通信系统第一章翻译
光纤通信系统Optical_Fiber_Communications_英文资料及中文翻译
光纤通信系统Optical Fiber Communications英文资料及中文翻译Communication may be broadly defined as the transfer of information from one point to another .When the information is to be conveyed over any distance a communication system is usually required .Within a communication system the information transfer is frequently achieved by superimposing or modulating the information on to an electromagnetic wave which acts as a carrier for the information signal .This modulated carrier is then transmitted to the required destination where it is received and the original information signal is obtained by demodulation .Sophisticated techniques have been developed for this process by using electromagnetic carrier waves operating at radio requites as well as microwave and millimeter wave frequencies.The carrier maybe modulated by using either optical an analog digital information signal.. Analog modulation involves the variation of the light emitted from the optical source in a continuous manner. With digital modulation, however, discrete changes in the length intensity are obtained (i.e. on-off pulses). Although often simpler to implement, analog modulation with an optical fiber communication system is less efficient, requiring a far higher signal to noise ratio at the receiver than digital modulation. Also, the linearity needed for analog modulation is mot always provided by semiconductor optical source, especially at high modulation frequencies .For these reasons ,analog optical fiber communications link are generally limited to shorter distances and lower bandwidths than digital links .Initially, the input digital signal from the information source is suitably encoded for optical transmission .The laser drive circuit directly modulates the intensity of the semiconductor last with the encoded digital signal. Hence a digital optical signal is launched into the optical fiber cable .The avalanche photodiode detector (APD) is followed by a front-end amplifier and equalizer or filter to provide gain as well as linear signal processing and noise bandwidth reduction. Finally ,the signal obtained isdecoded to give the original digital information .Generating a Serial SignalAlthough a parallel input-output scheme can provide fast data transfer and is simple in operation, it has the disadvantage of requiring a large number of interconnections. As an example typical 8 bit parallel data port uses 8 data lines, plus one or two handshake lines and one or more ground return lines. It is fairly common practice to provide a separate ground return line for each signal line, so an 8 bit port could typically use a 20 core interconnection cable. Whilst such a multi way cable is quite acceptable for short distance links, up to perhaps a few meters, it becomes too expensive for long distance links where, in addition to the cost of the multiword cable, separate driver and receiver circuits may be required on each of the 10 signal lines. Where part of the link is to be made via a radio link, perhaps through a space satellite, separate radio frequency channels would be required for each data bit and this becomes unacceptable.An alternative to the parallel transfer of data is a serial in which the states of the individual data bits are transmitted in sequence over a single wire link. Each bit is allocated a fixed time slot. At the receiving end the individual bit states are detected and stored in separate flip-flop stages, so that the data may be reassembled to produce a parallel data word. The advantage of this serial method of transmission is that it requires only one signal wire and a ground return, irrespective of the number of bits in the data word being transmitted. The main disadvantage is that the rate at which data can be transferred is reduced in comparison with a parallel data transfer, since the bits are dealt with in sequence and the larger the number of bits in the word, the slower the maximum transfer speed becomes. For most applications however, a serial data stream can provide a perfectly adequate data transfer rate . This type of communication system is well suited for radio or telephone line links, since only one communication channel is required to carry the data.We have seen that in the CPU system data is normally transferred in parallel across the main data bus, so if the input -output data is to be in serial form, then a parallel to serial data conversion process is required between the CPU data bus andthe external I/O line. The conversion from parallel data to the serial form could be achieved by simply using a multiplexed switch, which selects each data bit in turn and connects it to the output line for a fixed time period. A more practical technique makes use of a shift register to convert the parallel data into serial form.A shift register consists of a series of D type flip-flops connected in a chain, with the Q output of one flip-flop driving the D input of the next in the chain. All of the flip-flops ate clocked simultaneously by a common clock pulse, when the clock pulse occurs the data stored in each flip-flop is transferred to the next flip-flop to the right in the chain. Thus for each clock pulse the data word is effectively stepped along the shift register by one stage, At the end of the chain the state of the output flip-flop will sequence through the states of the data bits originally stored in the register. The result is a serial stream of data pulses from the end of the shift register.In a typical parallel to serial conversion arrangement the flip-flops making up the shift register have their D input switchable. Initially the D inputs are set up in a way so that data can be transferred in parallel from the CPU data bus into the register stages. Once the data word has been loaded into the register the D inputs are switched so that the flip-flops from a shift register .Now for each successive clock pulse the data pattern is shifted through the register and comes out in serial form at the right hand end of the register.At the receiving end the serial data will usually have to be converted back into the parallel form before it can be used. The serial to parallel conversion process can also be achieved by using a shift register .In this case the serial signal is applied to the D input of the stage at the left hand end of the register. As each serial bit is clocked into the register the data word again moves step by step to the right, and after the last bit has been shifted in the complete data word will be assembled within the register .At this point the parallel data may be retrieved by simply reading out the data from individual register stages in parallel It is important that the number of stages in the shift register should match the number of bits in the data word, if the data is to be properly converted into parallel form.To achieve proper operation of the receiving end of a serial data link, it isimportant that the clock pulse is applied to the receive shift register at a time when the data level on the serial line is stable. It is possible to have the clock generated at either end of the link, but a convenient scheme is to generate the clock signal at the transmitting end (parallel-serial conversion )as the master timing signal. To allow for settling time and delays along the line, the active edge of the clock pulse at the receive end is delayed relative to that which operates the transmit register. If the clock is a square wave the simples approach might be to arrange that the transmit register operates on the rising edge of the clock wave, and the receive register on the falling edge, so that the receiver operates half a clock period behind the transmitter .If both registers operate on arising edge, the clock signal from the transmitter could be inverted before being used to drive the receive shifty register.For an 8 bit system a sequence of 8 clock pulses would be needed to send the serial data word .At the receiving end the clock pulses could be counted and when the eighth pulse is reached it might be assumed that the data in the receive register is correctly positioned, and may be read out as parallel data word .One problem here is that, if for some reason the receive register missed a clock pulse ,its data pattern would get out of step with the transmitted data and errors would result. To overcome this problem a further signal is required which defines the time at which the received word is correctly positioned in the receive shift register and ready for parallel transfer from the register .One possibility is to add a further signal wire along which a pulse is sent when the last data bit is being transmitted, so that the receiver knows when the data word is correctly set up in its shift register. Another scheme might be to send clock pulses only when data bits are being sent and to leave a timing gap between the groups of bits for successive data words. The lack of the clock signal could then be detected and used to reset the bit counter, so that it always starts at zero at the beginning of each new data word.Serial and Parallel Data lion is processed. Serial indicates that the information is handled sequentially, similar to a group of soldiers marching in single file. In parallel transmission the info The terms serial and parallel are often used in descriptions of data transmission techniques. Both refer to the method by which information isdivided in to characters, words, or blocks which are transmitted simultaneously. This could be compared to a platoon of soldiers marching in ranks.The output of a common type of business machine is on eight—level punched paper tape, or eight bits of data at a time on eight separate outputs. Each parallel set of eight bits comprises a character, and the output is referred to as parallel by bit, serial by character. The choice of cither serial or parallel data transmission speed requirements.Business machines with parallel outputs, how—ever, can use either parallel outputs, how—ever, can use either direct parallel data trans—mission or serial transmission, with the addition of a parallel—to—serial converter at the interface point of the business machine and the serial data transmitter. Similarly, another converter at the receiving terminal must change the serial data back to the parallel format.Both serial and parallel data transmission systems have inherent advantages which are some—what different. Parallel transmission requires that parts of the available bandwidth be used as guard bands for separating each of the parallel channels, whereas serial transmission systems can use the entire linear portion of the available band to transmit data, On the other hand, parallel systems are convenient to use because many business machines have parallel inputs and outputs. Though a serial data set has the added converters for parallel interface, the parallel transmitter re—quires several oscillators and filters to generate the frequencies for multiplexing each of the side—by—side channels and, hence, is more susceptible to frequency error.StandardsBecause of the wide variety of data communications and computer equipment available, industrial standards have been established to provide operating compatibility. These standards have evolved as a result of the coordination between manufacturers of communication equipment and the manufacturers of data processing equipment. Of course, it is to a manufacturer’s advantage to provide equipment that isuniversally acceptable. It is also certainly apparent that without standardization intersystem compatibility would be al—most impossible.Organizations currently involved in uniting the data communications and computer fields are the CCITT, Electronic Industries Association (EIA), American Standards Association (ASA), and IEEE.A generally accepted standard issued by the EIA, RS—232—B, defines the characteristics of binary data signals, and provides a standard inter—face for control signals between data processing terminal equipment and data communications equipment. As more and more data communications systems are developed, and additional ways are found to use them, the importance ways are found to use them, the importance of standards will become even more significant.Of the most important considerations in transmitting data over communication systems is accuracy. Data signals consist of a train of pulses arranged in some sort of code. In a typical binary system, for example, digits 1 and 0 are represented by two different pulse amplitudes. If the amplitude of a pulse changes beyond certain limits during transmission, the detector at the receiving end may produce the wrong digit, thus causing an error.It is very difficult in most transmission systems to completely avoid. This is especially true when transmission system designed for speech signals. Many of the inherent electrical characteristics of telephone circuits have an adverse effect on digital signals.Making the circuits unsatisfactory for data transmission—especially treated before they can be used to handle data at speeds above 2000 bits per second.V oice channels on the switched (dial—up) telephone network exhibit certain characteristics which tend to distort typical data signal waveforms. Since there is random selection of a particular route for the data signal with each dialed connection, transmission parameters will generally change, sometimes upsetting the effect of built—in compensationNetworks. In addition, the switched network cannot be used of for large multipleaddress data systems using time sharing. Because of these considerations, specially treated voice bandwidth circuits are made available for data use. The characteristics and costs of these point—to—point private lines are published in document called tariffs, which are merely regulatory agreements reached by the FCC, state public utilities commissions, and operating telephone companies regarding charges for particular types of telephone circuits. The main advantage of private or dedicated facilities is that transmission characteristics are fixed and remain so for all data communications operations.Correlative TechniqueCorrelative data transmission techniques, particularly the Duobinary principle, have aroused considerable interest because of the method of converting a binary signal into three equidistant levels. This correlative scheme is accomplished in such a manner that the predetermined level depends on past signal history, forming the signal so that it never goes from one level extreme to another in one bit interval.The most significant property of the Duobinary process is that it affords a two—to—one bandwidth compression relative to binary signaling, or equivalently twice the speed capability in bits per second for a fixed bandwidth. The same speed capability for a multilevel code would normally require four levels, each of which would represent two binary digits.The FutureIt is universally recognized that communication is essential at every level of organization. The United States Government utilizes vast communications network for voice as well as data transmission. Likewise, business need communications to carry on their daily operations.The communications industry has been hard at work to develop systems that will transmit data economically and reliably over both private—line and dial