PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Analog and Digital Filters 659

FIGURE 6.83

Plots of Butterworth denormalized HP and BP fi lters of Example 6.22.

Butt. HPF, wp=2

Butt. BPF, cent freq=2, BW=1

Butt. HPF

0

0.5

1

1.5

magnitude

Butt. BPF

0246 0

0

246

0246 0246

− 200

− 100

0

100

200

phase (deg)

− 200

− 100

100

200

phase (deg)

0

0.2

0.4

0.6

0.8

1

magnitude

frequency (rad/sec) frequency (rad/sec)

FIGURE 6.82

Four-pole analog Butterworth and Chebyshev/type-1 denormalized fi lters with wc = 2 rad/s of Example 6.22.

0246

Butt. LPF, wp=2

0246

− 200

− 100

0

0

100

200

phase (deg)

− 200

− 100

100

200

phase (deg)

Butt. LPF

Cheb. LPF

0246

0

0.2

0.4

0.6

0.8

1

magnitude

0

0.2

0.4

0.6

0.8

1

magnitude

Cheb. LPF, wp=2

frequency (rad/sec)

0246

frequency (rad/sec)

3. Replace t by the discrete time nT in the impulse system response h(t).


4. Take the z transform of h(nT) times T given by Z[h(n)] * T.
   a. The analog transfer function of the RC-LPF of Example 6.1 is given by

Hs jw

s

()





1

(^1)