通信类文章
『壹』 关于通信类的英文翻译文章
这是 中文http://cn.maxim-ic.com/appnotes10.cfm/filter/partnumber
这是 英文 http://www.maxim-ic.com/appnotes10.cfm/filter/partnumber
在里面搜索DS18b20 官方开发笔记中英文对应
或者其他单总线产品
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基于WIN CE的ADSL线路参数研究
ADSL line parameters research based on WIN CE
http://books.google.com.sg/books?hl=en&id=jDmiKarm_EMC&dq=ADSL&printsec=frontcover&source=web&ots=oJXbatzNWO&sig=fyomvlADYeB7NRS2gjTJAfpSapQ
http://books.google.com.sg/books?hl=en&id=HsXaS5y6SZoC&dq=ADSL&printsec=frontcover&source=web&ots=EdCHuJT2WG&sig=QnNSogd7OIvYS7Z6Vr2UYal4iw8
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Windows CE (also known officially as Windows Embedded CE since version 6.0[2][3], and sometimes abbreviated WinCE) is a variation of Microsoft's Windows operating system for minimalistic computers and embedded systems. Windows CE is a distinctly different kernel, rather than a trimmed-down version of desktop Windows. It is not to be confused with Windows XP Embedded which is NT-based. It is supported on Intel x86 and compatibles, MIPS, ARM, and Hitachi SuperH processors.
Features
Windows CE is optimized for devices that have minimal storage—a Windows CE kernel may run in under a megabyte of memory. Devices are often configured without disk storage, and may be configured as a “closed” system that does not allow for end-user extension (for instance, it can be burned into ROM). Windows CE conforms to the definition of a real-time operating system, with a deterministic interrupt latency. It supports 256 priority levels and uses priority inheritance for dealing with priority inversion. The fundamental unit of execution is the thread. This helps to simplify the interface and improve execution time.
Microsoft has stated that the ‘CE’ is not an intentional initialism, but many people believe CE stands for ‘Consumer Electronics’ or ‘Compact Edition’; users often disparagingly called it “Wince”.[4] Microsoft says it implies a number of Windows CE design precepts, including “Compact, Connectable, Compatible, Companion, and Efficient.”[5] The first version, known ring development under the codename “Pegasus”, featured a Windows-like GUI and a number of Microsoft's popular applications, all trimmed down for smaller storage, memory, and speed of the palmtops of the day.
Since then, Windows CE has evolved into a component-based, embedded, real-time operating system. It is no longer targeted solely at hand-held computers. Many platforms have been based on the core Windows CE operating system, including Microsoft's AutoPC, Pocket PC 2000, Pocket PC 2002, Windows Mobile 2003, Windows Mobile 2003 SE, Windows Mobile 5.0, Windows Mobile 6, Smartphone 2002, Smartphone 2003 and many instrial devices and embedded systems. Windows CE even powered select games for the Sega Dreamcast, was the operating system of the controversial Gizmondo handheld, and can partially run on modified Microsoft Xbox game consoles.
A distinctive feature of Windows CE compared to other Microsoft operating systems is that large parts of it are offered in source code form. First, source code was offered to several vendors, so they could adjust it to their hardware. Then procts like Platform Builder (an integrated environment for Windows CE OS image creation and integration, or customized operating system designs based on CE) offered several components in source code form to the general public. However, a number of core components that do not need adaptation to specific hardware environments (other than the CPU family) are still distributed in binary form only.
Development tools
Visual Studio
Late versions of Microsoft Visual Studio support projects for Windows CE / Windows Mobile, procing executable programs and platform images either as an emulator or attached by cable to an actual mobile device. A mobile device is not necessary to develop a CE program. The .NET Compact Framework supports a subset of the .NET Framework with projects in C# and VB.NET, but not Managed C++.
