Consider an analog periodic sinusoid x(t) = cos (3*pi*t + pi/4) being sampled using a sampling period Ts to obtain the discrete time signal x[n] = x(t)I t=nTs = cos (3*pi*t + pi/4).
a.) Determine the discrete frequency of x[n].
b.) Choose a value of Ts for which the discrete time signal x[n] is periodic. Use MATLAB to plot a few periods of x[n], and verify its periodicity.
c.) Choose a value of Ts for which the discrete time signal x[n] is not periodic. Use MATLAB to plot x[n] and choose an appropriate length to show the signal is not periodic.
d.) Determine under what condition the value of Ts makes x[n] periodic.