Digital Signal Processing Reference
In-Depth Information
Optimal vector
0.0
500.0
Codebook Index
(a)
1000.0
Reference vector
v1
v2
v3
v4
v5
0.0
10.0
20.0
30.0
Samples
40.0
50.0
60.0
(b)
Figure 7.6
Typical example of a distinctive codebook vector selection for CELP
(a) Plot of error versus codebook index for CELP, and (b) Synthesized best codebook
entries compared with original
structure may exist in the selected time index for LTP2. Figure 7.8 shows a
plot of the distribution of the time-delay index for both LTP1 and LTP2 for
a female speaker. From the histogram of LTP1, it is clear that the speaker
used for the test had a pitch period peaking at around 42 samples. However,
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