电子信息与通信工程专业英语lesson6(太原理工大学版)
电子与通信工程专业英语DX电子教案Unit6
电子与通信工程专业英语DX电子教案Unit6Unit 6 Portable Media PlayerI．Lead-inInformation related to the textDo you know what a PMP is? Where is the data typically stored? Which are digital audio players generally categorized? What is usually used as a display when PMPs play digital audio, images and video? Today, we’ll study Unit 6 “Portable Media Player”. We’ll study the definition of PMP and the categorization of digital audio players. Now, let’s study key words and phrases of the text together.II. Word study1. device [di'vais] n.仪器；装置；设备；策略；商标图案1) The recording device has activated.录音装置已开动起来。
2) an electronic device that protects your vehicle 24 hours a day24小时保护车辆的电子装置3) a device that could measure minute quantities of matter能够测量微量物质的设备4) They claim that military spending is used as a device for managing the economy. 他们声称军费开支是用来作为调控经济的手段的。
信息与通信工程专业科技英语课件
For Information and Communication Engineering
2024/10/14
0
Unit Sixteen
Optical Communication Components
1
概述
光纤作为通信传输媒介的基本原理 均芯光纤和渐变折射率光纤 传输引起的失真和误码 多模和单模光纤 光纤作为调制和检测元件
inside the core of the waveguide. In such a fiber rays
traveling at larger angles to the axis have to traverse a larger path and hence take a longer time than those rays which propagate with lesser angles to the axis.1
11
Unit 16
Each mode has most of the energy inside the core, but due to the evanescent fields outside the core, a part of the energy is also traveling in the cladding. By making the cladding sufficiently thick, the fields of the mode at the cladding-air boundary can be made small, thus making it easy to handle and support without causing much disturbance to the modes.
通信英语 课文UNIT 6
UNIT 8Introduction to Optical Fiber Communication光纤通信介绍One of the most important technological developments during the 1980s has been the emergence of optical fiber communication as a major international industry.光纤通信介绍80年代一项最重要的技术发展是光纤通信成为一个主要的国际性产业。
One indication of the extent of this development is the total length of installed fiber, which was estimated to be 3.2million kilometers in the U.S. alone by the end of 1987.用光纤敷设总长度可以表明其发展程度,据估计,到1987年底仅美国的关切敷设总长将达320万公里Over 90% of this fiber was placed in service during the time period of 1982-1987.其中90%以上是在1982-1987年间敷设并开通的Long-haul trunk installations have been dominated, accounting for about 95% of the fiber in the U.S.95%Although telecommunication is the rationale for most of the current interest in fiber optics, this was not the case during the early days of the technology.The researchers who produced the first clad glass optical fibers in the early 1950s were not thinking of using them for communications; they wanted to make imaging bundles for endoscopy.50年代初研究人员制造出第一根具有包层玻璃光纤时,并不想用于通信而是想用它们传送内窥镜需要的成像光束。
电子通信专业英语单词
通过对…的深
刻了解 deviate from 偏离 deviate 偏离 devices 装置 devoted 投 DFT 离散型福利叶 变换 diagnostic 诊断 diameter 直径 dictate 口授 dielectric constant
结构 circuitry 电路 classified 分类 climate 思潮 clocked 时钟控制 clocked 锁存 clockwise 顺时针 close proximity 接 近 closed-loop 闭合环路 closed-path 闭合路径 closethe relay contact
连续性方程 continuously 持续 continuous-time 时 间上连续 contour 轮廓，等高线 contrast 对比度 contribution 权、重值 contuct 触点 convenient packaging
简易封装 convention 协定，习 俗，习惯 convention 协定 converge 收敛 converted 转换 convolution 卷积 coordinated 协调的, 同等的
conductor 导体 conduit 水管，管道 configuration 结构 conflict 斗争，冲突 consequently 因而 conservation 保持 conservation 守恒 consist of 由……组 成
constant group delay
“通信工程专业英语”Unit06_Evolution of Lightwave Systems
WangChengyou © Shandong University, Weihai
Specialized English / 专业英语
12
Conventional InGaAsP semiconductor lasers could not be used because of pulse spreading occurring as a result of simultaneous oscillation of several longitudinal modes. semiconductor lasers：半导体激光器 pulse spreading：脉冲展宽 longitudinal modes：纵模 由于多纵模震荡导致的脉冲展宽，使得传统的InGaAsP半导体激光 器不能使用。
Specialized English / 专业英语
3
翻译长句时：
不要因为句子太长而产生畏惧心理，无论是多么复杂的句 子，都是由一些基本的成分组成的 弄清英语原文的句法结构，找出整个句子的中心内容及其 各层意思 分析几层意思之间的逻辑关系，按汉语的表达方式正确译 出原文的意思，不必拘泥于原文的形式。
Specialized English / 专业英语
1
Specialized English
——Unit6 Evolution of Lightwave Systems
王成优 博士、讲师 wangchengyou@
WangChengyou © Shandong University, Weihai
Specialized English / 专业英语
2
第一部分 专业英语基础知识
长句的翻译：
英语：习惯于用长句表达复杂的概念 汉语：常使用若干短句并列表达思想 长句在科技英语中出现得极为频繁，原因有三方面： 修饰语过多 并列成分多 语言结构层次多
电子信息专业英语——13+unit+6+Electronic+Communication
Unit 6 Electronic Communications
4. Bandwidth and Information Capacity The two most significant limitations on the performance of a communications system are noise and bandwidth.
