What are the basic applications of radio engineering?

3. Does radio equipment provide the reliable communication with spaceships?

4. What do radio systems enable us to do?

5. How did radio methods influence well-known sciences?

6. Can radio be used for solving problems not associated with radiation of electromagnetic waves?

7. What are the spheres of radio techniques' application?

Вариант 3

Задание 1. Переведите следующие слова и словосочетания на русский язык, не обращаясь к словарю:

1. bias voltage 2. to be related (to) 3. primary circuit 4. band 5. efficiency 6. value 7. deposition 8. interior 9. velocity 10. coating 11. fraction 12. incident radiation 13. to impair 14. variable

15. light beam 16. unilateral 17. waveguide 18. rectangular 19. inductor 20. capacitor 21. ruggedness 22. limiter 23. duration 24. amplification 25. to introduce 26. to convert 27. at the expense of 28. etching 29. power gain

30. magnitude 31. source 32. separation 33. inverse resistance 34. to exhibit 35. to enclose 36. to seal 37. timing 38. array 39. target 40. substitutional 41. to dissolve 42. cluster 43. by means of

Задание 2. Переведите на русский язык следующие предложения:

1. New machinery used there exceeded accepted standards of the day.

2. These questions were answered in a series of investigations, both experimental and theoretical.

3. Much data was accumulated concerning the condition of life and work in space before the beginning of further investigations.

4. Stage two involved planning the experiment, conducting it, data taking and data evaluation. Stage three – drawing the conclusions and making recommendations.

5. The method discussed during the conference is worth thinking.

Задание 3. Прочтите текст и переведите его письменно на русский язык, пользуясь словарем.

Separation of the Message from a high-frequency oscillation

(detection and decoding)

The detection or demodulation is the reverse of the modulation. This process consists in obtaining a voltage (current) that varies in time according to the variations of some parameter (amplitude, frequency or phase) of the modulated wave. In other words, detection results in the restoration of the original message. The detector is usually inserted into an output stage of the receiver. Consequently, it processes a modulated oscillation already amplified in the preceding stages. The main requirement for the detector is the exact reproduction of the form of the original signal.

After detection, the decoding of the signal is carried out, which is the reverse of the coding. In many radio channels coding and decoding are not used.

Besides the above processes associated in some way or other with the conversion of frequency spectra, radio engineering often employs amplification without frequency conversion, carried out by means of amplifiers. These include:

- low -frequency control-signal amplifiers inserted before the modulator of the transmitter and also at the output of the receiver;

- short-pulse amplifiers used in television, radar, and pulsed radio communication systems;

- high-power, high-frequency amplifiers employed in radio transmitters;

- radio-frequency weak-signal amplifiers employed in radio receivers and measuring instruments.

In addition to the above-mentioned processes, which are typical of all radio engineering systems, many other processes, such as frequency multiplication and division, short-pulse generation, and various types of pulse modulation, are used in special cases.

Задание 4. Ответьте письменно на следующие вопросы по содержанию прочитанного текста:

1. What does the process of detection consist in?

2. Does detection result in restoration of a message?

3. What follows the detection of a signal?

4. How is amplification without frequency conversion carried out?

5. What devices are short-pulse amplifiers used in?

6. What processes are not so typical of radio engineering systems?

Итоговая контрольная работа

Вариант 1

Задание 1. Переведите следующие предложения на русский язык:

1. Low-energy radio waves are reflected and absorbed by the electrons and ions of the ionosphere.

2. The velocity of a moving object can change by its speeding up, slowing down, or changing its direction of motion.

3. The results were reproduced in space flight under the conditions of overloading and weightlessness.

4. In 1904, semiconductors were shown to be good detectors of radio waves.

5. The magnitude of this effect is also affected by the strength of any electric field that happens to be present.

Задание 2. Прочтите текст и переведите его на русский язык в письменной форме, пользуясь словарем.

Reception and Amplification of weak signals

The antenna of a radio receiver “catches” just a minute fraction of the energy radiated by the transmitting antenna system. Depending on the distance between the transmitter and receiver, directivity patterns of the antennas, and propagation conditions, the input power of the receiver is about 10^-10 to 10^-14W, while for reliable reproduction of the signal the output power must be of the order of several milliwatts to several watts or higher. Therefore, the receiver must ensure a gain of 10⁷ to 10¹⁴ in power or 10⁴ to 10⁷ in voltage.

Modern receivers provide steady reception of radio signals at an input voltage of about 1µV. Such a high sensitivity of up-to-date receivers has become possible due to the latest achievements in radioelectronics. Of fundamental importance are also special methods of designing the receiver circuits to provide a high gain and ensure steady operation of all the units in the system. These methods allow one to convert (lower) the oscillation frequency in the receiver channel without breaking the structure of the signal being received.

In addition to the receiving systems, the frequency conversion process is widely used in various radio engineering and measuring devices. The problem of amplifying in a receiver is intimately associated with the problem of detecting them in the midst of random noise. Therefore, one of the basic parameters of any receiver is its selectivity or its ability to differentiate the desired signal from interfering signals broadcast on other frequencies.

The frequency selectivity is accomplished with the aid of resonance circuits.

Задание 3. Составьте аннотацию к тексту на русском или на английском языке.

Вариант 2

Задание 1. Переведите следующие предложения на русский язык:

1. Advancement in electronic techniques appears to be endless.

2. The reaction must have taken place, with the data showing a change in characteristics.

3. The results were arrived at when no hope remained in the research group.

4. To detect weak radio signals, a directive antenna and a highly sensitive radio receiver must be used.

5. Research work is constantly in progress to find materials with properties better than those in use.

Задание 2. Прочтите текст и переведите его на русский язык в письменной форме, пользуясь словарем.