AMBE2000 ETC, AMBE2000 Datasheet - Page 34

• Manufacturer Part Number: AMBE2000
• Description: VOCODER CHIP
• Manufacturer: ETC

5.4.2 Unformatted Serial Input Format
The Unformatted Input format contains 1 to 4 bits within each 16 bits serial output word. For the formats which contain more
than one bit each word the MSB of the data bits is considered first in the transmission. In Unformatted mode, the header data
from Formatted 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.
2 bits per Word Format
3 bits per Word Format
4 bits per Word Format
1 bit per Word Format
See Table 4-A
Bits per Word
Table 5-Q Unformatted Serial Input Data Format
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15
msb
msb
msb
msb
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Data
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User’s Manual Version 3.0
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page 34
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Control Offset
10
0
0
0
0
0
0
0
0
9
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
2
X
X
X
X
1
X
X
X
X
0