Question:
A $100 \mathrm{~V}$ carrier wave is made to vary between $160 \mathrm{~V}$ and $40 \mathrm{~V}$ by a modulating signal. What is the modulation index?
Correct Option: 3,
Solution:
(3) Maximum amplitude $=\mathrm{E}_{m}+\mathrm{E}_{c}=160$
$E_{m}+100=160$
$E_{m}^{\prime}=160-100=60$
Modulation index,
$\mu=\frac{E_{m}}{E_{c}}=\frac{60}{100}$
$\mu=0.6$