Platform Builder
This programming tool is used for building the platform (BSP + Kernel), device drivers (shared source or custom made) and also the application. This is a one step environment to get the system up and running. One can also use Platform Builder to export an SDK (standard development kit) for the target microprocessor (SuperH, x86, MIPS, ARM etc.) to be used with another associated tool set named below.
Embedded Visual C++ (eVC)
The Embedded Visual C++ tool is for development of embedded application for Windows CE based devices. This tool can be used standalone using the SDK exported from Platform Builder or using the Platform Builder using the Platform Manager connectivity setup.
Relationship to Windows Mobile, Pocket PC, and SmartPhone
Often Windows CE, Windows Mobile, and Pocket PC are used interchangeably. This practice is not entirely accurate. Windows CE is a molar/componentized operating system that serves as the foundation of several classes of devices. Some of these moles provide subsets of other components' features (e.g. varying levels of windowing support; DCOM vs COM), others which are mutually exclusive (Bitmap or TrueType font support), and others which add additional features to another component. One can buy a kit (the Platform Builder) which contains all these components and the tools with which to develop a custom platform. Applications such as Excel Mobile/Pocket Excel are not part of this kit. The older Handheld PC version of Pocket Word and several other older applications are included as samples, however.
Windows Mobile is best described as a subset of platforms based on a Windows CE underpinning. Currently, Pocket PC (now called Windows Mobile Classic), SmartPhone (Windows Mobile Standard), and PocketPC Phone Edition (Windows Mobile Professional) are the three main platforms under the Windows Mobile umbrella. Each platform utilizes different components of Windows CE, as well as supplemental features and applications suited for their respective devices.
Pocket PC and Windows Mobile is a Microsoft-defined custom platform for general PDA use, and consists of a Microsoft-defined set of minimum profiles (Professional Edition, Premium Edition) of software and hardware that is supported. The rules for manufacturing a Pocket PC device are stricter than those for procing a custom Windows CE-based platform. The defining characteristics of the Pocket PC are the digitizer as the primary Human Interface Device and its extremely portable size.
The SmartPhone platform is a feature rich OS and interface for cellular phone handsets. SmartPhone offers proctivity features to business users, such as email, as well as multimedia capabilities for consumers. The SmartPhone interface relies heavily on joystick navigation and PhonePad input. Devices running SmartPhone do not include a touchscreen interface. SmartPhone devices generally resemble other cellular handset form factors, whereas most Phone Edition devices use a PDA form factor with a larger display.
Windows Mobile 5 supports USB 2.0 and new devices running this OS will also conform to the USB Mass Storage Class, meaning the storage on PPC can be accessed from any USB-equipped PC, without requiring any extra software, except requiring a compliant host. In other words, you can use it as a flash drive.
Competing procts
Competitors to consumer CE based PDA platforms like Pocket PC – the main application of Windows CE – are Java, Symbian OS, Palm OS, iPhone OS and Linux based packages like Qtopia Embedded Linux environment from Trolltech, Convergent Linux Platform from a La Mobile, and Access Linux Platform from Orange and Access.
The secondary usage of CE is in devices in need of graphical user interfaces, (point of sale terminals, media centers, web tablets, thin clients) as the main selling point CE is the look and feel being similar to desktop Windows. The competition is Windows XP, Linux and graphical packages for simpler embedded operating systems.
Being an RTOS, Windows CE is also theoretically a competitor to any realtime operating system in the embedded space, like VxWorks, ITRON or eCos. The dominating method, however, of mixing Windows look and feel with realtime on the same hardware, is to run double operating systems using some virtualization technology, like TRANGO Hypervisor from TRANGO Virtual Processors or Intime from TenAsys in the case of Windows, and OS Ware from VirtualLogix, Padded Cell from Green Hills Software, OKL4 from Open Kernel Labs, TRANGO Hypervisor from TRANGO Virtual Processors, RTS Hypervisor from Real-Time Systems or PikeOS from Sysgo, in case of the competition.
