1. . . .
Vocabulary
to impress - ,
to disturb - ,
hum - ,
hiss -
whistle -
statics -
steady - ,
poor - ,
therefore - ,
alternating current
direct current
steady current -
NOISES
Noises are serious problems for radio communication practically of any kind. There exist different types of noise. Each type has its cause and, therefore, has been given its name. Among different types of noise there is hum, a steady low-frequency note, produced when the frequency of the alternating-current power supply becomes impressed onto the signal.
The usual cause of hum is poor filtering. Hiss and whistle, steady high-frequency notes, are produced by audio-frequencies oscillations, or by beats. Naturally, these noisescause disturbances and, therefore, they should be minimized and, in the end, eliminated. The elimination of noises depends, first of all, on the designand construction of the receiver. It should be noted, however, that there exist types of noise that cannot be eliminated.
The most important of these are statics noises caused by electrical disturbances in the atmosphere. To the causes of statics also belong disturbances caused by the operation of nearby electrical equipment, such as, for example, automobiles.
Questions
What type of noise is called statics?
Why should noises be minimized and eliminated?
What types of noises do you know?
What depends on the elimination of noises?
What can you say about statics?
Task 2. Translate and write down the following words and word combinations in your workbooks. Make up a short plan of the text NOISES and write it down in your workbooks, summarize the text in short.
2. . ۻ , .
Short theoretical information and a sample of implementation
( )
Past perfect
Past Perfect / o . , . Past Perfect: had + V3
Past Perfect to have , .
To have had.
, (Participle II), , - ed:
examine examined, enjoy enjoyed, close closed
, .
|
|
|
, :
Had you opened the textbookbefore you passed the exam?
?
not. hadnt.
How did you hope to pass the exam if you had not (hadnt) even opened the textbook?
, ?
Choose the correct variant. .
- I _____ the key that he had given to me.
lost
losted
had lost - I _____ downstairs because I had heard a noise
go
had gone
went - The waiter served something that we _____.
have not ordered
had not ordered
not had ordered - Had she found a place to stay when she ____ to Boston?
will go
went
go - His mother was angry because he ____ her with the shopping.
have not helped
not had helped
had not helped
Translate the following words and word combinations in written form.
.
Words
automobile___________________
serious______________________
minimize____________________
Word combinations
poor filtering _____________________________________
serious disturbances _______________________________
steady statics _____________________________________
nearby electrical equipment _________________________
steady low-frequency note __________________________
alternating-current power supply _____________________
Fill in the table. Follow the model.
.
(Model):
| process () | action () |
| interaction - | to interact |
| reconstruction - | |
| elimination - | |
| existence - | |
| decrease - | |
| disturbance - | |
| impression - | |
| increase - |
Task 3. Prepare a presentation of the topic NOISES: make up slides about the topic NOISES, write down the material of the slides in your workbooks, prepare your report (presentation) for the demonstration it in the lecture-room.
3. ۻ: ۻ, , () .
10. 10. Unit 2.1. SPHERES OF USE OF THE RADARS
2.1.
