Question

A carrier wave of peak voltage 12 V is used to transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of 75%?

Answer 1

Amplitude of the carrier wave, A_c = 12 V

Modulation index, m = 75% = 0.75

Amplitude of the modulating wave = A_m

Using the relation for modulation index:

`m = A_m/A_c`

`:. A_m = mA_c`

`= 0.75 xx 12 = 9 V`