带宽与信息容量
Unit 6 Electronic Communications
In recent years, transistors and linear integrated circuits have simplified the design of electronic communications circuits, thus allowing for miniaturization, improved performance and reliability, and reduced overall costs.
(13) 国际电信联盟
(14)
(15)
Unit 6 Electronic Communications
3. Answer the following questions. (1) When and by whom was the first electronic communications system developed? (2) What is the first amplifying device for electrical signals? (3) What systems are included in modern electronic communications systems? (4) What’s the difference between analog signal, discrete signal and digital signal? (5) Could you state Hartley’s law and Shannon’s formula?
电子与通信工程硕士专业英语part 6
Lesson 3 电 信 Telecommunications
精读详解 Intensive reading：
Applications · File-Transfer …… An outgrowth of file transfer is electronic mail. For example, an employee might write a document such as a letter, memorandum, or report on a computer and then send the document to another employee’s computer.
• 技术背景 Background：
Lesson 3 电 信 Telecommunications
Lesson 3 电 信 Telecommunications
• 内容大纲 Outline：
Hardware and Software ·Hardware ·Software
·Host-Terminal
Lesson 3 电 信 Telecommunications
精读详解 Intensive reading：
Hardware and Software Each telecommunications device uses hardware, which connects a device to the transmission line; and software, which makes it possible for a device to transmit information through the line. · Hardware Hardware usually consists of a transmitter and a cable interface, or if the telephone is used as a transmission line, a modulator/ demodulator, or modem.
(完整版)电子信息与通信工程专业英语期末必考翻译
1."In most cases, these signals originate as sensory data from the real world: seismic vibrations visual images, sound waves, etc. DSP isthe mathematics, the algorithms, and the techniques used to manipulate these signals after they have been converted into a digital form." 在大多数情况下，这些信号来源于人对真实世界的感觉，比如地震的震动，视觉图像，声音波形等。
数字信号处理是一种数学工具，是一种用来处理那些将上述信号转换成数字形式后的信号的算法和技术。
2.Fourier’s representation of functionsas a superposition of sines and cosines has become Ubiquitous for both the analytic and numerical solution of differential equations and for the analysis and treatment of communication signals 函数的傅里叶表示，即将函数表示成正弦和余弦信号的叠加，这种方法已经广泛用于微分方程的解析法和数值法求解过程以及通信信号的分析和处理。
3.If f (t ) is a nonperiodic signal, the summation of the periodic functions ,such as sine and cosine, does not accurately represent the signal. You could artificially extend the signal to make it periodic but it would require additional continuity at the end points . 如果f(t)是非周期信号，那么用周期函数例如正弦和余弦的和，并不能精确的表示该信号f(t)。
太原理工大学各学院及专业方向中英文对照表
太原理工大学各学院及专业(方向)中英文对照表【机械工程学院】College of Mechanical Engineering机械设计制造及其自动化Mechanical Design & Manufacturing and Automation1.机械制造及其自动化Mechanical Manufacturing and Automation2.机械设计及理论Mechanical Design and Theory3.机械电子工程Mechatronics Electronics Engineering4.车辆工程Vehicle Engineering工业设计Industrial Design机械系Department of Mechanical Engineering机械制造工艺及设备Machinery Manufacturing Process and Equipment【材料科学与工程学院】College of Materials Science and Engineering材料成型及控制工程Materials Processing and Controlling Engineering金属材料工程Metallic Materials Engineering无机非金属材料工程Inorganic Non-metallic Materials Engineering冶金工程Metallurgical Engineering高分子材料与工程Macromolecular Materials and Engineering材料物理Materials Physics材料化学Materials Chemistry1.材料物理与化学Materials Physics and Chemistry2.材料科学与工程Materials Science and Engineering3.材料加工工程Materials Processing Engineering4.钢铁冶金Iron and Steel Metallurgy5.有色金属冶金Nonferrous Metallurgy【电气与动力工程学院】College of Electrical and Power Engineering电气工程及其自动化Electrical Engineering and Automation热能与动力工程Thermal Energy and Power Engineering培养方向：1.热动力工程Thermo Power Engineering2.动力机械及工程Power Machinery and Engineering3.