Q1 Consider the signal $x(n) = a^n u(n)$, $|a| < 1$.
(a) Determine the spectrum $X(\omega)$.
(b) The signal $x(n)$ is applied to a decimator that reduces the rate by a factor of 2. Determine the output spectrum.
(c) Show that the spectrum in part (b) is simply the Fourier transform of $x(2n)$.