Digital Signal Processing Reference
In-Depth Information
1
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
−0.2
−0.2
−0.4
−0.4
−0.6
−0.6
−0.8
−0.8
−1
−1
−1
−0.5
0
0.5
1
−1
−0.5
0
0.5
1
real part
real part
(a)
(b)
1
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
−0.2
−0.2
−0.4
−0.4
−0.6
−0.6
−0.8
−0.8
−1
−1
−1
−0.5
0
0.5
1
−1
−0.5
0
0.5
1
real part
real part
(c)
(d)
Fig. 16.11. Locations of the
poles and zeros for IIR filters.
(a) Lowpass (specified as item 1
in Section 16.5.1); (b) highpass
(Example 16.5); (c) bandpass
(Example 16.6); (d) bandstop
(Example 16.7).
poles, which are plotted in Fig. 16.11(d)). Four of its poles are well inside the
unit circle, while the remaining four are somewhat close to the unit circle. On a
relative scale, the highpass filter provides a better resilience against quantization
among the latter three filters. The bandpass and bandstop filters are sensitive to
stability issues after quantization.
16.5.2 Implementation complexity
In this section, we compare the implementation complexity of the FIR fil-
ters designed in Examples 15.5-15.7 with that of the IIR filters designed in
Examples 16.5-16.7. Table 16.4 provides a list of the number of adders, mul-
tipliers, and unit delay elements required in each case. For IIR filters, we use
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