau cov ntawv thov niaj hnub no, nws yuav tsum raug sau tseg tias txhua qhov sib xyaw hauv cov coaxial cable system yuav tsum muaj tib qho kev cuam tshuam kom tsis txhob teeb liab ploj thiab cov teeb liab ploj ntawm qhov txuas. Sab hauv reflections uas txo cov video zoo.

Cov teeb liab digital 3 (DS3) teeb liab siv hauv hauv chaw ua haujlwm hauv nruab nrab (tseem hu ua T3 kab) kev pabcuam kev xa xov kuj tseem siv cov xov tooj coaxial, suav nrog 75Ω 735 type and 734 type. The 735 type cable has a coverage distance of up to 69 meters, while the 734 type cable has a coverage distance of up to 137 meters. RG6 cable tuaj yeem also be used to transmit DS3 signals, but the coverage distance is shorter.

Rau txhua qhov coaxial cable, kev ua tiav zoo yog nyob ntawm kev siv cov khoom sib txuam zoo thiab cov txheej txheem kho kom raug, tshwj xeeb tshaj yog kev teeb tsa cov khoom sib txuas. Qhov tsis txaus ntseeg cuam tshuam los ntawm tag nrho qhov ntev ntawm qhov txuas txuas thiab yog qhov tseem ceeb tshaj plaws los xyuas kom meej tias cov coaxial cable txhawb nqa cov ntawv thov.