Question

An amplitude modulated wave is modulated to 50%. What is the saving in power if carrier as well as one of the side bands are suppressed

• A. 70%
• B. 65.4%
• C. 94.4%
• D. 25.5%

Answer 1

The correct option is C 94.4%

$P_{sb}$ = $P_c(\frac{m_a}{2}{)}^2$ = $P_c\frac{\left({0.5}^2\right)}{4}=0.0625P_c$
Also P = $P_c(1+\frac{{m_a}^2}{2})=P_c(1+\frac{{\left(0.5\right)}^2}{2})=1.125P_c$
$\therefore$ % saving = $\frac{(1.125P_c-0.0625P_c)}{1.125P_c}\times 100$ = 94.4%