8. For/With small values of ω, ……

IX、

1. Reduction of the charging-time constant will improve both bandwidth and sampling efficiency.

2. Operation beyond this hyperbola will result in diode power dissipation in excess of its maximum rating of 1W.

3. Application of a current pulse in the opposite direction reverses the magnetization.

4. Comparing [Comparison of] Eq. (1 – 2) with Eq. (1 – 3) shows that such a phase shift would result in system oscillation.

5. The removal of that current does not guarantee that the galvanometer will return to its initial position.

6. Substituting [Substitution of] this number in Eq. (9 – 4) yields [produces; gives; results in; leads to] the following expression.

7. Inclusion of the meter circuit in the feedback path minimizes the effects of diode nonlinearities on circuit performance.

8. Differentiation of this equation gives the following expression. 9. Increasing the thickness of the lagging will reduce the heat losses.

10. The testing of machines by this method will entail/result in some losses of power.

11. A study of these listings will greatly help the programmer in finding any errors made in writing the program.

12. A temperature rise of 50oC [A rise in/of temperature by 50oC] would damage the device.

13. A cascade of such seven gates would yield an output of only 0.1 V. 14. The large size of the resistor makes it possible to neglect it.

15. Limited space allows only a brief discussion of quartz-crystal technology. 15. The deflection of electrons by an electric field is used to control the direction of an electron stream in many electronic devices. X、

1. This fraction is rationalized by multiplying the numerator and denominator by the complex conjugate.

2. The addition of two complex numbers is accomplished by separately adding the real and imaginary parts.

3. The/Its solution is accomplished by first finding out I1.

4. These three parameters are related by the following equation.

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5. V is related to t by Eq. (1 – 1). XI、

1. This oscillator is linearly tunable over the range of 2 to 3GHz. 2. This distortion is usually acceptable.

3. The analyzer is a representation [representative] of the superheterodyne type.

4. This example is an illustration [illustrative] of the fact that an ideal inductor behaves as a short circuit to dc.

5. Isolators are useful [usable] as stabilizers. 6. This multiplier is calculable [computable].

7. Relative values of the various harmonics can be indicative of the nature of the phenomenon.

8. In most practical situations, the system output signal is not visible directly.

9. This term is descriptive of FM (frequency modulation). 10. This number is divisible by 8. XII、

1. This paper presents a new design method, with emphasis on the guidelines of thought for its derivation. It has many advantages over those available [the existing ones]. Finally [Lastly], Its application is illustrated with an example.

2. Radar is used for determining by radio echoes the presence of objects, their directions and ranges. A radar set consists mainly [chiefly; principally]of six units.

When the transmitted energy strikes an object, a portion [part] of it is reflected back, thus enabling the receiver to receive the echo and transform [convert; change; turn; translate] it into a visual [visible] signal. The timer measures the time [time period] that elapses between the transmission of the signal and the reception of its echo. The distance of the radar set from the target [from the radar set to the target] is half the time [time period] multiplied by the speed of light [half the time period times the speed of light; half the product of time period and speed of light]. XIII、

1. We can solve equation (3) for αn, thus obtaining Uo.

2. Fig. 3 shows a transmission line with a length of I and a characteristic

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impedance of 500 Ω.

3. Although there are many ways to produce random numbers, the procedure for producing them is quite complicated.

4. As is known, when one reads a Chinese character, he or she does not consider every detail in it.

5. We have obtained a recognition rate of 86.3%.

6. After being processed, these data are sent to the database server immediately.

7. We have also developed an algorithm for recording the changes of tables. 8. The Hash algorithm is a scheme by which data of any length can be compressed into data of a fixed length.

9. Unlike what was described in literature [reference] [2], g and u are not evenly distributed.

10. The number of times this value occurs in the observations is given in the first column.

练习

17

I、

1. （略）

2. David J. Minot attended the University of California, Berkeley, CA. from 1994 – 1998. He earned the BS degree in botany there in 1998, and the M. Eng. Degree in electrical engineering from the University of Toronto, Toronto, Ontario, Canada in 2000. Since 2004 he has been working towards the Ph.D. degree in computer science at the University of Pennsylvania, Philadelphia, PA, USA.

In 1998 he served as a teaching assistant at the University of California. From 2000 to 2001 he was with the Moore School of Electrical Engineering, University of Pennsylvania. His research interests concentrate on the development of software. II、

1. This paper outlines some problems on/about/concerning the application at home and abroad in recent years of the optimization theory in the design of

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antenna structures. They play an important role/part in both raising the effectiveness of designing antenna structures and improving the performance of an antenna. Also/In addition/Besides/What is more, this paper presents several problems which remain to be solved in the design of antenna structures.

2. The electric waveguide structure, with which a great number of passive and active devices have been developed, ha found various applications in millimeter-wave integrated circuits. This paper gives an introduction to the method of designing directional couplers using dielectric waveguides, with some simplified and effective formulae presented. Finally, the application of this method is illustrated with an example.

3. This device can identify whether an IC functions properly or not and it can determine the type of an unknown chip. It can test as many as more than 700 kinds of IC. It is characterized by easy operation, high testing speed and great portability. Its price is only about one-third that of the imported product of its kind/the same kind.

4. Mercury is the smallest of the nine major planets. Its average distance from the sun is approximately 57.5 million kilometers. It takes only 88 days to complete one revolution. Its mass is one-twenty-ninth that of the earth. It has no atmosphere. III、

1. To reduce the interval between elements, it is necessary to increase the number of elements of the array.

2. It is important how the transmitting antenna pattern is determined./What is important is how to determine the transmitting antenna pattern. 3. δandδe can be obtained from Eqs. (3) and (4).

4. For every point, there are only two features available.

5. There are two factors controlling the diffusive signal process: (1) the diffusive signal, which can be a brightness signal or a motion-matching signal; (2) the position of the diffusive signal, which determines where the diffusive process starts.

6. The following concept is one of the basic principles on which the neural system is based.

7. There are some basic differences between this system and the BSC.

8. A method to increase the accuracy of range alignment by applying the forward-backward linear prediction is presented.

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IV、

For the convenience of discussion, let the projection vector be the Z-axis, and therefore, the corresponding Y-axis is the cross-range axis.

A method for reducing the cross terms of WVD effectively but having a little effect upon signal terms is presented in this paper. Because each signal term has the characteristic of a straight line in the Wigner plane, signal terms appear as sharp peaks and cross terms are distributed in a wide area when the signal is transformed into the Hough plane.

From Fig. 4, we can see that the two signals’ auto-terms look like a butterfly and that cross terms’ magnitudes are low and distributed in a wide area. The WVD slice at the moment t = 0 restored by integration according to Eq. (10) may basically keep the principal components of the signal and reduce the cross term greatly. Furthermore, for multiple signals with almost an equal magnitude and different parameters, the RWT filtered in the Radon-Wigner plane will have /produce sharp peaks at the corresponding points.

Because of the fact that the strong suppresses the weak, in principle, the next component cannot be determined precisely. If we eliminate the component z 1(t) from z (t), the second component may stand out. How can we eliminate z1(t)?

The radar works in the C-band. The targets are AN-26 and YAK-42 aircraft.

练习 18

I、

1. Frequency is defined as the rate at which something occurs. / By frequency is meant the rate at which something happens.

2. Gravity is a force which pulls an object towards the center of the earth. / By gravity is meant the force which ….

3. A tape-recorder is a machine /a tool/an instrument which records sounds. 4. A thermometer is an instrument for measuring temperature.

5. Linear operation is defined as the ability of an amplifier to amplify signal with no distortion. / By linear operation is meant the ability ….

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