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Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call. A splitter - or microfilter - allows a single telephone connection to be used for both ADSL service and voice calls at the same time. Because phone lines vary in quality and were not originally engineered with DSL in mind, it can generally only be used over short distances, typically less than 3mi (5.5 km) [William Stallings' book].
At the telephone exchange the line generally terminates at a DSLAM where another frequency splitter separates the voice band signal for the conventional phone network. Data carried by the ADSL is typically routed over the telephone company's data network and eventually reaches a conventional internet network. In the UK under British Telecom the data network in question is its ATM network which in turn sends it to its IP network IP Colossus.
The distinguishing characteristic of ADSL over other forms of DSL is that the volume of data flow is greater in one direction than the other, i.e. it is asymmetric. Providers usually market ADSL as a service for consumers to connect to the Internet in a relatively passive mode: able to use the higher speed direction for the "download" from the Internet but not needing to run servers that would require high speed in the other direction.
There are both technical and marketing reasons why ADSL is in many places the most common type offered to home users. On the technical side, there is likely to be more crosstalk from other circuits at the DSLAM end (where the wires from many local loops are close to each other) than at the customer premises. Thus the upload signal is weakest at the noisiest part of the local loop, while the download signal is strongest at the noisiest part of the local loop. It therefore makes technical sense to have the DSLAM transmit at a higher bit rate than does the modem on the customer end. Since the typical home user in fact does prefer a higher download speed, the telephone companies chose to make a virtue out of necessity, hence ADSL. On the marketing side, limiting upload speeds limits the attractiveness of this service to business customers, often causing them to purchase higher cost Digital Signal 1 services instead. In this fashion, it segments the digital communications market between business and home users
How ADSL works
On the wire
Currently, most ADSL communication is full plex. Full plex ADSL communication is usually achieved on a wire pair by either frequency division plex (FDD), echo canceling plex (ECD), or time division plexing (TDD). FDM uses two separate frequency bands, referred to as the upstream and downstream bands. The upstream band is used for communication from the end user to the telephone central office. The downstream band is used for communicating from the central office to the end user. With standard ADSL (annex A), the band from 25.875 kHz to 138 kHz is used for upstream communication, while 138 kHz – 1104 kHz is used for downstream communication. Each of these is further divided into smaller frequency channels of 4.3125 kHz. During initial training, the ADSL modem tests which of the available channels have an acceptable signal-to-noise ratio. The distance from the telephone exchange, noise on the copper wire, or interference from AM radio stations may introce errors on some frequencies. By keeping the channels small, a high error rate on one frequency thus need not render the line unusable: the channel will not be used, merely resulting in reced throughput on an otherwise functional ADSL connection.
Vendors may support usage of higher frequencies as a proprietary extension to the standard. However, this requires matching vendor-supplied equipment on both ends of the line, and will likely result in crosstalk issues that affect other lines in the same bundle.
There is a direct relationship between the number of channels available and the throughput capacity of the ADSL connection. The exact data capacity per channel depends on the molation method used.
[edit] Molation
ADSL initially existed in two flavours (similar to VDSL), namely CAP and DMT. CAP was the de facto standard for ADSL deployments up until 1996, deployed in 90 percent of ADSL installs at the time. However, DMT was chosen for the first ITU-T ADSL standards, G.992.1 and G.992.2 (also called G.dmt and G.lite respectively). Therefore all modern installations of ADSL are based on the DMT molation scheme.
Annexes J and M shift the upstream/downstream frequency split up to 276 kHz (from 138 kHz used in the commonly deployed annex A) in order to boost upstream rates. Additionally, the "all-digital-loop" variants of ADSL2 and ADSL2+ (annexes I and J) support an extra 256 kbit/s of upstream if the bandwidth normally used for POTS voice calls is allocated for ADSL usage.
While the ADSL access utilizes the 1.1 MHz band, ADSL2+ utilizes the 2.2 MHz band.