up telephone circuits. The most ardent trend in data transmission today is toward higher speeds over voice—grade telephone channels. New transmission and equalization techniques now being investigated will soon permit transmitting digital data over telephone channels at speeds of 4800 bits per second or higher.To summarize: The major demand placed on telecommunications systems is for more information-carrying capacity because the volume of information produced increases rapidly. In addition, we have to use digital technology for the high reliability and high quality it provides in the signal transmission. However, this technology carries a price: the need for higher information-carrying capacity.The Need for Fiber-Optic Communications Systems The major characteristic of a telecommunications system is unquestionably its information-carrying capacity, but there are many other important characteristics. For instance, for a bank network, security is probably more important than capacity. For a brokerage house, speed of transmission is the most crucial feature of a network. In general, though, capacity is priority one for most system users. And there’s the rub. We cannot increase link capacity as much as we would like. The major limit is shown by the Shannon-Hartley theorem,Where C is the information-carrying capacity(bits/sec), BW is the link bandwidth (Hz=cycles/sec), and SNR is the signal-to-noise power ratio.Formula 1.1 reveals a limit to capacity C; thus, it is often referred to as the “ Shannon limit.” The formula, which comes from information theory, is true regardless of specific technology. It was first promulgated in 1948 by Claude Shannon, a scientist who worked at Bell Laboratories. R. V. L. Hartley, who also worked at Bell Laboratories, published a fundamental paper 20 years earlier, a paper that laid important groundwork in information theory, which is why his name is associated with Shannon’s formula.The Shannon-Hartley theorem states that information-carrying capacity is proportional to channel bandwidth, the range of frequencies within which the signals can be transmitted without substantial attenuation.What limits channel bandwidth? The frequency of the signal carrier. The higher the carrier’s frequency, the greater the channel bandwidth and the higher the information-carrying capacity of the system. The rule of thumb for estimating possible order of values is this: Bandwidth is approximately 10 percent of the carrier-signal frequency. Hence, if a microwave channel uses a 10-GHz carrier signal.Then its bandwidth is about 100 MHz.A copper wire can carry a signal up to 1 MHz over a short distance. A coaxial cable can propagate a signal up to 100 MHz. Radio frequencies are in the range of 500 KHz to 100 MHz. Microwaves, including satellite channels, operate up to 100 GHz. Fiber-optic communications systems use light as the signal carrier; light frequency is between 100 and 1000 THz; therefore, one can expect much more capacity from optical systems. Using the rule of thumb mentioned above, we can estimate the bandwidth of a single fiber-optic communication link as 50 THz.To illustrate this point, consider these transmission media in terms of their capacity to carry, simultaneously, a specific number of one-way voice channels. Keep in mind that the following precise value. A single coaxial cable can carry up to 13,000 channels, a microwave terrestrial link up to 20,000 channels, and a satellite link up to 100,000 channels. However, one fiber-optic communications link, such as the transatlantic cable TAT-13, can carry 300,000 two-way voice channels simultaneously. That’s impressive and explains why fiber-optic communications systems form the backbone of modern telecommunications and will most certainly shape its future.To summarize: The information-carrying capacity of a telecommunications system is proportional to its bandwidth, which in turn is proportional to the frequency of the carrier. Fiber-optic communications systems use light-a carrier with the highest frequency among all the practical signals. This is why fiber-optic communications systems have the highest information-carrying capacity and this is what makes these systems the linchpin of modern telecommunications.To put into perspective just how important a role fiber-optic communications will be playing in information delivery in the years ahead, consider the following statement from a leading telecommunications provider: “ The explosive growth of Internet traffic, deregulation and the increasing demand of users are putting pressure on our customers to increase the capacity of their network. Only optical networks can deliver the required capacity, and bandwidth-on-demand is now synonymous with wavelength-on-demand.” Th is statement is true not only for a specific telecommunications company. With a word change here and there perhaps, but withthe same exact meaning, you will find telecommunications companies throughout the world voicing the same refrain.A modern fiber-optic communications system consists of many components whose functions and technological implementations vary. This is overall topic of this book. In this section we introduce the main idea underlying a fiber-optic communications system.Basic Block DiagramA fiber-optic communications system is a particular type of telecommunications system. The features of a fiber-optic communications system can be seen in Figure 1.4, which displays its basic block diagram.Information to be conveyed enters an electronic transmitter, where it is prepared for transmission very much in the conventional manner-that is, it is converted into electrical form, modulated, and multiplexed. The signal then moves to the optical transmitter, where it is converted into optical detector converts the light back into an electrical signal, which is processed by the electronic receiver to extract the information and present it in a usable form (audio, video, or data output).Let’s take a simple example that involves Figures 1.1, 1.3, and 1.4 Suppose we need to transmit a voice signal. The acoustic signal (the information) is converted into electrical form by a microphone and the analog signal is converted into binary formby the PCM circuitry. This electrical digital signal modulates a light source and the latter transmits the signal as a series of light pulses over optical fiber. If we were able to look into an optical fiber, we would see light vary between off and on in accordance with the binary number to be transmitted. The optical detector converts the optical signal it receives into a set of electrical pulses that are processed by an electronic receiver. Finally, a speaker converts the analog electrical signal into acoustic waves and we can hear sound-delivered information.Figure 1.4 shows that this telecommunications system includes electronic components and optical devices. The electronic components deal with information in its original and electrical forms. The optical devices prepare and transmit the light signal. The optical devices constitute a fiber-optic communications system.TransmitterThe heart of the transmitter is a light source. The major function of a light source is to convert an information signal from its electrical form into light. Today’sfiber-optic communications systems use, as a light source, either light-emitting diodes (LEDs) or laser diodes (LDs). Both are miniature semiconductor devices that effectively convert electrical signals are usually fabricated in one integrated package. In Figure 1.4, this package is denoted as an optical transmitter. Figure 1.5 displays the physical make-up of an LED, an LD, and integrated packages.Optical fiberThe transmission medium in fiber-optic communications systems is an optical fiber. The optical fiber is the transparent flexible filament that guides light from a transmitter to a receiver. An optical information signal entered at the transmitter end of a fiber-optic communications system is delivered to the receiver end by the optical fiber. So, as with any communication link, the optical fiber provides the connection between a transmitter and a receiver and, very much the way copper wire and coaxial cable conduct an electrical signal, optical fiber “ conducts” light.The optical fiber is generally made from a type of glass called silica or, less commonly nowadays, from plastic. It is about a human hair in thickness. To protect very fragile optical fiber from hostile environments and mechanical damage, it is usually enclosed in a specific structure. Bare optical fiber, shielded by its protective coating, is encapsulated use in a host of applications, many of which will be covered in subsequent chaptersReceiver The key component of an optical receiver is its photodetector. The major function of a photodetector is to convert an optical information signal back into an electrical signal (photocurrent). The photodetector in today's fiver-optic communications systems is a semiconductor photodiode (PD). This miniature device is usually fabricated together with its electrical circyitry to form an integrated package that provides power-supply connections and signal amplification. Such an integrated package is shown in Figure 1.4 as an optical receiver. Figure 1.7 shows samples of a photodiode and an integrated package.The basic diagram shown in Figure 1.4 gives us the first idea of what a fiber-optic communications system is and how it works. All the components of this point-to-point system are discussed in detail in this book. Particular attention is given to the study of networks based on fiber-optic communications systems.The role of Fiber-Optic Communications Technology has not only already changed the landscape of telecommunications but it is still doing so and at a mind-boggling pace. In fact, because of the telecommunications industry's insatiable appetite for capacity, in recent years the bandwidth of commercial systems has increased more than a hundredfold. The potential information-carrying capacity of a single fiber-optic channel is estimated at 50 terabits a second (Tbit/s) but, from apractical standpoint, commercial links have transmitted far fewer than 100 Gbps, an astoundingamount of data in itself that cannot be achieved with any other transmission medium. Researchers and engineers are working feverishly to develop new techniques that approach the potential capacity limit.Two recent major technological advances--wavelength-division multiplexing (WDM) anderbium-doped optical-fiber amplifiers (EDFA)--have boosted the capacity of existing system sand have brought about dramatic improvements in the capacity of systems now in development. In fact,' WDM is fast becoming the technology of choice in achieving smooth, manageable capacity expansion.The point to bear in mind is this: Telecommunications is growing at a furious pace, and fiber-optic communications is one of its most dynamically moving sectors. While this book refleets the current situation in fiber-optic communications technology, to keep yourself updated, you have to follow the latest news in this field by reading the industry's trade journals, attending technical conferences and expositions, and finding the time to evaluate the reams of literature that cross your desk every day from companies in the field.光纤通信系统一般的通信系统由下列部分组成：(1) 信息源。
通讯行业专业英语词汇
通讯行业专业英语词汇(8)small tool欠费用户defaulting subscriber嵌入操作系统embedded operating system eoc嵌入对象embedded object嵌入控制通道embedded control channel ecc强拆(n) (v) forced releaserelease forcedly强行测试forced test强制链路无禁止信号link forced uninhibitation signal lfu 强制重新编路forced rerouting抢先多任务preemptive multitasking橇杠crowbar, pinch bar桥堆bridge rectifiers桥接,跨接bridge connection桥接,跨接bridge connection桥路器（桥式路由器) brouter桥路器，网桥路由器brouter撬杆crowbar切断cut off切换handover ho切换（小区的切换）handover hando切换候选查询handover candidate inquiry切换检测handover detect切换接入handover access切换请求handover request切换请求确认handover request acknowledge切换执行handover performed清除发送clear to send cts清空输出窗口clean up output windows清屏clear screen cls清洗剂detergent请求request req请求评议request for ments rfc区域处理机regional processor rp区域管理系统religion management system rms区域基准时钟源local primary reference lpr区域交换中心zone switching center区域漫游使用regional roaming subscription区域使用识别码regional subscription zone identity rszi 区域中心，大区中心regional center rc驱动变压器driver transformer驱动器drive取消位置cancel location去激活de-activate全方位omni- directional全光网all-optical network全价full rate全接入通信系统total access munication system tacs全局功能平面global function plane gfp全局名, 全局码, 总称global title gt全局名翻译global title translation gtt全忙,全部占线all busy全忙指示功能all busy indication function全面试验,综合试验prehensive test全面支持话务的管理和测量fully supports traffic measurement and management within the system全频道天线all-channel antenna全球第三代global 3g g3g全球定位系统global positioning system gps全球范围的可靠保证highest reliability proven in the world market全球小区识别cell global identification cgi全球寻址码global title gt全球移动通信系统global system for mobile munication gsm全数字化full digitalization全双工full duplex fd, fdx全速率full rate tch/f全速率话务信道full rate traffic channel tch/f全速率话音业务信道a full rate speech tch tch/fs全速率数据业务信道(2.4bit/s) a full rate data tch (2.4bit/s) tch/f2.4全速率数据业务信道(4.8bit/s) a full rate data tch (4.8bit/s) tch/f4.8全速率数据业务信道(9.6bit/s) a full rate data tch (9.6bit/s) tch/f9.6全速率业务信道a full rate tch tch/f全速率业务信道full-rate traffic channel bm全天候服务all-weather service全文检索full text search全向覆盖omnidirectional coverage全向天线omni antenna全业务接入网full service access network fsan全移动性full mobility权限authority缺省网关default gateway缺省值default value缺席服务absent subscriber service缺相default phase确认,肯定回执,肯定证实acknowledge ack 确认操作confirm operation aits确认链路号acknowledge link number群件groupware群路aggregate群内用户intra-group subscriber群外用户out-group subscriber扰码scramble扰码器,置乱器,扰频器scrambler绕线电阻器wire-wound resistor绕线枪cable winding gun热备用,热备份hot backup热备用发射机active standby transmitter 热表hotlist热插入hot plugging热点微蜂窝hot spot microcell热风枪heat gun热键hot key热敏电阻器thermistor热启动hot start热缩管，热缩套管heat-shrink tube热缩套管heat-shrinkable t bush热线hot line hl人工半自动呼叫semiautomatic call人工生命artificial life人工智能artificial intelligence ai人机接口man-machine interface mmi人机命令man-machine mand人机通信man-machine munication mmc 人机语言man-machine language mml 人为误差human error人为因素human factors认证, 证件,证书certification任务按钮task button任务切换task switch任务条taskbar任选部分optional part任选成分optional ponent仍打不通still can not be connected日限次day times limited日限额day sum limited容差error tolerance容许的tolerable容许畸变tolerable distortion熔断电阻器fuse resistor熔断器套件fuse suite熔接splicing柔性电缆soft cable柔性印制板连接器flexible pcb connector 入局ing入局/入中继闭塞ing blocking入局电路群ing circuit group入局呼叫禁止ing calls barred icb入网标志sign of network entry certification 入中继ing trunk ict软过载soft overload软件版本software version软件产生的群闭塞解除消息software generated group unblocking message sgu软件调试software debugging软件费用software charge软件工具箱,成套软件工具software toolkit软件可靠性software reliability软件容错software fault-tolerance软件套件software suite软盘floppy disk软盘驱动器diskette drive, floppy disk drive fdc塞套线,控制线,s线,c线sleeve lead三方通话three party service 3pty三极管triode三阶高密度双极性码high density bipolar three hdb3三频带tri-band三维的,三度的,立体的,空间的three dimensional三芯短路线3-core short circuit wire散件/备件spare parts散热片air cooling fan散热器件heat-sink device扫描仪scanner色彩的chromatic色码color code色散chromatic dispersion色散补偿dispersion pensation色散调节dispersion modation色散位移dispersion-shift色同步键控脉冲burst keying pulse闪存flash memory flash扇形天线（用在基站上）sectorized antenna商务管理信息层business management information