My speciality. Овчинникова Т.Е - 41 стр.

great significance. 3. Research work in the field of coherent radars is under way. 4.
Mention should be made that microwave power amplifier tubes are very expensive.
5. Provision is made of techniques for obtaining coherence with radars using
magnetron transmitter rather than microwave power amplifier. 6. This problem is still
under consideration. 7. Two operations which are necessary to determine the
Doppler shifts in frequency of the returns are of great importance.

      2.13.14 Read the text and summarize the main points of the text

                                        RADAR

Radar — the name was coined from Radio Detection And Ranging — was one of the
main factors in the rapid growth of electronics during the last years.
The principle of radar is simple: a beam of energy in the form of waves is directed at
an object and the time required for the reflected waves to return to the sender is
measured; if the speed of the waves is known the distance of the object can be
calculated. By using more than one sender, or a beam whose direction can be
precisely fixed, the position as well as the range of the object can be determined. This
is all straight forward for a large fixed object like a cliff a few miles away from a ship.
But if the target happens to be an aircraft travelling at, say, 500 m.p.h. and about 10
miles away, the use of sound waves is out of the question. It would require something
like a volcanic eruption to produce a sound powerful enough to have a detectable echo
from an aircraft 10 miles away, and the structure for focusing the sound so that the
echoes were confined to those from the aircraft which would have to be several miles
across. Even if some fantastic schemes along these lines were devised it would not be
very useful for aircraft detection since there would be a delay of at least 100 seconds
before the return of the echo, in which time the aircraft would have moved some 10
miles from its original position.

      2.14 Part 14

      2.14.1 Remember pronunciation of the following words

essential, simultaneously, antenna, successfully, carrier, emphasis, vehicle, control,
ferrite n, control v, array, waveguide, interface.



      2.14.2 Read the words, pay attention to stress shift

operate — operation; determine — determination; electron — electronic; parameter —
parametric; stable — stability; active — activity; definite — definition; filament —
filamentary.

      2.14.3 Remember the terms

electronic scan (scanning) — электронное сканирование