Question

The amplitude of a sinusoidal carrier is mofulated by a single sinusoidal signal to obtain the amplitude modulated signal
$s\left(t\right)=5cos\left(1600\pi t\right)+20cos\left(1800\pi t\right)+5cos\left(2000\pi t\right)$
The value of modulation index is

• A. 0.4
• B. 0.5
• C. 0.7
• D. 0.8

Answer 1

The correct option is B 0.5

$s\left(t\right)=\frac{\mu A_c}{2}cos\left[2\pi \right(f_c+f_m\left)t\right]+\frac{\mu A_c}{2}cos\left[2\pi \right(f_c-f_m\left)t\right]+A_c{A}_{m}cos\left(2\pi f_{c}t\right)Thus,\mu =0.5$