An amplitude-modulated signal is applied to a 100 Ω load. If the carrier peak voltage is 100 V and the modulation index is 0.4, what power is developed in the load?

50 W
54 W
104 W
4 W

Correct answer: 54 W

Solution

Carrier power P_c = Vc^2/(2R) = 100^2/(2*100) = 50 W. Total AM power = P_c(1 + mu^2/2) = 50(1 + 0.4^2/2) = 50 x 1.08 = 54 W.

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