layer bml商务配套件purchased mercial suite商业internet交换中心mercial internet exchange cix上、下围框upper/lower enclosure frame上/下话路add／drop a／d上边带upper sideband usb上变频器up converter上电复位power on reset上电自检power-on self-test post上端内存upper memory area uma上话路up channel上母线up highway uhw上下话路add/drop voice channel上下文有关的菜单context-sensitive menu上行功率控制uplink power control ulpc上行链路up link upl上游upstream上载, 加载下载，取回upload download烧焊burn-in稍后便回be back later bbl舍入, 四舍五入round-off舍入误差round-off error设备device设备,设施facilities fac设备标识寄存系统ace equipment identity register system ace eirsace设备布置equipment layout设备号equipment number en设备驱动程序device driver设备识别寄存器equipment identification register eir设备识别寄存器equipment identification register eir设施facilities fac设施拒绝facility reject frj设施请求facility request far设置周期再启动时间set periodically restarting time射发transmit tx射频，无线电频率radio frequency rf射频处理部分radio frequency processing unit rpu射频低噪声放大器ic rf low noise amplifier ic射频调制器rf modulator射频多功能器件rf multi-functional parts射频发射和接收radio frequency transmit and receive rftr 射频隔离器rf isolator射频功分器rf power splitter射频功率放大器rf power amplifier射频功率合成器rf power biner射频固定衰减器rf fixed attenuator射频环行器rf circulator射频混频器rf mixer射频技术radio technology射频解调器rf demodulator射频开关rf switch射频耦合器rf coupler射频器件ic radio frequency ic parts射频数字衰减器rf digital attenuator射频锁相环rf phase-lock loop射频特殊器件rf special parts射频头rf connector射频线rf cable射频压控衰减器rf voltage-controlled attenuator 射线传感器radiation sensor摄像机video camera申告用户plaining subscriber深空雷达deep space radar甚宽带ultra-broadband升位digit adding生产调测factory test生产辅料production auxiliary materials生存性survivability生存周期,生存期,生命期(软件) life cycle声霸卡,多媒体音响卡sound blaster sb声表面波acoustic surface wave声表面波滤波器surface acoustic wave filter声光告警audible and visual alarm声滤器acoustical filter声像audio/video声像会议audiographic conference声学,音响装置,音响效果, 音质acoustics声音控制voice control vc声音信号装置,报警器,寻呼机beeper声音噪声acoustic noise声音噪声要求acoustic noise specification剩余号码remaining number失幀out of frame oof失幀秒out-of-frame second ofs十字槽螺钉cruciform slot screw十字槽螺丝帽cruciform slot head十字槽盘头螺钉cross recess head screw十字槽平头螺钉cruciform slot panhead screw十字螺丝刀cross screwdriver时分cdma time division-code division multiple access td-cdma时分调制time division modulation tdm时分多址time division multiple access tdma时分交换time division switching tdsw时分双工time division duplex tdd时分制time division system时间分配话音插空time assignment speech interpolation tasi时间交换和控制单元time switch and control unit tcu时间接线器time switch ts时间-空间-时间交换网络time-space-time switching network tst时间片，时隙time slot ts时间偏差time deviation tde时间-时间-时间交换网络time-time-time switching network ttt时隙交换time slot interchange tsi时隙逻辑号time slot logic number tln时钟）自由振荡free run时钟丢失loss of clock时钟基准板clock reference board cki时钟驱动clock driving识别码identification code实际传输损失actual transmission loss al实况转播节目live program实模式real mode实时real time rt实时操作系统real time operating system rtos实时传输real time transmission实时计帐hot billing hb实时监控real time monitoring实时时钟real time clock rtc实体entity实线出中继a wire/b wire trunk out矢量和激励线性预测vector sum excited linear prediction vselp使用指南user“s guide世界电信标准化大会world munication standardization conference wtsc世界贸易组织world trade organization wto世界无线电管理大会world administrative radio conference warc市电mains supply市电电源mains supply市话/汇接合用交换机bined local and tandem exchange。
通信工程专业导论(第1-3章)
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2.8 电话通信的发明
2.8.1 电话机的发明
1876年3月7日，美国人贝尔申请的电话装置发明专利获 得批准。 初期的电话机称作磁石电话机：壁挂式、台式
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2.8.2 电话交换机的发明
利用交换机可以减少线路数量 人工交换机：由话务员将线路进行人工连接
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3.4 信号频谱的概念
光谱：光波也是电磁波，在日光光谱中红光的频率 最低，紫光的频率最高，所以光谱就是不同频率电 磁波的频谱。
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信号的频谱：信号的波形可以分解成许多不同频率 的正弦波形，这些正弦波的频率与其幅度和相位的 （函数）关系就是频谱。
下图中粗的波形包含频率为50、150和250Hz的三个正弦 波：
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3.1.2 Байду номын сангаас息量
以天气预报为例，一次天气预报的各种可能性越多，即 每种天气出现的可能性（概率）越小，接收者得到的信 息量就越大。 信息量的定义：I = log2 [1 / P(x)] 比特 (b) 式中，I为信息量；P(x)为事件x出现的概率。 例：若只用晴和雨两种状态预报天气 I = log2 [1 / 1/2] = 1 b 若用晴、阴、云、雨4种状态预报天气 I = log2 [1 / 1/4] = 2 b 若用晴、阴、云、雨、雾、雪、霜、霾8种状态预报天气 I = log2 [1 / 1/8] = 3 b
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频带名
缩写字
ITU 频带号 1
频率和波长范围 3～30Hz 99930.8～ 9993.1km 30～300Hz 9993.1～999.3km 300～3000Hz 999.3～99.9km 3～30kHz 99.9～10.0km 30～300kHz 10.0～1.0km 300～3000kHz 1.0～0.1km 3～30MHz 99.9～10.0m 30～300MHz 10.0～1.0m 300～3000MHz 1.0～0.1m 3～30GHz 99.9～10.0mm 30～300GHz 10.0～1.0mm 300～3000GHz 1.0～0.1mm
通信英语(第四版)课后习题名词解释答案加翻译句子
1.PCM原理抽样量化与编码:sampling,quantizing and coding话路:speech channel幅值: amplitude value抽样频率: sampling frequency抽样速率: sampling rate脉冲流: stream of pulses重复率: repetition rate编码过程: coding process模拟信号: analog signal传输质量: transmission quality数字通信: digital communication数字传输: digital transmission含噪声的环境: noisy environment传输路由: transmission path信噪比 :signal-to-noise ratio信号电平 :signal levels噪声功率: noise power地面系统: terrestrial system二进制传输: binary transmission反向操作: reverse operation8-位码序列: 8-digit sequence接受端: receiving terminal帧格式 :frame format同步字 :synchronization word实现这三项功能的方案 :the schemes for performing these three functions一串幅值: a series of amplitude values电话质量的话路 a speech channel of telephone quality一个8位二进制码的序列: a sequence of 8-binary digits理论上的最小抽样频率 :a minimum theoretical sampling frequency占据着300Hz到3.4kHz频率范围的话路: a voice channel occupying the range 300Hz to 3.4kHz 每个样值8-位码: 8-digits per sample value汽车点火系统的打火: the sparking of a car ignition system重复率为64kHz的脉冲流: the stream of the pulses with a repetition rate of 64kHz真实信号与噪声信号的关系: relationship of the true signal to the noise signal由卫星上接受到的信号 :the signal received from a satellite一条特定消息中的全部信息 :the complete informatian about a particular message被传信号的波形 :the shape of the transmitted signal由传输路由引入的衰减: the attenuation introduced by transmission path将抽样的幅值转换成一串脉冲的单元 :the unit that converts sampled amplitude value to a set of pulses涉及到第一路，第二路及其他各路的序列: a sequence relating to channel 1,2 and so on被称为同步字的独特码序列: a unique sequence of pulses called synchronization word地面系统 :terrestrial system脉冲的“有”或“无” : the presence or absence of the pulses高速的电子开关: a high-speed electronic switch时分多路复用器 :the time division multiplexer时分多路复用 :Time Division Multiplexer2.异步串行数据传输串行接口 serial interface显示终端 CRT terminal发送器与接收器 transmitter and receiver数据传输 data transmission数据流 data stream闲置状态 the idle state传号电平 mark level空号电位 space level起始位 start bit停止位 stop bitT秒的持续时间 duration of T seconds奇偶校检位 parity bit错误标志 error flag传输错误 transmission error下降沿 fallinf edge符号间的空格 intersymbol space接收机的定时 receiver timing本地时钟 local clock磁带 magnetic tape控制比特 control bit逻辑1电平 logical 1 level二进制数据 binary data明显的缺点 obvious disadvantage异步串行数据传输 asynchronous serial data transmission最为流行的串行接口 the most popular serial interface所传送的数据 the transmitted data发送器与接收器的时钟 the clocks at the transmitter and receiver电传机的时代 the era of teleprinter一个字符的点和划 the dots and dashs of a character符号间空格持续时间的三倍 three times the duration of intersymbol space被称为字符的比特组 the group of bits called characters由7或8个比特的信息组成的固定单元 the invariable units comprising 7 or 8 bits of information 由接收机本地产生的时钟 a clock generated locally by the receiver在字符后所收到的奇偶校检位 the received parity bit following the character起始位的下降沿 the falling edge of the start bit数据链路面向字符的特性 the character-oriented nature of the data link3.数据通信地下电缆 underground cable通信卫星 communication satellite微波设备 microwave facilities调制器与解调器 modulator and demodulator缓冲器 buffer定时信号 timing signals同步脉冲 synchronization pulses时隙 time slot移位寄存器 shift register传输媒体 transmission medium线形衰弱 linear attenuation信息安全 information security键盘 keyboard数据终端 data terminals某种类型的数据转换设备 some type of data conversion equipment视频显示终端 visual display terminal称为数据调制解调器的双向数据发送接收机 two-way data transmistter-receiver called a data modem 全双工的数据传输系统 full-duplex data trandmission system由数据处理器的运算速率所决定的速率 the rate determined by the operating speed of the data processor由接口部件来的定时信号 timing signals from the interface assembly磁心存储器 magnetic core memories线性衰减和时延特性 linear attenuation and delay characteristics传输损伤 transmission impairments语音中的冗余特性 the redundant nature of speech在数据发送器中的编码过程 coding process in the data transmitter二进制的不归零信号 binary nonreturn-to-zero signal4.互联网网络资源：network resource信息服务：information services远程终端：remote terminals互联的系统：interconnected systems命令：command电子邮件：electronic mail主机：host无线信道：wireless channels搜索工具：searching tools用户界面：user interface存取：access文本信息：textual messages协议：protocol超文本协议：hypertext protocol分布在全世界的计算机的巨大网络：gaint network of computers located all over the world主干系统：backbone system全国范围的网络：nationwild network电子会议：electronic conferences实时对话：live conversation最大的信息库the largest repository of the computers on the net网络设备资源：network facilities resources在网上的绝大多数计算机：the vast majority of the computer on the netUNIX操作系统：the UNIX operating system在因特网和你的PC机之间传送数据的方法：a way to move data between the internet and your PC 方便的搜索工具：the convenient searching tools联网的超文本协议：the network hypertext protocol5.光纤通信介绍光纤通信:optical fiber communications光源：light source波长：wavelength激光器：laser色散：dispersion传输介质：transmission medium多模光纤：multi-mode fiber长途干线：long-houl trunks单模光纤：singer-mode fiber带宽：bandwidth带宽用户：wideband subscriber纤维光学：fiber-optics商用技术：commercial technologe门限电流：threshod current光检测器：photodetector波分复用：wavelength multiplexing纤维光网络：fiber-optic network视频带宽：video bandwidth长途传输：long distance transmission中继距离：repeater spacing已装光纤的总长度：the total length of installed fiber长途通信系统：long-haul telecommunication system低衰减的石英纤维：the low-loss silica fiber衰减接近瑞利极限的光纤：fibers with losses approaching the Rayleigh limit室温下的门限电流：room temperature threshold currents较长波长区：the longer wavelength region用户接入工程：subscriber access project部件性能和可靠性的改进：improvements in component performance and reliability已安装的光纤系统的数据速率：data rates for installed fibre optic system每秒吉比特：gigabit per second range波分复用：wavelength multiplexing带宽用户环路系统：widebend subscriber loop system多纤连接器：multifibre connectors设计寿命：projected lifetime光源：light source单模光纤：single-mode fibre分布反馈式激光器：distributed-feedback laser信息容量：information capacity交换体系：switching hierarchy带宽业务：broadband services9.蜂窝式移动电话系统蜂窝式移动电话：cellular mobile telephone服务性能：services performance频谱：frequency spectrum频带：frequency band微处理器：microprocessor移动手机：mobile unit广播业务：broadcast servise天线：antenna子系统：subsystems移动用户：mobile subscriber服务能力：service capability利用率：utilization带宽：bandwidth单边带：single-sideband扩频：spread spectrum大规模集成电路：large scale integrated circuits蜂窝点：cellular site蜂窝交换机：cellular switch无线机架：radio cabinet呼叫处理：call processing频谱利用率：frequency spectrum utilization有限的指定频带：the limited assigend ferquency band 服务区：servise area复杂的特性和功能：complicated features and functions大规模集成电路技术：large-scale integraesd circuit technology试验性的蜂窝系统：developmental cellular system中央协调单元：central coordinating element蜂窝管理：cellular administration传统移动电话的运行限制：operational limitiation of conventional mobile telephone system 有限的服务能力：limitied service capability无线通信行业：radio communcation industry可用的无线电频谱：available radio frequency spectrum所分配的频带：the allocated frequency band移动收发信机：mobile transceiver技术上的可行性：techological feasibility严格的频谱限制：severe spectrum limitations调频广播业务：FM broadcasting services传播路径衰耗：propagration path loss多径衰耗：multipath fading电话公司地方局:telephone company zone offices10.全球移动通信系统个人通信 personal communcation通信标准 communcation standrads固定电话业务 fixed telephone services网络容量 network capability移动交换中心 mobile switching center国际漫游 international roaming宽带业务 broadband services接口转换 interface conversion频谱分配 frequency allocation模拟方式 analogue mode蜂窝通信原理 cellular communcation principe拥塞 jamming蜂窝裂变 cellular splitting基站 base station寄存器 register收费功能 billing function接入方法 access method突发脉冲传输方式 brusty transimission mode开销信息 overhead information切换算法 handover algorithms短消息服务 short message services技术规范 technical specificationtotal access communcation system 全接入的通信系统global mobile communcation system 全球移动通信系统time division multiple access 时分多址facsimile and short message services 传真和短消息服务fixed communcation networks 固定通信网络a more personalized system 更加个性化的系统the cost and quality of the link 链路的价格和质量market growth 市场的发展fixed telephone service 固定电话服务coxial cable 同轴电缆interface convision 接口转换cellular communcation priciple 蜂窝通信原则frequency reuse and cell splitting 频率复用和蜂窝裂变cochannel interference 共信道干扰theoretical spectual capability 理论上的频谱容量micro-cellular system 微蜂窝系统base station transceiver 基站收发信机subscriber register 用户寄存器burst transmission mode 突发脉冲传输模式overhead information 开销信息advanced handover algorithms 先进的切换算法facsimile and short message services 传真和短消息服务the GSM technique specications GSM技术规范说明一1 . 研究二进制的传输可见, 只要简单地去判别脉冲的“有”和“无”, 我们就获得了一条消息的全部信息。
中英论文翻译对照：全球移动通信系统
ABSTRACTGSM is Global System for Mobile Communications acronym, which means Glob al System for Mobile Communications is the world's leading cellular systems in the w orld. GSM is based on narrowband TDMA standard that allows radio frequency in a gr oup call at the same time. GSM rised in Europe, put into use in 1991. In the end of 19 97, it has operationed in more than 100 countries, 162 countries have already built m ore than 400 GSM communications network until 2001. But the capacity of GSM s ystem is limited, users of the network are overload, it had to construct additional net work facilities. What is gratifying is that GSM performance in other areas, which in ad dition to providing a standardized list and signaling systems, but also opened up som e of the more intelligent business such as international roaming and so on. The conven ience of GSM mobile phone is that it provides a smart card, known as SIM cards, an d card could be separated, so that the replacement of mobile phone users and custom p ersonal information in this area are facilitated. GSM network have improved after year s of development, is now very mature, less blind spots, signal stability, automatic roam ing, and the communication distance from the impact of the surrounding environment.GSM（Global System for Mobile Communication）The success of mobile systems across the world is a sign that communication is moving towards a more personalized, convenient system. People who have to use a mobile phone on business soon begin to realize that the ability to phone any time, any place in one's personal life rapidly becomes a necessity, not a convenience.The speed and rapidity with which the personal communications revolution takes place is, unlike fixed transmission systems, highly dependent on technology and communication standards.For mobile the three key elements to achieving service take-up are the cost, the size and the weight of the phone, and the cost and quality of the link. If any of these are wrong, especially the first two, then market growth is liable to be severely restricted. The fixed telephone service is global and the interconnection varies from coaxial cable to optical fiber and satellite.The national standards are different, but with common interfaces and interface conversion, interconnection can take place. For mobile the problem is far more complex, with the need to roam creating a need for complex networks and systems. Thus in mobile the question of standards is far more crucial to success than fixed systems. In addition, there is also the vexed question of spectrum allocation in the mobile area.Mobile systems originally operated in analog mode in the 450 MHz band, moving later to 900 MHz with digital GSM and then to 1800 MHz with personalcommunication systems. The history of mobility can split into generations. The first generation systems were the advanced mobile phone systems (AMPS) in the US, total access communication system (TACS) in most of Europe and Nordic mobile telephone system (NMT); which were all analogue systems. The second generation is vary much dominated by the standard first set out in Europe by the group special mobile (GSM) committee, which was designed as a global mobile communication system.The GSM system is based on a cellular communications principle which was first proposed as a concept in the 1940s by Bell System engineers in the US. The idea came out of the need to increase network capacity and got round the fact that broadcast mobile networks, operating in densely populated areas, could be jammed by a very small number of simultaneous calls. The power of the cellular system was that it allowed frequency reuse.The cellular concept is defined by two features, frequency reuse and cell splitting. Frequency reuse comes into play by using radio channels on the same frequency in coverage areas that are far enough apart not to cause co-channel interference. This allows handling of simultaneous calls that exceed the theoretical spectral capacity. Cell splitting is necessary when the traffic demand on a cell has reached the maximum and the cell is then divided into a micro-cellular system. The shape of cell in a cellular system is always depicted as a hexagon and the cluster size can be seven, nine or twelve.The GSM system requires a number of functions to be created for a fully operational mobile system.The cell coverage area is controlled by a base station which is itself made up of two elements. The first element is the transmission system which communicates out to the mobile and also receives information from it to set up and maintain calls when actually in operation. The base station transceiver (BST) is controlled by the base station controller (BSC), which communicates with the mobile switching center (MSC) ---- the essential link to the local public switched telephone network (PSTN), and to the subscriber data which is stored in registers within the system. The subscriber registers allow the GSM system to check a subscriber who requests the use of the network, allow access and then set up the charging function, etc.The GSM system was allocated part of the 900 MHz band at the 1978 World Administration Conference (W AC), the actual bands being 890 to 915 MHz for the uplink transmission and 935 to 960 MHz for the downlink. The access method is time division multiple access (TDMA).The GSM system operates in a burst transmission mode with 124 radio channels in the 900 MHz band, and these bursts can carry different types of information. The first type of information is speech, which is coded at 6.5 kbit/s or 13 kbit/s. The second type is data, which can be sent at 3.6 kbit/s, 6 kbit/s or 12.6kbit/s. These two forms of transmission are the useful parts of the transmission, but have to be supported by overhead information which is sent in control channels (CCH).The use of digital radio transmission and the advanced handover algorithms between radio cells in GSM network allows for significantly better frequency usage than in analogue cellular systems, thus increasing the number of subscribers that canbe served. Since GSM provides common standard, cellular subscribers will also be able to use their telephones over the entire GSM service area. Roaming is fully automatic between and within all countries covered by GSM system. In addition to international roaming, GSM provides new services, such as high-speed data communication, Facsimile and short message service. The GSM technical specifications are designed to work in concert with other standards, e. g. ISDN. Interworking between the standards is in this way assured. In the long term perspective cellular systems, using a digital technology, will become the universal method of telecommunication.The third generation mobile communication system being developed in Europe is intended to integrate all the different services of second generation systems and cover a much wider range of broadband services (voice, data, video and multimedia) consistent and compatible with technology developments taking place within the fixed telecommunication networks.。
通信工程专业英语翻译
通信工程专业英语翻译Part B1. Desktop systems allow remote users to share CAD files as well as other office documents created in spreadsheets, word processors, presentation packages, etc.桌面系统让远程用户能够共享计算机辅助设计档案与其他一些制作在电子表格、文字处理器、图像程序包中的办公室文件。
3. At the World’s Fair 1964, AT&T demonstrated its first videophone, a desktop (or countertop)configuration that provided low quality images using analog technology.在1964年的世界博览会上，美国电话电报公司展示了其首款可视电话-一种桌面（或者台式）机器。
由于使用的是模拟技术，它提供的图像质量不高。
5. Today, systems level implementers have to live within the constraints of standards-based compression algorithms, since standards are the foundation for interoperability, which in the communications field is absolutely necessary.如今，系统水平的操作者不得不受限于基于标准的压缩算法，由于标准时互用性的基础。
而在通行领域，互用性是极其重要的。
Part A1. The word “multimedia”is being used to describe a mixture of hardware, software and applications, with a consequent confusion in people’s mind as to what it is.“多媒体”一词被用来描述硬件、软件及应用的混合体。
通信工程翻译
通信工程翻译通信工程翻译，内容尽量丰富，加一些用法和中英文对照例句Translation of Telecommunications Engineering, with rich contents and addition of usage and corresponding example sentences in both Chinese and English.1. 通信工程(tōng xìn gōng chéng) - Telecommunications Engineering- Example sentence: 我对通信工程有浓厚的兴趣。
(Wǒ duì tōng xìn gōng chéng yǒu nóng hòu de xìng qù) - I have a strong interest in telecommunications engineering.2. 信号传输(xìn hào chuán shū) - Signal Transmission- Example sentence: 无线电波是一种常用的信号传输方式。
(Wú xiàn diàn bō shì yī zhǒng cháng yòng de xìn hào chuán shū fāng shì) - Radio waves are a commonly used method of signal transmission.3. 无线通信(wú xiàn tōng xìn) - Wireless Communication- Example sentence: 无线通信技术在现代社会中起着重要的作用。
通信基础培训-第1章__通信与通信系统的基本概念
1.1 通信的概念
•
谈到通信，我们每个人都不陌生。古代的烽火报警，就是
把敌人入侵的消息通过烽火传达给远方的人们(类似的例子还有抗
日战争时期的“消息树”)；舰船上的灯语和旗语通过灯的闪烁和旗
子的挥动与另一舰船或港口进行无声的对话；
• 传统的信函以文字形式把游子的思乡之情浓 缩于尺素之中，再利用邮政媒体送达家人；在 各种建设工地上，工人们经常使用对讲机相互 联络，协调工作；在电影电视中经常看到军人 或警察利用无线电台进行作战指挥；还有电报、 电传、电话、寻呼、移动电话、有线广播、无 线广播、有线电视、无线电视等当代最为普及 的通信手段都是现实生活中我们所熟悉的通信 实例。
第1章 通信与通信系统的基本概念
• 1.1 通信的概念 • 1.2 通信系统 • 1.3 通信方式 • 1.4 信道和传输介质 • 1.5 信号与噪声 • 1.6 信号频谱与信道通频带
• 1.7 信息的度量与香农公式 • 1.8 多路复用的基本概念 • 1.9 常用的通信手段 • 1.10 通信系统的性能评价 • 1.11 通信技术发展史
发
传
接
信
送
输
收
信
源
设
介
设
宿
备
质
备
干 扰
图1―1 模拟通信系统的一般模型
•
比如电话通信系统就包括：送话器、电
线、交换机、载波机、受话器等要素。广播通
信系统包括麦克风、放大器、发送设备、无线
电波、收音机等。两个通信系统实例示意图如
图1―2所示。
导线 载波机
载波机
(a) 有 线 长 途 电 话 系 统 示 意 图
声被不断地放大，形成噪声积累直到通信终端。
通信工程专业外文翻译--通信系统简介
外文原文：Introduction to Communication SystemIt is often said that we are living in the information age. Communication technology is absolutely vital to the generation, storage, and transmission of this information.Any communication system moves information from a source to a destination through a channel. Figure 1 illustrates this very simple idea. The information from the source will generally not be in a form that can travel through the channel, so a device called a transmitter will be employed at one end and a receiver at the other.Figure 1 simple communication systemThe source or information signal can be analog or digital. Common examples are analog audio, video signals and digital data. Sources are often described in terms of the frequency range that they occupy. Telephone-quality analog voice signals, for instance, contain frequencies from 300Hz to 3kHz, while analog high-fidelity music needs a frequency range of approximately 20Hz to 20kHz.Digital sources can be derived from audio or video signals can have almost any bandwidth depending on the number of bits transmitted per second, and the method used to convert binary ones and zeros into electrical signals.A communication channel can be almost anything: a pair of conductors, an optical fiber or a free space that we live. Sometimes a channel can carry the information signal directly. For example, an audio signal can be carried directly by a twisted-pair telephone cable. On the other hand, a radio link through free space cannot be used directly for voice signals. Such situation require the use of a carrier wave will be altered, or modulated m, by the information signals in such a way that the information can be recovered at the destination. When a carrier is used, the information signal is also known as the modulating signals.Technology is at the core of many new and emerging digital information products and applications that support the information society. Such products and applications often require the collection, sometimes in real time. The ability of technology to handle real world signals digitally has made it possible to create affordable, innovative; and high quality products and applications for large consumer market for example: digital cellular mobile phone, digital television and video games. The impact of is also evident in many other areas, such as medicine and healthcare. For example: in patient monitors for intensive care, digital X-ray appliances, advanced cardiology and brain mapping systems and so on, digital audio, for example: CD players; audio mixers and electronic music and so on. And personal computer systems for example: disks for efficient data storage and error correction, moderns, sound cards and video conferencing and so on.Most of the major cities in the domestic bus stop artificial voice. Every one of the key points from thedriver or attendant to stop by voice. But sometimes due to various factors such as weather, vehicle congestion, flight attendants are feeling the effects of the changes. There being given the station's reporting stations, especially for passengers not familiar with the topography of the city, causing a lot of unnecessary trouble. Well thus affect the image of a city construction window, then developed automatic stop system inevitable. As required before the docking system bus GPS information (latitude and longitude information, etc.), longitude and latitude information generated by the distance between bus stops with the message that this is going to experience the tedious, use the micro-controller difficult to achieve, and when using chips, the proper solution of this problem.Using radians per second in the mathematics dealing with modulation makes the equation simpler. Of course, frequency is usually given in hertz, rather than in radians per second, when practical devices are being discussed. It is easy to convert between the two systems per second, when practical devices are being discussed. It is easy to convert between the two systems by recalling from basic AC theory, ω=2πf.In modulati on, the parameters that can be changed are amplitude E, frequency ω,and phase θ. Combinations are also possible. For example, many schemes for transmitting digital information use both amplitude and phase modulation.Multiplexing is the term used in communications to refer to the combining of two or more information signals. When the available frequency range is divided among the signals, the process is known as frequency-division multiplexing (FDM).Radio and television broadcasting, in which the available spectrum is divided among many signals, are everyday examples of FDM. There are limitations to the number of signals that can be crowded into a given frequency range because each requires a certain bandwidth, For example, a television channel only occupies s given bandwidth of 6MHz in 6~8MHz bandwidth of VHF.Parallel DSP chip to enhance the performance of a traditional improved through the use of multiply-add units and the Harvard structure, it goes far beyond the computational capabilities of the traditional microprocessor. A reasonable inference is: chip operations by increasing the number of modules and the corresponding number of bus linking computational modules. The chip can be doubled to enhance the overall operational capacity. Of course, such an inference two preconditions must be met : First, the memory bus bandwidth as necessary to meet the increase in the number of enhanced data throughput; In addition, various functional units involved in the parallel scheduling algorithm is its complexity can be achieved.An alternative method for using a single communication channel to send many signals is to use time-division multiplexing (TDM). Instead of dividing the available bandwidth of the channel among many signals, the entire bandwidth is used for each signal, but only for a small part of the time. A nonelectronic example is the division of the total available time on a television channel among the various programs transmitted. Each program uses the whole bandwidth of the channel, but only for part of the time.It is certainly possible to combine FDM and TDM, For example, the available bandwidth of a communication satellite is divided among a number of transmitter-receiver combinations called transponders. This is an example of FDM. A single transponder can be used to carry a large number of digital signals using TDM.This course presents a top-down approach to communications system design. The course will cover communication theory, algorithms and implementation architectures for essential blocks in modern physical-layer communication systems (coders and decoders, filters, multi-tone modulation, synchronization sub-systems). The course is hands-on, with a project component serving as a vehicle for study of different communication techniques, architectures and implementations. This year, the project is focused on WLAN transceivers. At the end of the course, students will have gone through the complete WLAN System-On-a-Chip design process, from communication theory, through algorithm and architecture all the way to the synthesized standard-cell RTL chip representation.中文译文：通信系统简介人们常说我们正生活在一个信息时代，通信技术对信息的产生，存储与转换有着至关重要的作用。
通信与电子信息科技英语北京邮电大学出版社翻译Unit1
Unit 1 Random Processes确定一个实验的各种可能结果的概率，它重复多次实验是必要的。
那么假设我们有兴趣建立抛模具相关的统计。
我们可以在两种方式。
一方面，我们可以使用一个单一的模具，把它反复。
或者，我们可以同时多个骰子掷。
直观地说，我们希望两种方法得到相同的结果。
因此，我们可以预期一个单一的模具会产生特定的结果，平均而言，1出6次。
同样，许多骰子我们希望1 / 6的骰子掷将产生一个特定的结果类推，让我们考虑一个随机过程等噪声波形n (t)。
若要确定噪声的统计数字，我们可能会使重复的测量的噪声电压输出的一个单一的噪音源，或我们可能，至少在概念上，做出的统计学上相同的噪声源的收集了大量输出的同时测量。
源的集合称为合奏，个别噪声波形称为样本函数。
可以从一些固定的时间t 进行测量确定统计平均值= t1 在合奏的所有样本函数。
因此，确定n2 (t)，我们会在t = t1，测量电压n (t1) 每个噪声源，方形并添加电压和除以合奏中的源（大）数。
所以确定的平均是n2 的合奏平均（t1）。
现在n (t1) 是一个随机变量，并将会有与之关联的概率密度函数。
合奏平均值将与统计平均数相同，可能由相同的符号表示。
因此统计或n2 合奏平均可能写入（t1）E [n2 (t1)] = n2 （t1）。
在连续的时间取决于测量单个样本函数的平均数将产生时间平均，我们代表as 〈n2 (t) 〉。
一般情况下，合奏平均，而且时间平均数是不相同的。
例如，假设在合奏中的示例函数的统计特征随时间而变化。
这种变异可能不会反映在固定的时间，所作的测量和合奏平均值会在不同的时间不同。
当统计特征的示例函数不改变随着时间的推移时，随机过程是被描述为固定式。
然而，即使被固定的属性不确保合奏和时间的平均值是相同。
它可能会发生虽然每个示例函数是平稳个别样本函数可能不同统计上从另一个。
在这种情况下，时间平均将取决于特定的样本函数，用于形成平均。
通信工程专业英语Unit 2：Digital Communication System
专业英语的翻译
省略：根据汉语语法的修辞习惯，将原文中的某些词语略 去不译。（如英语中的冠词、代词和连词）
Air is a fluid but not a liquid.
空气是流体, 不是液体。（省略冠词） If you know the frequency, you can find the wave length. 如果知道频率，就能求出波长。（泛指的人称代词you 可省略不译）
TEXT
The use of digital methods for the transmission of analog signals is becoming increasingly common in telecommunication systems. There are two major reasons for this. digital :数字的, 数位的
Specialized English for Communication Engineering
专业英语的翻译
句子结构上有差异 词汇上很少对等
English
Chinese
死译 硬译 直译：基本上保留原文的表达形式及内容，不做大的改 动，同时译出的文字又明白易懂； 胡译 意译：在正确理解原意的基础上，重新遣词造句，把原 文的意思用通顺的汉语表达出来。
The reliability can be further improved by using errordetecting and error-correcting codes.
