Digital Signal Processing Reference
In-Depth Information
CONVERGENCE of ABSORPTION TOTAL SHAPE SPECTRA (BENIGN); FFT (Left), FPT
(−)
(Right); FID LENGTH: N/M, N = 1024, M = 8 − 32
Fourier Absorption Total Shape Spectrum
Pade Absorption Total Shape Spectrum
10
4000
B
0
14.1T
N/32 = 32 (N = 1024)
FPT
(−)
≈
B
0
14.1T
N/32 = 32 (N = 1024)
FFT
≈
Benign
Benign
2000
Lac
Glc
7.5
1000
500
300
Gln
5
200
100
Val
2.5
50
Ala
2
30
Cr
Crn
0
Lys
10
5
3
−2.5
1
Met
−5
0.5
5
4
3
2
1.5
1
5
4
3
2
1.5
1
(i) Chemical shift (ppm)
(iv) Chemical shift (ppm)
Fourier Absorption Total Shape Spectrum
Pade Absorption Total Shape Spectrum
50
4000
B
0
14.1T
N/16 = 64 (N = 1024)
FPT
(−)
≈
B
0
14.1T
N/16 = 64 (N = 1024)
FFT
≈
Benign
Benign
Lac
2000
Glc
40
1000
500
Converged
300
Gln
Ala
30
200
100
Val
Lys
Thr
Crn
20
50
Cr
30
20
10
10
Cho
Iso
Met
5
3
0
2
1
−10
0.5
5
4
3
2
1.5
1
5
4
3
2
1.5
1
(ii) Chemical shift (ppm)
(v) Chemical shift (ppm)
Fourier Absorption Total Shape Spectrum
Pade Absorption Total Shape Spectrum
50
4000
B
0
14.1T
N/8 = 128 (N = 1024)
FFT
≈
B
0
≈
14.1T
N/8 = 128 (N = 1024)
FPT
(−)
Benign
Benign
Lac
2000
40
Glc
1000
500
30
300
Converged
Ala
Gln
200
20
100
Val
Lys
Thr
Crn
50
Cr
30
10
20
10
Cho
Iso
0
Met
5
3
2
1
−20
0.5
5
4
3
2
1.5
1
5
4
3
2
1.5
1
(iii) Chemical shift (ppm)
(vi) Chemical shift (ppm)
FIGURE 9.1
Convergence of absorption total shape spectra for the benign ovarian case
using input data derived from Ref. [343]. The left panels correspond to the
FFT and the right panels to the FPT. The signal lengths are N/32 = 32 (top
panels (i), (iv)), N/16 = 64 (middle panels (ii), (v)), and N/8 = 128 (bottom
panels (iii), (vi)), where N is the full signal length (N = 1024).
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