The downstream and upstream rates displayed are theoretical maxima. Note also that because Digital subscriber line access multiplexers and ADSL modems may have been implemented based on differing or incomplete standards some manufacturers may advertise different speeds. For example, Ericsson has several devices that support non-standard upstream speeds of up to 2 Mbit/s in ADSL2 and ADSL2+.
[edit] Installation issues
Due to the way it uses the frequency spectrum, ADSL deployment presents some issues. It is necessary to install appropriate frequency filters at the customer's premises, to avoid interferences with the voice service, while at the same time taking care to keep a clean signal level for the ADSL connection.
In the early days of DSL, installation required a technician to visit the premises. A splitter was installed near the demarcation point, from which a dedicated data line was installed. This way, the DSL signal is separated earlier and is not attenuated inside the customer premises. However, this procere is costly, and also caused problems with customers complaining about having to wait for the technician to perform the installation. As a result, many DSL vendors started offering a self-install option, in which they ship equipment and instructions to the customer. Instead of separating the DSL signal at the demarcation point, the opposite is done: the DSL signal is "filtered off" at each phone outlet by use of a low pass filter, also known as microfilter. This method does not require any rewiring inside the customer premises.
A side effect of the move to the self-install model is that the DSL signal can be degraded, especially if more than 5 voiceband devices are connected to the line. The DSL signal is now present on all telephone wiring in the building, causing attenuation and echo. A way to circumvent this is to go back to the original model, and install one filter upstream from all telephone jacks in the building, except for the jack to which the DSL modem will be connected. Since this requires wiring changes by the customer and may not work on some household telephone wiring, it is rarely done. It is usually much easier to install filters at each telephone jack that is in use.
『贰』 无线电通信的毕业论文
