Question

The maximum and minimum amplitude of an amplitude modulated wave is $16\text{V}$ and $8\text{V}$ respectively. The modulation index for this amplitude modulated wave is $x\times {10}^{-2}$. The value of $x$ is _____. $($up to two significant figures$)$

Answer 1

$A_m=\frac{A_{max}-A_{min}}{2}=\frac{16-8}{2}=4\text{V}$

$A_c=\frac{A_{\text{max}}+A_{\text{min}}}{2}=\frac{16+8}{2}=12\text{V}$

So, Modulation Index,

$MI=\frac{A_m}{A_c}=\frac{4}{12}=0.333$

$\Rightarrow MI=33.3\times {10}^{-2}\approx 33\times {10}^{-2}$