Digital Voice Systems AMBE-3000 Specifications download pdf (Page 44)

AMBE-3000™ Vocoder Chip Users Manual

Version 2.8, August, 2011

O Management

silence fram

e if no silence frames have been received

yet).

4-6 Reserved.4-Reserved.6

7 CP_SELECT

Compand Select.

If companding is enabled and CP_SELECT=0, then u-

law companding is selected. If companding is

enabled, and CP_SELECT=1 then a-law companding

is selected. If companding is not enabled, then this bit

has no effect.

After reset, this

bit is initialized

using the setting

from the

CP_SELECT pin.

8 CP_ENABLE

Compand Enable

If CP_ENABLE=1, then companding is enabled

(either a-law or u-law, depending on the setting of

CP_SELECT). If CP_ENABLE=0, then companding

is disabled and all speech samples are 16-bit linear.

After reset, this

bit is initialized

using the setting

from the

CP_ENABLE pin.

9-13 Reserved.9-Reserved.13

14 TS_ENABLE

Tone Synthesis Enable. If TS_ENABLE=1, then the

Decoder ignores any channel data provided to it and

synthesizes the specified tone.

0 at reset.

15 Reserved.15

Table 15 DCMODE_IN Flags

The I/O handler also passes a frame of channel data, if available, to the decoder once every 20 ms. The decoder produces

160±4 speech samples for every 20 ms frame. In addition to outputting speech samples for each 20 ms frame, the decoder

outputs a 16-bit status word named DCMODE_OUT. The DCMODE_OUT flags are as specified in Table 16

DCM

ODE_OUT Flags. If the I/O handler does not have a frame of channel data to pass to the decoder at the scheduled time,

then t

he I/O Handler forces the decoder to perform a frame repeat by setting the appropriate bit in DCMODE_IN for that frame

only.

Bit

Number

Bit Name Bit description

0 Reserved.0 Reserved

1 VOICE_ACTIVE

The decoder sets VOICE_ACTIVE=1 if the decoder synthesized a voice

frame or a tone frame. If the decoder synthesized a comfort noise frame,

then it sets VOICE_ACTIVE=0. The decoder can synthesize comfort

noise in the following circumstances:

(a) a comfort noise frame (silence frame) was received by the decoder.

(b) The decoder FEC (if enabled) found too many errors.

2-4 Reserved.2-Reserved.4

5 DATA_INVALID

The decoder sets this bit whenever it performs a frame repeat. It also sets

this bit if it inserted comfort noise due to channel errors or missing frames.

The decoder will set DATA_INVALID=0 if it received a valid (voice,

silence, or tone frame).

6-14 Reserved.6-Reserved.14

15 TONE_FRAME The decoder sets this bit whenever it decodes a tone frame.

Table 16 DCMODE_OUT Flags

(Subject to Change) Page 34

DVSI CONFIDENTIAL PROPRIETARY

1 2 ... 39 40 41 42 43 44 45 46 47 48 49 ... 101 102

Comments to this Manuals

No comments

Digital Voice Systems AMBE-3000 Specifications Page 44

Comments to this Manuals