近来有人对光纤通信的发展情景,有些困惑。其一,在2000年IT行业的泡沫,使光纤通信的生产规模投入过大,生产过剩,IT行业中许多小公司倒闭。特别是光纤,国外对中国倾销。其二,有人认为:光纤通信的传输能力已经达到10Tbps,几乎用不完,而且现在大干线已经建设得差不多,埋地的剩余光纤还很多,光纤通信技术不需要更多的发展。
笔者认为,光纤通信技术尚有很大的发展空间,今后会有很大的需求和市场。主要是:光纤到家庭FTTH、光交换和集成光电子器件方面会有较大的发展。在此主要讨论光纤通信的发展趋势和市场。
光纤通信的发展趋势
1、光纤到家庭(FTTH)的发展
FTTH可向用户提供极丰富的带宽,所以一直被认为是理想的接入方式,对于实现信息社会有重要作用,还需要大规模推广和建设。FTTH所需要的光纤可能是现有已敷光纤的2～3倍。过去由于FTTH成本高,缺少宽带视频业务和宽带内容等原因,使FTTH还未能提到日程上来,只有少量的试验。近来,由于光电子器件的进步,光收发模块和光纤的价格大大降低;加上宽带内容有所缓解,都加速了FTTH的实用化进程。
发达国家对FTTH的看法不完全相同:美国AT&T认为FTTH市场较小,在0F62003宣称:FTTH在20-50年后才有市场。美国运行商Verizon和Sprint比较积极,要在10—12年内采用FTTH改造网络。日本NTT发展FTTH最早,现在已经有近200万用户。目前中国FTTH处于试点阶段。
◆FTTH[遇到的挑战:现在广泛采用的ADSL技术提供宽带业务尚有一定优势。与FTTH相比:①价格便宜②利用原有铜线网使工程建设简单③对于目前1Mbps—500kbps影视节目的传输可满足需求。FTTH目前大量推广受制约。
对于不久的将来要发展的宽带业务,如:网上教育,网上办公,会议电视,网上游戏,远程诊疗等双向业务和HDTV高清数字电视,上下行传输不对称的业务,AD8L就难以满足。尤其是HDTV,经过压缩,目前其传输速率尚需19.2Mbps。正在用H.264技术开发,可压缩到5～6Mbps。通常认为对QOS有所保证的ADSL的最高传输速串是2Mbps,仍难以传输HDTV。可以认为HDTV是FTTH的主要推动力。即HDTV业务到来时,非FTTH不可。
◆ FTTH的解决方案:通常有P2P点对点和PON无源光网络两大类。
F2P方案一一优点:各用户独立传输,互不影响,体制变动灵活;可以采用廉价的低速光电子模块;传输距离长。缺点:为了减少用户直接到局的光纤和管道,需要在用户区安置1个汇总用户的有源节点。
PON方案——优点:无源网络维护简单;原则上可以节省光电子器件和光纤。缺点:需要采用昂贵的高速光电子模块;需要采用区分用户距离不同的电子模块,以避免各用户上行信号互相冲突;传输距离受PON分比而缩短;各用户的下行带宽互相占用,如果用户带宽得不到保证时,不单是要网络扩容,还需要更换PON和更换用户模块来解决。(按照目前市场价格,PEP比PON经济)。
PON有多种,一般有如下几种:(1)APON:即ATM-PON,适合ATM交换网络。(2)BPON:即宽带的PON。(3)OPON:采用通用帧处理的OFP-PON。(4)EPON:采用以太网技术的PON,0EPON是千兆毕以太网的PON。(5)WDM-PON:采用波分复用来区分用户的PON,由于用户与波长有关,使维护不便,在FTTH中很少采用。
发达国家发展FTTH的计划和技术方案,根据各国具体情况有所不同。美国主要采用A-PON,因为ATM交换在美国应用广泛。日本NTT有一个B-FLETts计划,采用P2P-MC、B-PON、G-EPON、SCM-PON等多种技术。SCM-PON:是采用副载波调制作为多信道复用的PON。
中国ATM使用远比STM的SDH少,一般不考虑APON。我们可以考虑的是P2P、GPON和EPON。P2P方案的优缺点前面已经说过,目前比较经济,使用灵活,传输距离远等;宜采用。而比较GPON和EPON,各有利弊。GPON:采用GFP技术网络效率高;可以有电话,适合SDH网络,与IP结合没有EPON好,但目前GPON技术不很成熟。EPON:与IP结合好,可用户电话,如用电话需要借助lAD技术。目前,中国的FTTH试点采用EPON比较多。FTTH技术方案的采用,还需要根据用户的具体情况不同而不同。
近来,无线接入技术发展迅速。可用作WLAN的IEEE802.11g协议,传输带宽可达54Mbps,覆盖范围达100米以上,目前已可商用。如果采用无线接入WLAN作用户的数据传输,包括:上下行数据和点播电视VOD的上行数据,对于一般用户其上行不大,IEEES02.11g是可以满足的。而采用光纤的FTTH主要是解决HDTV宽带视频的下行传输,当然在需要时也可包含一些下行数据。这就形成“光纤到家庭+无线接入”(FTTH+无线接入)的家庭网络。这种家庭网络,如果采用PON,就特别简单,因为此PON无上行信号,就不需要测距的电子模块,成本大大降低,维护简单。如果,所属PON的用户群体,被无线城域网WiMAX(1EEE802.16)覆盖而可利用,那么可不必建设专用的WLAN。接入网采用无线是趋势,但无线接入网仍需要密布于用户临近的光纤网来支撑,与FTTH相差无几。FTTH+无线接入是未来的发展趋势。
2、光交换的发展什么是通信?
