Question

(i) Define modulation index.
(ii) Why is the amplitude of modulating signal kept less than the amplitude of carrier wave?

Answer 1

(i) Modulation Index: The modulation index of an amplitude modulated wave is defined as the ratio of the amplitude of modulating signal (E_m) to the amplitude of carrier wave (E_c)  i.e., amplitude modulation index,

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