Given an analog signal
x(t) = 10 cos(11000 pi t) + 5 sin(15000 pi t) , for t>=0
sampled at a rate of 8000 Hz.
a. Sketch the spectrum of the original signal and the sampled signal from 0 kHz and 25 kHz.
b. Sketch the recovered analog signal spectrum if an ideal lowpass filter with a cutoff frequency of 4 kHz is used to filter the sampled signal.
c. Determine the frequency/frequencies of aliasing noise.