This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “Generation of DSBSC Waves”.
1. LCD uses ________
a) sematic crystals
b) twisted nematic crystals
c) nematic crystals
d) cholesteric crystals
Explanation: Twisted nematic display consist a substance called nematic which is placed in between two plates of polarized glass.
2. Which of the following stage is present in FM receiver but not in AM receiver?
a) Amplitude limiter
c) AM amplifier
d) AF amplitude
Explanation: Amplitude limiter clips or removes the amplitude of output signals to a desired margin. So it is only used in amplitude modulation and not in frequency modulation.
3. Function of duplexer in a RADAR is to permit the use of same antenna for transmission and reception.
Explanation: Duplexer in a RADAR allows bi-directional communication over the same path. Its function is to isolate the receiver from transmitter while permitting them to share a common antenna.
4. Single Sideband Modulation (SSB) is generally reserved for point-to-point communication.
Explanation: The two sidebands exist in double side band modulation is found to have exactly same information. So if we remove one of the sidebands then also the same information is transmitted. This also reduces the bandwidth of the modulation. So it is basically used for point-to-point communication.
5. For an AM transmitter, class C amplifier can be used after the modulation stage.
Explanation: In an AM transmitter, the required transmission power is obtained from class C amplifier. So it is not used after the modulation stage.
6. For which of the modulated system, the linear amplified modulated stage is used?
a) low level amplitude modulated system
b) high level amplitude modulated system
c) high level frequency modulated system
d) low level frequency modulated system
Explanation: Linear amplified modulation is used to amplify the amplitude. Thus it is used for low level modulated system.
7. When noise is passed through a narrow band filter, the output of filter should be?
Explanation: Narrow band filter is used to isolate a narrow band of frequencies from a wider bandwidth signal. It is a combination of band pass and band reject filter. When noise gets passed through it, the output of it should be sinusoidal.
8. A narrow band noise can exist in _________
a) AM only
b) PCM only
c) FM only
d) AM and FM both
Explanation: Narrow band filter is used to isolate a narrow band of frequencies from a wider bandwidth signal. It is a combination of band pass and band reject filter. So it can be used in both AM and FM.
9. The upper and lower sideband frequencies for 5KHz amplitude modulation with a 30KHz carrier frequency will be?
a) 35KHz and 25KHz
b) 34KHz and 24KHz
c) 25KHz and 35KHz
d) 0.35KHz and 0.25KHz
Explanation: Upper sideband frequency will be (30 + 5) = 35 KHz and Lower sideband frequency will be (30 – 5) = 25 KHz.
10. Phase array radar can track many targets together.
Explanation: A phased array is a computer controlled array of antennas which is used to create a beam of radio waves that can be electronically steered in different directions without moving the antenna.
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.