出自:河南师范大学-计算机科学与技术-专业英语

In ()transmission, data can be sent in both directions at the same time. A.simplex B.half-duplex C.full-duplex D.none of the above
A special sequence of number or letters that limits access to eletronic mail boxes:( ) A.Authentication B.code C.Encryption D.Password
program designed to destroy data on your computer which can travel to “infect ” other computers.( ) A.message B.information C.hacker D.virus
Internet is simply what? ( ) A.The WWW B.A worldwide system of computer networks C.A modem D.An ISP or Internet Service Provider
A computer calculate using the ( ) system. A.fast B.trianary C.hexadecimal D.binary
The “WWW”is exactly what?( ) A.A web of resources on the Internet that are accessed using HTTP. B.The internet C.An ISP or Internet Service Provider D.Internet
Digital data can be produced by all of the following expect (). A.a voice B.a computer C.a radio-wave D.a visual signal
() can be regarded as a general-purpose digital network capable of supporting a wide range of services such as voice, data and image. A.Local area networks B.Integrated services digital networks C.Packet switching networks D.Mobile communication networks
The principle of converting analog signals to digital signals became popular with the introduction of (). A.pulse code modulation B.packet switching technology C.quadrature amplitude modulation D.stored-program control
In a ()switching system, a call was established and routed in a set of progressive electromechnical steps, each under the direct control of the user ’ s dialing pulse. A.step-by-step B.crossbar C.stored-program-control D.manual
PC-to-PC networking could be easily accomplished between buildings (). A.on one campus B.between campuses C.a or b D.none of them
()are not utilized for the detection of the signal and the optical-electrical conversion. A.Light emitting diodes B.Phototransistors C.Photoconductors D.Photodiodes
The electrical transmission medium can consist of (). A.a pair of wires B.a coaxial cable C.a radio link through free space down D.all of above
There can be no doubt ()the 1900s is remembered as the electronic century. A.which B.that C.what D.all of above
The transmission method which uses start stop bits after each character is () A.synchronous B.asynchronous C.full duplex D.none of the above
The term modem is derived from the words ()modulate emphasis A.all B.modular emulation C.multiplex or demultiplex D.modulate demodulate
A ()amplifier provides signal amplification with little or no distortion, so that the output is proportional to the input. A.nonlinear B.linear C.electronic D.all of above
In a diode, current flows in ()direction across the junction. A.only one B.two C.three D.all of above
An electronic device often used for amplifying voltage and current is (). A.transistor B.conductor C.diode D.all of above
For a 4-band resistor with “color code ”, the first band is the ()values. A.hundreds B.tens C.ten D.all of above
A capacitor will block ()current, but appears to pass ()current by charging and discharging. A.DC …IC B.AC …DC C.DC …. AC D.all of above
The sixth power of two is (). A.12 B.36 C.64 D.all of above
Frequency is the reciprocal of the period, if the period is 4ms, then the frequency would be (). A.4m/s B.0.25KHz C.25Hz D.all of above
A resistor is an electrical component that ()the flow of electrical current. A.increases B.changes C.resists D.all of above
Electrons, as one knows, are minute ()charge of electricity. A.negative B.positive C.reverse D.all of above
Which of the following is an “output device? ”( ) A.CD ROM B.Microphone C.Printer D.All the above
The software used to control the computer and run programs.( ) A.application B.systew software C.games D.virus
Passive electrical circuits
Assembler language
The address bus
Analog multimeter
Semiconductor material
chip holders
peak-to-peak voltage
dual-trace oscilloscope
flowchart
signal generator
switch
device
instruction
junction
combination
Upgrade a computer You can Upgrade a computer to enhance it ’s 1 .. For many upgrades,you will need the assistance of an experienced computer 2 erson.Upgrading usually refer to replacing an old or obsolete computer with a newer one to improve the efficiency of the computer.Upgrading can also include adding a new 3 ,such as a tape drive or DVD-ROM drive,to increse the capabilities of the computer. You should always determine the cost of an upgrade before performing it.If you are planning a major upgrade,such as the system board or CPU ,it may be less expensive to purchase a new computer. Increasing the 5 of memory in a computer is one of the most effetive upgrade you can perform.Doubling the existing memory in a computer can significantly increase its performance. 1.A.cost B.height C. performance D.experience 2. A.repair B.check C.administer D.keep 3.A.member B.tape C.drive D. component 4.A.replace B.replacing C.to replace D.replaced 5. A. amount B.cost C.speed D.quality
[阅读题,8.3分] The higher the frequency of the analogue signal, the more often it must be sampled. However, it is usually adequate to sample a signal at twice its highest frequency. Each binary digit used to show a binary bits used by the ADC. If the conversion is made using a four-bit ADC, only sixteen different binary values can be produced. The smallest value is 0000 and the largest is 1111. If an 8-bit ADC is used, then 256 different digital values can be produced. When a measurement of the analogue signal does not coincide with one of these binary values, it must be rounded up or down. 1) If the analogue signal is u=sin(200 t), then the adequate sampling frequency must be more than () A .50Hz. B.200 Hz C.100 Hz D.50 Hz 2) If the conversion is made using a ten-bit ADC, different binary values can be produced. () A. 1024 B.512 C. 256 D.10
The traditional mechanical wristwatch uses a balance wheel and hairspring to keep time. In a digital watch these mechanical parts have been replaced by vibrating quartz crystal controlled by minute electronic circuits. The artificial quartz crystals used in digital watches are designed to vibrate up to 32768 cycles per second when the current from a battery is passed through them. These vibrations produce electric pulses. As the pulses travel through the electronic circuits of the microchip, their rate is gradually halved. The result creates a pulse rate of one per second. Each one –second pulse triggers the microchip to send signal to the digital display to advance the numerals by one second. The pulses are also used to control different functions such as the hour display, date and alarm signal. 1) The best title of this article is () A. Mechanical wristwatch. B. Digital Watch C. Electronic circuits D. Counter 2) How many times do the electronic circuits of the microchip halve when creating a pulse rate of one per second? () A. 10 B.15 C.13 D.12
The system unit is a box-like case made of metal or plastic.
Computers are good for storing and manipulating both structured and unstructured data.
Data is a collection of un_organized facts.
Storage hold data,instruction,and information for future use.
Information is data that is organized ,has meaning,and is useful.
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