电机与电器Electrical Machinery and Appliances4.电力系统及其自动化Electrical System and its Automation5.高压电绝缘技术High-V oltage Electricity an Insulation Technology6.电气，电子和传动装置Electrical, Electronics and Transmission7.电工理论与新技术Theory and New Technology of Electrical Engineering 【信息工程学院】College of Information Engineering自动化Automation培养方向：电路系统Electric Circuit and System电子信息工程Electronic Information Engineering测控技术与仪器Measurement Control Technology and Instruments培养方向：1.检测技术与自动化设备Detecting Technology and Automatic Equipment2.系统工程Systems Engineering3.模式识别与智能系统Pattern Recognition and Intellectual System通讯工程Telecommunication Engineering培养方向：1.通信与信息系统Communication and Information System2.信号与信息处理Signal and Information Processing电子科学与技术Electronic Science and Technology培养方向：控制理论与控制工程Control Theory and Control Engineering 【计算机科学与技术学院】College of Computer Engineering and Software 计算机科学与技术Computer Science and Technology物联网工程Internet of Things Engineering【软件学院】College of Software软件工程Software Engineering【建筑与土木工程学院】College of Architecture and Civil Engineering建筑学Architecture城市规划Urban Planning土木工程Civil Engineering【水利科学与工程学院】College of Water Conservancy Science and Engineering水利水电工程Water Conservancy and Hydroelectric Engineering农业水利工程（含水利信息化方向）Agricultural Water Conservancy Engineering水文与水资源工程Hydrology and Water Resources EngineeringAgricultural Soil and Water EngineeringHydrology and Water ResourcesHydraulics and River DynamicsWater Engineering and Structural EngineeringWater Conservancy and Hydroelectric EngineeringHarbor Beach and Inshore Engineering【化学化工学院】College of Chemistry and Chemical Engineering化学工程与工艺Chemical Engineering and Technology（化学工艺、能源化工、精细化工、高分子化工方向）Chemical Engineering and Technology (Chemical Process、Chemical Energy、Fine Chemical、Polymer Chemistry)应用化学Applied Chemistry生物工程Bioengineering制药工程（化学与生物制药工程方向）Pharmaceutical Engineering过程装备与控制工程Process Equipment and Control Engineering化学和生物制药工程方向Chemical and Biological Pharmaceutical Engineering Direction【矿业工程学院】College of Mining Engineering采矿工程Mining Engineering安全工程Safety Engineering资源勘查工程Resource Prospecting Engineering测绘工程Geodesy and Geomatics Engineering地理信息系统工程Geographical Information System Engineering矿物加工工程Mineral Processing Engineering城市地下空间工程City Underground Space Engineering勘查技术与工程Exploration Technology and Engineering【轻纺工程学院】College of Textile Engineering with Academy of Fine Arts 纺织工程Textile Engineering服装设计与工程Apparel Design and Engineering艺术设计Artistic Design(2012级以前学生)服装与服饰设计Fashion Design【艺术学院】艺术设计Artistic Design(2012级以前学生)摄影Photography(2012级以前学生)绘画Painting动画Animation数字媒体艺术Digital Media Art文化产业管理Cultural Industry Management视觉传达设计Visual Communication Design环境设计Environment Design影视摄影与制作Photography and Video Production【环境科学与工程学院】College of Environmental Science and Engineering 给水排水工程Water Supply and Drainage Engineering环境工程Environmental Engineering建筑环境与设备工程Constructing Environment and Equipment Engineering 【数学学院】College of Mathematics数学与应用数学Mathematics and Applied Mathematics信息与计算科学Information and Computing Science统计学Statistics【物理与光电工程学院】College of Physics and Photo Electricity Engineering 光信息科学与技术Optical Information Science and Technology应用物理Applied Physics光源与照明Light Source and Lighting【力学学院】College of Mechanics工程力学Engineering Mechanics【外国语学院】College of Foreign Languages英语English【政法学院】College of Politics and Law法学Law行政管理Public Administration思想政治教育Ideological and Political Education【经济管理学院】College of Economics and Management 市场营销Marketing and Sales工程管理Construction Management会计学Accounting国际经济与贸易International Economics and Trade物流管理Logistics Management电子商务Electronic Business【体育学院】College of Physical Education体育教育Physical Education。
最新-电子信息类专业英语(西电第二版)Unit 6 Electronic Communications-PPT文档资料
~(t ) are concentrated m
about f =0; consequently, they are said to be baseband signals.
