DTFT, DFT, ZT, and FFT
545
0
10
20
30
40
50
0
5
10
15
20
abs[fft(gf(n))]
abs[fft(gf(n))] versus k
0
10
20
30
40
50
−4
−2
0
2
4
angle[fft(gf(n))] versus k
angle[fft(gf(n))]
0
10
20
30
40
50
0
5
10
15
20
abs[fft(gc(n))] versus k
index k
abs[fft(gc(n))]
0
10
20
30
40
50
−4
−3
−2
−1
0
angle[fft(gc(n))] versus k
index k
angle[fft(gc(n))]
FIGURE 5.58
Magnitude and phase plots of fft[g f (n)] and fft[g c (n)], over the range 1 ≤ k ≤ 50 of Example 5.13.
0
5
10
15
20
25
30
35
40
45
50
−0.5
0
0.5
error plots in time and frequency
Amplitude
0
5
10
15
20
25
30
35
40
45
50
−10
−10
10
0
Magnitude error
0
5
10
15
20
25
30
35
40
45
50
0
10
phase error
index k
index n
error = g(n) - g(n)
∠error(k) = ∠DFT[gf(n)] - ∠DFT[gf(n)]
error = DFT[g(n) - DFT[g(n)]
FIGURE 5.59
Error plots in the time and frequency domains of Example 5.13.
CRC_47760_CH005.indd 545
CRC_47760_CH005.indd 545
7/23/2008 1:47:41 PM
7/23/2008 1:47:41 PM