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In communication system, the process o...

In communication system, the process of superimposing a low frequency signal on a high frequency wave is known as

A

repeater

B

attenuation

C

modulation

D

demodulation

Text Solution

Verified by Experts

The correct Answer is:
C
Modulation is the phenomenon of superimposing the low frequency signal on a high frequency wave.
Attenuation refers to the loss of strength of a signal during its propagation through
Communication channel . Demodulation is the reverse process of modulation.
Repeater amplifire the signal received from transmitter and retransmits it to receiver.
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Perhaps, the most commonly used mode of communication involves use of free space as a communication channel between transmitter and receiver. The various possible modes of using of free space have been described below Ground wave communication : This mode is used for low frequency as at high frequency, losses become large. This is useful for distance of the order of 1 km. Space wave communication: The signals are transmitted directly from transmitter to receiver. There is no limit to upper frequency, but its range is limited to few hundred kilometers. The range depends on the height of transmitting antenna Sky wave communication : The signals are sent towards sky They are reflected back towards earth by ionosphere. Its range can be above 500 km. But, very high frequencies (above 10 MHz) are not reflected back. Satellite communication: The signals that cannot be reflected back by ionosphere are reflected back by satellite. Moon is a passive satellite of earth. The cordless phone installed in a house uses

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Perhaps, the most commonly used mode of communication involves use of free space as a communication channel between transmitter and receiver. The various possible modes of using of free space have been described below Ground wave communication : This mode is used for low frequency as at high frequency, losses become large. This is useful for distance of the order of 1 km. Space wave communication: The signals are transmitted directly from transmitter to receiver. There is no limit to upper frequency, but its range is limited to few hundred kilometers. The range depends on the height of transmitting antenna Sky wave communication : The signals are sent towards sky They are reflected back towards earth by ionosphere. Its range can be above 500 km. But, very high frequencies (above 10 MHz) are not reflected back. Satellite communication: The signals that cannot be reflected back by ionosphere are reflected back by satellite. Moon is a passive satellite of earth. The frequency range allotted to FM radio broadcast is 88 MHz to 108 MHz. Which of the following communication channels can be used for its transmission?

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