Unit 6 Electronic Communications
Figure 6.1 Communication System
Unit 6 Electronic Communications
Although the fundamental concepts and principles of electronic communications have changed little since their inception, the methods and circuits used to implement them have
Unit 6 Electronic Communications
Unit 6 Electronic Communications
Passage A Introduction to Electronic Communications Passage B The Principle of PCM Passage C Information Sources
undergone considerable change. In recent years, transistors and
linear integrated circuits have simplified the design of electronic communications circuits, thus allowing for miniaturization,
Unit 6 Electronic Communications
专业英语（电子与信息工程类）翻译
专业英语（电子与信息工程类）翻译1.As data networks advanced…also grew more complex.由于数据网络从面向终端的系统向分组交换、计算机与计算机连接的方向发展，执行网络功能所必需的协议也变得愈来愈复杂。
2.An additional bit called a parity bit…during transmission.在每个字符的后面有时还包括一个称为奇偶校验位的附加位，它们测试数据位在传输过程中是否被意外改变。
3.As already stated，with…downlink（FDD paired bands）.如前所述，在非对称通信量应用中，TD-SCDMA利用可用频谱的效率比其他3G 标准高，因为它在只利用一个频带（TDD单一频带）而不是两个独立的频带（FDD成对频带）进行上行及下行通信。
4.Although often simpler to implement，…digital modulation.虽然光纤系统的模拟调制易于实现，但其效率较低，且要求在接收端有比数字调制高得多的信噪比。
5.At present，the bandwidth…electronics （）is possible.目前传输100km的几吉赫兹的调制信号和传输300km的几百兆赫兹的调制信号都是可能的，因此光纤系统的可用带宽并没有得到充分利用。
6.Both TD-SCDMA deployments-TSD…unpaired bands awarded.TD-SCDMA的两种部署——TSM和TDDCLR的数据速率、频谱利用率、覆盖率、移动性和可靠性等性能是一样的，并基本上为所有取得非成对TDD频段牌照的运营商所采用。
7.Crossbar switching was carried…selection for all calls.纵横制交换由一个称为标志器的特定电路控制，标志器提供整个号码的公共控制并选择所有呼叫的路由。
Drineas_SECON_06
ABSTRACT This paper initiates the principled study of distance reconstruction for distance-based node localization. We address an important issue in node localization by showing that the highly incomplete set of inter-node distance measurements obtained in ad-hoc node deployments carries sufficient information for the accurate reconstruction of the missing distances, even in the presence of noise. We provide an efficient and provably accurate algorithm for this reconstruction, and we show that the resulting error is bounded, √ decreasing at a rate that is inversely proportional to n, the square root of the number of nodes in the region of deployment. Although this result is applicable to many localization schemes, in this paper we illustrate its use in conjunction with the popular MultiDimensional Scaling algorithm. Our analysis reveals valuable insights and key factors to consider during the sensor network setup phase, to improve the quality of the position estimates. 1. INTRODUCTION In the past few years the sensor network community has reached a consensus that knowledge of node locations is unquestionably one of the most desirable attributes of adhoc sensor networks. Knowledge of location can support many networking and maintenance services, and more importantly map the sensed data to physical space. Since the manual recording of node positions is a difficult task even for modest sized networks, the community has invested significant effort in creating algorithms that can derive locations based on inter-node measurements. The simplest and most common embodiment of such algorithms considers the estimation of a coordinate system from a set of pairwise distance measurements among sensor nodes. However, it is well known, that in realistic deployments obstacles and large node separations render the collection of all n2 distances infeasible. Many of the existing
(完整版)电子信息与通信工程专业英语期末必考翻译