实际上可表示为:通信输+交换。
光纤只是解决传输问题,还需要解决光的交换问题。过去,通信网都是由金属线缆构成的,传输的是电子信号,交换是采用电子交换机。现在,通信网除了用户末端一小段外,都是光纤,传输的是光信号。合理的方法应该采用光交换。但目前,由于目前光开关器件不成熟,只能采用的是“光-电-光”方式来解决光网的交换,即把光信号变成电信号,用电子交换后,再变还光信号。显然是不合理的办法,是效串不高和不经济的。正在开发大容量的光开关,以实现光交换网络,特别是所谓ASON-自动交换光网络。
通常在光网里传输的信息,一般速度都是xGbps的,电子开关不能胜任。一般要在低次群中实现电子交换。而光交换可实现高速XGbDs的交换。当然,也不是说,一切都要用光交换,特别是低速,颗粒小的信号的交换,应采用成熟的电子交换,没有必要采用不成熟的
大容量的光交换。当前,在数据网中,信号以“包”的形式出现,采用所谓“包交换”。包的颗粒比较小,可采用电子交换。然而,在大量同方向的包汇总后,数量很大时,就应该采用容量大的光交换。
目前,少通道大容量的光交换已有实用。如用于保护、下路和小量通路调度等。一般采用机械光开关、热光开关来实现。目前,由于这些光开关的体积、功耗和集成度的限制,通路数一般在8—16个。
电子交换一般有“空分”和“时分”方式。在光交换中有“空分”、“时分”和“波长交换”。光纤通信很少采用光时分交换。
光空分交换:一般采用光开关可以把光信号从某一光纤转到另一光纤。空分的光开关有机械的、半导体的和热光开关等。近来,采用集成技术,开发出MEM微电机光开关,其体积小到mm。已开发出1296x1296MEM光交换机(Lucent),属于试验性质的。
光波长交换:是对各交换对象赋于1个特定的波长。于是,发送某1特定波长就可对某特定对象通信。实现光波长交换的关键是需要开发实用化的可变波长的光源,光滤波器和集成的低功耗的可靠的光开关阵列等。已开发出640x640半导体光开关+AWG的空分与波长的相结合的交叉连接试验系统(corning)。采用光空分和光波分可构成非常灵活的光交换网。日本NTT在Chitose市进行了采用波长路由交换的现场试验,半径5公里,共有43个终端节,(试用5个节点),速率为2.5Gbps。
自动交换的光网,称为ASON,是进一步发展的方向。
3、集成光电子器件的发展
如同电子器件那样,光电子器件也要走向集成化。虽然不是所有的光电子器件都要集成,但会有相当的一部分是需要而且是可以集成的。目前正在发展的PLC-平面光波导线路,如同一块印刷电路板,可以把光电子器件组装于其上,也可以直接集成为一个光电子器件。要实现FTTH也好,ASON也好,都需要有新的、体积小的和廉价的和集成的光电子器件。
日本NTT采用PLO技术研制出16x16热光开关;1x128热光开关阵列;用集成和混合集成工艺把32通路的AWG+可变光衰减器+光功率监测集成在一起;8波长每波速串为80Gbps的WDM的复用和去复用分别集成在1块芯片上,尺寸仅15x7mm,如图1。NTT采用以上集成器件构成32通路的OADM。其中有些已经商用。近几年,集成光电子器件有比较大的改进。
中国的集成光电子器件也有一定进展。集成的小通道光开关和属于PLO技术的AWG有所突破。但与发达国家尚有较大差距。如果我们不迎头赶上,就会重复如同微电子落后的被动局面。
光纤通信的市场
众所周知,2000年IT行业泡沫,使光纤通信产业生产规模爆炸性地发展,产品生产过剩。无论是光传输设备,光电子器件和光纤的价格都狂跌。特别是光纤,每公里泡沫时期价格为羊1200,现在价格Y100左右1公里,比铜线还便宜。光纤通信的市场何时能恢复?
