什么叫"藍(lán)牙"？What is Bluetooth?

　　Bluetooth is a universal radio interface in the 2.45GHz frequency band that enables portable electronic devices to connect and communicate wirelessly via short-range，ad hoc networks. Each unit can simultaneously communicate with up to sever other units per piconet. Moreover，each unit can simultaneously belong to several piconets.

　　What is Bluetooth Technology？

　　Bluetooth technology which apart from Ericsson，has gained the support of Nokia，IBM，Toshiba，Intel and many other manufacturers

　　eliminates the need for wires，cables and connectors for and between cordless or mobile phones，modems，headsets，PDAs，Computers，printers，projectors，local area networks，and so on，and paves the way for new and completely different devices and applications.Technology Characteristics

　　1Ms/s symbol rate exploits maximum available channel bandwidth

　　Fast frequency hopping avoids interference

　　Adaptive output power minimizes interference

　　Short data packets maximize capacity during interference

　　Fast acknowledge allows low coding overhead for links

　　CVSD（Continuous Variable Slope Delta Modulation）voice coding enables

　　operation at high bit- error rates

　　Flexible packet types supports wide application range

　　Air interface tailored to minimize current consumption

　　Basic Technical Information―Based upon a small，high performance integrated radio transceiver，each of which is allocated a unique 48-bit address derived from the IEEE 802?standard .

　　Operate in the unrestricted 2.45GHz ISM free band，Which is available globally although slight variation of location and width of band apply

　　Range set at 10m to optimize for target market of mobile and business user

　　Gross data rate 1Mbit/s with second generation plans to increase to 1Mbit/s

　　One-to-one connections allow maximum data transfer rate of 721kbit/s（3 voice channels）

　　Uses packet switching protocol based on frequency hop scheme with 1600 hops/s to enable high performance in noisy radio environments .The entire available frequency spectrum is used with 79 hops of 1Mhz bandwidth，analogous to the IEEE 802.11 standard

　　Low power consumption longevity for battery powered devices . During data transfer the maximum current drain is 30mA. However during pauses or at lower data rates will be lower

　　藍(lán)牙是一個(gè)頻率為2.45GHz的通用無(wú)線(xiàn)電通信接口，它通過(guò)一個(gè)特殊的網(wǎng)絡(luò)可以在各種便攜設(shè)備之間建立起無(wú)線(xiàn)連接并進(jìn)行短程通信。在一個(gè)微微網(wǎng)中，每個(gè)單元都能同時(shí)與其它各單元進(jìn)行通信。而且，每一個(gè)單元可以同時(shí)屬于幾個(gè)微微網(wǎng)。

　　什么是“藍(lán)牙”技術(shù)？

　　“藍(lán)牙”技術(shù)最先是由愛(ài)立信開(kāi)始研制的，現(xiàn)在已經(jīng)得到了諾基亞、IBM、東芝、因特爾及許多其它相關(guān)制造廠(chǎng)家的支持。其目的是為了免除在無(wú)繩電話(huà)或移動(dòng)電話(huà)、調(diào)制解調(diào)器、頭套式送/受話(huà)器、PDAs、計(jì)算機(jī)、打印機(jī)、幻燈機(jī)、局域網(wǎng)等之間加裝電線(xiàn)、電纜和連接器。而且，這種技術(shù)可以延伸到那些完全不同的新設(shè)備和新應(yīng)用中去。“藍(lán)牙”的技術(shù)特性―以每秒1M個(gè)碼元的字符速率傳輸，充分利用信道的最大有效帶寬。

　　快速跳頻避免干擾

　　可變的電源輸出使干擾減小到最小

　　采用短數(shù)據(jù)包傳輸增強(qiáng)抗干擾能力

　　快速確認(rèn)允許有附加低速率的編碼被發(fā)送到鏈路上

　　連續(xù)可變斜率增量調(diào)制的語(yǔ)音編碼可以在高誤碼率的情況下正常工作

　　靈活的分組類(lèi)型支持多種應(yīng)用

　　無(wú)線(xiàn)電空中接口使電耗達(dá)到最小“藍(lán)牙”基本技術(shù)概要

　　每一個(gè)小型、高性能、集成的無(wú)線(xiàn)電收發(fā)機(jī)都有IEEE 802標(biāo)準(zhǔn)所規(guī)定的一個(gè)唯一的48比特位地址

　　開(kāi)放的2.45GHz ISM自由頻段，全球都可以自由使用。

　　10公里是最適于移動(dòng)通信市場(chǎng)和商業(yè)用戶(hù)的通信范圍

　　總速率為1Mbit/s，計(jì)劃下一代產(chǎn)品將達(dá)到2Mbit/s

　　點(diǎn)到點(diǎn)連接允許的最大數(shù)據(jù)傳輸速率為721kbit/s

　　在無(wú)線(xiàn)電噪聲環(huán)境里，利用基于每秒1600跳跳頻表的分組交換協(xié)議可以提高系統(tǒng)性能。以1Mhz帶寬79跳來(lái)利用這個(gè)完整的可用頻譜。這類(lèi)似于IEEE 802.11標(biāo)準(zhǔn)。

　　低電能的消耗。在備用模式下僅需0.3mA，這能延長(zhǎng)那些使用電池供電設(shè)備的壽命。數(shù)據(jù)傳送時(shí)電流的最大消耗為30mA.當(dāng)暫停工作或低速傳送數(shù)據(jù)時(shí)電流消耗更低。

更多 英文美文、英語(yǔ)美文、英文短文、英語(yǔ)短文，請(qǐng)繼續(xù)關(guān)注 英語(yǔ)作文大全