Communication Systems(Electrical Engineering ) Questions and Answers

Question 1. Skip distance depends on time of day and angle of incidence.
  1.    True
  2.    False
Explanation:-
Answer: Option A. -> True
Question 2. A buffer amplifier is
  1.    A double-tuned amplifier
  2.    A high gain D.C. amplifier
  3.    A cathode follower stage
  4.    None of the above
Explanation:-
Answer: Option B. -> A high gain D.C. amplifier
Question 3. SSB can be generated by
  1.    Filter method
  2.    Phase cancellation method
  3.    Good attenuation characteristics
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
Question 4. What is the purpose of peak clipper circuits in radio transmitters?
  1.    To prevent overmodulation
  2.    To reduce bandwidth
  3.    To increase bandwidth
  4.    To regulate oscillator I/P voltage
Explanation:-
Answer: Option A. -> To prevent overmodulation
Question 5. It is found that a ship to ship communication suffers from fading. This can be avoided by using
  1.    Space diversity
  2.    Frequency diversity
  3.    Broad band antenna
  4.    Directional antenna
Explanation:-
Answer: Option B. -> Frequency diversity
Question 6. In Pulse Code Modulation system
  1.    Large bandwidth is required
  2.    Quantising noise can be overcome by companding
  3.    Quantising noise can be reduced by decreasing the number of standard levels
  4.    Suffers from the disadvantage of its incompatibly with TDM
Explanation:-
Answer: Option A. -> Large bandwidth is required
Question 7. If output power of a radio receiver is doubled, its volume is increased by __________ dB.
  1.    2
  2.    3
  3.    1
  4.    -3
Explanation:-
Answer: Option B. -> 3
Question 8. DVD uses
  1.    Laser beam for both recording and playback
  2.    Laser beam for recording and video head for playback
  3.    Video head for recording and laser beam for playback
  4.    None of the above
Explanation:-
Answer: Option A. -> Laser beam for both recording and playback
Question 9. An audio signal (say from 50 Hz to 10000 Hz) is frequency translated by a carrier having a frequency of 106 Hz. The values of initial (without frequency translation) and final (after frequency translation) fractional change in frequency from one band edge to the other are
  1.    200 and 1.01
  2.    200 and 10.01
  3.    200 and 100.1
  4.    200 and 200
Explanation:-
Answer: Option A. -> 200 and 1.01
Question 10. For attenuation of high frequencies we should use
  1.    Shunt capacitance
  2.    Series capacitance
  3.    Inductance
  4.    Resistance
Explanation:-
Answer: Option A. -> Shunt capacitance
© Lakshya_Education.com, All Right Reserved.
Contact Us services