英语翻译随着ADSL技术在全球范围的大规模推广以及针对于DSL技术的应用和服务的不断推出,基于电话双绞线的XDSL宽带接

英语翻译
随着ADSL技术在全球范围的大规模推广以及针对于DSL技术的应用和服务的不断推出,基于电话双绞线的XDSL宽带接入已经占据宽带接入市场的半壁江山.但是,迫于业务发展的需要和更好地迎合网络运营和信息消费的需求,ADSL2和ADSL2＋技术应运而生.
ADSL2＋?G．992．5?标准在ADSL2?G．992．3?的基础上进一步扩展的,所以从整体上看可以把ADSL2+看成是ADSL的升级版本它具备了ADSL所具备的所有功能,并且在ADSL原有的基础上进行了一定的发展,如：将ADSL原有的1.1MHz 的频谱扩展到了2.2MHz,相应的把子信道也扩大了一倍到了511个子信道,而且子信道所负责的内容也不一样了,不过每个子信道所占的频谱并为增加依然是约为4.3KHz.另外从速率从也是有很大的提高的ADSL2+的最大下行速率为24Mbit/s最小的下行速率为16Mbit/s,上行则是800Kbit/S.
与ADSL相比,ADSL2＋在技术和应用上都取得了突破.
第一,传统的ADSL系统能提供的最大下行速率为8M；而ADSL2＋通过频谱的扩展,实现从26KHz到2．2MHz的频率分布,实现512个子载频,最大下行速率至少可以达到20Mbps,可以在较宽松的距离内轻松提供如视频电话、VOD、视频会议等宽带业务.
第二,传统的ADSL系统最大覆盖范围约为3km,如果线路有损伤、噪音干扰,那么覆盖的范围就更小,严重限制了用户的接入能力.而ADSL2＋采用增强的调制方式和无缝速率适配,可以更好地降低线路噪声对信号的影响,可将覆盖距离延伸至6km左右,能接入的用户数量大大提高,尤其是农村和城乡结合部.
第三,传统的ADSL系统在业务开通前或业务运行期间无法对线路的参数进行监测,对线路是否能开通ADSL业务或发生故障时判断故障点无能为力；而ADSL2＋具有强大的线路诊断能力,整个系统的线路质量评测和故障定位功能比从前有了很大改善,使ADSL业务变得更加容易管理和维护.
相当一段时间内,ADSL都将是宽带接入的主流方式,而ADSL2＋凭借其技术上的领先性,必将延续ADSL的既有地位成为市场应用主流

Unceasingly promotes along with the ADSL technology in the globalscope large-scale promotion as well as in view of to the DSLtechnology application and the service,turned on based on thetelephone twisted pair line XDSL wide band already occupies the wideband to turn on the market the half of the country.But,and caters tothe demand well under the service need to develop which the networkoperation and the information expends,ADSL2 and the ADSL2 +technology arises at the historic moment.ADSL2 + the G 992.5 standard further expands in the ADSL2G 992.3foundation,therefore from the whole looked was allowed to regard asADSL2+ is the ADSL promotion edition it has had all functions whichADSL had,and has carried on the certain development in the ADSLoriginal foundation,for example:Expanded 2.2MHz the ADSL original1.1MHz frequency spectrum,the corresponding target channel alsoexpanded a time to arrive 511 stature channels,moreover the sub-channel was responsible the content has been dissimilar,but eachstature channel occupied the frequency spectrum and for the increasestill was approximately is 4.3KHz.Moreover quickly leads from also tohave the very big enhancement the ADSL2+ maximum under stroke speedrate is the 24Mbit/s minimum under stroke speed rate is 16Mbit/s,theprevious line is 800Kbit/S.Compares with ADSL,ADSL2 + has all obtained the breakthrough in thetechnology and the application.First,the traditional ADSL system can provide the maximum understroke speed rate is 8M; But ADSL2 + through the frequency spectrumexpansion,realizes from 26KHz to 2.2MHz frequency distribution,realizes 512 stature carrier frequencies,the maximum under strokespeed rate at least may achieve 20Mbps,may with ease provide likewide band service and so on video frequency telephone,VOD,videofrequency conference in a more loose distance.Second,the traditional ADSL system biggest cover scope approximatelyis 3km,if the line has the damage,the noise disturbance,then coversthe scope is smaller,seriously limited the user to turn on theability.But ADSL2 + uses the enhancement the modulation way and theseamless speed suitably matches,may reduce the line noise well to thesignal the influence,may cover the distance to extend to 6km about,can turn on the user quantity greatly enhances,in particularcountryside and city and countryside union department.Front third,the traditional ADSL system clears or service movementperiod in the service is unable to the line parameter to carry on themonitor,to line whether can clear the ADSL service or breaks downwhen a diagnosis helplessness; But ADSL2 + has the formidable linediagnosis ability,the overall system line quality evaluation and thebreakdown localization function had the past a has been very biggerthan improvement,caused the ADSL service to change easier to manageand the maintenance.Quite in period of time,ADSL all will be the mainstream way which thewide band turns on,but ADSL2 + relies on in its technical being inthe lead,will certainly to continue ADSL already to have the statusto become the market application mainstream