電子信息工程外文翻譯--綜合布線的未來適用于畢業(yè)論文外文翻譯中英文對(duì)照(存儲(chǔ)版)
【正文】 of the radio waves may be limited to distances of 200 feet to 500 feet. In a closedwall office environment, propagation may be limited to as little as 100 feet. Undoubtedly, the cost of wireless networking will be reduced 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。 we are now faced with transport speeds demanding transmission bandwidths of 250MHz and beyond. Manufacturers have risen to the challenge and provided UTP ponents for today39。s transmission requirements in excess of 600 MHz. What media and connectors will be available that will be economically feasible at bandwidths of 1G MHz? At what point does UTP bee less easy to use and less economical than other media?Future directionsAs far as we can see into the future, mercial information tr
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