Digital Signal Processing Reference
In-Depth Information
Table 5.2
Intra-frame correlation coefficients
j
i
1
2
3
4
5
6
7
8
9
10
1
1.00
0.65
−
0.30
−
0.35
−
0.41
−
0.49
−
0.39
−
0.40
−
0.36
−
0.20
2
0.65
1.00
0.28
0.11
−
0.07
−
0.13
−
0.07
−
0.05
−
0.06
−
0.07
3
−
0.30
0.28
1.00
0.72
0.50
0.53
0.46
0.54
0.39
0.28
4
−
0.35
0.11
0.72
1.00
0.72
0.62
0.46
0.42
0.45
0.21
5
−
0.41
−
0.07
0.50
0.72
1.00
0.79
0.52
0.47
0.34
0.26
6
−
0.49
−
0.13
0.53
0.62
0.79
1.00
0.71
0.61
0.49
0.28
7
−
0.39
−
0.07
0.46
0.46
0.52
0.71
1.00
0.73
0.58
0.41
8
−
0.40
−
0.05
0.54
0.42
0.47
0.61
0.73
1.00
0.58
0.46
9
−
0.36
−
0.06
0.39
0.45
0.34
0.49
0.58
0.58
1.00
0.41
−
−
10
0.20
0.07
0.28
0.21
0.26
0.28
0.41
0.46
0.41
1.00
Table 5.3
Inter-frame correlation coefficients
k
i
1
2
3
4
5
6
7
8
9
10
1
0.93
0.84
0.76
0.68
0.61
0.55
0.50
0.45
0.41
0.36
2
0.89
0.75
0.63
0.54
0.46
0.38
0.32
0.27
0.22
0.18
3
0.92
0.80
0.70
0.60
0.51
0.43
0.36
0.30
0.24
0.20
4
0.92
0.82
0.73
0.64
0.56
0.49
0.43
0.37
0.32
0.27
5
0.95
0.88
0.81
0.74
0.67
0.61
0.54
0.48
0.43
0.37
6
0.94
0.85
0.77
0.69
0.62
0.56
0.49
0.44
0.38
0.33
7
0.93
0.83
0.75
0.66
0.58
0.50
0.43
0.37
0.31
0.26
8
0.91
0.81
0.72
0.64
0.56
0.49
0.43
0.37
0.32
0.28
9
0.87
0.73
0.64
0.55
0.48
0.42
0.37
0.33
0.29
0.25
10
0.82
0.66
0.57
0.50
0.44
0.38
0.34
0.30
0.27
0.24
5.6 LSF Quantization
Most modern speech coders make use of LPC modelling during speech
processing. Although some coders use a backward-adaptive LPC filter [8],
most speech coders extract the LPC parameters from the input speech at
regular intervals, transform them into the LSF domain, and quantize them
for transmission to the decoder.
Low distortion LSF quantization is essential for the overall quality of
decoded speech, and the number of bits allocated to LSFs usually takes a
significant proportion of the overall bit rate, up to over 50% for very low
Search WWH ::
Custom Search