Numerical - Power in Amplitude Modulation - 100% Modulation

Numerical - Power in Amplitude Modulation - 100% Modulation

An un modulated AM signal produces a current of 5.4 A. If the modulation is 100 percent, calculate (a) the carrier power, (b) the total power, and (c) the sideband power when it is transmitted through an antenna having an impedance of 50Ω.

a) 1458W, 2187.5W, 729.25W
b) 278W, 2187.5W, 1917.25W
c) 1438W, 2187.5W, 759.25W
d) 280W, 2187.5W, 750.25W

Correct Answer: a) 1458W, 2187.5W, 729.25W

Explanation:


a) P_C=I²R = (5.4)²*50 = 1458W

b) I_T = I_c√(1+m²/2) = 5.4√(1+1²/2)
=6.614 A

P_T = I_T²R
= (6.614)²* 50
= 2187.25 W

c) P_SB = P_T - P_C
= 2187.25- 1458 W
= 729.25W (for two bands)

For single band, P_SB = 729.25/2
= 364. 625 W