This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “Costas Loop”.
1. Costa’s receiver is used for ________
a) coherent detection of AM-SC signal
b) asynchronous detection of AM-SC signal
c) amplitude modulation of signal
d) frequency modulation of signal
Explanation: Costa’s receiver is based on phase-locked loop (PLL). It is generally used for coherent detection of AM-SC signal.
2. Helical antenna is mainly used for ________
a) bandwidth calculation
b) television production
c) radio transmission
d) satellite tracking
Explanation: Helical antenna consists conducting wire. These conducting wires is wound around it in the form of helix. It is mainly used for satellite tracking.
3. Sampling frequency of a compact disk is about ________
a) 30 KHz
b) 50 KHz
c) 10 KHz
d) 70 KHz
Explanation: Sampling frequency is the number of samples per second. For a CD it is about 10 KHz.
4. In frequency modulation, there is a large increase in noise and hence increase in the signal to noise ratio.
Explanation: In frequency modulation, there is a large decrease in noise and hence increase in the signal to noise ratio.
5. Image frequency is given by ________
a) fs + fi
b) fs ± fi
c) fs + 2fi
d) fs ± 2fi
Explanation: Image frequency is generally observed in heterodyne receivers. It is an undesired input frequency which is further equal to the sum of station frequency and twice of intermediate frequency. It is usually responsible for interference.
6. Atmospheric noise, extraterrestrial noise and man-made noise is part of internal noise in communication.
Explanation: Atmospheric noise, extraterrestrial noise and man-made noise is part of external noise in communication. External noise are those noises whose sources are external.
7. Thermal noise is a synonym of ________
a) Atmospheric noise
b) shot noise
c) white noise
d) transit time noise
Explanation: Thermal noise is a type of internal noise in communication. It can also be called white noise or johnson noise.
8. Distance at which a sky wave is received back on earth ________ with angle of incidence.
c) can be increase or decrease
d) can neither be increase or decrease
Explanation: Distance at which a sky wave is received back on earth decreases with angle of incidence for all angle of incidence.
9. In a Vidicon camera tube, both sides of the target plate have the coating of Sno2.
Explanation: In a Vidicon camera tube, the side of target plate facing the light has a coating of Sno2 and the side facing electron gun has a coating of antimony trisulphide.
10. Ground wave can be used for communication upto ________
a) 5 KHz
b) 12 KHz
c) 16 KHz
d) 25 KHz
Explanation: Ground wave is that wave which reaches a receiver from a transmitter directly without reflecting from ionosphere. It can be used for communication upto 16 KHz.
Sanfoundry Global Education & Learning Series – Analog Communications.
To practice all areas of Analog Communications, here is complete set of 1000+ Multiple Choice Questions and Answers.