question_answer

Give reasons for the following.

(i) For ground wave transmission, size of antenna should be comparable to wavelength of signal.

(ii) Audio signals converted into an electromagnetic wave, are not directly transmitted as such.

(iii) The amplitude of modulating signal is kept less than the amplitude of carrier wave.

Answer:

(i) When the size of the antenna is comparable to wavelength of the signal, the time variation of the signal is properly sensed by the antenna.

(ii) An electromagnetic wave of audio signal frequency would have a very large wavelength. It would, therefore need an antenna, whose size would be practically unattainable.

(iii) The amplitude of modulating signal is kept less than the amplitude of carrier wave to avoid distortion.