根据RHK的对北美通信产业投入的统计和预测,如图2.在2002年是最低谷,相当于倒退4年。现在有所回升,但还不能恢复。按此推测,在2007-2008年才能复元。光纤通信的市场也随IT市场好转。这些好转,在相当大的程度是由FTTH和宽带数字电视所带动的。
笔者认为:FTTH毕竟是信息社会的需求,光纤通信的市场一定有美好的情景。发达国家的FTTH已经开始建设,已经有相当的市场。大体上看,器件和设备随市场的需要,其利润会逐步回升,2007-2008年可能良好。但光纤产业,尽管反倾销成功,目前价格也仍低迷不起,利润甚微。实际上,在世界范围内,光纤的生产规模过大,而FTTH的发展速度受社会环境、包括市民的经济条件和数字电视的发展的影响,上升缓慢。据了解,有大公司目前封存几个光纤厂,根据市场情况,可随时启动生产,其结果是始终供大于求。供不应求才能涨价,是通常的市场规律,所以光纤产业要想厚利,可能是2009年后的事情。中国经济不发达地区和小城镇,还需要建设光纤线路,但光纤用量仍然处于供太子求的范围内。
对中国市场,FTTH受ADSL的挑战和数字电视HDTV发展的制约,会有所延后。目前,中国大量建设FTTH的社会环境和条件尚未具备,可能需要等待一段时间。不过,北京奥运会需要HDTV的推动和设备价格的下降,会促进FTTH的发展。预计在2007-2008年在中国FTTH可开始推广。不过也有些大城市的所谓中心商业区CBD,有比较强的经济力量,现在已经采用光纤到住地PTTP来建设。总的来说,目前中国的FTTH处于试点阶段。试点的作用,一方面是摸索技术和建设的经验,另一方面,还起竞争抢占用户的作用。所以,现在电信运行商,地方业主都积极对FTTH试点,以便发展宽带业务。因此,广播运行商受到巨大的挑战,广播商应加快发展数字电视的进程,并且要充实节目内容和采取有竞争力的商业模式。如果广播商要发展VOP点播电视,还需要对电缆电视网双向改造,如果采用光纤网,可更充分地适应未来的技术发展和市场需求。
『叁』 我要写一篇关于近几年通信方式蓬勃发展的文章，取什么题目
一篇关于通信方面新发展的文章:
移动智能网 移动通信在近几年得到了蓬勃发展,极大地影响和改变着人们的学习、生活和工作方式,它使人们可以方便地同别人交换信息.但在传统的通信网中,网络能提供的业务是由厂家生产的交换机的功能决定的,若要提供新的业务,则需对交换机软件进行修改,这样不仅周期长,耗资大,也很不灵活.而在原有的通信网基础上采用智能网新技术,就可以克服上述缺点.智能网是在原有通信网的基础上,为快速、方便、经济、灵活地提供新的电信业务而设置的附加网络结构,它依靠先进的信令网和智能数据库将交换机中各种业务的建立从传统的结构中分离出来,实现交换和控制的分离.智能网一般由业务交换点(SSP)、业务控制点(SCP)、业务管理点(SMP)、业务生成环境(SCE)和智能外设(IP)等组成.
