Задание 4. Выпишите из текста предложения содержащие модель Passive Voice, подчеркните модель.
1. What does the radar give? 2. What is the principle of operation of the radar set? 3. What type of antenna is used in radars? 4. What device makes the echoes visible in the radar receiver? 5. What is the purpose of radar beacons?
Задание 6. Переведите предложения на английский.
1. Радарная установка состоит из передатчика, приемника и антенны. Передатчик излучает короткие мощные импульсы. Часть энергии отражается от объекта и принимается антенной приемника. Отраженные сигналы становятся видимыми благодаря катодно-лучевой лампе. Антенна вращается, поэтому может просматриваться весь горизонт. На экране приемника мы можем видеть контурное изображение окружающей среды, включая суда и аналогичные предметы.
2. Определение пеленга по радио - первое электронное навигационное средство. Пеленгатор состоит из радиоприемника с вращающейся рамочной антенной. Направление пеленга видно на шкале, разделенной градусы. Для получения пеленгов установлены специальные радиомаяки. Эти маяки указаны на всех навигационных картах. Расстояние до этих маяков и их характеристика указаны в специальных справочниках для штурманов.
Вариант 3
Задание 1. Прочитайте и переведите текст письменно.
Electronic AIDS to navigation.
General remarks.
The classical aids to navigation are the compass, sounding equipment, instruments for observing celestial bodies and terrestrial marks. These basic aids will always be in use. To use most of them visibility of various degrees is needed. Meteorological conditions may render these aids useless for long periods of time. Another weakness in astronomical navigation is the amount of knowledge and training required. Position finding is time consuming.
The position of the vessel is derived be crossing two or more lines of position, these are not necessarily straight lines. If the position is determined by range and bearing, the point is determined by the crossing of the circumference of a circle and a “straight line”. By “straight line” is usually meant a part of a great circle. The expression “straight line” is used to describe the different systems clearly.
In the electronic navigation systems the position lines may have various forms:
- two straight lines (bearings)
- one straight line and a circle (radar)
- hyperbolic lines (Decca, Loran)
In principle it is of no consequence by which means the position is fixed. It may be best to get one line be reading the Loran receiver and the other by radio bearing. It may be desirable to check the position by more than two lines.
The following is a revue of the various electronic systems with remarks concerning their function, accuracy, time required for obtaining positions etc. To clarify the description of radio wave propagation some technical definitions used later are set down.
Ground wave is that part of the emission from a radio transmitter which follows the surface of the earth. The range of the ground wave depends among other factors on the wave length and the nature of the surface of the earth. The sea is favorable to the propagation of the ground wave.
Night effect is generally used in describing reflection of radio waves from the ionosphere. The name is used because this effect is most noticeable at night in the medium wave range. Reflection occurs in day time as well as in the long wave and short wave ranges. Night effect is in some cases desirable as the range of transmission is increased, in other cases it is undesired, as it possesses certain irregularities.
Signal/noise ratio denotes the relative strength between the desired signal and noise from many sources, such as other radio signals, atmospheric disturbances, noise from electric conductors and other electrical equipment. When no other disturbances are present, the internal noise in the radio receiver limits the usefulness of any radio reception.
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