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本课程起止时间为:2018-05-08到2018-07-06
本篇答案更新状态:已完结
专业英语基础知识 专业英语基础知识单元测试
1、 A continuous signal is also called because its waveform is often analogous to that of the physical variable.
A:an analog signal
B:a discrete signal
C:a digital signal
D:a sampled signal
答案: an analog signal
2、 A system is called linear if it has two mathematical properties: .
A:continuous and shift-invariance
B:shift-invariance and homogeneity
C:additivity and homogeneity
D: additivity and shift-invariance
答案: additivity and homogeneity
3、 Basic circuit theory can be used at .
A:FR/microwave frequency
B: the optical field
C:lower frequency
D:any frequency
答案: lower frequency
4、 In the analysis and design of communication systems, ______ is particularly important.
A:the characteristics of the physical channels
B:the source output
C:the binary information sequence
D:the amount of redundancy introduced
答案: the characteristics of the physical channels
5、 In order to form a cluster in a cellular network, cells are generally organized in groups of ______
A:Six
B:seven
C:five
D:eight
答案: seven
6、 The idea, originated with Bell, of using glass fiber to carry an opticalcommunication signal had to wait some 80 years to be useful because ______.
A:people were not interested in this idea
B:nobody sponsored this project
C:didn’t have suitable glass and low-cost electronics for it
D:other reasons
答案: didn’t have suitable glass and low-cost electronics for it
作业专业英语基础知识 专业英语基础知识作业
1、 Translate into Chinese.The invention of radio has made it possible for mankind to communicate with each other over a long distance.
评分规则: 无线电的发明使人类有可能进行远距离通信。
2、 The power gain in decibels is equal to 10 times the logarithm base 10 of the power gain.
评分规则: 用分贝表示的功率增益等于10乘以以10为底的功率增益的对数
3、 The study of sound is of importance not only in music and speech, but also in communication and industry.
评分规则: 研究声音不仅对音乐和语言，而且对通信和工业都有重要意义。
4、 A signal is a description of how one parameter varies with another parameter.
评分规则: 信号用以描述一个参量如何随另一个参量的变化而变化。
5、 If the electrons and ions can lose energy through collisions, the electromagnetic energy is dissipated by the collisions and turned into heat.
评分规则: 如果电子和离子可通过碰撞损失能量，则碰撞导致电磁能耗尽并转化成热能。
项目一 通信技术基础 通信技术基础单元测试
1、 A continuous signal is also called because its waveform is often analogous to that of the physical variable.
A: an analog signal
B:a discrete signal
C:a digital signal
D:a sampled signal
答案: an analog signal
2、 A system is called linear if it has two mathematical properties: .
A:continuous and shift-invariance
B:shift-invariance and homogeneity
C:additivity and homogeneity
D:additivity and shift-invariance
答案: additivity and homogeneity
3、 The unit impulse signal is the unit step signal.
A:the same as
B:the differential of
C:the integral of
D:the cumulative sum of
答案: the differential of
4、 Which of the following statements best describes the property of the system T if y1(t)=T[x1(t)], y2(t)= T[x2(t)] implies T[ax1(t-s)+bx2(t-s)]= ay1(t-s)+by2(t-s), .
A:the system is linear
B:it is a linear time-invariant system
C:the system satisfies the principle of superposition
D:the system satisfies additivity and time-invariance
答案: it is a linear time-invariant system
5、 Any signal can be represented as .
A:the sum of a series of sinusoids with the same amplitudes
B:the sum of a series of sinusoids at the same frequencies
C:the sum of a series of shifted and scaled unit step function
D:the sum of a series of shifted and scaled unit impulse function
答案: the sum of a series of shifted and scaled unit impulse function
6、 The beginning of microwave engineering is characterized by
A:a piece of paper written by Oliver Heaviside
B:The discovery that electromagnetic wave propagation was possible in waveguide
C:The experimental demonstration of the propagation of electromagnetic waves
D:Maxwell’s equations
答案: Maxwell’s equations
7、 showed experimentally the possibility of electromagnetic wave propagation in waveguide?
A:Heinrich Hertz
B: George Southworth and W.L.Barron
C: Oliver Heaviside
D:Lord Rayleigh
答案: George Southworth and W.L.Barron
8、 Basic circuit theory can be used at .
A:FR/microwave frequency
B:the optical field
C:lower frequency
D:any frequency
答案: lower frequency
9、 Which is not considered as the advantage to using RF/microwaves?
A:larger bandwidth available
B:use of high-speed semiconductors along with their less-mature technology.
C:higher antenna gain possible in a smaller space
D:better resolutions for radars due to smaller wavelengths
答案: use of high-speed semiconductors along with their less-mature technology.
10、 RF/microwaves are used as signal for audio signals in broadcasting.
A:modulated
B:carrier
C:modulating
D:demodulated
答案: modulating
作业项目一 通信技术基础 任务1 Signals,Linear Systems,and Convolution作业
1、 Translate into Chinese：(1)If the input to a linear system is a sinusoidal wave, the output will also be a sinusoidal wave, and at exactly the same frequency as the input.(2)Just as we can express any signal as the sum of a series of shifted and scaled impulses, so too we can express any signal as the sum of a series of (shifted and scaled) sinusoids at different frequencies.(3)A signal is formally defined as a function of one or more variables that conveys information on the nature of a physical phenomenon.(4)Nyquist sampling theorem states that if the highest-frequency component of a CT signal x(t) is fmax, then x(t) can be recovered from its sampled sequence x(nT) if the sampling frequency fs is larger than 2fmax.(5) In fact, if a discrete-time sequence is absolutely summable, then its spectrum is, as in the continuous-time case, a bounded and continuous function of ω.(6) Systems are defined to be stable if every bounded input excites a bounded output. The condition for discrete-time systems to be stable is that all poles of H(x) lie inside the unit circle on the z-plane.
评分规则: 信达雅
作业项目一 通信技术基础 任务2 Radio Frequency and Microwave Applications作业
1、 Translate into Chinese.(1) Microwaves are normally considered to embrace the frequency range 109-1012 Hz or a characteristic wavelength range of 30 cm to 0.3 mm.(2) The study of electromagnetic radiation is an exact science because it can be represented exactly by mathematical expressions.(3) Microwaves are necessary for communication with satellites because they can pass through the ionosphere which reflects lower frequency radio waves.(4) The rate of microwave power absorption in most materials is proportional to its water content. This property can be used to provide microwave heating. Because the microwave signal penetrates most non-conductors, microwave power provides a most efficient means of applying heat uniformly throughout a body.(5)Microwaves are potentially hazardous because of their heating effect. The effect may not be felt until damage has already been done because the heating may be internal whereas our body is designed to warm us about externally applied heat.(6) For seismic signals traveling through a portion of the earth and picked up by appropriate transducers , one can extract from their particular shape and appearance information concerning the underlying strata.
评分规则: 翻译要求：信达雅
项目二 数字信号处理 数字信号处理单元测试
1、 The application areas of DSP include the following but .
A:earthquake recording & analysis
B:cognitive science
C:echo reduction
D:simulation and modeling
答案: cognitive science
2、 According to the text, which of the following statement is false ? Knowledge base
A:Is very complex
B:can be used to guide the operation of each processing module
C:helps to control the interaction between modules
D:is a collection of encoded knowledge about a problem domain in a digital image system
答案: Is very complex
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