1. . . .
Vocabulary
beam -
missile -
to seek (sought) -
feeder cable
scanning beam
beam aerial
located objects
seeker -
PRINCIPLE OF RADAR
The basic principle of radar is the scanning of the area by a beam of microwaves and detection of the waves that are reflected from the object to be located. The time taken for a pulse to travel to the object and back can be measured. In this way the distance to the object from the transmitter can be calculated, and its direction defined from the detection of the aerial direction.
This technique has extended to the use of computers, which accept data, apply logical processes to the data and supply the results of these processes as the information sought.
Questions
What for a radar is used?
What is the basic principle of radar?
How can be calculated the distance to the object from the transmitter?
Task 2. Translate and write down the following words and word combinations in your workbooks. Make up a short plan of the text PRINCIPLE OF RADAR and write it down in your workbooks, summarize the text in short.
2. . , .
Short theoretical information and a sample of implementation
( )
Present Perfect Past Simple
, .
. , :
| Past Simple | Present Perfect |
| : + -ed | : to have + -ed |
| : ( ) | : to have + (Past Participle) |
| ( -ed) | |
|
Choose the correct variant. .
1. Since then I ______ my job several time.
changed
has changed
have changed
2. They ______ in construction business for 5 years.
were
have been
are
3. They ______ the computer yesterday.
|
|
|
has just repaired
repaired
just repaired
4. He ______ to London last year.
go
going
went
5. He cant find a job. He ______ unemployed for half a year.
was
has been
have been
6. He ______ his driving test. He is so happy. He hasnt been able to pass it for three years.
has just passed
have just passed
just passed
Translate the following words and word combinations in written form.
.
Words
identify____________________
object_____________________
scan______________________
Word combinations
the code in common use_____________________________________
the generator under construction ______________________________
the problem under discussion _________________________________
Fill in the table by these words. Follow the model.
:
employment, development, fault, extension, scan, scanner, beam, employer, fed, seek, seeker, employ, feed.
(Model):
| verb () | noun () |
| to press | press |
Task 3. Prepare a presentation of the topic PRINCIPLE OF RADAR: make up slides about the topic PRINCIPLE OF RADAR, write down the material of the slides in your workbooks, prepare your report (presentation) for the demonstration it in the lecture-room.
3. : , , () .
12. 12. Unit 3.1. SPHERES OF USE OF TELEVISION AND RADIO BROADCASTING
3.1.
