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参数资料
| 型号： | MAS3519F |
| 厂商： | MICRONAS SEMICONDUCTOR HOLDING AG |
| 元件分类： | Codec |
| 英文描述： | MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| 中文描述： | 新加坡金融管理局35x9F的MPEG 2 / 3层，AAC音频解码器，G.729的附件A编解码器 |
| 文件页数： | 44/92页 |
| 文件大小： | 1186K |
| 代理商： | MAS3519F |
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MAS 35x9F
DATA SHEET
44
June 30, 2004; 6251-505-1DS
Micronas
3.3.7. DSP Volume Control
The digital baseband volume matrix is used for control-
ling the digital gain as shown in Fig. 3–3. This volume
control is effective on both, the digital audio output and
the data stream to the D/A converters. The values are
in 20-bit 2’s complement notation.
Table 3–14 shows the proposed settings for the 4 vol-
ume matrix coefficients for stereo, left and right mono.
The gain factors are given in fixed point notation
(
1.0
×
2
19
= 80000
hex
).
If channels are mixed, care must be taken to prevent
clipping at high amplitudes. Therefore, the sum of the
absolute values of coefficients for one output channel
must be less than 1.0.
For normal operating conditions it is recommended to
use the main volume control of the audio codec
instead (register 00 10
hex
of the audio codec).
Fig. 3–3:
Digital volume matrix
3.3.8. Explanation of the G.729A Data Format
The codec is working on a page basis where the
encoding and decoding is performed in blocks of 50
G.729 frames, whereas each frame consists of
10 bytes in byte-swapped order (see Fig. 3–4). There-
fore most changes to the UserControl register become
effective when processing of the current page is fin-
ished. The pages are optionally preceeded by 10 byte
header frames (see Table 3–15).
Switching directly from encoding to decoding mode (or
vice versa) is not allowed. Instead, the controller has to
send a stop request to the MAS 35x9F (writing 0
hex
to
UserControl) and must keep on sending data in decod-
ing mode or receive data in encoding mode until the
current page of 50 frames is finished. After this run-out
time, the encoding or decoding can be started again.
Fig. 3–4:
Schematic timing of the data transmission with preceeding header
1
1
1
1
LL
LR
RL
RR
+
+
left audio
right audio
f
t
Table 3–14:
Settings for the digital volume matrix
Memory
D0:354
D0:355
D0:356
D0:357
Name
LL
LR
RL
RR
Stereo
(default)
1.0
0
0
1.0
Mono left
1.0
1.0
0
0
Mono right
0
0
1.0
1.0
Table 3–15:
Content of page header
Byte
1
2
3
4
5
6
7
8
9
10
Value
(hex)
64
6d
72
31
64
61
74
61
F4
01
...
...
...
...
...
page
header
frame
1
frame
2
frame
3
frame
49
frame
49
page
header
frame
51
frame
52
frame
99
frame
100
page
header
frame
101
frame
102
10 ms
10 ms
byte
2
byte
1
byte
4
byte
3
byte
6
byte
5
byte
8
byte
7
byte
10
byte
9
64
6D
72
31
64
61
74
61
F4
01
相关PDF资料 |
PDF描述 |
|---|---|
| MAS3529F | MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| MAS3539F | MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| MAS3549F | MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| MAS3587F | MPEG Layer 3 Audio Encoder/Decoder |
| MAS7848L | RDS MODEM / MANCHESTER DECODER |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAS3529F | 制造商:MICRONAS 制造商全称:MICRONAS 功能描述:MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| MAS3539F | 制造商:MICRONAS 制造商全称:MICRONAS 功能描述:MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| MAS3549F | 制造商:MICRONAS 制造商全称:MICRONAS 功能描述:MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| MAS3559F | 制造商:MICRONAS 制造商全称:MICRONAS 功能描述:MAS 35x9F MPEG Layer 2/3, AAC Audio Decoder, G.729 Annex A Codec |
| MAS3587F | 制造商:未知厂家 制造商全称:未知厂家 功能描述:MPEG Layer 3 Audio Encoder/Decoder |
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