5. (20 pts.) An audio equalizer with a sampling rate of 7 kHz has the frequency response given below. Design a 7-tap FIR filter using the frequency sampling method. Magnitude (absolute filter gain) 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 500 1000 1500 2000 2500 3000 3500 Frequency (Hz) (a) Obtain the H(k) coefficients by sampling the desired frequency response above. (b) Calculate the FIR coefficients h(n) of the filter. (c) Determine the difference equation required to produce this filter. (d) Find the lower- and upper-cutoff frequencies of this bandpass filter.