Question

The maximum amplitude of an amplitude modulated wave is found to be 15 V while its minimum amplitude is found to be 3 V. The modulation index is

• A. $\frac{3}{2}$
• B. $\frac{2}{3}$
• C. $\frac{1}{2}$
• D. $\frac{1}{3}$

Answer 1

Answer: (B)

$\frac{2}{3}$

Answer 2

: here $A_{c} + A_{m} = 15V$…… (i)

$A_{c} - A_{m} = 3V$……. (ii)

Solving (i) and (ii) we get

$A_{c} = 9V,A_{m} = 6V$

$\therefore$Modulation index, $\mu = \frac{A_{m}}{A_{c}} = \frac{6}{9} = \frac{2}{3}$