EASY
12th Andhra Pradesh Board
IMPORTANT
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What should be the size of the antenna or aerial? How the power radiated is related to length of the antenna and wavelength?

Important Questions on Communication Systems

MEDIUM
12th Andhra Pradesh Board
IMPORTANT
Explain amplitude modulation.
EASY
12th Andhra Pradesh Board
IMPORTANT
A carrier wave of peak voltage 12 V is used transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of 75 %?
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
A modulating signal is a square wave, as shown below,
Question Image
The carrier wave is given by c (t)= 2 sin (8πt) volts. What is the modulation index?
EASY
12th Andhra Pradesh Board
IMPORTANT
For an amplitude modulated wave, the maximum amplitude is found to be 10 V  while the minimum amplitude is found to be 2 V. Determine the modulation index, μ. What would be the value of μ  if the minimum amplitude is zero volt?
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
Due to economic reasons, only upper side-band of an AM wave is transmitted, but at the receiving station, there is a facility for generating the carrier. Show that if a device is available which can multiply two signals, then it is possible to recover the modulating signal at the receiver station.
EASY
12th Andhra Pradesh Board
IMPORTANT
Define modulation. Why is it necessary?
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
A modulating signal is a square wave, as shown below:
Question Image
The carrier wave is given by c(t) =2 sin 8πt volts.Sketch the amplitude modulated waveform.
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
How can an amplitude modulated wave be detected?