专业英语复习资料改
A serial out shift register 串行输出移位寄存器
a serial-in shift register 串行输入移位寄存器
AMPS先进移动电话业务
Analog to digital converter数模转换器
application specific integrated circuit(ASIC)专业集点电路automatic Frequency control(AFC)自动频率控制器
bipolar-junction transistor（BJT)双极性晶体管
CCI同信道干扰
CDMA码分多址
Clock pulse 时钟脉冲
Closed-loop gain 闭环增益
DC transducer amplifier 直流传感放大器
DOS服务拒绝
DPSK差分移位键控
DQPSK回相移位键控
DSP数字信号处理
error rate误码率
FAT文件列表
FDMA频分多址
field-effect transistor(FET)场效应晶体管
Field-programmable gate arrays(FPGA)现场可编写门阵列
FIR有限脉冲响应
Gate-level netlist门极网表
GSM欧洲数字系统
GUI图形用户接口
hardware description language(HDL)计算机硬件描述语言Hybrid TDMA混合时分复用
IDS入侵检测
IIR无限脉冲响应
ISDN综合数字业务网
ISI(Inter-symbol interference)码间干扰
JK flip-flops JK触发器
LAN局域网
LEO低地球轨道
lossless data compression无损数据压缩
lossy data compression有损数据压缩
MAC媒体接入控制
mental-oxide semiconductor(MOS)金属氧化物半导体
MTSO移动交换机构
noisy-channel coding theorem噪信道编码理论
OFDM正交平分
OOA面向对象分析
OOD面向对象设计
OOPL面向对象程序设计语言
Operational amplifiers 运算放大器
PAPTR高峰值平均功率比
pass-band 通带
PDM 脉冲宽度调制
Per bit/sec每秒比特数
Phase lock loop(PLL)锁相环
rate-distortion theory率失真理论
RF communication射频通信
ripple counters 波纹计数器
RS 触发器
RTL（register transfer level)寄存转换极
SAN存储区域网络
SFN单频网
sign-to-noise ratio 信噪比
source-channel separation theorems信源分离理论
System-on-chip(SOC)片上系统
T flip-flops T触发器
throughput 吞吐量
time-division multiplexing时分多路
TMDA时分多址
UMTS移动通信系统
Uncommitted logic array(ULA)同化逻辑阵列
VISI超大规模集成芯片
voltage-controlled oscillator(VCO)压控振荡器
WDM波分复用
A wire carrying a current looks exactly the same and weighs exactly the same as it does when it is not carrying a current. 一根带电的导线其外表与重量都与不带电导线完全一样。
A fiber may either be single-mode or multimode, dictated by the specific design and the wavelength of the light propagating in the fiber.
一根光纤根据其设计和在其中传播的光的波长，可以是单模的也可以是多模的。
An interleaver in essence scrambles the time order of the bits according to an algorithm known by the receiver.交织器实质上根据接收端已知的某种算法打乱比特位的时间顺序。
A channel is a division in a transmission medium so that it can be used to send multiple streams of information.信道在传输媒介中分隔区域，以用于使传输媒介传送多个信息流。
As wavelengths decrease to approach the size of circuit components, circuit elements are no longer lumped, and leads can act as reflective components and/or antennas and lumped elements as electromagnetic resonators.
