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4‑5x
Content for
TS 46.020
Word version: 16.0.0
1…
3…
3
Definitions, symbols and abbreviations
4
Functional description of the GSM half rate speech codec
5
Homing sequences
A
Codec parameter description
B
Order of occurrence of the codec parameters over Abis
C
Bibliography
$
Change History
3
Definitions, symbols and abbreviations
3.1
Definitions
3.2
Symbols
Word‑p. 8
3.3
Abbreviations
Word‑p. 9
4
Functional description of the GSM half rate speech codec
Word‑p. 10
4.1
GSM half rate speech encoder
4.1.1
High-pass filter
Word‑p. 12
4.1.2
Segmentation
Word‑p. 13
4.1.3
Fixed Point Lattice Technique (FLAT)
4.1.4
Spectral quantization
Word‑p. 14
4.1.4.1
Autocorrelation Fixed Point Lattice Technique (AFLAT)
4.1.5
Frame energy calculation and quantization
Word‑p. 16
4.1.6
Soft interpolation of the spectral parameters
4.1.7
Spectral noise weighting filter coefficients
Word‑p. 17
4.1.8
Long Term Predictor lag determination
Word‑p. 18
4.1.8.1
Open loop long term search initialization
Word‑p. 19
4.1.8.2
Open loop lag search
Word‑p. 20
4.1.8.3
Frame lag trajectory search (Mode ≠ 0)
Word‑p. 25
4.1.8.4
Voicing mode selection
Word‑p. 27
4.1.8.5
Closed loop lag search
4.1.9
Harmonic noise weighting
Word‑p. 28
4.1.10
Code search algorithm
Word‑p. 30
4.1.10.1
Decorrelation of filtered basis vectors
Word‑p. 31
4.1.10.2
Fast search technique
Word‑p. 32
4.1.11
Multimode gain vector quantization
Word‑p. 33
4.1.11.1
Coding GS and P0
4.2
GSM half rate speech decoder
Word‑p. 36
4.2.1
Excitation generation
Word‑p. 37
4.2.2
Adaptive pitch prefilter
4.2.3
Synthesis Filter
4.2.4
Adaptive spectral postfilter
4.2.5
Updating decoder states
Word‑p. 39
5
Homing sequences
5.1
Functional description
5.2
Definitions
5.3
Encoder homing
Word‑p. 40
5.4
Decoder homing
5.5
Encoder home state
5.6
Decoder home state
A
(Normative) Codec parameter description
Word‑p. 41
A.1
Codec parameter description
A.1.1
MODE
A.1.2
R0
A.1.3
LPC1 - LPC3
Word‑p. 42
A.1.4
LAG_1 - LAG_4
A.1.5
CODEx_1 - CODEx_4
A.1.6
GSP0_1 - GSP0_4
A.2
Basic coder parameters
B
(Normative) Order of occurrence of the codec parameters over Abis
Word‑p. 43
C
Bibliography
Word‑p. 44
$
Change History
Word‑p. 45