what is the need for modulation?

Answer Posted / durga bhantana

modulation is necessary in communication system due to the
following reasons
1)for efficient radiation and reception the transmiting
reciving antennas most antennas have length equal to a
quarter wave length of the frequency used.
2)the energy of the wave depends upon frequency the greater
the frequency of the wave the greater the energy lossesed
by it as the audio signal frequencies are small
therefour ;these cannot be transmitted are larg distamces
it radiated directly into space. the only practical
solution is to modulated a high frequency carrier wave with
audio signal and permit the transmission fo occur of the
this high frequnecy
3)............

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