D2

D1

Filter

0

0

No Filter

0

1

Level 1

1

0

Level 1

1

1

Level 2

Level 2 sets maximum filtering.

Figure 8 depict the filter output to in response to a step input

and an impulse input. Figure 9 depicts the digital filter in use

in a Pentium 4 processor system. Note that the two curves,

with filter and without, have been purposely offset so that

both responses can be clearly seen. Inserting the filter does

not induce an offset as shown.

10130325

a)Step Response

10130326

b)Impulse Response

FIGURE 8. Filter Output Response to a Step Input

10130327

FIGURE 9. Digital Filter Response in a Pentium 4 processor System. The filter on and off curves were purposely

offset to better show noise performance.

www.national.com

12