Amplitude Modulation - Power

Ask

Consider an angle modulated signal $ x(t) = 6 cos [2\pi 106t + 2sin(8000\pi t) + 4 cos(8000\pi t)] $The average power of x(t) is

(a) 10W

(b) 18W

(c) 20W

(d) 28W

Answer is (b )

Concept

Average power of the signal = $(A_c)^2/2 $

                                              = $(6^2)/2$

                                              = 36/2

                                              = 18 W