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Free download in PDF Modulation and Demodulation Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for competitive exams. These short solved questions or quizzes are provided by Gkseries.
1
In TV transmission, sound signal is ………………… modulated
A
Amplitude
B
Frequency
C
Phase
D
None of the above
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2
In a TRF radio receiver, the RF and detection stages are tuned to …………
A
Radio frequency
B
IF
C
Audio frequency
D
None of the above
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3
The diode detector in an AM radio receiver is usually found ………….
A
Before the first RF stage
B
After the first RF stage
C
After several stages of amplification
D
None of the above
View Answer
Answer: After several stages of amplification
4
In a superhetrodyne receiver, the difference frequency is chosen as the IF rather than the sum frequency because …………….
A
The difference frequency is closer to oscillator frequency
B
Lower frequencies are easier to amplify
C
Only the difference frequency can be modulated
D
None of the above
View Answer
Answer: Lower frequencies are easier to amplify
5
In the above question, what is the power in sidebands?
A
8 kW
B
6 kW
C
06 kW
D
9 kW
View Answer
6
A 50 kW carrier is to be amplitude modulated to a level of 85%. What is the carrier power after modulation?
A
50 kW
B
5 kW
C
8 kW
D
25 kW
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7
A 100 V carrier is made to vary between 160 V and 40 V by the signal. What is the modulation factor?
A
3
B
6
C
5
D
None of the above
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8
In a radio receiver, we generally use ………….. oscillator as a local oscillator
A
Crystal
B
Wien-bridge
C
Phase-shift
D
Hartley
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9
The function of ferrite antenna is to …………….
A
Reduce stray capacitance
B
Stabilise d.c. bias
C
Increase the Q of tuned circuit
D
Reduce noise
View Answer
Answer: Increase the Q of tuned circuit
10
If Amin = 40 and Amax = 60, what is the percentage of modulation?
A
20 %
B
40 %
C
50 %
D
10 %
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11
The IF is 455 kHz. If the radio receiver is tuned to 855 kHz, the local oscillator frequency is ………….
A
455 kHz
B
1310 kHz
C
1500 kHz
D
1520 kHz
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12
Modulation refers to a low-frequency signal controlling the …………
A
Amplitude of the carrier
B
Frequency of the carrier
C
Phase of the carrier
D
May be any of the above
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Answer: May be any of the above
13
When the modulating signal controls the frequency of the carrier, we get……….
A
Phase modulation
B
Amplitude modulation
C
Frequency modulation
D
May be any one of the above
View Answer
Answer: Frequency modulation
14
The major advantage of FM over AM is …………..
A
Reception is less noisy
B
Higher carrier frequency
C
Smaller bandwidth
D
Small frequency deviation
View Answer
Answer: Reception is less noisy
15
In superhetrodyne receiver, the input at mixer stage is ……….
A
IF and RF
B
RF and AF
C
IF and AF
D
RF and local oscillator signal
View Answer
Answer: RF and local oscillator signal
16
The superhetrodyne principle provides selectivity at ………. stage
A
RF
B
IF
C
audio
D
Before RF
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17
The letters AVC stand for …………..
A
Audio voltage control
B
Abrupt voltage control
C
Automatic volume control
D
Automatic voltage control
View Answer
Answer: Automatic volume control
18
Most of the amplification in a superhetrodyne receiver occurs at ………. stage
A
IF
B
RF amplifier
C
Audio amplifier
D
Detector
View Answer
19
a radio receiver amplifies all the signal frequencies equally well, it is said to have high …………
A
Sensitivity
B
Selectivity
C
Distortion
D
Fidelity
View Answer
20
Superhertodyne principle refers to
A
Using a large number of amplifier stages
B
Using a push-pull circuit
C
Obtaining lower fixed intermediate frequency
D
None of the above
View Answer
Answer: Obtaining lower fixed intermediate frequency
