Question

A message signal of peak voltage 12 V is used to amplitude modulate a carrier signal of frequency 1.2 MHz. The amplitude of the side bands is:

• A. \( 12 \) V
• B. \( 3 \) V
• C. \( 6 \) V
• D. \( 8 \) V

Hint:

The sideband amplitude in AM is given by \( A_{\text{sideband}} = \frac{m A_c}{2} \).
- For 100% modulation, \( m = 1 \) and \( A_{\text{sideband}} = \frac{A_m}{2} \).

Answer 1

The Correct Option is C

The amplitude of the sidebands in an Amplitude Modulation (AM) signal is given by: \[ A_{\text{sideband}} = \frac{m A_m}{2} \] where: - \( m \) is the modulation index, given by: \[ m = \frac{A_m}{A_c} \] - \( A_m = 12V \) (message signal peak voltage), - \( A_c \) is the carrier amplitude (not provided, but assumed from standard modulation theory), - The sideband amplitude is given as \( \frac{m A_c}{2} \). 1. Assuming the modulation index \( m = 1 \) for 100% modulation: \[ A_{\text{sideband}} = \frac{1 \times 12}{2} \] \[ = 6V \] Thus, the correct answer is \(\boxed{6V}\).