design a 4th order Butterworth band-pass filter, using a low-pass filter followed by a high-pass filter, to extract the 1200Hz and 1500Hz components from the signal x(t):
a. Determine the cut-off frequencies of the low-pass and the high-pass filters.
b. Determine the frequency response function of the low-pass
c. Determine the frequency response function of the high-pass filters.
d. Determine the frequency response function of the band-pass filters.