Question

What is the total modulation index, if one wave has a modulation index of m1 and other wave has a modulation index of m2?

(a) m1 + m2

(b) \( \frac{m_1+m_2}{2}\)

(c) \(\sqrt{(m_1 \times m_2) + (m_1 \times 2m_2)}\)

(d) \(\sqrt{(m_1 \times m_1) + (m_2 \times m_2)}\)

I had been asked this question in a national level competition.

I would like to ask this question from Chopper Circuit in division Side Band Techniques of Analog Communications

Answer 1

Correct choice is (d) \(\sqrt{(m_1 \times m_1) + (m_2 \times m_2)}\)

The explanation is: Modulation index tells us the amount by which the carrier wave is varied with respect to the message signal. The total modulation index of two waves having modulation index m1 and m2 is  \(\sqrt{(m_1 \times m_1) + (m_2 \times m_2)}\).