Question

For $100\%$ modulation (AM), the useful part of the total power radiated is

• A. $\frac{1}{2}$ of the total power
• B. $\frac{1}{3}$ of the total power
• C. $\frac{1}{4}$ of the total power
• D. $\frac{2}{3}$ of the total power

Answer 1

The correct option is B $\frac{1}{3}$ of the total power

$100\%$ modulation $⟹m_a=1$
$\frac{usefulpower}{totalpowerradiated}=\frac{{m_a}^2}{2+{m_a}^2}=\frac{1}{2+1}=\frac{1}{3}$
$⟹$Useful power $=\frac{1}{3}$ (total power radiated).