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) PC=I2R = (5.4)2*50 = 1458W
b) IT = Ic√(1+m2/2) = 5.4√(1+12/2)
=6.614 A
PT = IT2R
= (6.614)2* 50
= 2187.25 W
c) PSB = PT - PC
= 2187.25- 1458 W
= 729.25W (for two bands)
For single band, PSB = 729.25/2
= 364. 625 W