Infinite Impulse Response Filters - Digital Signal Processing and Applications with the C6713 and C6416 DSK - page 186

FIGURE 5.8. All-pole IIR lattice filter structure for the i th section.

FIGURE 5.9. All-pole IIR lattice filter structure with two sections.

1

() =

Hz (5.26)

102 + . z

- 1

- 05 . z

- 2

This transfer function is the inverse of the transfer function for the all-zero FIR
lattice structure in Exercise 4.3, where the k -parameters were found to be

k
k

=
=-

04
05

.

1

.

2

Figure 5.9 shows the IIR lattice structure for this example, extending Figure 5.8 to
a two-stage structure.

IIR Lattice Structure with Poles and Zeros
For an IIR lattice structure with poles and zeros, the previous results for all-zero
and all-pole structures can be used. The notation used for the coefficients must be
changed to reflect both the numerator and denominator polynomials in an IIR
system. Figure 5.10 shows the IIR lattice structure with both poles and zeros.
It shows a ladder (bottom half) portion added to the all-pole structure. A set of
coefficients c i , expressed in terms of both the numerator ( a i ) and denominator ( b i )