5.12 (a) Plot the spectrum of a PAM wave produced by the modulating signal m(t) = Am cos(2πft) assuming the modulation frequency f = 0.2 Hz, sampling period T, = 1s, and pulse duration T= 0.45s (b) Using an ideal reconstruction filter, plot the spectrum of the filter output. Compare this result with the output that would be obtained if there were no aperture effect.