Question

A modulating signal is a square wave as shown in figure.

The carrier wave is given by
`c(t)=2 sin(8pit)"volt"`.
(`i`) Sketch the amplitude modulated wave from
(`ii`) What is the modulation index?

Answer 1

(`i`) Amplitude of modulating signal from fig is
`A_(m)=1`
Amplitude of carrier wave from the equation
is `A_(c)=2`
Then maximum amplitude of modulated wave
is `A_(max)=A_(c)+A_(m)`
`, A_(max)=2+1=3` and
minimum amplitude of modulated wave is
`A_(min)=A_(c)-A_(m)`
Then the sketch for amplitude modulated wave is as below.

(`ii`) Modulation index `mu=(A_(m))/(A_(c))=(1)/(2)=0.5`