随着波长减小到接近于电路元件的尺寸，电路单元就不再是集总的，导线可起到反射元件以及（或）天线的作用，集总单元则成为电磁谐振器。
A filter may also be described as a difference equation, a collection of zeroes and poles or, if it is an FIR filter, an impulse response or step response.7
滤波器也可以用差分方程或一组零极点表示，对于FIR滤波器还可以用冲击响应或阶跃响应表示。
Communication is the transmission of information from one point to another. This transmission requires the ability to vary signals with time in a manner which is unpredictable to the receiver. 通信就是信息从一点传送到另一点。这种传送要求信号随时间发生的变化不能在接收端预测
The reverse link is not orthogonal, resulting in significant inter-user interference. For this reason the reverse channel sets the capacity of the system.反向连接是非正交的，导致用户间的严重干扰。由于这一原因，反向信道限制了系统的容量。
The output of one flip-flop is the input to the next; the state changes consequently “ripple through”the flip-flops, requiring a time proportional to the length of the counter.一个触发器输出是下一个的输入，因而状态变化以波动形式通过各触发器，所需时间与计数器长度成正比。
The task of a phaselock receiver is to reproduce the original signal while removing as much of the noise as possible锁相接收机的作用是重建原信号而尽可能地去除噪声。
The input data to be transmitted is buffered over the previous frame and burst transmitted at a higher rate during the time slot for the channel.待发送的输入数据在前一帧期间被缓存，在分配给该信道的时隙中以较高速率爆发式发送出去
The main function of the receiver is to extract the input message signal from the degraded version of the transmitted signal coming from the channel.接收器的主要功能是从由信道传输来的退化了的信号中提取出输入消息
Since the very beginning,communications systems have consisted of three major parts, namely, the equipment, the medium, and the protocol. It is still the case today. However, the close link of telecommunications with the computer technology has brought about tremendous changes in communications, from the concepts, to thecontents and the methods. 从一开始通信系统就由设备、媒介和协议三个要素组成。至今依然如此。然而电信与计算机技术的紧密联系使得通信从概念到内容和手段都发生了重大的变化
The process gain of a system indicates the gain or signal to noise improvement exhibited by a spread spectrum system by the nature of the spreading and despreading process.系统处理增益是指扩频系统通过扩频和反扩频的性质所表现出来的增益或信噪比的提高
The idea is that, if the center cell uses a frequency f1 for communication, the six neighboring cells cannot utilize this frequency but the cells beyond the immediate neighbors may.频率重用概念是：如果位于中央的蜂窝
使用频率f1进行通信，那么与其相邻的6个蜂窝就不能使用这个频率，但外面不直接相邻的蜂窝可再次使用这个频率
The concept of availability means that the information, the computing systems used to process the information, and the security controls used to protect the information are all available and functioning correctly when the information is needed.
信息可用性是指当需要某一信息时，信息本身、用来处理信息的计算机、保护信息的安全控制都处于有效可用的状态，并且功能正常。
The swithing of the MCU is commonly achieved by voice activation so that the site where the audio is active is transmitting to all receiving sites.
MCU 的切换通常是用语音驱动，这样有语音出现的的节点就向所有接收点发送信息。
e. The objective is to be able to design a circuit from the basis of the published data, and know that it will function as predicted when the prototype is constructed.能按公布的数据设计电路，并确认构建的样机具有预计的功能
When the loop is locked, the control voltage is such that the frequency of the VCO is exactly equal to the average frequency of the input signal 当锁相环处于锁定状态时，控制电压使压控振荡器的频率正好等于输入信号频率的平均值。
Roughly speaking, the transistor can be likened to an electronically controlled valve whereby energy applied to one connection of the valve enables energy to flow between two other connections.粗略地说，晶体管好似一种电子控制阀，由此加在阀一端的能量可以使能量在另外两个连接端之间流动
Gate array design is a manufacturing method in which the diffused layers, i.e. transistors and other active devices, are predefined and wafers containing such devices are held in stock prior to metallization, in other words, unconnected. 门阵列设计是一种制造方法，事先定义好扩散层（晶体管和其它有源器件），包含这些器件的晶片在金属化之前被库存，就是说先不进行联接。
Synchronous transmission uses no start and stop bits but instead synchronizes transmission speeds at both the receiving and sending end of the transmission using clock signals built into each component.同步传输不使用起始和结束位，而是用插入各数据单元中的时钟信号使接收端和发送端传输速度同步。
If one were to transmit such information without impressing it on an optical carrier but instead on a radio frequency (RF) carrier a bit higher than the maximum rate, the transmission wavelength of the RF carrier would be centimeters or larger.
如果传输这样的信息不是将它加载到光纤上，而是加载在略高于最大速率的射频载波上，则此射频载波就会是厘米波或是波长更长一些的波。
句意转换
Linear filters satisfy the superposition condition, i.e., if an input is a weighted linear combination of different signals, the output is an equally weighted linear
combination of the corresponding output signals.
线性滤波器满足叠加条件，就是说，如果输入是不同信号的加权线性组合，输出就是（各信号）相应输出的同样加权线性组合。
While the subject of coding often carries with it an air of secrecy, a more important motive in many coding systems is the improved efficiency in conveying information. 如果说编码这一主题常带有一种秘密的色彩，那么许多编码系统的一个更重要的目的则是为了提高信息传递的效率。
To keep your computer in the best of health it only makes sense to have anti-virus sofeware running and to keep it UPDATED!
