Altera Stratix - Page 330

7–44 Altera Corporation
Stratix Device Handbook, Volume 2 September 2004
Infinite Impulse Response (IIR) Filters
Figure 7–25. Cascaded Butterworth Biquads Note (1)
Note to Figure 7–25:
(1) The gain factor is compensated for at the end of the filtering stage and is not shown in this figure.
D Q
D Q
D Q
D Q
w
1
(n-1)
b
11
w
1
(n-2)
b
12
D Q
D Q
w
2
(n-1)
b
21
w
2
(n-2)
b
22
w
1
(n)
w
1
(n-2)
DSP
block
w
2
(n)
D Q
D Q
w
2
(n-2)
w
2
(n-1)
y(n)
x(n)
w
1
(n-1)
Second
biquad
First
biquad
D Q
D Q
D Q
D Q