Finite Impulse Response Filter Design - Digital Signal Processing: Fundamentals and Applications - page 235

0

-10

-20

-30

0 500 1000 1500 2000 2500 3000 3500 4000

Frequency (Hz)

50

0

-50

-100

-150

-200

0 500 1000 1500 2000 2500 3000 3500 4000

Frequency (Hz)

FIGURE 7.11

The frequency responses in Example 7.5.

and

(

U if 0:2 þ 0:02994 cos U > 0

: Hðe jU Þ¼

U þ p if 0:2 þ 0:02994 cos U < 0

The calculation details of the magnitude response for several normalized values are listed in Table 7.4 .
Figure 7.11 shows the plots of the frequency responses.

EXAMPLE 7.6
a. Design a 5-tap FIR band reject (bandstop) filter with a lower cutoff frequency of 2,000 Hz, an upper cutoff
frequency of 2,400 Hz, and a sampling rate of 8,000 Hz using the Hamming window method.
b. Determine the transfer function.
Solution:
a. Calculating the normalized cutoff frequencies leads to

U L ¼ 2pf L T ¼ 2p 2; 000=8; 000 ¼ 0:5p radians