PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

DTFT, DFT, ZT, and FFT 517

20

15

10

5

0

0 50 100 150 200 250

0 50 100 150 200 250

DTFT

DTFT

DFT for k = 32

DFT for k = 64

Magnitudes of the DTFT and DFT

Amplitude

Amplitude

Index k

0

5

10

15

20

25

FIGURE 5.29

Magnitude plots of DTFT and DFT of the discrete sequence f(n) of Example 5.5.

FIGURE 5.30

Phase plots of DTFT and DFT of the discrete sequence f(n) of Example 5.5.

0 50 100 150 200 250

0 50 100 150 200 250

Index k

DTFT

DTFT

DFT for k = 64

DFT for k = 32

Phase of the DTFT and DFT

4

2

0

− 2

− 4

4

2

0

− 2

− 4

Phase angle

Phase angle