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

3 V 6 V 9 V 12 V

9 V

The correct answer is Option (3) → 9 V Modulation Index = $\frac{V_m}{V_c}$ $\frac{75}{100}=\frac{V_m}{12}$ $V_m$ = 9 V Option (3) is correct.