A wide-sense stationary random process X is Gaussian, has zero mean, and has a power spectral density shown below. Sx(f) = 0.5 for -100Hz ≤ f ≤ 100Hz and Sx(f) = 0 for |f| > 100Hz.
(a) Find the standard deviation of the random process Xt.
(b) The random process Xt is passed through an ideal lowpass filter with gain equal to 4.0 and passband extending from -160Hz to +160Hz. If Y(t) is the output of the filter, find its mean and plot its power spectral density.