Question

A carrier is modulated simultaneously by $3$ sine waves of modulation indices $0.3$, $0.4$ and $0.45$ respectively. The net modulation index is

• A. $1.15$
• B. $0.67$
• C. $0.57$
• D. $0.84$

Answer 1

Answer: (B)

$0.67$

Net modulation index $=\sqrt{{{\mu }_1}^2+{{\mu }_2}^2+...}=\sqrt{{0.3}^2+{0.4}^2+{0.45}^2}=\sqrt{0.09+0.16+0.2025}=0.67$