Sum up what the text said about the Radio Compass

LESSON 5. RADAR

1. Read the new words:

radarрадиолокатор, радар; радиолокационная установка

to сoin создавать неологизмы ( новые слова и выражения )

electromagnetic radiation электромагнитное излучение, ЭМИ

to bounce off отскакивать рикошетом от чего-л.

pathпуть; траектория

echo эхо; эхо-сигнал

returnвозврат, замыкание, эхо

to detect обнаруживать, выявлять, детектировать

tiny очень маленький, крошечный

resolutionразрешающая способность; разрешение

targetцель, мишень

beam луч, пучок лучей, испускаемое излучение

transmitter (радио)передатчик

receiver радиоприемник

oscillator осциллятор, излучатель

modulator модулятор

to vary менять(ся); изменяться

to modulate понижать частоту, регулировать, модулировать

incoming входящий; поступающий

return signal (= returned signal) отраженный сигнал

duplexer антенный переключатель, дуплексер

to perform исполнять, выполнять

to maximize увеличивать до предела; максимизировать

to eliminate устранять, исключать

noise шум,помеха

interfering signal помеха

to convey передавать

pulse radar импульсная РЛС

regular intervals строго соблюдаемые интервалы, постоянный интервал

continuous-wave radar РЛС непрерывного излучения

continuous signal непрерывный сигнал; аналоговый сигнал

Read the text and translate it:

Radar is an electronic system that measures the position, speed, or other characteristics of a far-off object. It was first suggested as a "ship finder" coined in 1941 as an acronym for Radio Detection and Ranging.

A radar system starts by sending out electromagnetic radiation, called the signal. The signal bounces off objects in its path. When the radiation bounces back, part of the signal returns to the radar system; this echo is called the return. The radar system detects the return and analyzes the signal for more information. Even though radio waves and microwaves reflect better than electromagnetic waves of other lengths, only a tiny portion—about a billionth of a billionth—of the radar signal gets reflected back. Therefore, a radar system must be able to transmit high amounts of energy in the signal and to detect tiny amounts of energy in the return.

Most radar systems operate in frequencies ranging from the Very High Frequency (VHF) band, at about 150 MHz (150 million Hz), to the Extra High Frequency band, which may go as high as 95 GHz (95 billion Hz). The frequency of the radar system is related to the resolution of the system. Resolution determines how close two objects may be and still be distinguished by the radar, and how accurately the system can determine the target’s position. Higher frequencies provide better resolution than lower frequencies because the beam formed by the antenna is sharper.

A radar system is composed of four basic components: a transmitter, an antenna, a receiver, and a display.

The transmitter produces the electrical signals in the correct form for the type of radar system. The system surrounding the transmitter is made up of three main elements: the oscillator(which produces a pure electrical signal at the desired frequency), the modulator (which rapidly varies, or modulates, the signal from the oscillator), and the transmitter(which increases the power of the oscillator signal) .

The antenna sends these signals out as electromagnetic radiation. The antenna also collects incoming return signals and passes them to the receiver, which analyzes the return and passes it to a display.

Because a radar antenna may both transmit and receive signals, the duplexer determines whether the antenna is connected to the receiver or the transmitter.

The receiver determines whether the signal should be reported and often performs other functions to maximize the strength of the return signal and to eliminate noise and other interfering signals before sending the results to the display.

The display conveys the results to the human operator through a visual display or an audible signal.

All radar systems perform the same basic tasks, but the way systems carry out their tasks has some effect on the system’s parts. A type of radar called pulse radar sends out bursts of radar at regular intervals. Pulse radar requires a method of timing the bursts from its transmitter, so this part is more complicated than the transmitter in other radar systems. Another type of radar called continuous-wave radar sends out a continuous signal. Continuous-wave radar gets much of its information about the target from subtle changes in the return, or the echo of the signal. The receiver in continuous-wave radar is therefore more complicated than in other system

4) Answer the following questions:

1) Is the word “Radar” a contraction?

b. How does radar system start?

c. Why must a radar system be able to transmit high amounts of energy in the signal?

d. What frequencies do most radar systems operate in?

5) What is the resolution of the radar system?

6) Why do higher frequencies provide better resolution than lower frequencies?

7) How many components does the radar system include? What are they?

8) What function does the transmitter system produce?

9) What is the main function of the antenna?

10) Is it necessary to use the receiver and the display in the radar system and why?

11) What types of radar do you know?

5) Correct the wrong statements:

Radar is a system used to defect, range and map objects such as aircraft, ships and others.

2) Radar is a contraction of Radio Direction and Ragging.

3) Radar relies on sending and receiving magnetic fields.

4) A radar system should transmit only a tiny portion of energy in the signal.

5) A radar system is composed of the following components: a transmitter, an

oscillator, a modulator, an antenna, a duplexer, a receiver, a display.

6) The transmitter in the transmitter system is used to decrease the power of the

oscillator signal.

7) A continuous – wave radar sends out bursts of continuous signals at regular

intervals.

6) Change the sentences according to the pattern, using the Passive constructions instead of Active Voice ones:

Model: The Radar system transmits high amounts of energy.

High amounts of energy are transmitted by the Radar system.

Radar can pierce any atmospheric disturbance.

2) The modulator should vary the signal, but not distort it.

3) The antenna gathers the weak returning radar signals and converts them into an

electric current.

4) Most modern radar systems use digital equipment.

5) Early radar systems used a display of received signal amplitude.

6) Advanced radar can detect individual features of the target.

7) Rain, snow and the surface of the earth reflect energy.

8) Bats and dolphins are able to emit high – frequency sounds.

9) Meteorologists use a continuous – wave version called Doppler radar to track storms

and hurricanes.

10) A radio transmitter oscillates an electrical current.