Calculation of sideband and carrier power in AM signal

An AM signal has a total power of 48 Watts with 45% modulation. Calculate the power in the carrier and the sidebands.

a.) 39.59 W, 4.505W
b.) 40.59 W, 4.205W
c.) 43.59 W, 2.205W
d.) 31.59 W, 8.205W

Correct Answer: c) 43.59 W, 2.205W

Explanation:

Given that P_t = 48 W

Modulation index m= 0.45

The total power in an AM is given by

P_t= P_c ( 1 + m²/2)
= P_c ( 1 +0.45₂/2)
48 = P_c * 1.10125

Therefore, P_c = 48/ 1.10125
= 43.59 W

The total power in two sidebands is 48 – 43.59 = 4.41 W

So the power in each sideband is 4.41/2 = 2.205 W