Tesis previa a la obtención del Título de Ingeniero en Electrónica y ...

728 audio
e LD-CELP 2.5 ms frarae consiste of the following 40 numbered bits:
Codeword O, bit 9 (MSB) to bit O (LSB): 09,08,07,06,05,04,03,02,01,00
Codeword 1, bit 9 (MSB) to bit O (LSB): 19,18,17,16,15,14,13,12,11,10
Codeword 2, bit 9 (MSB) to bit O (LSB): 29,28,27,26,25,24,23,22,21,20
Codeword 3, bit 9 (MSB) to bit O (LSB): 39,38,37,36,35,34,33,32,31,30
iese are pacfced into two 8 kbit/s H.221 sub-channels by putting odd nurabered bits in the first sub-channel and even nurabered bits
the second. This structure ¡s repeated four limes ¡n each 10 ras H.221 frarae as shown below. The ftrst codeword in each H.221
une is then always the first codeword in the speech coder frarae also. The speech coder synchronization can then be derived frora
221 FAS (frame alignment slgnal). '
Bit number
Speech
coder
frame 0
Speech
coder
trame 1
Speech
coder
frame 2
Spaech
coder
frame 3
1
09
07
05
03
01
19
17
•
11
29
•
21
39
•
31
09
07
•
33
31
09
07
-
33
31
09
07
•
33
31
2
08
06
04
02
00
18
16
•
10
28
•
20
38
•
30
08
06
"
32
30
08
06
•
32
30
08
06
"
32
30
The 10 ms H.221 frame
3 4 5 6 7 8
FIGURE 5d/H.221
Bit positions for audio
F
A
S
Octel
number
1
2
3
-
-
-
•
•
-
-
-
•
•
•
-
•
-
•
-
•
•
-
-
•
-
•
-
•
79
80
Recommendation H.221 (03/93) 13