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AMBE-3000F™ Vocoder Chip Users Manual

Version 3.4, April, 2014

Dat

a and Configuration Packets

6.8 Output Speech Packets Format (Packet Type 0x02)

A speech packet (packet type 0x02) is output from the AMBE-3000F™ Vocoder chip, whenever the chip receives an input

channel packet (packet type 0x01). The format of the output speech packet can be configured using PKT_SPCHFMT control

field see Table 64 PKT_SPCHFMT Field.

6.9 Input Channel Packet Format (Packet Type 0x01)

A channel packet uses the format as shown in Table 28 General Packet Form

at WITHOUT Parity Field where the PACKET

TYPE is equal to 0x01. For every channel packet input (packet type 0x01) to the AMBE-3000F™ Vocoder chip, the chip will

output speech packet (packet type 0x02).

6.9.1 Channel Packet Fields

The channel packet supports the following packet fields:

Channel Packet Fields

Field Name Field Identifier Field Length Description

PKT_CHANNEL0 0x40 2 bytes The vocoder for subsequent fields

CHAND 0x01 Variable bytes Compressed speech data to be decoded for current vocoder

CHAND4 0x17 Variable bytes

Compressed speech data with four bit soft decision error

correction enabled to be decoded for current vocoder

SAMPLES 0x30 2 bytes Number of samples to generate for current decoder frame

CMODE 0x02 3 bytes CMODE flags for current vocoder’s decoder

TONE 0x08 3 bytes Force current vocoder’s decoder to generate tone frame

Table 106 Channel Packet Fields

PKT_CHANNEL0 field (2 bytes) indicates the vocoder the control is intended for. It is the same as described in the Table 33

T_CHANNEL(0) Field Format

CHAND (variable number of bytes) channel bits to be decoded, packet 8 bits per byte.

Compressed data bits from the encoder or to the decoder (packed 8 bits per byte). The data is denoted by Chand[0]

Chand[(Bits-1)/8]. Chand[0] contains the bits which are most sensitive to bit errors. Chand[(Bits-1)/8] contain the bits which

are least sensitive to bit errors. 2 thru 1+(Bits+7)/8 bytes

CHAND Field - Format

Field Identifier Number of Bits Data

1 Byte 1 Byte

Variable Number of Channel

Data Bits

0x01 40 ≤ {bits} ≤ 192 chand[0] – chand[(bits-1)/8]

Table 107 CHAND Field - Format

CHAND4 (variable number of bytes) channel bits to be decoded, with soft decision error correction enabled.

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