Analog Communications Questions and Answers – Frequency Translation


This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “Frequency Translation”.

1. FSK stands for ________
a) Frequency Segregation Keying
b) Frequency Section Keying
c) Frequency Signal Keying
d) Frequency Shift Keying
View Answer

Answer: d
Explanation: FSK stands for Frequency Shift Keying. In FSK, information is transmitted through discrete frequency changes in the carrier signal.

2. When analyzing a transmission line, its inductance and capacitance are considered as _________
a) distributed
b) lumped
c) equal reactances
d) equal impedances
View Answer

Answer: a
Explanation: For a transmission line, inductance and capacitance are two components that are considered as distributed.

3. What effect will be seen on the resistance of a wire if we increase the frequency?
a) it will also increase
b) it starts to decrease
c) it will remain same
d) it starts changing periodically
View Answer

Answer: a
Explanation: Skin effect becomes more and more apparent as frequency increases as skin depth becomes smaller. It is due to alternating current flowing through the outer surface of conducting material. It refers to the increase of wire resistance with frequency.
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4. What is speed of radio waves in free space?
a) 3 x 106 m/s
b) 3 x 109 m/s
c) 300 x 106 m/s
d) 300 x 109 m/s
View Answer

Answer: c
Explanation: he speed of radio waves in free space is same as the speed of light which is 3 x 108 m/s. It cal also be written as 300 x 106.

5. An antenna has “gain” as compared to ________
a) Helical antenna
b) Marconi antenna
c) Vertically polarized radiator
d) Isotropic radiator
View Answer

Answer: d
Explanation: Isotropic radiator is considered as an ideal antenna. So all the gains of any antenna is estimated by comparing with it only.

6. Ground waves are most effective when _________
a) it is above about 20MHZ
b) it is below about 3MHz
c) it is at microwave frequencies
d) usually in the UHF range
View Answer

Answer: b
Explanation: Ground wave is generally preferred for long distance communication using frequencies that are below 3MHz. It can be used for short distance communication by using frequencies between 3 and 30MHZ.

7. The microwave frequency range is considered to start at ________
a) 1 GHz
b) 10 GHz
c) 100 GHz
d) 5 GHz
View Answer

Answer: a
Explanation: Microwave frequency range is considered to be start at 1 GHz. It is standard and fixed.

8. What is the approximate reliability of a microwave system?
a) 90%
b) 99%
c) 99.99%
d) 90.99%
View Answer

Answer: c
Explanation: Microwave system is mostly known for its reliability. Its reliability is of the order of 99.99%.

9. Which modulation is used by a microwave system?
a) FM
b) SSB
c) QAM
d) Either FM or SSB or QAM
View Answer

Answer: d
Explanation: Microwave system is used for point-to-point communication links, which is the communication between two nodes. It can either use frequency modulation or single sideband modulation or quadrature modulation.

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.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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