要保持你的计算机处于最佳状态，只有运行抗病软件并保持不断更新才是明智的。
In recent years,there has been a tremendous increase in the use of digital computers and special-purpose digital circuitry for performing varied signal processing functions that were originally achieved with analog equipment. 近年来为实现各种信号处理功能，数字计算机和专用数字电路的使用有了巨大的增长，这些处理功能原先都是用模拟设备实现的。
It is all too easy with linear circuits, which appear relatively simple when compared with today’s complex logic arrangements, to ignore detailed performance parameters which can drastically reduce the expected performance.（D）
A.which has bad influence upon the system performance
B.B. which is important to ensure circuit linearity
C.which is possible to enhance the system performance
D. which is crucial for maintaining the desired performance
Therefore there will be a slight time delay, due to the propagation delay of the flip-flops between the time one flip-flop changes state and the time the next one changes state, i.e., the change of state ripples through the counter, and these counters are therefore called ripple counters.（A）
A.the state change is propagated through the counter like ripples
B.the state changes cause ripples in the counter
C.passing through the counter, the state ripple changes
D.the state of the counter changes due to ripples
Instead of triggering on each pulse, a phase lock technique examines the relative phase between each oscillator and many of its sync pulses and adjusts oscillator frequency so that the average phase discrepancy is small. （B）
A.checks each oscillator for many sync pulses
B.checks the phase relationship between individual oscillators and a
collection of sync pulses
C.looks at the relations between the phase and the sync pulses
D.examines whether the phase is relative to the oscillator
A second major step would be to develop design specifications that consider the functionality of the human with the same degree of care that has been given to the rest of the system.（D）
A.develop design procedures to account for the human behavior and
activities
B.promote design arrangements and take the human factors into
consideration
C.make used of design steps that respect the human functionality
D.draft and effect design requirements that take into
Click mouse on the waveform and drag it to change the pulse repetition rate or directly enter a new value of the period in the provided dialogue box, keeping the pulse width unchanged.(A)
A.simply type a new period value in the given dialogue box
B.direct an entry for the new period value to the dialogue box
C.point a straightforward new period value to the dialogue box provided
D.enter a direction of a new period value to provide a dialogue box For a decade there has been a search for a programmable
processor which, given the cost and volume constraints, is general enough to be programmed with different algorithms. (D)
A.with controlled measures of price and magnitude
B. given the condition of risk and number
C. given the constants of charge and weight
D. given the limits of price and size
Synchronous transmission uses no start and stop bits but instead synchronizes transmission speeds at both the receiving and sending end of the transmission using clock signals built into each component(B).
https://www.360docs.net/doc/e01190629.html,ing synchronization signals to build each component
https://www.360docs.net/doc/e01190629.html,ing timing pulses that are incorporated in each component
https://www.360docs.net/doc/e01190629.html,ing timing signals in order to build each component
https://www.360docs.net/doc/e01190629.html,ing clocks that can build signal components
Information theory, however,does not involve message importance or meaning, as these are matters of the quality of data rather than the quantity of data, the latter of which is determined solely by probabilities.(D)
A.which is the later one of the determined probabilities
B.the later one being probably deterministic
C.in which the later one is deterministic rather than probabilistic
D.the data quantity being determined by probabilities only Consequently, electronic equipment is constantly subjected to unwanted sources of energy and is constantly producing energy that adjacent equipment is not designed to accept.(A)
A.continually making unaccepted interference to adjacent equipment
B.continuously causing neighboring equipment not to accept expected
energy
C.constantly producing energy that is acceptable only to neighboring
equipment
D.ceaselessly generating energy that is considered acceptable in the
design of adjacent equipment
The process gain of a system indicates the gain or signal to noise improvement exhibited by a spread spectrum system by the nature of the spreading and despreading process. (C)
A.by virtue of the spreading/dispreading process
B.by processing the spreading/despreading naturally
C. according to the spreading/despreading characteristics
https://www.360docs.net/doc/e01190629.html,ing the natural spreading/dispreading process
For example, when a part of the channel bandwidth is faded, frequency interleaving ensures that the bit errors that would result from those subcarriers in the faded part of the bandwidth are spread out in the bit-stream rather than being concentrated.(A)
A.that would be produced in those subcarriers suffering from frequency
selective fading
B.that would cause some subcarriers being faded in some part of the
bandwidth
C.that would came from the fading subcarriers falling in part of the
bandwidth
D.that would result in those faded subcarrier of the part of the
bandwidth
Early we introduced the concept that the identity of an amplitude modulated message signal may under certain circumstances be communicated by transmitting regular samples of the message, rather than the continuous signal.(A)
A.values of the message signal taken at regular intervals
B.formally obtained message samples
C.samples of the message produced in a specific manner
D.samples of the regularly obtained message
Wireless servic es have been growing at a rate greater than 50% per year, with the current second-generation European digital systems (GSM) being expected to be filled to capacity by the early 2000s.(A)
A.going to become saturated by the early 2000s
B.going to fill the gap by the early 2000s
C.presumably being expanded to the capacity by the early 2000s
D.expectedly being exceeding the filled capacity by the early 2000s We shall use this parameter as a measure of degradationduring the evaluation of different quantization systems later in this chapter.
