Assume that a DSB signal x c (t) = A c m(t) cos (2f c t +

Assume that a DSB signal 

x_c (t) = A_cm(t) cos (2πf_ct + ϕ₀) 

is demodulated using the demodulation carrier 2 cos [2πf_ct + θ(t)]. Determine, in general, the demodulated output y_D (t). Let A_c = 1 and θ(t) = θ₀, where θ₀ is a constant, and determine the mean-square error between m(t) and the demodulated output as a function of ϕ₀ and θ₀. Now let θ₀ = 2πf₀t and Compute the mean-square error between m(t) and the demodulated output.