Exercises

I. Translate the following sentences into Chinese.

1. As with series resonance, the greater the resistance in the circuit the lower the Q and, accordingly, the flatter and broader the resonance curve of either line current or circuit impedance.

2. A wire carrying a current looks exactly the same and weighs exactly the same as it does when it is not carrying a current.

3. 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, while keeping the pulse width unchanged.

4. Electronics is the science and the technology of the passage of charged particles in a gas, in a vacuum, or in a semiconductor. Please note that particle motion confined within a metal only is not considered electronics.

5. Hardware technologies have played vital roles in our ability to use electronic properties to process information, but software and data processing aspects have not developed at the same speed.

6. However, in a properly designed DC amplifier the effect of transistor parameter variation, other than Ico, may be practically eliminated if the operation point of each stage is adjusted so that it remains in the linear operation range of the transistor as temperature varies.

Ⅱ. Fill in the blanks with the most appropriate choice.

1. A message signal can________any amplitude value between 0 and A volts.

A. assume

B. use

C. receive

D. accept

2. Each time a positive clock edge occurs, the flip-flop changes state, leading to half as many pulses at the output________to the clock input.

A. as

B. compared

C. due

D. so as

3. In the previous section we discussed sine-wave or CW modulation systems in which the modulating signal _______ of a digital pulse train.

A. made

B. consisted

C. contained

D. got

4. In this book we shall emphasize the limitations imposed on the information transmitted by the system through which it was _______ and shall attempt some comparison of different systems.

A. put

B. traveled

C. passed

D. viewed

5. This signal either does not change, or it changes ______ by an amount equivalent to one or more quantum steps.

A. interruptedly

B. rudely

C. abruptly

D. absolutely

6. We shall only be _______ with logical representations, not absolute values

A. interested

B. caring

C. referred

D. concerned

Ⅲ. Choose the phrase that is closest in meaning to the underlined part.

1. 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.

A. which has bad influence upon the system performance

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

2. 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. 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

3. 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.

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 and the sync pulses

4. By keeping the off state slightly below threshold, the delay between the applied electrical pulse and the resulting optical output pulse is minimized; this delay must indeed not be more than the bit interval so that the optical pulse can accurately reproduce the input signal.

A. ensuring that the system is off the threshold by a small margin

B. maintaining the system's shut-down state somewhat below a prescribed level

C. making sure the system is below its threshold so that the state is kept off

D. keeping the system in a shut-down state that is under a given level with a tiny tolerance

5. If the original signal is well behaved, the local oscillator will need very little information to be able to track, and that information can be obtained by averaging for a long period of time, thereby eliminating noise that could be very large.

A. the LO will not require any information in order to keep tracking

B. the LO will make use of tracking information that is scarce in the system

C. the LO will require some information, but not much, so that the system can track

D. the LO will use no information other than some little one to maintain tracking

6. The third section describes quantization schemes that take account of the characteristics of speech.

A. take measure of the speech characteristics

B. take the speech characteristics into consideration

C. count the speech characteristics

D. make use of the speech characteristics

7. In a properly designed DC amplifier the effect of transistor parameter variation may be practically eliminated if the operating point of each stage is adjusted so that it remains in the linear operation range of the transistor as temperature varies.

A. the effective variation of the transistor parameters

B. the effort to change transistor parameters

C. the transistor parameters that effectively change

D. the results caused by transistor parameter changes

8. Stability and repeatability are fundamental attributes of digital circuits, however, and the necessary accuracy can be obtained in a digital version of the modulator by an appropriate choice of word length to represent the signals.

A. by expressing the signals with a suitable word length

B. by using a word long enough to describe the signals

C. by choose to characterize the signals in terms of word length appropriately

D. by appropriately representing the signals to choose a length of words