1. . . .
Vocabulary
to receive ,
to mix
to reject ,
to remain
to select ,
to tune - ,
fidelity -
sensitivity -
intermediate -
nearby - ,
RADIO RECEIVER
Most modern radio receivers are of superheterodyne type. In them an oscillator generates a radio-frequency wave that is mixed with the incoming signal. As a result, a radio-frequency wave of lower frequency (called intermediate frequency) is being produced. In order to tune the receiver to different frequencies, the frequency of oscillations changes but the intermediate frequency always remains the same.
The oscillator is tuned by changing the capacity of the capacitor in its tuned circuit. The aerial circuit is also tuned by a capacitor in its tuned circuit.
Questions
1. What wave does an oscillator generate?
2. Is the oscillator tuned by changing the capacity?
3. Does the intermediate frequency change or does it remain the same?
4. Is a radio-frequency wave of lower frequency being produced?
5. How the aerial circuit is tuned?
Task 2. Translate and write down the following words and word combinations in your workbooks. Make up a short plan of the text RADIO RECEIVER and write it down in your workbooks, summarize the text in short.
2. . ʻ , .
Short theoretical information and a sample of implementation
( )
Present Continuous
:
+ to be (am, is, are) + Present Participle ( to -ing).
1. The tuner is selecting the required signal now. .
is to be
selecting select + ing
now () ,
2. AF amplifier (amp) is modulating the audio signal. - -
().
is to be
modulating modulate + -ing
3. The detectors are separating off the audio parts of signals. -
().
are to be
separating separate + ing
Choose the correct variant. .
1. I ______ in the car now.
am waiting
wait
is waiting
2. My colleague ______ overtime this week.
works
are working
is working
3. At the moment we _____ over the Earth.
have flying
flied
are flying
|
|
|
4. I ________ what you said.
am thinking about
am thinking
think about
think
5. Look! They _______ home.
come
are coming
have come
Translate the following words and word combinations in written form.
.
Words
selector _________________________
station __________________________
superheterodyne __________________
Word combinations
rejected design______________________
achieved purposes___________________
noisy system________________________
Fill in the table. Follow the model.
.
(Model):
| verb () | noun () |
| to tune | tune , |
| to note - | |
| to noise - | |
| to tape - | |
| to sound - |
Task 3. Prepare a presentation of the topic RADIO RECEIVER: make up slides about the topic RADIO RECEIVER, write down the material of the slides in your workbooks, prepare your report (presentation) for the demonstration it in the lecture-room.
3. ʻ: ʻ, , () .
7. 7. Unit 1.7. TYPES OF TYPES OF RADIO RECEIVERS
1.7.