利用检错和纠错编码能进一步提高可靠性。（被动语态 转译为主动语态） Specialized English for Communication Engineering
蜂窝无线通信系统中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)原文：RESEARCH OF CELLULAR WIRELESS COMMUNATIONSYSTEMA wide variety of wireless communication systems have been developed to provide access to the communications infrastructure for mobile or fixed users in a myriad of operating environments. Most of today’s wireless systems are based on the cellular radio concept. Cellular communication systems allow a large number of mobile users to seamlessly and simultaneously communicate to wireless modems at fixed base stations using a limited amount of radio frequency (RF) spectrum. The RF transmissions received at the base stations from each mobile are translated to baseband, or to a wideband microwave link, and relayed to mobile switching centers (MSC), which connect the mobile transmissions with the Public Switched Telephone Network (PSTN). Similarly, communications from the PSTN are sent to the base station, where they are transmitted to the mobile. Cellular systems employ eitherfrequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or spatial division multiple access (SDMA) .Wireless communication links experience hostile physical channel characteristics, such as time-varying multipath and shadowing due to large objects in the propagation path. In addition, the performance of wireless cellular systems tends to be limited by interference from other users, and for that reason, it is important to have accurate techniques for modeling interference. These complex channel conditions are difficult to describe with a simple analytical model, although several models do provide analytical tractability with reasonable agreement to measured channel data . However, even when the channel is modeled in an analytically elegant manner, in the vast majority of situations it is still difficult or impossible to construct analytical solutions for link performance when error control coding, equalization, diversity, and network models are factored into the link model. Simulation approaches, therefore, are usually required when analyzing the performance of cellular communication links.Like wireless links, the system performance of a cellular radio system is most effectively modeled using simulation, due to the difficulty in modeling a large number of random events over time and space. These random events, such as the location of users, the number of simultaneous users in the system, the propagation conditions, interference and power level settings of each user, and the traffic demands of each user, combine together to impact the overall performance seen by a typical user in the cellular system. The aforementioned variables are just a small sampling of the many key physical mechanisms that dictate the instantaneous performance of a particular user at any time within the system. The term cellular radio system, therefore, refers to the entire population of mobile users and base stations throughout the geographic service area, as opposed to a single link that connects a single mobile user to a single base station. To design for a particular system-level performance, such as the likelihood of a particular user having acceptable service throughout the system, it is necessary to consider the complexity of multiple users that are simultaneously using the system throughout the coverage area. Thus, simulation is needed to consider the multi-user effects upon any of the individual links between the mobile and the base station.The link performance is a small-scale phenomenon, which deals with the instantaneouschanges in the channel over a small local area, or small time duration, over which the average received power is assumed constant. Such assumptions are sensible in the design of error control codes, equalizers, and other components that serve to mitigate the transient effects created by the channel. However, in order to determine the overall system performance of a large number of users spread over a wide geographic area, it is necessary to incorporate large-scale effects such as the statistical behavior of interference and signal levels experienced by individual users over large distances, while ignoring the transient channel characteristics. One may think of link-level simulation as being a vernier adjustment on the performance of a communication system, and the system-level simulation as being a coarse, yet important, approximation of the overall level of quality that any user could expect at any time.Cellular systems achieve high capacity (e.g., serve a large number of users) by allowing the mobile stations to share, or reuse a communication channel in different regions of the geographic service area. Channel reuse leads to co-channel interference among users sharing the same channel, which is recognized as one of the major limiting factors of performance and capacity of a cellular system. An appropriate understanding of the effects of co-channel interference on the capacity and performance is therefore required when deploying cellular systems, or when analyzing and designing system methodologies that mitigate the undesired effects of co-channel interference. These effects are strongly dependent on system aspects of the communication system, such as the number of users sharing the channel and their locations. Other aspects, more related to the propagation channel, such as path loss, shadow fading (or shadowing), and antenna radiation patterns are also important in the context of system performance, since these effects also vary with the locations of particular users. In this chapter, we will discuss the application of system-level simulation in the analysis of the performance of a cellular communication system under the effects of co-channel interference. We will analyze a simple multiple-user cellular system, including the antenna and propagation effects of a typical system. Despite the simplicity of the example system considered in this chapter, the analysis presented can easily be extended to include other features of a cellular system.2 Cellular Radio SystemSystem-Level Description：Cellular systems provide wireless coverage over a geographic service area by dividing the geographic area into segments called cells as shown in Figure 2-1. The available frequency spectrum is also divided into a number of channels with a group of channels assigned to each cell. Base stations located in each cell are equipped with wireless modems that can communicate with mobile users. Radio frequency channels used in the transmission direction from the base station to the mobile are referred to as forward channels, while channels used in the direction from the mobile to the base station are referred to as reverse channels. The forward and reverse channels together identify a duplex cellular channel. When frequency division duplex (FDD) is used, the forward and reverse channels are split in frequency. Alternatively, when time division duplex (TDD) is used, the forward and reverse channels are on the same frequency, but use different time slots for transmission.Figure 2-1 Basic architecture of a cellular communications system High-capacity cellular systems employ frequency reuse among cells. This requires that co-channel cells (cells sharing the same frequency) are sufficiently far apart from each other to mitigate co-channel interference. Channel reuse is implemented by covering the geographic service area with clusters of N cells, as shown in Figure 2-2, where N is known as the cluster size.Figure 2-2 Cell clustering:Depiction of a three-cell reuse pattern The RF spectrum available for the geographic service area is assigned to each cluster, such that cells within a cluster do not share any channel . If M channels make up the entire spectrum available for the service area, and if the distribution of users is uniform over the service area, then each cell is assigned M/N channels. As the clusters are replicated over the service area, the reuse of channels leads to tiers of co-channel cells, and co-channel interference will result from the propagation of RF energy between co-channel base stations and mobile users. Co-channel interference in a cellular system occurs when, for example, a mobile simultaneously receives signals from the base station in its own cell, as well as from co-channel base stations in nearby cells from adjacent tiers. In this instance, one co-channel forward link (base station to mobile transmission) is the desired signal, and the other co-channel signals received by the mobile form the total co-channel interference at the receiver. The power level of the co-channel interference is closely related to the separation distances among co-channel cells. If we model the cells with a hexagonal shape, as in Figure 2-2, the minimum distance between the center of two co-channel cells, called the reuse distance ND, is（2-1）R3D N Nwhere R is the maximum radius of the cell (the hexagon is inscribed within the radius).Therefore, we can immediately see from Figure 2-2 that a small cluster size (small reuse distance ND), leads to high interference among co-channel cells.The level of co-channel interference received within a given cell is also dependent on the number of active co-channel cells at any instant of time. As mentioned before, co-channel cells are grouped into tiers with respect to a particular cell of interest. The number of co-channel cells in a given tier depends on the tier order and the geometry adopted to represent the shape of a cell (e.g., the coverage area of an individual base station). For the classic hexagonal shape, the closest co-channel cells are located in the first tier and there are six co-channel cells. The second tier consists of 12 co-channel cells, the third, 18, and so on. The total co-channel interference is, therefore, the sum of the co-channel interference signals transmitted from all co-channel cells of all tiers. However, co-channel cells belonging to the first tier have a stronger influence on the total interference, since they are closer to the cell where the interference is measured.Co-channel interference is recognized as one of the major factors that limits the capacity and link quality of a wireless communications system and plays an important role in the tradeoff between system capacity (large-scale system issue) and link quality (small-scale issue). For example, one approach for achieving high capacity (large number of users), without increasing the bandwidth of the RF spectrum allocated to the system, is to reduce the channel reuse distance by reducing the cluster size N of a cellular system . However, reduction in the cluster sizeincreases co-channel interference, which degrades the link quality.The level of interference within a cellular system at any time is random and must be simulated by modeling both the RF propagation environment between cells and the position location of the mobile users. In addition, the traffic statistics of each user and the type of channel allocation scheme at the base stations determine the instantaneous interference level and the capacity of the system.The effects of co-channel interference can be estimated by the signal-tointerference ratio (SIR) of the communication link, defined as the ratio of the power of the desired signal S, to the power of the total interference signal, I. Since both power levels S and I are random variables due to RF propagation effects, user mobility and traffic variation, the SIR is also a random variable. Consequently, the severity of the effects of co-channel interference onsystem performance is frequently analyzed in terms of the system outage probability, defined in this particular case as the probability that SIR is below a given threshold 0S IR . This isdx p ]SIR Pr[SIR P )x 0SIR 0SIR 0outpage （⎰=<= （2-2）Where is the probability density function (pdf) of the SIR. Note the distinction between the definition of a link outage probability, that classifies an outage based on a particular bit error rate (BER) or Eb/N0 threshold for acceptable voice performance, and the system outage probability that considers a particular SIR threshold for acceptable mobile performance of a typical user.Analytical approaches for estimating the outage probability in a cellular system, as discussed in before, require tractable models for the RF propagation effects, user mobility, and traffic variation, in order to obtain an expression for PSIR （x ）. Unfortunately, it is very difficult to use analytical models for these effects, due to their complex relationship to the received signal level. Therefore, the estimation of the outage probability in a cellular system usually relies on simulation, which offers flexibility in the analysis. In this chapter, we present a simple example of a simulation of a cellular communication system, with the emphasis on the system aspects of the communication system, including multi-user performance, traffic engineering, and channel reuse. In order to conduct a system-level simulation, a number of aspects of the individual communication links must be considered. These include the channel model, the antenna radiation pattern, and the relationship between Eb/N0 (e.g., the SIR) and the acceptable performance.SIR(x)p翻译：蜂窝无线通信系统的研究摘要蜂窝通信系统允许大量移动用户无缝地、同时地利用有限的射频（radio frequency，RF）频谱与固定基站中的无线调制解调器通信。
码分多址通信系统、扩频通信外文翻译
中文2800字毕业设计英文翻译专业电子信息工程班级2010级学生姓名学号课题码分多址通信系统的建模、仿真和设计——初始化模块、基站接收模块指导教师2014 年06 月10 日译文原文1.1 The basic concept of spread-spectrum communicationSpread spectrum communication’s basic characteristics, is used to transmit information to the signal bandwidth(W) is far greater than practical required minimum(effective) bandwidth (F∆),as the radio of processing gain P G.=/G P∆FWAs we well know,the ordinary AM,FM,or pulse code modulation,GP value in the area more than 10 times,collectively,the “narrow-band communication”,and spread-spectrum communication GP values as hundred or even thousands of times, can be called “broadband communication”.Due to the spread-spectrum signal,it is very low power transmitters,transmission space mostly drowned in the noise,it is difficult to intercepted by the other receiver ,only spreading codes with the same (or random PN code) receiver, Gain can be dealt with ,and despreading resume the original signal.1.2 The technology superiority of spread-spectrum communication.Strong anti-interference, bit error rate is low. As noted above, the spread spectrum communication system due to the expansion of the transmitter signal spectrum, the receiver despreading reduction signal produced spreading gain, thereby greatly enhancing its interference tolerance. Under the spreading gain, or even negative in the signal-to-noise ratio conditions, can also signal from the noise drowned out Extraction, in the current business communications systems, spread spectrum communications systems, spread spectrum communication is only able to work in a negative signal-to-noise ratio under the conditions of communication .Anti-multi-path interference capability, increase the reliability of system. Spread-spectrum systems as used in the PN has a good correlation, correlation is very weak. Different paths to the transmission signal can easily be separated and may intime and re-alignment phase, formation of several superimposed signal power, thereby improving the system’s performance to receive increased reliability of the system.Easy to use the same frequency, improving the wireless spectrum utilization. Wireless spectrum is very valuable,although long-wave microwave have to be exploited, and still can not meet the needs of community. To this end, countries around the world are designed spectrum management, users can only use the frequency applications,rely on the channel to prevent the division between the channel interference.Due to the use of spread-spectrum communication related receive this high-tech,low signal output power(“a W,as a general-100mW),and will work in the channel noise and thermal noise in the background,easy to duplicate in the same area using the same frequency,can now all share the same narrow-band frequency communication resources.Spread-spectrum communication is digital communication,particularly for digital voice and data transmission with their own encryption, only in the same PN code communication between users, is good for hiding and confidential in nature, facilitating communication business. Easy to use spread-spectrum CDMA communications, voice compression and many other new technologies, more applicable to computer networks and digitization of voice,image information transmission.Communication in the most digital circuits, equipment, highly integrated, easy installation, easy maintenance, but also very compact and reliable. The average failure rate no time was very long.1.3 Spread spectrum communication systemSpread spectrum communication,namely, spread spectrum communications (Spread spectrum communication), with fiber-optic communications,satellite communications,with access to the information age as the three major high-tech communications transmission. Spread spectrum communication is to send the information to be pseudo-random data is coded(Spread spectrum sequence: spread sequence) modulation, spread spectrum and then the realization of transmission; thereceiving end is using the same modem code and related processing, the restoration of the original data. Spread spectrum communication system has three main characteristics.