Digital Voice Systems AMBE-3000 Especificaciones descargar pdf (Pagina 93)

AMBE-3000F™ Vocoder Chip Users Manual

Version 3.4, April, 2014

Dat

a and Configuration Packets

ompressed data bits from the encoder or to the decoder (packed 2 bits per byte). The data is denoted by Chand[0]

Chand[(bits-1)/2].

CHAND4 Field - Format

Field Identifier Number of Bits Data

1 Byte 1 Byte

Variable Number of Channel

Data Bits

0x17 40 ≤ {bits} ≤ 192 chand[0] – chand[(bits-1)/2]

Table 108 CHAND4 Field - Format

SAMPLES field (2 bytes) denotes the number of samples to generate for current decoder frame. The second byte, contains the

data for the number of samples. The normal number of samples is 160 but the number can range between 156 to 164 when it

produces the resulting speech packet.

SAMPLES Field - Format

Field Identifier Number of Samples

1 Byte 1 Byte

0x03 156 ≤ {number of samples} ≤ 164

Table 109 SAMPLES Field - Format

CMODE fields (3 bytes total) may be used to change the mode of the decoder on a frame-by-frame basis. The CMODE field

will enable/disable advanced features of the decoder when sent as part of a channel packet.

CMODE will overwrite any values set by the PKT_DCMODE field as well as, the state as set by the corresponding hardware

configuration pin. In order not to inadvertently turn off or on features that were originally set by DCMODE_IN or set via

hardware configuration pins to be sure that CMODE is or'd with the correct value of the desired DCMODE_IN. Except for

Tone Synthesis Enable, once these values are set they typically do not change. So it is not necessary to send CMODE fields on

a frame-by-frame basis.

For example, to enable both LOST_FRAME and CNI_FRAME CMODE data value would be 0xXXXC.

CMODE Field - parameters

Decoder Input Flag Parameters CMODE Value

LOST_FRAME Frame repeat enable. 0xXXX4

CNI_FRAME Comfort Noise Insertion Enable. 0xXXX8

TS_ENABLE Tone Synthesis Enable. 0x4XXX

TONE

TONE fields (3 bytes total) can be used to force the decoder to synthesize a tone frame. The frequency (or frequencies) and

amplitude of the tone are specified by this field. For durations of greater than 20 ms, the TONE field must be repeated for

consecutive frames. (DTMF Code Value and Amplitude Value are in Hex)

TONE Field - Format

Field Identifier DTMF TONE Data Amplitude Data

1 Byte 1 Byte 1 Byte

(Subject to Change) Page 83

DVSI CONFIDENTIAL PROPRIETARY

1 2 ... 88 89 90 91 92 93 94 95 96 97 98 ... 110 111

Sin comentarios

Digital Voice Systems AMBE-3000 Especificaciones Pagina 93