AMBE-2000 Digital Voice Systems, Inc., AMBE-2000 Datasheet - Page 36

• Manufacturer Part Number: AMBE-2000
• Description: 2.0 - 9.6 KBPS Single ic For Toll-quality, Low Data Rate, Real Time Speech Compression
• Manufacturer: Digital Voice Systems, Inc.

5.4.2
The Unframed Input format contains 1 to 4 bits within each 16 bits serial output word. For the formats that contain more than
one bit in each word, the MSB of the data bits is considered first in the transmission. In Unframed mode, the header data from
Framed mode is dropped and each 16-bit write contains 1 to 4 coded voice data bits. The number of words that need to be
transferred into the decoder for each 20-millisecond frame will be the number of bits per frame divided by the number of bits
per word. So a system coding at 4800 bps with 3 bits per word will need to write exactly 32 ([4800 ÷50] ÷3 = 32) words each
frame.
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Unframed Serial Input Format
2 bits per Word Format
3 bits per Word Format
4 bits per Word Format
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1 bit per Word Format
See Table 4-A
Bits per Word
Table 5-Q Unframed Serial Input Data Format
D
D
D
D
15
msb
msb
msb
msb
Data
14
D
D
D
0
AMBE-2000™ Vocoder Chip
User’s Manual Version 4.0
13
D
D
0
0
12
D
0
0
0
11
0
0
0
0
Control Offset
10
0
0
0
0
0
0
0
9
0
X
X
X
X
8
X
X
X
X
7
X
X
X
X
6
X
X
X
X
5
Control Data
X
X
X
X
4
X
X
X
X
3
X
X
X
X
Page 36
2
X
X
X
X
1
X
X
X
X
0