Question

In amplitude modulation of waves, the maximum amplitude is $30~\text{mV}$ and minimum amplitude is $5~\text{mV}$, then the modulation index is

• A. $\dfrac{4}{7}$
• B. $\dfrac{3}{7}$
• C. $\dfrac{5}{7}$
• D. $\dfrac{2}{7}$

Hint:

Always calculate modulation index using max and min amplitudes for amplitude modulation.

Answer 1

The Correct Option is C

- Modulation index ($m$) is defined as:
\[ m = \frac{A_{\max} - A_{\min}}{A_{\max} + A_{\min}} \] - Substitute the values:
\[ m = \frac{30 - 5}{30 + 5} = \frac{25}{35} = \frac{5}{7} \] - This quantifies the extent of modulation in amplitude modulated waves.