Question

An audio signal represented as $25\sin 2\pi \left(2000t\right)$ amplitude modulated by a carrier wave: $60\sin 2\pi (100,000t)$. The modulation index of the modulated signal is

• A. $25\%$
• B. $41.6\%$
• C. $50\%$
• D. $75\%$

Answer 1

The correct option is B $41.6\%$

Modulation index $=\frac{B}{A}$
$B=25$, $A=60$
$⟹M.I.=\frac{25}{60}=0.416⟹m\%=41.6\%$