Minimum stopband attenuation of 40 dB
Sampling rate of 4 kHz.
25. Design an IIR Butterworth bandpass filter with the following specifications:
Passband edges at 450 Hz and 650 Hz
Stopband edges at 300 Hz and 750 Hz
Passband ripple of 1 dB
Minimum stopband attenuation of 40 dB
Sampling rate of 4 kHz.
26. Design a type I Chebyshev IIR highpass filter with passband edge at 700 Hz, stopband edge
at 500 Hz, passband ripple of 1 dB, and minimum stopband attenuation of 32 dB. The
sampling frequency is 2 kHz. Plot the magnitude response of the design filter.
27. Given an IIR lowpass filter with transfer function
Hz
0:06621 3z
À1
3z
À2
z
À3
1 À 0:9356z
À1
0:5671z
À2
À 0:1016z
À3
,
(a) plot the first 32 samples of the impulse response using MATLAB,
(b) filter the input signal that consists of two sinusoids of normalized frequencies 0.1 and 0.8
using MATLAB.
28. It is interesting to examine the frequency response of the second-order resonator filter given
in (6.6.15) as the radius r
p
and the pole angle !
0
are varied. Using the MATLAB to compute
and plot
(a) The magnitude response for !
0
p=2 and various values of r
p
.
(b) The magnitude response for r
p
0:95 and various values of !
0
.
Part C
29. An IIR filter design and implementation using the direct-form II realization.
(a) Use MATLAB to design an elliptic bandpass IIR filter that meets the following speci-
fications:
± Sampling frequency is 8000 Hz
± Lower stopband extends from 0 to 1200 Hz
± Upper stopband extends from 2400 to 4000 Hz
± Passband starts from 1400 Hz with bandwidth of 800 Hz
± Passband ripple should be no more than 0.3 dB
± Stopband attenuation should be at least 30 dB.
(b) For the elliptic bandpass IIR filter obtained above,
± plot the amplitude and phase responses
EXERCISES
301