1."In most cases, these signals originate as sensory data from the real world: seismic vibrations visual images, sound waves, etc. DSP isthe mathematics, the algorithms, and the techniques used to manipulate these signals after they have been converted into a digital form." 在大多数情况下，这些信号来源于人对真实世界的感觉，比如地震的震动，视觉图像，声音波形等。
数字信号处理是一种数学工具，是一种用来处理那些将上述信号转换成数字形式后的信号的算法和技术。
2.Fourier’s representation of functionsas a superposition of sines and cosines has become Ubiquitous for both the analytic and numerical solution of differential equations and for the analysis and treatment of communication signals 函数的傅里叶表示，即将函数表示成正弦和余弦信号的叠加，这种方法已经广泛用于微分方程的解析法和数值法求解过程以及通信信号的分析和处理。
3.If f (t ) is a nonperiodic signal, the summation of the periodic functions ,such as sine and cosine, does not accurately represent the signal. You could artificially extend the signal to make it periodic but it would require additional continuity at the end points . 如果f(t)是非周期信号，那么用周期函数例如正弦和余弦的和，并不能精确的表示该信号f(t)。
电子信息工程专业英语翻译清华出版社English for IT and EE-06
这个值导致信号ff
What happens when a mobile unit “roams” from cell A to cell B? Since the power level received from the base station in cell A is insufficient to maintain communication, the mobile must change its server to the base station in cell B. Furthermore, since adjacent cells do not use the same group of frequencies, the channel must also change. Called “handoff,” this process is performed by the MTSO. 因为从单元A 因为从单元A的基站接收到的功率 电平不足以维持通信， 电平不足以维持通信，手机必须将 服务器更换为单元B的基站。 服务器更换为单元B的基站。
3
New Words
delay spread 延迟扩展 reflective 反射的 RMS (root mean square) 均方根 replica 复制品 scramble 打乱，使混杂 打乱， entail 需要，使必须 需要， attenuation 衰减 refractive 折射的 alleviate 减轻 interleaving 交叉，交织 交叉， overhead 开销 latency 等待时间，时间延迟 等待时间，
6
1
Most of our treatment relates to the mobile unit because, compared to the base station, hand-held units constitute a handmuch larger portion of the market and their design is much more similar to other types of RF systems. systems.
通信专业英语Unit 06
《信息与通信工程专业科技英语》Unit VIElectronic Documents and WorkflowManagement(1) Fill in the blanks with the most appropriate word or phrase.1. Achieving a high data rate over a large HDTV service area requires high power transmission thatresults _____ much interference to existing NTSC service.A. inB. ______C. fromD. to2. Each time a positive clock edge occurs, the flip-flop changes state, leading to half as many pulses atthe output to the clock input.as B. compared C. due D. so asA.3. Frequency converters are basically similar ______ the modulators previously discussed, with alarge injected signal of frequency close ______ that of the incoming signal superimposed on anincoming waveform.A. with, withB. to, withC. to, toD. with, to4. Having a hard disk means you won’t have to pop floppy disks in and out to capture the treasuresyou retrieve the Net.from B. off C. at D. overA.5. HDTV technology will not only revolutionize the television industry, but it will have a profoundimpact _______ a wide range of industries.inA. throughB. atC. acrossD.6. Imagine that a digital signal is to be conveyed via a cable ______ a very long distance.for B. over C. at D. inA.7. In the previous section we discussed sine-wave or CW modulation systems in which themodulating signal _______ of a digital pulse train.made B. consisted C. contained D. gotA.8. Inter-symbol interference is a significant problem in many data transmission systems, ______particularly troublesome in the transmission of data via telephone lines.A. to beB. andC. ______D. being9. In this book we shall emphasize