“随着电信与信息技术的飞速发展，对传统的信息传播方式有了许多突破性创新，我们的生活也将悄然改变。”日前举行的南京邮电大学与福建省信息产业厅及企业家代表团产学研合作洽谈会上，有关专家描绘了一些已经或正在实现的通信技术给人们带来的便捷图景。
未来手机将取代手提电脑、相机
随着4月1日中国移动面向8个城市正式启动TD―SCDMA社会化业务测试和试商用工作，我国第三代移动通信(3G)“中国标准”迈出了真正踏入市场前的最后一步。“已经到来的3G时代,使得手机由通信工具变身为个人信息服务中心，未来将会逐步取代数码相机、摄像机，最终还能取代手提电脑。”与会的南京邮电大学校长杨震教授、福建富士通信息软件公司市场副总监黄震奇等专家如此预言。
据专家介绍，3G手机是指将无线通信与互联网等多媒体通信结合的新一代移动通信系统。用户可以通过3G手机浏览网页、发电子邮件、购物、付账、购票、连网玩游戏，或是寻找想去的商店等。由此，手机上网或许将取代电脑上网，成为未来主要的上网方式。此外，有不少型号的3G手机还自带摄像头，这使得用户可以利用手机进行视频通话或电脑会议，也将使数码相机、摄像机成为一种“多余”。
据专家透露，第四代移动通信(4G)技术目前也已提上日程，国际上正在就其标准征集草案，两年之内有望提交国际电联进行讨论，并进入试验、测试阶段。“手机比电脑更普及，比报纸更互动，比电视更便携，比广播更丰富。终将有一天，以手机为中心的第五媒体将成为未来媒体的主流。”专家对此充满信心。
三网融合，看电视上网打电话一根线搞定
电话线、有线电视线、网络线，不少人装修新房时都会被这些似蛛网般的线路搞得头昏眼花。南京邮电大学校长杨震教授等与会专家在接受记者采访时表示，随着电信与信息技术的发展，将来这些一根线就可以搞定。
目前国际上出现了三网融合的潮流，即原先独立设计运营的传统的电信网、计算机网和有线电视网正在趋向于相互渗透和相互融合。相应的，三类不同的业务、市场和产业也正在相互渗透和相互融合，以三大业务来分割三大市场和行业的界限正逐步变得模糊。
杨震告诉记者，在我国，三网融合在技术上早已不存在障碍，但由于“无法可依”，其发展壮大受到很大限制，导致目前三网融合进程迟滞，阻碍了人们早日分享数字革命带来的好处，而且非常严重的重复建设也带来很大浪费。但三网融合是通信技术和业务发展的必然趋势。我国应借鉴世界先进经验，建立融合的通信管制机构，积极推进三网融合，这更有利于信息化的深入推进。
利用电线上网已成为可能
一幢大楼里，仅仅通过普通的电源插座，联上一个电力线宽带调制解调器，整个楼里所有的计算机都可以同时享用高速网络。杨震等与会专家告诉记者，这可不是天方夜谭，而是已经在一些国家实现的现实。通过电力线上网这种颠覆性的应用，将来不仅仅是“三网融合”，还有可能“四网融合”。
电力线上网，是用电力线作为传输媒介，至于线上有没有电，或者说电压是多少伏都不重要，只要有一根线，就可以进行数据流的传输。由于每家每户都有现成的电线，用户布网成本很低，电力线在接入价格上极具竞争优势，拥有光明前景，特别是在偏远农村，有可能没有电信网络，却会有电网。因而，作为一种新的电信服务载体，电力线正在得到越来越多的认同。目前美国、德国、奥地利、西班牙、法国等国的电力线通信网络已经开始运营，并有众多的电力企业在悄悄地进行相关试验，争取有朝一日进入电信运营市场分一杯羹。
『肆』 什么是通信,新闻有哪些分类
通信：人与人或人与自然之间通过某种行为或媒介进行的信息交流与传递，从广通信义上指需要信息的双方或多方在不违背各自意愿的情况下无论采用何种方法，使用何种媒质，将信息从某方准确安全传送到另方。
参考资料：http://ke..com/view/15007.htm?fr=ala0_1_1
不论报纸、广播和电视，新闻一般分为三类。
第一类：是我们最常见的消息，如报纸上的本报讯、广播中的新闻和报纸摘要节目、电视节目中的新闻联播。消息类节目最大的特点是可以迅速简要地报道国内外新闻。刊发篇幅和播报时间都很短，观众可以在很短的时间里接受大量的信息。
第二类：是专题类节目，这类节目的话题一般是当下人们关注的热点问题。如报纸上的新闻背景分析、广播中的广播讲话、电视节目中的焦点访谈等。这类专题节目在动态新闻的基础上又做深入详尽地报道，因此占用的版块大或时间长。
第三类：是新闻评论类节目，如报纸和广播中的评论、评论员文章，电视讲话和电视评论等。
参考资料：http://www.ccnettv.cc/onews.asp?id=782