A.an action of processing
B.a degree of enhancement
C.an amount of impairment
D.an effect of interference
The development of optical fiber over the last twenty years has resulted in the production of optical fiber cables that exhibit very low attenuation and transmission loss in comparison with the best copper conductors. (A)
A cause very small reduction in the power of signals traveling over them B. make very severe enhancement resulting in loss of transmission
C. show very weak coupling and infrequent transmission failure
D. attract very little attention so as to cause transmission degradation
Both intermodal and intramodel dispersions arise as a result of (a) waveguide effects and (b) material effects; the latter due to the finite bandwidth of the source and the fact that at different wavelengths the refractive indices are different.
A.the later is caused by the fine bandwidth of the source
B. the latter effects being confined to the finite bandwidth
of the source
C. the material effects being a result of the restricted source bandwidth
D. both effects being the cause of the limited source bandwidth
Linear filters satisfy the superposition condition, i.e., if an input is a weighted linear combination of different signals, the output is an equally weighted linear combination of the corresponding output signals. (A)
A. an input is the sum of different signals, each being multiplied by a different weight
B. an input is weighted and linearly combined with different signals
C. an input is linearly weighted by combining different signals
D. an input is linear with a weight to combine different signals
It also means that data stored in one part of a database system is in agreement with other related data stored inanother part of the database system (or another system).
(C)
A.equal to other data that is related to the database system
B. similar to other data in relation to another section of the database system
C. consistent with related data stored in a different part of the database
D. identical to other related data else where in the database system
5. Are they better able to do logical reasoning than people, but less intuitive to do the everyday task? (A)
A. inference
B. reason finding
C. proving
D. recognizing logically
In addition, businesses are relying on increasingly powerful servers to handle transaction and database processing and to support massive client/server networks that have replaced the huge mainframe computer centersof yesteryear. (A)
A. to deal with business operations and database processing
B. to treat and process database transmission
C. to manipulate interaction of database operations
D. to carry out interchange of data in the database
Support of premises-wide data communications requires a networking service that is capable of spanning the distances involved and that interconnects equipment in a single (perhaps large) building or a cluster of buildings. (D)
A.that can cross long distances of involvement
B. that involves distance capable of covering the service cost
C. that is able to support the distant involvement
D. that can cover the necessary distances for the service
Multimedia has been around for years, of course, through movies and television, but the word multimedia refers almost exclusively to computer technology. (D)
A.the word multimedia can only be used together with computer technology
B. the term multimedia indicates that it is almost used by computers
C. multimedia is a word of reference in the computer world that is almost exclusive
D. the word multimedia is meant to be related to computer technology with few exceptions
Most people would agree that the advent of multimedia on the Internet is a change for the better, although longtime users may contend that the Internet’s newfound ease of use(B)
is making cyberspace a wee bit crowded for their tastes.
A.the better use of the Internet changes everything
B. the introduction of the Internet is a good development
C. the invention of the Internet makes live better
D. the development of the Internet is changing rapidly
As DoD urgently wanted military command and control networks that could survive a nuclear war, ARPA wascharged with inventing a technology that could get data to its destination reliably even if arbitrary parts of the network disappeared without warning as a result of a nuclear attack. (B)
A.obtain data for its design
B. deliver data to the intended location
C. get data to fulfill its task
D. produce data to meet the demand