Question

The carrier wave is given by

C(t) = 2sin(8πt) volt.

The modulating signal is a square wave as shown. Find modulation index.

 

Answer 1

Modulation index (μ) is the ratio of the amplitude of the modulating signal to the amplitude of the carrier wave.

The generalised equation of a carrier wave is given below:
c(t) =A_csinω_ct

The generalised equation of a modulating wave is given below:

cm(t)=A_csinω_ct+μA_csinω_mtsinω_ct

Here, μ is defined as `A_m/A_c`

On comparing this with the equations of carrier wave and modulating wave, we get:

Amplitude of modulating signal, A_m=1 V

Amplitude of carrier wave, A_c=2 V

`:.mu=A_m/A_c=1/2=0.5`