Question

A carrier wave of peak voltage 16 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%?

• A. 8 V
• B. 10 V
• C. 12 V
• D. 14 V

Hint:

The modulation index determines the relationship between the peak voltage of the modulating signal and the carrier signal in amplitude modulation.

Answer 1

The Correct Option is C

The modulation index \( m \) is given by the ratio of the peak voltage of the modulating signal \( V_m \) to the peak voltage of the carrier wave \( V_c \): \[ m = \frac{V_m}{V_c} \] Given that \( m = 0.75 \) and \( V_c = 16 \, {V} \), we can solve for \( V_m \): \[ 0.75 = \frac{V_m}{16} \] \[ V_m = 0.75 \times 16 = 12 \, {V} \] Thus, the peak voltage of the modulating signal is 12 V. 
Final Answer: 12 V.