the limitations imposed on the information transmitted by thesystem through which it was _______ and shall attempt some comparison of different systems.A. putB. traveledC. passedD.viewed10. Let the sampling frequency ______ greater than twice the system bandwidth.A. to beB. beC. ______D. becomesTechnical English for Information and Communication Engineering(2) Translate the following passages into Chinese.1. A typical radar used for the detection of conventional aircraft at ranges of 100 or 200 miles mightemploy a peak power of 1 to 10 Mw, a pulse width of several microseconds, and a pulse repetition frequency of several hundred pulses per second. The modulated RF pulse generated by thetransmitter travels along the transmission line to the antenna, where it is radiated into space. Acommon antenna is usually used for both transmitting and receiving. A fast-acting switch called the transmit-receive (TR) switch disconnects the receiver during transmission. If the receiver were not disconnected and if the transmitter power were too large, the receiver might be damaged. Afterpassage of the transmitted signal, the TR switch reconnects the receiver to the antenna. A portion of the radiated power is then reflected by the target back to the radar and enters the receiver via the same antenna as used for transmitting.一个用于探测100或200英里以外的常规飞机的典型雷达可能采用1～10兆瓦的峰值功率、数十微秒的脉宽、每秒几百周的脉冲重复频率。
通信专业英语
radio 无线电、收音机
radar 雷达 14
laser 激光
0.1 科技英语的特点 features
0.1.2 词汇 Vocabularies or words
❖转意词汇 Transfered words
从普通词汇借用、移植过来，赋予了专业含 义。出现在专业文献中，一般就是使用其专业含 义。
resistance current charge 2020/1c2i/r2 cuit
转意词汇还有：failure，relay，antenna，coherent，filter， spectrum，modulator，flip-flop，potential , carrier , line , loop 等等
2020/12/2
17
0.1 科技英语的特点 features
0.1.2 词汇 Vocabularies or words
❖转意词汇 Transfered words
有些单词的通用含义很接近，但它们的专业含义却完全不 同，如：
differential ：微分 difference ：差分 probability ：概率 possibility ：可能性
信息与通信工程专业英语
Simon R. Saunders, Antennas and Propagation for Wireless Communication Systems, Wiley.
Path loss prediction models Shadowing Radio Propagation : Small Scale Effects Multi-path models : Rayleigh, Rician Doppler effect, power spectra and signal correlation Coherence time and bandwidth, flat and selective fading channel Modulation Techniques Constant envelope and phase modulation QPSK, π /4 QPSK, FSK, GMSK
in transmission mode on 900, 2.4, and 5.8, but practice virtually all 900
MHz phones are inexpensive, bare-bones analog models; digital features such as DSSS and FHSS are generally only available on the higher frequencies. The recently allocated 1.9 GHz band is used by the popular DECT phone standard from Europe
u06p1_Typical DSP Application_DSP的典型应用_20090426
DSP的典型应用电信领域的应用电信就是将信息从一端传输至另一端。
信息的形式有多种，包括电话交谈、电视信号、计算机文件和其他形式的数据。
为了传输这些信息，需要在两地之间构建一条信道。
信道可能是线对、射频信号、光纤等。
电信公司为用户传输信息并收取费用，因为电信公司建立、维护信道需要花钱。
商业底线非常简单：单条信道传输的信息越多，赢利越多。
DSP已使电信行业的许多领域发生了巨大的变化，包括信令音产生与检测、频带搬移、去除电力线哼声的滤波等。
这里讲讨论复用压缩和回声控制这三个电话网络中的例子。
复用全世界约有10亿部电话。
交换网络会在几秒内完成任意两部电话间的连接。
这件任务之庞大令人难以想象！在20世纪60年代之前，两部电话连接需要通过机械开关和放大器传输话音信号。
一个连接需要一个线对。
而DSP将音频信号转换为串行数据流。
因为比特易于组合和分离，所以在一条信道上可以传输多个电话。
例如，“T载波系统”电话标准可同时传送24路语音信号。
每路信号的采样率为8000Hz，采用8位压扩（对数压缩）模数转换。
这样，每路话音信号可用64,000bps表示；全部24路由1.544Mbps表示。
该信号可用22号铜质电话线传输6000英尺（典型互连距离）。
数字传输带来的经济利益是巨大的。
导线和模拟开关价格昂贵；数字逻辑门价格低廉。
压缩当话音信号以8000S/s数字化时，大多数信息是多余的。
也就是说，任一样本携带的信息大都可由其周围样本得到。
十几种DSP算法开发出来，用于将数字话音信号转换为较低数据率的数据流。
这些算法叫“数据压缩算法”。
而“解压缩算法”用于将信号恢复到原来的形式。
不同压缩算法的压缩量不同，获得的音质也不同。
将数据率从64kbps减至32kbps一般不会有音质的损失。
当压缩到8kbps时，声音受到明显影响，但还可用于长途电话网络。
最高的压缩率约为2kbps，此时音质高度畸变；但也可用于军事通信和海底通信等应用。