This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “Singletone SSB Modulation”.
1. PDM can be generated by either free running multi-vibrator or monostable multi-vibrator.
Explanation: Pulse density modulation (PDM) is used to represent an analog signal with a binary signal. For generating PDM, only monostable multi-vibrator is used.
2. In case of FM, if the modulating frequency is lowered and the modulating voltage remains constant then the amplitude of distant sidebands first increases and then decreases.
Explanation: If the modulating frequency in FM lowered and the modulating voltage remains constant then the amplitude of distant sidebands only increases.
3. Skip distance depends on time of day.
Explanation: A skip distance is the distance between the two points where radio waves from a transmitter refracted downwards by different layers of the ionosphere. It basically depends on time of day as well as on angle of incidence.
4. Leak type bias is used in plate modulated amplifier to ________
a) increase bandwidth
b) decrease bandwidth
c) prevent tuning
d) prevent excessive grid current
Explanation: Leak bias is mainly used to prevent excessive grid current in plate modulated amplifiers.
5. Full duplex operation allows transmission in only one direction at the same time.
Explanation: Full duplex operation allows transmission in both directions at the same time.
6. A woofer is connected from the input through a ________
a) high pass filter
b) low pass filter
c) band pass filter
d) band stop filter
Explanation: A woofer is connected from the input through a low pass filter to restrict the high frequencies.
7. Which of the following is used for attenuating high frequencies?
c) series capacitance
d) shunt capacitance
Explanation: Shunt capacitance is used to improve the power factor in the network. It also improves voltage stability. It is used in communication system for attenuating high frequencies.
8. If the length of antenna is equal to whole wavelength the radiation is zero in all direction?
Explanation: If the length of antenna is equal to whole wavelength only the radiations which is at right angles is zero.
9. For getting zero radiation at right angles, length of antenna should be __________
b) 2 ʎ
Explanation: For getting zero radiation at right angles, length of antenna should be equal to the whole wavelength.
10. What is the commercial frequency deviation of frequency modulation?
a) 70 KHz
b) 75 KHz
c) 80 KHz
d) 85 KHz
Explanation: Frequencies lying nearly about 75KHz is considered as commercial frequency deviation for frequency 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.