(1) Carrier is an unpredictable, or so-called pseudo-random broadband signal.(2) Carrier data bandwidth than the modulation bandwidth is much wilder.(3) Receiving process is generated by local broadband carrier signal and receiving a copy of the signal to the broadband signal to achieve.The main way of spread spectrum are as follows: Direct Sequence Spread Spectrum(DSSS) using high-speed pseudo-random code on to the low-speed data transmission spread spectrum modulation; Frequency-hopping system using pseudo-random code to control the carrier frequency in a wider band of the change; TH is the data transmission time slot is a pseudo-random; chirp frequency system is a linear extension of the process of change. Combination of a number of ways of hybrid systems are often applied.The most important measure pf spread-spectrum system is an indicator of spreading gain, also known as processing gain. It is precisely because of the spread spectrum system itself with its performance characteristics with a series of advantages.1.4 Code division multiple accessCode division multiple access (CDMA) is a channel access method used by various radio communication technologies. It should not be confused with the mobile phone standards called cdmaOne, CDMA2000(the 3G evolution of cdmaOne) and WCDMA (the 3Gstandard used by GSM carrier), which are often referred to as simply CDMA, and use CDMA as an underlying channel access method.One of the concepts in data communication is the idea of allowing several transmitters to send information simultaneously over a signal communication channel. This allows several users to share a band of frequencies (see bandwidth). This concept is called multiple access. CDMA employs spread-spectrum technology and a special coding scheme( where each transmitter is assigned a code) to allow multiple user to be multiplexed over the same physical channel. By contrast, time division multipleaccess (FDMA) divides it by frequency. CDMA is a form of spread-spectrum signaling, since the modulated coded signal has a much higher data bandwidth than the data being communicated.1.5 Spread-spectrum characteristic of CDMAMost modulation schemes try to minimize the bandwidth of this signal since bandwidth is a limited resource. However, spread spectrum use a transmission bandwidth that is several orders of magnitude greater than the minimum required signal bandwidth. One of the initial reasons for doing this was military applications including guidance and communication systems. These system were designed using spread spectrum because if its security and resistance to jamming. Asynchronous CDMA has some level of privacy built in because the signal is spread using a pseudo-random code; this code makes the spread spectrum signals appear random or have noise-like properties. A receiver cannot demodulate this transmission without knowledge of the pseudo-random sequence used to encode the data. CDMA also resistant to jamming. A jamming signal only has a finite amount of power available to jam the signal. The jammer can either spread its energy over the entire bandwidth of the signal or jam only part of the entire signal.CDMA can also effectively reject narrow band interference. Since narrow band interference affects only a small portion of the spread spectrum signal, it can easily be removed through notch filtering without much loss of information. Convolution encoding and interleaving can be used to assist in recovering this lost data. CDMA signal are also resistant to multipath fading. Since the spread spectrum signal occupies a large bandwidth only a small portion of this will undergo fading due to multipath at any give time. Like the narrow band interference this will result in only a small loss of data and can be overcome.Another reason CDMA is resistant to multipath interference is because the delayed versions of the transmitted pseudo-random code, and will thus appear as another user, which is ignored at the receiver. In other words, as long as the multipath channel induces at least one chip of delay, 天the multipath channel induces at least one chip of delay,the multipath signals will arrive at the receiver.in other words, as long as the multipath channel induces at least one chip of delay, the multipath signalswill arrive at the receiver such that they are shifted in time by at least one chip from the intended signal. The correlation properties of the pseudo-random codes are such that this slight delay causes the multipath to appear uncorrelated with the intended signal, and it is thus ignored.Some CDMA devices use a rake receiver, which exploits multipath delay components to improve the performance of the system. A rake receiver combines the information from several correlators, each one tuned to a different path delay, producing a stronger version of the signal than a simple receiver with a signal correlation tuned to the path delay of the strongest signal.Frequency reuse is the ability to reuse the same radio channel frequency at other cell sites within a cellular system. In the FDMA and TDMA systems frequency planning is and important consideration. The frequencies used in different cells must be planned carefully to ensure signals from different cells do not interfere with each other. In a CDMA system, the same frequency can be used in every cell, because channelization is done using the pseudo-random codes. Reusing the same frequency in every cell eliminates the need for frequency planning in a CDMA system; however, planning of the different pseudo-random sequences must be done to ensure that the received signal from one cell does not correlate with the signal from a nearby cell.Since adjacent cell use the same frequencies, CDMA systems have the ability to perform soft handoffs. Soft handoffs allow the mobile telephone to communication simultaneously with two or more cells. The best signal quality in selected until the handoff is complete. This is different from hard handoffs utilized in other cellular systems. In a hard handoff situation, as the mobile telephone approaches a handoff, signal strength may vary abruptly. In contrast, CDMA systems use the soft handoff, which is undetectable and provides a more reliable and higher quality signal.Concluding remarksspread-spectrum technology in the initial stages of development, it has become a theory and a major technological breakthrough. Later in the development process is the improvement and hardware performance improved. Development to thepresent,spread-spectrum technology and the theory has been almost perfect,mainly from the point of view of overall performance, and the other new technology applications. Therefore, the application has been driven by the development of spread-spectrum technology is a power driving force, the future wireless communication systems, such as mobile communication. Wireless LAN, global personal communications, spread-spectrum technology will certainly play an important role.译文正文1.扩频通信系统概述扩频通信，即扩展频谱通信（Spread spectrum communication)，它与光纤通信、卫星通信，一同誉为进入信息时代的三大高技术通信传输方式，扩频通信是将待传送的信息数据被伪随机码调制，实现频谱扩展后再传输；接收端则采用相同的编码进行解调及相关处理，恢复原始信息数据。
蜂窝无线通信系统的研究英文翻译
蜂窝无线通信系统的研究英文翻译Research on Cellular Wireless Communication SystemWith the increasing demand for wireless communication services, the cellular wireless communication system has become one of the most widely adopted systems for providing mobile communication services. The cellular wireless communication system is comprised of a network of base stations that communicate with mobile devices, allowing for mobile communication services such as voice calls, messaging, and internet access.This article will focus on the research conducted on the cellular wireless communication system, including its history, current status, and future development trends.History of Cellular Wireless Communication SystemThe cellular wireless communication system can trace its origins back to the 1940s, when a concept known as cellular radio was first proposed. The idea was to divide a geographical region into smaller cells, each with its own radio frequency, to allow for more efficient use of the limited frequency spectrum available.In the 1960s, the first automated mobile communication system was developed, which allowed for mobile communication over a larger geographic area. In the 1980s, the development ofdigital cellular wireless communication technology allowed for the transmission of more data, and the widespread adoption of the cellular wireless communication system.Current Status of Cellular Wireless Communication SystemToday, the cellular wireless communication system is widely adopted around the world, with over 7 billion mobile devices in use. The system has evolved from the first generation (1G) analog system to the current fourth generation (4G) digital system, with the fifth generation (5G) currently under development.The 4G system provides high-speed data transmission capabilities, allowing for mobile applications such as video streaming, online gaming, and real-time navigation. The 5G system is expected to provide even higher speeds, lower latency, and better coverage, enabling new applications such as autonomous vehicles, smart homes, and advanced healthcare services.Research on Cellular Wireless Communication SystemResearch on the cellular wireless communication system is ongoing, with a focus on improving the performance, efficiency, and reliability of the system. Some of the key areas of research include:1. Spectrum Allocation: With the increasing demand for wireless communication services, there is a need to efficiently allocate the limited frequency spectrum available. Research isbeing conducted on new frequency bands and dynamic spectrum management techniques to improve spectrum utilization.2. Antenna Technology: Antenna technology plays a crucial role in the performance of the cellular wireless communication system. Research is being conducted on new antenna designs and beamforming techniques to improve signal strength, coverage, and interference rejection.3. Network Architecture: The current cellular wireless communication system is based on a hierarchical network architecture, with a limited number of base stations providing coverage over a large geographic area. Research is being conducted on new network architectures, such as small cells and heterogeneous networks, to improve coverage and capacity.4. Authentication and Security: With the increasing amount of sensitive information being transmitted over the cellular wireless communication system, there is a need for strong authentication and security measures. Research is being conducted on new authentication and encryption methods to improve the security of the system.Future Trends in Cellular Wireless Communication SystemThe cellular wireless communication system is expected to continue to evolve and improve in the coming years. Some of the key trends expected in the future include:1. 5G Deployment: The deployment of the 5G system is expected to accelerate in the coming years, providing faster speeds, lower latency, and better coverage.2. Internet of Things (IoT): The growth of the IoT is expected to drive demand for connectivity, with millions of devices expected to be connected to the cellular wireless communication system.3. Virtual and Augmented Reality: The development of virtual and augmented reality applications is expected to drive demand for high-speed, low-latency communication services.4. Autonomous Vehicles: The deployment of autonomous vehicles is expected to drive demand for reliable, low-latency communication services.ConclusionThe cellular wireless communication system has come a long way from its origins in the 1940s, and is now a critical component of modern society. Ongoing research and development will continue to improve the performance and capabilities of the system, enabling new applications and services that were previously impossible.。
通信英语词汇中英翻译
A 安全地线 safe ground wire 安全特性 security feature 安装线 hook-up wire 按半周进⾏的多周期控制 multicycle controlled by half-cycle 按键电话机 push-button telephone set 按需分配多地址 demand assignment multiple access（DAMA） 按要求的电信业务 demand telecommunication service 按组编码 encode by group B ⼋⽊天线 Yagi antenna ⽩噪声 white Gaussian noise ⽩噪声发⽣器 white noise generator 半波偶极⼦ halfwave dipole 半导体存储器 semiconductor memory 半导体集成电路 semiconductor integrated circuit 半双⼯操作 semi-duplex operation 半字节 Nib 包络负反馈 peak envelop negative feed-back 包络延时失真 envelop delay distortion 薄膜 thin film 薄膜混合集成电路 thin film hybrid integrated circuit 保护⽐（射频） protection ratio （RF） 保护时段 guard period 保密通信 secure communication 报头 header 报⽂分组 packet 报⽂优先等级 message priority 报讯 alarm 备⽤⼯作⽅式 spare mode 背景躁声 background noise 倍频 frequency multiplication 倍频程 actave 倍频程滤波器 octave filter 被呼地址修改通知 called address modified notification 被呼⽤户优先 priority for called subscriber 本地PLMN local PLMN 本地交换机 local exchange 本地移动⽤户⾝份 local mobile station identity （ LMSI） 本地震荡器 local oscillator ⽐功率（功率密度） specific power ⽐特 bit ⽐特并⾏ bit parallel ⽐特号码 bit number （BN） ⽐特流 bit stream ⽐特率 bit rate ⽐特误码率 bit error rate ⽐特序列独⽴性 bit sequence independence 必要带宽 necessary bandwidth 闭环电压增益 closed loop voltage gain 闭环控制 closed loop control 闭路电压 closed circuit voltage 边瓣抑制 side lobe suppression 边带 sideband 边带⾮线性串扰 sideband non-linear crosstalk 边带线性串扰 sideband linear crosstalk 边带抑制度 sideband suppression 边⾓辐射 boundary radiation 编号制度 numbering plan 编解码器 codec 编码 encode 编码律 encoding law 编码器 encoder 编码器输出 encoder output 编码器总⼯作时间 encoder overall operate time 编码效率 coding efficiency 编码信号 coded signal 编码约束长度 encoding constraint length 编码增益 coding gain 编译程序 compiler 鞭状天线 whip antenna 变频器 converter 变频损耗 converter conversion loss 变容⼆极管 variable capacitance diode 变形交替传号反转 modified alternate mark inversion 便携电台 portable station 便携设备 portable equipment 便携式载体设备 portable vehicle equipment 标称调整率（标称塞⼊率） nominal justification rate （nominal stuffing rate） 标称值 nominal value 标称呼通概率 nominal calling probability 标准码实验信号 standard code test signal （SCTS） 标准模拟天线 standard artificial antenna 标准频率 standard frequency 标准时间信号发射 standard-time-signal emission 标准实验调制 standard test modulation 标准输出功率 standard power output 标准输⼊信号 standard input signal 标准输⼊信号电平 standard input-signal level 标准输⼊信号频率 standard input-signal frequency 标准信躁⽐ standard signal to noise 表⾯安装 surface mounting 表⽰层 presentation layer 并串变换器 parallel-serial converter （serializer） 并馈垂直天线 shunt-fed vertical antenna 并⾏传输 parallel transmission 并⾏终端 parallel terminal 拨号错误概率 dialing mistake probability 拨号后延迟 post-dialing delay 拨号交换机 dial exchange 拨号线路 dial-up line 拨号⾳ dialing tone 拨号终端 dial-up terminal 波动强度（在给定⽅向上的） cymomotive force （c. m. f） 波段覆盖 wave coverage 波峰焊 wave soldering 波特 baud 泊送过程 Poisson process 补充业务 supplementary service （of GSM） 补充业务登记 supplementary service registration 补充业务询问 supplementary service interrogation 补充业务互连 supplementary service interworking 捕捉区（⼀个地⾯接收台） capture area （of a terrestrial receiving station） 捕捉带 pull-in range 捕捉带宽 pull-in banwidth 捕捉时间 pull-in time 不连续发送 discontinuous transmission （DTX） 不连续⼲扰 discontinuous interference 不连续接收 discontinuous reception （DRX） 不确定度 uncertainty 步谈机 portable mobile station C 采样定理 sampling theorem 采样频率 sampling frequency 采样周期 sampling period 参考边带功率 reference side band power 参考差错率 reference error ratio 参考当量 reference equivalent 参考点 reference point 参考结构 reference configuration 参考可⽤场强 reference usable fiend-strength 参考灵敏度 reference sensibility 参考频率 reference frequency 参考时钟 reference clock 参考输出功率 reference output power 残余边带调制 vestigial sideband modulation 残余边带发射 vestigial-sideband emission 操作维护中⼼ operation maintenance center （OMC） 操作系统 operation system （OS） 侧⾳消耗 sidetone loss 层2转发 layer 2 relay （L2R） 插⼊组装 through hole pachnology 插⼊损耗 insertion loss 查号台 information desk 差错控制编码 error control coding 差错漏检率 residual error rate 差分脉冲编码调制（差分脉码调制） differential pulse code modulation （DPCM） 差分四相相移键控 differential quadrature phase keying （DQPSK） 差分相移键控 differential phase keying （DPSK） 差模电压，平衡电压 differential mode voltage, symmetrical voltage 差拍⼲扰 beat jamming 差频失真 difference frequency distortion 长期抖动指⽰器 long-term flicker indicator 长期频率稳定度 long-term frequency stability 场强灵敏度 field intensity sensibility 场效应晶体管 field effect transistor （FET） 超长波通信 myriametric wave communication 超地平对流层传播 transhorizon tropospheric 超地平⽆线接⼒系统 transhorizon radio-relay system 超⾼帧 hyperframe 超帧 superframe 超⼤规模集成电路 very-large scale integrated circuit （VLSI） 超再⽣接收机 super-regenerator receiver 车载电台 vehicle station 撤消 withdrawal 成对不等性码（交替码、交变码） paired-disparity code （alternative code, alternating code） 承载业务 bearer service 城市交通管制系统 urban traffic