Question
The carrier wave is given by C (t) = 2sin (8πt) Volt.
The modulating signal is a square wave as shown. Find modulation index. 
Solution
The generalized equation of a carrier wave is given by, 
The generalized equation of a modulating signal is given by,
On comparing the given equation of carrier wave with the generalized equation, we get,
Amplitude of modulating signal, Am = 1 V
Amplitude of carrier wave, Ac = 2 V
Modulation index is the ratio of the amplitude of modulating signal to the amplitude of carrier wave 
.
It is denoted by,
So, 
