Question

What is the modulation index of an FM signal having a carrier swing of 100kHz when the modulating signal has a frequency of 8kHz?

Answer 1

Given: Carrier Swing = 100kHz

$f_a=8kHz$

From the defining equation,$m_f=\frac{△f}{f_a}$

First determining $△f,△f=\frac{CarrierSwing}{=50kHz}=\frac{100\times {10}^3}{2}$
Now substituting into the equation of $m_f$
$m_f=\frac{50\times {10}^3}{8\times {10}^3}=6.25$