What is the primary purpose of modulation in analog communication?
A
To increase the power of the signal
B
To reduce the bandwidth requirement
C
To shift the signal to a suitable frequency for transmission
D
To amplify the signal at the receiver
Analysis & Theory
Modulation is used to shift the baseband signal to a higher frequency for efficient transmission over long distances.
In Amplitude Modulation (AM), which parameter of the carrier wave is varied?
Analysis & Theory
In AM, the amplitude of the carrier signal is varied in proportion to the message signal.
Which of the following is a disadvantage of AM?
A
Requires high bandwidth
D
Has high power efficiency
Analysis & Theory
AM is less efficient in power and more susceptible to noise, and it also requires larger bandwidth compared to single sideband systems.
Frequency Modulation (FM) varies which aspect of the carrier signal?
Analysis & Theory
In FM, the frequency of the carrier wave is varied in accordance with the modulating signal.
Which of the following is true about FM compared to AM?
A
FM has more noise immunity than AM
B
FM uses less bandwidth than AM
C
FM is easier to demodulate
D
FM cannot be used for music broadcast
Analysis & Theory
FM has better noise immunity and is preferred for high-fidelity audio transmission like music broadcasting.
What is the function of a demodulator in a communication system?
A
Amplify the received signal
B
Convert analog to digital signal
C
Extract the original information signal from the modulated carrier
D
Increase the transmission frequency
Analysis & Theory
A demodulator recovers the original baseband signal from the received modulated signal.
What type of modulation is used in standard AM radio broadcasting?
Analysis & Theory
Standard AM radio broadcasting uses amplitude modulation.
The bandwidth of an AM signal is equal to:
A
Twice the message signal bandwidth
B
Same as the message signal bandwidth
C
Half the message signal bandwidth
D
Equal to the carrier frequency
Analysis & Theory
The AM signal contains two sidebands, so its bandwidth is twice the maximum frequency of the message signal.
Which device is commonly used to generate AM signals?
Analysis & Theory
A modulator is used to combine the message signal with the carrier wave to produce AM signals.
What is the major source of noise in analog communication?
C
Atmospheric and thermal sources
D
Linearity of amplifiers
Analysis & Theory
In analog systems, noise mainly comes from natural sources like atmosphere and thermal agitation of electrons.