IP- .
:
1. . - () - (), . , /.
2. . . - . , .
3. () / , DSP. - . IP- /, .
, IP-, G (. 4.2).
- | - | |||||
G.722 ( 7 64 /) | G.723 ( 5,3 6,3 /) | |||||
G.711 (- ) | G.728 ( 16 / ) | |||||
G.729 ( 8 /) |
. 4.2.
, , . , , , , - , . LPC (Linear Predicative Coding). LPC , , . : , . . , -, , , -, , , , .
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, ( , ), . LPC , 2,4 4,8 /. , , . LPC . , . , , , . , , . , .
LD-CELP (Low-Delay Code-Excited Linear Prediction). 16 /. , - 16- . 10- - 16 /. : , 1995 . ITU - G.723, . .324, . - . G.723 MP-MLQ (Multipulse Maximum Likelihood Quantization). . . 4,8, 6,4, 7,2 8 /. . 20 . , .
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IP- , . GSM (13,5 /) - G. G.711. G.723 G.729.
G. 711.
G.711, 1984 ., , 8 8 . 64 / (8 8 ). - : - -30/32 μ- -24.
60- . G.711 . , G.711 IP- , IP- - . G.711 I- , . G.711 IP- Cisco.
G.723.
G.723 , , MP-MLQ (Multi-Pulse - Multi Level Quantization - , ). , / . . - , IP-. - . G.723 64 / (), / , IP- . 5,3-6,3 / . : 6,3 / MP-MLQ 5,3 / CELP. , (/).
DSP 16,4-16,7 MIPS (Million Instructions Per Second) 37 . G.729a, .
G.729.
G.729, G.729 Annex A, G.729 Annex ( VAD ). CS-ACELP (Conjugate Structure - Algebraic Code Excited Linear Prediction - ). DSP 21,5 MIPS 15 . 8 /. VoIP , . IP-.
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IP-, G.726 G.728.
G.726.
ADPCM - ( G.726 1984 .). , , 16-32 /. , , , , , , , . ADPCM , . DSP 5,5-6,4 MIPS. G.711 . .
G.728.
, G.728 1992 ., LD-CELP (Low Delay - Code Excited Linear Prediction - ). 16 /, 3 5 40 MIPS. , , . IP- .
2.1.
QDU (Quantization Distortion Unit): 1 QDU . QDU 4.2.
. 4.1.
G.726 | ADPCM | 32/24/16 / | (8 MPS) | (32), (16) | (0,125 ) |
G.729 | CS-ACELP | 8 / | (30 MIPS) | (3-5 ()))0))) ))) ) | |
G.729A | CA-ACELP | 8 / | (20 MIPS) | (3-5 ) | |
G.723.1 | MP-MLQ | 6,3/5,3 / | (16 MIPS) | (6,3), (5,3) | (37 ) |
G.728 | LD-CELP | 16 / | (40 MIPS) | (3-5 ) |
QDU
. 4.2.
QDU | |
ADPCM 32 / | 3,5 |
j ADPCM 24 / | |
ILD-CELP 16 / 1 | 3,5 |
JCS-CELP 8 / | 3,5 |
. -, QDU 14, , , 4 QDU. , QDU, / . , .