control system 程序设计技术 programming technique 程序设计环境 programming environment 程序优化 program optimization 程序指令 program command 充电 charge 充电率 charge rate 充电效率 charge efficiency 充电终⽌电压 end-of charge voltage 抽样 sampling 抽样率 sample rate 初级分布线路 primary distribution link 初始化 initialization 处理增益 processing gain 传播时延 propagation delay 传播系数 propagation coefficient 传导⼲扰 conducted interference 传导杂散发射 conducted spurious emission 传递函数 transfer function 传递时间 transfer time 传声器 microphone 传输保密 transmission security 传输层协议 transport layer protocol 传输集群 transmission trunking 传输结束字符 end of transmission character 传输媒体 transmission medium 传输损耗 transmission loss 传输损耗（⽆线线路的） transmission loss （of a radio link） 传输通道 transmission path 传输信道 transmission channel 传真 facsimile, FAX 船舶地球站 ship earth station 船舶电台 ship station 船舶移动业务 ship movement service 船上通信电台 on-board communication station ,ship communication station 船⽤收⾳机 ship radio 串并变换机 serial to parallel （deserializer） 串并⾏变换 serial-parallel conversion 串话 crosstalk 垂直⽅向性图 vertical directivity pattern 唇式传声器 lip microphone 磁屏蔽 magnetic shielding 次级分布线路 secondary distribution link 猝发差错 burst error 猝发点⽕控制 burst firing control 存储程序控制交换机 stored program controlled switching system D ⼤规模集成电路 large scale integrated circuit （LSI） ⼤信号信躁⽐ signal-to-noise ratio of strong signal 带成功结果的常规操作 normal operation with successful outcome 带宽 bandwidth 带内导频单边带 pilot tone-in-band single sideband 带内谐波 in-band harmonic 带内信令 in-band signalling 带内躁声 in-band noise 带通滤波器 band-pass filter 带外发射 out-of-band emission 带外功率 out-of-band power 带外衰减 attenuation outside a channel 带外信令 out-band signalling 带状线 stripline 单边带发射 single sideband （SSB） emission 单边带发射机 single side-band （SSB） transmitter 单边带调制 single side band modulation 单边带解调 single side band demodulation 单边带信号发⽣器 single side band signal generaltor 单端同步 single-ended synchronization 单⼯、双半⼯ simplex, halfduplex 单⼯操作 simplex operation 单⼯⽆线电话机 simplex radio telephone 单呼 single call 单频双⼯ single frequency duplex 单频信令 single frequency signalling 单相对称控制 symmetrical control （single phase） 单相⾮对称控制 asymmetrical control （single phase） 单向 one-way 单向的 unidirectional 单向控制 unidirectional control 单信道地⾯和机载⽆线电分系统 SINCGARS 单信道⽆绳电话机 single channel cordless telephone 单信号⽅法 single-signal method 单⾳ tone 单⾳脉冲 tone pulse 单⾳脉冲持续时间 tone pulse duration 单⾳脉冲的单⾳频率 tone frequency of tone pulse 单⾳脉冲上升时间 tone pulse rise time 单⾳脉冲下降时间 tone pulse decay time 单⾳制 individual tone system 单元电缆段（中继段） elementary cable section （repeater section） 单元再⽣段 elementary regenerator section （regenerator section） 单元增⾳段，单元中继段 elementary repeater section 当被呼移动⽤户不回答时的呼叫转移 call forwarding on no reply （CFNRy） 当被呼移动⽤户忙时的呼叫转 calling forwarding on mobile subscriber busy （CFB） 当漫游到原籍PLMN国家以外时禁⽌所有⼊呼 barring of incoming calls when roaming outside the home PLMN country （BIC-Roam） 当前服务的基站 current serving BS 当⽆线信道拥挤时的呼叫转移 calling forward on mobile subscriber not reachable （CENRc） ⼑型天线 blade antenna 导频 pilot frequency 导频跌落pilot fall down 倒L型天线 inverted-L antenna 等步的 isochronous 等幅电报 continuous wave telegraph 等权（互同步） democratic network （mutually synchronized network） 等效⽐特率 equivalent bit rate 等效地球半径 equivalent earth radius 等效⼆进制数 equivalent binary content 等效全向辐射功率 equivalent isotropically radiated power （e. i. r. p.） 等效卫星线路躁声温度 equivalent satellite link noise temperature 低轨道卫星系统 LEO satellite mobile communication system 低⽓压实验 low atmospheric pressure test 低时延码激励线性预测编码 low delay CELP （LD-CELP） 低通滤波器 low pass filter 低温实验 low temperature test 低躁声放⼤器 low noise amplifier 地-空路径传播 earth-space path propagation 地-空通信设备 ground/air communication equipment 地波 ground wave 地⾯连线⽤户 land line subscriber 地⾯⽆线电通信 terrestrial radio communication 地⾯站（电台） terrestrial station 第N次谐波⽐ nth harmonic ratio 第⼆代⽆绳电话系统 cordless telephone system second generation （CT-2） 第三代移动通信系统 third generation mobile systems 点波束天线 spot beam antenna 点对地区通信 point-area communication 点对点通信 point-point communication 点⾄点的GSM PLMN连接 point to point GSM PLMN 电报 telegraphy 电报电码 telegraph code 电波衰落 radio wave fading 电池功率 power of battery 电池能量 energy capacity of battery 电池容量 battery capacity 电池组 battery 电磁波 electromagnetic wave 电磁波反射 reflection of electromagnetic wave 电磁波饶射 diffraction of electromagnetic wave 电磁波散射 scattering of electromagnetic wave 电磁波⾊射 dispersion of electromagnetic wave 电磁波吸收 absorption of electromagnetic wave 电磁波折射 refraction of electromagnetic wave 电磁场 electromagnetic field 电磁发射 electromagnetic field 电磁辐射 electromagnetic emission 电磁⼲扰 electromagnetic interference （EMI） 电磁感应 electromagnetic induction 电磁环境 electromagnetic environment 电磁兼容性 electromagnetic compatibility （EMC） 电磁兼容性电平 electromagnetic compatibility level 电磁兼容性余量 electromagnetic compatibility margin 电磁脉冲 electromagnetic pulse （EMP） 电磁脉冲⼲扰 electromagnetic pulse jamming 电磁敏感度 electromagnetic susceptibility 电磁能 electromagnetic energy 电磁耦合 electromagnetic coupling 电磁屏蔽 electromagnetic shielding 电磁屏蔽装置 electromagnetic screen 电磁骚扰 electromagnetic disturbance 电磁噪声 electromagnetic noise 电磁污染 electromagnetic pollution 电动势 electromotive force （e. m. f.） 电话机 telephone set 电话局容量 capacity of telephone exchange 电话型电路 telephone-type circuit 电话型信道 telephone-type channel 电离层 ionosphere 电离层波 ionosphere wave 电离层传播 ionosphere propagation 电离层反射 ionosphere reflection 电离层反射传播 ionosphere reflection propagation 电离层散射传播 ionosphere scatter propagation 电离层折射 ionosphere refraction 电离层吸收 ionosphere absorption 电离层骚扰 ionosphere disturbance 电流探头 current probe 电路交换 circuit switching 电屏蔽 electric shielding 电视电话 video-telephone, viewphone, visual telephone 电台磁⽅位 magnetic bearing of station 电台⽅位 bearing of station 电台航向 heading of station 电⽂编号 message numbering 电⽂队列 message queue 电⽂格式 message format 电⽂交换 message switching 电⽂交换络 message switching network 电⽂结束代码 end-of-message code 电⽂路由选择 message routing 电⼩天线 electronically small antenna 电信管理络 telecommunication management network （TMN） 电信会议 teleconferencing 电压变化 voltage change 电压变化持续时间 duration of a voltage change 电压变化的发⽣率 rate of occurrence of voltage changes 电压变化时间间隔 voltage change interval 电压波动 voltage fluctuation 电压波动波形 voltage fluctuation waveform 电压波动量 magnitude of a voltage fluctuation 电压不平衡 voltage imbalance, voltage unbalance 电压浪涌 voltage surge 电压骤降 voltage dip 电源 power supply 电源电压调整率 line regulation 电源抗扰性 mains immunity 电源持续⼯作能⼒ continuous operation ability of the power supply 电源去耦系数 mains decoupling factor 电源骚扰 mains disturbance 电⼦⼲扰 electronic jamming 电⼦⼯业协会 Electronic Industries Association （EIA） 电⼦系统⼯程 electronic system engineering 电⼦⾃动调谐 electronic automatic tuning 电⼦组装 elect r o n i c p a c k a g i n g / p >。
量子通信系统外文翻译中英文2020
量子通信系统的研发进展中英文2020英文R&D advances for quantum communication systemsGerd Leuchs, Christoph MarquardtLuis L. Sánchez-Soto，Dmitry V. Strekalov1 Communication as transfer of information1.1 Introduction to this chapterUnderstanding the nature of light leads to the question of how the principles of quantum physics can be harnessed in practical optical communication. A deeper understanding of fundamental physics has always advanced technology. However, the quantum principles certainly have a distinctly limiting character when looked upon from the engineering point of view. A particle cannot have well-defined momentum and position at the same time. An informative measurement will unpredictably alter the state of a quantum object. One cannot reliably clone an arbitrary quantum state. These and a number of other similar principles give rise to what is commonly known as the quantum “no-go theorems”—a disconcerting term when it comes to building something practical. And yet a search for novel principles of communication enabled by quantum physics began already in its early days and has only intensified since. On this path physicists are faced with a remarkable challenge: to turn a series of negative statements into new technological recipes.This chapter presents the progress of this search achieved over the past several years. The first section starts with a brief review on communication as dispatching of information. We revisit the general concept of information as a physical parameter and the means of transferring it from a sender to a recipient: the communication channels. Principal characteristics of communication channels, such as their information throughput capacity and noise, are discussed in this section.Discussion of the QKD principles started in Section 2.3 leads us into a review of historic and modern QKD R&D, presented in Section 2.4. We emphasize that QKD is perhaps the most technologically mature area of quantum communication, which in some aspects has already reached the commercialization stage. Therefore Section 2.4 may be viewed as central to our chapter. Here we discuss the state-of-the-art QKD techniques and systems in fiber and free-space. Special emphasis is placed on the satellite communication QKD programs that have shown an explosive worldwide growth in the last couple of years. Finally, reviews the information technologies enabled by quantum physics that are proven or expected to surpass their classical alternatives. Here we focus on the technologies that go beyond transferring information and tap into information processing—that is, into applying logic. The most famous, but not the only, example of such technology concepts is the quantum computer. The authors are well aware that this topic alone is worthwhile of a sizable book volume. Therefore we only provide a most fundamental outline of the principles underlying quantum computation and review the modern approaches to its realization. Other examples of specialized quantum-logic systems, such as those allowing for creating counterfeit-proof money or conducting truly anonymous decision making, are also discussed.1.2 Information measuresThere is a general consensus that information theory was established in 1948 with Shannon’s famous paper [1], which answered two simple questions: what is information, and what are the limits on the transmission of information? According to the Shannon paradigm, the process of communication, that is, of carrying information between two points, includes the following essential elements:• A sender, which gen erates the message and a receiver, which is the recipient of that message.• An encoder, which converts the message into a physical signal, and a decoder, which interprets the signal to convert it into a message.• A transmission channel, which is the ph ysical medium used to connect the sender to the receiver.2 Quantum physics for communication2.1 Quantum uncertaintyUncertainty relations are in many respects central to quantum physics. They arise directly from the property of certain physical parameters, such as atomic energy levels, to only take on discrete (“quantum”) values, in contrast with the classical physics that allows them to be continuous. This realization is not dissimilar to Democritus insight on the atomic theory of matter around 490460 BCE, except that in quantum theory the discreteness pertains to the physical observables1 rather than to the structure of matter. One such discrete observable is the action. The minimum action that can be performed with a physical system is defined as the Planck constant h. The quantized action implies that a physical system state cannot be represented as a point in a phase space spanned by the canonical coordinate x and momentum p, but has to occupy the area equal to at least h.There is still a long way from the state-dependent relations to the general form. In fact, it is shown that this connection can be made only as an approximation. In a more strict sense, the number-phase uncertainty relation remains state-dependent, and its lower bound is reached only for a specific set of parameters within each state. It is common to call the states reaching the minimal uncertainty the intelligent states. Importantly for our discussion, coherent and squeezed states of electromagnetic field are intelligent states.2.2 Measurement and detectorsThe process of measurement is important both in classical and quantum communications systems; however, its roles in these two cases are different. In quantum physics, a measurement defines the boundary between the quantum and the classical words. It may be said not just to record but actually to create an element of the observer’s reality, in the sense of J.A. Wheeler’s remark that “No phenomenon is a real phenomenon until it is an observed phenomenon.” In particular, the question “what is a photon?” is inseparable from the method we choose to detect one. Consequently the properties of a photon, including its information content, also depend on the type of measurement.In quantum physics, measurement is described as projection of a quantum system’s state onto a state specified by the measuring device. Energy basis is most commonly used for detecting photons, in which case detection of a photon is accomplished by absorbing its energy, that is, by its annihilation. A photon defined by this type of detection is indivisible: it can be absorbed only as a whole and only at one point of space and time.3 If a single-photon state |1i is incident on a beam splitter, the photon can be detected in one its output or the other—never in both.The energy-basis, or photon-counting, measurements have certain practical advantages for communications: an optical photon energy is large compared to room temperature, so the thermal noise can be low. Furthermore, the physical transitions caused by a photon absorption can be very fast, so there is a potential for high-bandwidth communications. But photon absorption is not the only possible measurement strategy. Instead of the energy basis, one may choose the basis of optical field quadratures. This type of measurement is known as homodyne measurement and is widely used in classical communications. In a homodyne measurement a weak signal is mixed with a strong reference beam, conventionally called the local oscillator (LO), and directed to a photo detector. The phase between the signal and LO determines the observed quadrature. Note that in this measurement scenario the main portion of the absorbed optical power is carried by the LO.Once reliably implemented, the nondestructive strategies of photons detection may become beneficial for long-range communication scenarios when the signal photons are few and precious, as they potentially may allow for reusing these photons for multiple measurements. However, the information content of such measurements needs to be carefully analyzed and weighted against the information available from a direct measurement for each measurement scenario.2.3 True random numbers generationRandom number sequences are important in mathematics, physics, and communication technology. In mathematics, random numbers are used in Monte-Carlo computations. In this application it is important to have a fair (not biased by inadvertent correlations) random sampling across the entire parameter space. If theparameter space is large and samples are many, pseudo-random sequences may start showing the built-in correlations and lead to biased sampling and computation errors.Importance of true random numbers in fundamental physics can be exemplified by Bell tests. One of the known loopholes in these tests is associated with the choice of Bell-basis for measurements. The necessity to choose a new random basis for every detection arises from closing another loophole based on the possible causal relation between the preset measurement basis and the “true” (hidd en) values of Bell observables. If this choice is based on a pseudo-random process correlated with some other part of the universe, it is conceivable that this correlation will find its way to the hidden values of Bell observables and void the test.In communication technology, specifically in cryptography, the presence of an inadvertent correlation in the key-generating sequence may become discovered by the eavesdropper and can compromise the communication protocol’s security. A classic example is breaking codes by analyzing the characters occurrence frequency. The standard pseudo-random number generators are inadequate for these tasks. The significance of this problem is indicated by a recent Bell-test experiment involving human conciseness as a source of randomness [28]. In this truly epic effort, some 100,000 volunteers around the world generated 97,347,490 binary choices. These choices were streamed in real time to 12 laboratories on five continents, where they were used to determine the local settings in various types of Bell measurements. All the measurements strongly contradicted the local realism in favor of quantum mechanics.Besides the proven tendency to impart chaos to every aspect of their lives, there is a deeper reason for using human subjects as sources of true random numbers. It is possible, at least fundamentally, to include any measuring device into the quantum system that is being observed, thereby shifting the boundary between the quantum evolution and the irreversible measurement—the border line between the quantum and classical worlds—closer