電子信息工程外文翻譯--綜合布線的未來(lái)（適用于畢業(yè)論文外文翻譯+中英文對(duì)照）-預(yù)覽頁(yè)
【正文】 uced and the bandwidth will increase. Wireless networking can serve admirably in numerous applications. Coaxial Coaxial cable has been the medium of choice for wideband applications ranging from highfidelity audio to television to baseband and broadband munications. Coaxial cable was the primary media for 10Base5 and 10Base2 Ethernet. The advent of higherbandwidth UTP cable and connector technology replaced coaxial cable in mercial networks and has relegated its primary use to legacy networks and cable television. Cost considerations Numbers being what they are, one cannot just look at the cost of materials when making a purchasing decision. The applications to be run and the anticipated requirements must be factored into any decision. For instance, Category 5 cable is characterized at frequencies to 100 MHz, while Category 6 is characterized at 21/2 times bandwidth. Trying to double the bit rate of a signal using the same bandwidth will considerably increase electronics costs, as it will take moresophisticated equipment to decipher the transmitted signal. Unless there is a need to reduce electromagnetic interference (EMI), most users cannot justify the up to 300% price premium of STP over UTP. The use of fiber, at 4 to 41/2 times the cost of UTP, may be justified on several levels: EMI cancellation, increased bandwidth, and longer distances. Shielded twistedpair and screened twistedpair media will also continue to find their use in highEMI environments for a long time to e. Their cost premium and increased installation costs are a disadvantage, but they offer solid performance at frequencies higher than those that UTP can acmodate. Wireless technology will undoubtedly advance and continue to support greater bandwidth requirements. It will probably see an even greater share of the market, especially in residential environments. Users should be interested in the informationtransfer system as a tool to provide productivity for their enterprise, rather than support one technology versus another technology. And, even though in terms of application protocol Gigabit Ethernet will be with us for awhile, and Category 5E and Category 6 will support it just fine, we do know that in the next 5 to 10 years, 10Gigabit Ethernet will require a totally opticalfiber infrastructure. Debate continues on employing the new multimode fiber versus single mode fiber, short wavelength (SX) versus long wavelength (LX) transmission, and using WDM for new fiber installations. The development of a 1,300nm VCSEL will enhance single mode fiber39。電話公司只負(fù)責(zé)電話的安裝和維修服務(wù)。多媒體擴(kuò)展連接接口缺乏標(biāo)準(zhǔn)傳輸規(guī)范，廠商介紹的各種布線方案給使用者造成了許多混亂。這些標(biāo)準(zhǔn)有助于發(fā)展高速傳輸系統(tǒng)。1991年雙絞線的最高帶寬是16MHz，現(xiàn)在面臨的是帶寬超過(guò)250MHz及以上的要求。語(yǔ)音信息可以從中央辦公室傳遞到智能外設(shè)，但并不需要增加帶寬。如果未來(lái)是可以預(yù)測(cè)的，我們將看到信息的傳遞速度每十年至少提高一個(gè)數(shù)量級(jí)。要達(dá)到如此高的速度應(yīng)選擇哪種傳輸介質(zhì)呢？是雙絞線，電纜，屏蔽雙絞線，光纖還是無(wú)線技術(shù)？系統(tǒng)性能和經(jīng)濟(jì)性是挑選布線系統(tǒng)的兩項(xiàng)重要依據(jù)。非屏蔽雙絞線目前，非屏蔽雙絞線的傳輸速度已達(dá)到250MHz。人們普遍認(rèn)為，非屏蔽雙絞線的傳輸速率還尚未達(dá)到極限。屏蔽雙絞線屏蔽雙絞線的特點(diǎn)是其頻率目前在300MHz。毫無(wú)疑問(wèn)，屏蔽雙絞線還尚未達(dá)到傳輸極限。光纖波分復(fù)用光纖波分復(fù)用是一種新興的技術(shù)。在不久的將來(lái)，可達(dá)到128通道。塑料光纖縱觀歷史，塑料光纖已被應(yīng)用到低速，短距離的傳輸系統(tǒng)當(dāng)中。如果要讓一個(gè)標(biāo)準(zhǔn)化組織認(rèn)可塑料光纖，它應(yīng)該具有比玻璃光纖成本低且更加穩(wěn)定的性能。無(wú)線技術(shù)很多人指出，在綜合布線系統(tǒng)中無(wú)線技術(shù)將會(huì)逐步取代傳統(tǒng)的線纜。但是無(wú)線網(wǎng)絡(luò)所有的魔法都有缺點(diǎn)。在一個(gè)開(kāi)放的辦公方案中，傳播的無(wú)線電波可能受限的距離為200英尺到500英尺。例如，5類(lèi)電纜的特點(diǎn)是在頻率為100MHz，而6類(lèi)的特點(diǎn)是21/2倍帶寬。在很長(zhǎng)的一段時(shí)間內(nèi)屏蔽雙絞線將在高電磁干擾的環(huán)境中繼續(xù)使用。用戶應(yīng)該有興趣將信息傳輸系統(tǒng)作為一種提高的企業(yè)生產(chǎn)力工具，而不是一個(gè)技術(shù)與其他技術(shù)的支持?？磥?lái)，最終的解決辦法可能是將多種光纖
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