and closer to the observer’s mind. The mind may be the ultimate place where this line can be drawn and where the final projection operation on the quantum state of the outside world is performed. It is therefore plausible thatonly past this boundary can the true random number sequence originate. Ruling out the local realism, a much simpler method of true random numbers generation is offered by quantum mechanics. Let us return to a single-photon incident on a balanced beam splitter. According to the quantum theory, it is fundamentally impossible to predict out of which port of the beam splitter the incident photon will emerge. Repeating this measurement again and again, one can obtain a sequence of truly random binaries. This can be implemented by injecting a weak coherent state on the beam splitter. The same experiment can be construed as a quadrature measurement of the vacuum field at the other port of the beam splitter against the coherent LO [29], which similarly leads to a fundamentally random result.2.4 Entanglement and communicationThe concept that nonclassical light may be useful for communication that emerged in the early days of quantum optics. Squeezed light was proposed to enhance communication rates [32,33], while two-photon parametric light was proposed to enable noiseresilient dual communication channels [34]. The latter proposal hinges on the idea that the parametric photons are tightly correlated in time, and therefore detecting the intensity modulation encoded in two channels via photon coincidence counting is more robust against background noise than single-channel detection. This technique does not actually rely on entanglement: two-channel communication with synchronized short pulses would achieve practically the same.73 Quantum mechanics for securing communication channelsAn important aspect of practical communications is protecting the messages from tampering and eavesdropping—that is, cryptography. The field of cryptography has a long and rich history, which leads to a commonly accepted conclusion that a truly unbreakable cipher requires a random string of key characters privately shared by the two communicating parties. A sender (Alice) performs an XOR operation on her message and the key (in a binary alphabet), and sends the result to the recipient (Bob). It is easy to see that if Bob now performs an XOR operation on the encoded message and the key, he will recover the original message. This encryption technique is called the one-time pad9 (OTP) encryption. Originally proposed by F. Miller in1882, it was reinvented by G. Vernam and J. Mauborgne in 1917, and is also known as the Vernam cipher. The “one-time” aspect of the OTP cipher points at the fact that it is secure only if the random key string is used only once and then discarded. Thus the main problem of the OTP-based cryptography is replenishment of the secure key bits. The no-cloning theorem allows for accomplishing this task with fundamentally unconditional security, providing a rare example of a quantum no-go theorem serving as a technology vehicle rather than a hindrance.3.1 Basic principles of quantum key distributionQuantum key distribution (QKD) is a family of protocols used to generate a secure key sequence shared by two parties: Alice and Bob. All QKD protocols require that besides a quantum communication channel, Alice and Bob share a publicly accessible classical channel. It is assumed that a potential eavesdropper, traditionally called Eve, can listen to the public channel and furthermore has a full control over the quantum channel. This means, in particular, that she can spoof any transmissions in the quantum channel. Moreover, Eve is assumed to have unlimited computation power and access to any possible technology that abides by laws of physics. But she is not allowed to have access to Alice’s and Bob’s setups or hijack the classical communication channel. The last limitation is important, because if Eve is able to impersonate one legitimate user for the other and prevent their secure authentication, she can successfully intercept the key by the so-called man-in-the-middle attack.The unconditional security of QKD hinges on the fact that a symbol-encoding quantum state cannot be cloned, whereas simply intercepting it automatically removes this symbol from the legitimate user’s key string. This can be achieved by employing the prepare-and-measure, the entanglement-sharing, or the bidirectional strategy. We note that the term “unconditional security” should not be m isread as not needing any condition at all. Of course, certain fundamental conditions of all security systems have to apply, most importantly matching the security proof model to the experimental implementation.In the prepare-and-measure strategy Alice encodes her symbol into a quantum state, which she sends to Bob. Bob performs a measurement and extracts the symbolas explained below. Alice needs to make sure that her sequence of transmitted characters is truly random and free from spurious correlations that could potentially supply Eve with information. A true random number generator becomes necessary if Alice and Bob plan to generate an arbitrary long key with unconditional security. In fact, one of the attacks that Eve can launch in order to gain a partial access to the secure key consists of tampering with an unprotected random number generator. This can be done by obtaining the random number seed or influencing the process of random number generation. The attack may be directed at the software by hacking or intentionally planted backdoors, or at hardware through the shared environment such as, for example, power lines. Furthermore, the necessity to encode known symbols opens up a number of technical loopholes that Eve can use to her advantage. Perhaps the most classic example of such a loophole is the radiofrequency pulses broadcast by Pockels cells used for polarization encoding or by electro-optical modulators used for phase encoding. Matching the security proof model to practical implementations is an important task of certification processes. This includes using properly working true random number generators, transmitters, detection systems, and shielding against external coupling. Some of that work is known from classical high-security products (TEMPEST requirements), some work directly related to the quality or unintended readout of quantum states and related to the field of “quantum hacking.”In the entanglement-sharing scheme, Alice and Bob derive their identical keys from a shared bipartite entangled state. This approach eliminates the need for encoding known symbols and the consequent security problems. Now the strings of symbols are created by Alice’s and Bob’s measurements and do not exist until these measurements are complete. Symbols in these strings have truly random order, as we discussed in Section 12.2.3, whereas the quantum correlations guarantees the identity of the generated key sets. The cost of these benefits is the need for the entangled light source. In practice this amounts to using significantly more powerful lasers and specially designed optically nonlinear crystals or waveguides and quantum state generation rates that are still orders of magnitude lower than those of weak laser sources. In addition, especially in satellite-based QKD the requirement of twosimultaneous free space channels with potentially large loss renders an efficient implementation challenging. Notably, the entanglement-sharing QKD is also not free from the technical loopholes open for Eve. One of these loopholes is the transient emission of light from an avalanche photo diode (APD, the most common type of photon-counting optical detectors), which occurs upon a photon detection. Again, as with every security product, proper certification measures have to be taken into account that ensure to avoid unwanted loopholes and side-channels. In the bidirectional strategy Alice and Bob assume highly asymmetric roles. Bob sends light pulses to Alice, who encodes them with the key by performing certain unitary operations on the phase or polarization, and returns the encoded pulses to Bob. Both communication directions require an eavesdropping check to ensure security. The bidirectional approach has a significant practical advantage, as it does not require the exchange of measurement basis information between Alice and Bob, but it also has a major disadvantage of effectively doubling the communication distance. Because of this disadvantage, the bidirectional approach is less common than the prepare-and-measure and entanglement-sharing approaches. However, it is still a field of active research. Recently a new version of bidirectional protocol has emerged that suppresses Eve’s information gain by utilizing nonorthogonal unitary transformations for encoding a binary alphabet.3.2 Eavesdropping challengeIncreasingly more sophisticated techniques that might allow Eve to breach the QKD security have been proposed along with the advanced QKD protocols R&D. There is a natural competition between these two fields, and any breakthrough in one stimulates research in the other. Information-theoretical classification distinguishes individual, collective, and coherent attacks. All these attacks consist of three common steps:Allowing an ancillary quantum state to interact with a state transmitted via the quantum channel and storing this state in a quantum memory.Listening to the key sifting or reconciliation on the public channel.Deducing and performing the optimal measurement on the stored quantum state.To launch an individual attack, Eve uses a single quantum state, for example, a qubit, as the ancillary state. For a more powerful collective attack, she uses an ensemble of identically prepared independent ancillary states. For the most powerful coherent attack, Eve employs a multipartite entangled state. The security against these attacks under various scenarios has been analyzed in a large number of publications; see for example, Ref. for review. Note that it is very difficult to prove security against the coherent attack in a general case for many QKD protocols.The attacks discussed above are designed to break the QKD protocols at the conceptual level. From a practical standpoint we should also consider the attacks exploiting flaws in the protocol implementations or in the hardware, which is known as quantum hacking. One example of a flawed implementation is the BB84 or a similar DV QKD protocols using weak coherent pulses instead of single photons. Such a “sloppy” implementation is justified by considerable practical benefits of using coherent light sources, but it opens the doors to the PNS attack, which is not possible in the single-photon implementation. Examples of faulty hardware are the already mentioned APDs emitting their own light after a detection and electro-optical devices broadcasting electromagnetic pulses when operated.中文量子通信系统的研发进展1作为信息传递的渠道1.1引言了解光的本质可以知道在实际的光通信中如何利用量子物理学的原理。
信息管理专业英语 unit1-12 单词以及句子翻译
专业英语一、专业术语RFID射频识别IOT物联网Cloud Computing云计算ANN神经网络BI商业智能E-business /Web-business / e-commerce电子商务KM知识管理GIS地理信息系统PDA掌上电脑Bluetooth蓝牙技术CAD计算机辅助设计CMD计算机辅助制作branch manager部门经理binary format二进制格式USB（Universal Serial Bus）通用串行总线computer case计算机机箱temporary storage of information临时存储信息floppy disk软盘CD-ROM只读光盘textual源代码video card视频卡，显卡sound card音频卡，声卡DVD数字化视频光盘SISP战略信息系统计划Project Management项目管理Human Resources人力资源End-User Systems Development最终用户系统开发rolling business plans流动业务计划MIS(management information system)管理信息系统DB（database）数据库DBMS（database Management system）数据库管理系统DSS（decision support system）决策支持系统operational manager运营经理Senior manager 高级经理semi-structured decision半结构化决策ANS（Advanced Network&Service）高级网络及服务公司TPS（Transaction Processing systems）事务管理系统KWS（Knowledge Work Systems）只是工作系统GRASP绘制机器人技术应用软件包OAS（Office Automation Systems）办公自动化系统ESS（Executive Support Systems）经理支持系统EIS（Executive Information Systems）经理信息系统OLAP（on-line analytical processing）联机分析处理GIS（Group Information Systems）集群信息系统GDSS（Group Decision Support Systems）集群决策支持系统MIT（Management Information technology）管理信息技术RAD（rapid application development）快速应用开发Two-way communications 双工通讯client-server environment 客户服务环境Data warehouse 数据仓库logistics information systems 物流信息系统ERP（Enterprise resource planning）企业资源规划CRM（customer relationship Management）客户关系管理OOD（Object-Oriented design）面向对象设计OOP（Object0Oriented Programming）面向对象编程HLLs（High Level Languages）高级语言ADTs（Abstract Data Types）抽象数据类型Software Ics软件的组成单元machine code机器码op-code输出码EDI（Electronic Data interchange）电子数据交换SMEs（small and medium sized enterprises）中小企业B2B企业对企业电子商务B2C企业对用户电子商务CERT(Character Error Rate Tester)字符出错率测试器CIAS（Communication Link Analyzer System）通信链路分析系统IMS（Information Management System）管理信息系统NDMS（Netware Data Management System）网络数据管理系统二、翻译Unit 11. Management is the attainment of organizational goals in an effective and efficient manner through planning, organizing, leading, and controlling organizational resources.管理是组织目标通过计划、组织、领导、控制组织资源实现的有效方式。
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现在，可以正式的定义一个
random process X(t) as an
随机过程 X（t）为具有一定
ensemble of time functions
概率规则的时间函数的集
together with a probability
合，这个概率规则就是为任
rule that assigns a probability
delta function energy spectral density symbol shaping pulse
symbol duration
mixing
the power spectral density of the output process Y(t) equals the power spectral density of
autocorrelation function
ergodic in the autocorrelation
自相关函数遍历
function
1.6 Transmission of a Random Process Through a Linear Time-Invariant Filter
随机过程通过一个线性时不变滤波器
自相关函数
the autocorrelation function of a strictly stationary process depends only on the time
difference t1 − t2
second-order
stationary,
wide-sense stationary, or
1.1 Introduction 简介
数学模型 确定的 可能性 随机的
信载信号
interference component channel noise thermal noise
干扰成分 信道噪声
热噪声
1.2 Mathematical Definition of a Random Process
随机过程的数学定义
联合严平稳
平稳函数的一维分布函数与 时间无关。
The second-order distribution
平稳过程的二维分布函数只
function of a stationary
与观测的时间差有关
random process depends only
on the time difference
between the observation
sample point
采样点
sample space
采样空间
random or stochastic process
随机过程
total observation interval
总观测区间
realization
实现
sample function
样本函数
random variable
随机变量
We may now formally define a
Sources of noise and their narrowband form.
采用功率谱密度对随机过程 进行频域描述。
重要的一种随机过程：高斯 过程的特性。
噪声源及其窄带形式。
Rayleigh and Rician distributions, which represent
瑞利分布和莱斯分布是通信 系统研究中产生的两类重要
two special probability distributions that arise in the study of communication systems.
的概率分布。
mathematical model deterministic probability
stochastic or random information-bearing signal
process multiplied by the
squared magnitude response
of the filter
Einstein-Wiener-Khintchine Einstein-Wiener-Khintchine 关
relations
系式
The zero-frequency value of
the input process X(t) multiplied by the squared magnitude response of the
filter. power signal
periodogram estimating
delta 函数 能量谱密度 符号整形脉冲 符号持续时间
Chapter 1 Random Processes
第一章 随机过程
英文斜体部分
词语翻译
句子翻译
The notion of a random
随机过程的概念。
process.
The requirement that has to
一个随机过程是平稳随机过
be satisfied for a random
What happens to a stationary random process when it is transmitted through a linear time-invariant filter?
平稳随机过程具有遍历性必 须满足的条件，这为采用集 平均代替时间平均提供了可 能。
当一个平稳随机过程通过一 个线性时不变滤波器时会发 生的变化。
程必须满足的条件。
process to be stationary.
The partial description of a random process in terms of its mean,correlation,and covariance functions.
对随机过程的均值、相关函 数、以及协方差函数的分别 描述。
何与随机过程的一个样本函
to any meaningful event
数观察值有关的有意义事件
associated
with
an
都分配一定的概率。
observation of one of the
sample functions of the
random process.
stationary nonstationary stationary in the strict sense or strictly stationary
平稳过程功率谱密度的零频
the power spectral density of
率值等于自相关函数曲线下
a stationary process equals
的全部面积
the total area under the graph of the autocorrelation function The mean-square value of a stationary process equals the total area under the graph of the power spectral density The power spectral density of a stationary process is always nonnegative The power spectral density of a real-valued random process is an even function of frequency The power spectral density, appropriately normalized, has the properties usually associated with a probability density function
1.3 Stationary Processes 平稳过程 平稳的 不平稳
严格意义上的平稳或者严平 稳
a random process X(t), initiated at time t=-∞,is strictly stationary if the joint distribution of any set of random variables obtained by observing the random process X(t) is invariant with respect to the location of the origin t=0.
The conditions that have to be satisfied for a stationary random process to be ergodic, a property that enables us to substitute time averages for ensemble averages.
数学期望 或
ensemble averages
集平均
long-term sample averages
长期样本平均 或
or
时间平均
time averages
estimation
估计
unbiased estimate
无偏估计
ergodic in the mean
均值遍历
time-averaged
时间平均自相关函数
如果观测随机过程 X(t)（从 t=-∞开始）所得到的每一组随 机变量的联合分布函数对于 不同的时间原点 t=0 是时不 变的，那么随机过程 X(t)是严 平稳的。
jointly strictly stationary The first-order distribution of a stationary random process is independent of time.