AMBE-1000 Digital Voice Systems, Inc., AMBE-1000 Datasheet - Page 33

• Manufacturer Part Number: AMBE-1000
• Manufacturer: Digital Voice Systems, Inc.

4.1.2
4.1.3
4.1.4
Unused : 0
7 : MSB
The AMBE-1000 is not recommended for new designs.
Please refer to the AMBE-2000/2020 product line.
Framed Output : Header
Framed Output : ID
Framed Output : Status_0
The header is a 16 bit word that begins each valid frame corresponding to 20
milliseconds of speech. This field will always be 0x13EC.
The encoder will always use 0x00 in the 8-bit ID field of an output frame.
Table 4-B Status_0 Format
Frame Repeat : The Frame Repeat Flag is set to a 1 when the AMBE-1000™ decoder
outputs a waveform corresponding to the parameters of the previous frame. A frame
repeat serves to mask from the listener the effects of receiving corrupted data.
frame repeat will automatically be performed by the decoder if it deems that the
received frame has too many bit errors, or if the decoder has received a specific
command from the host to perform a frame repeat through the command interface as
described in section 4.1.12.
Decoder Output Silence : The Decoder Output Silence Flag is set to a 1 when the
previous frame that the decoder receives is a silence frame. When a silence frame is
received by the decoder a frame of ‘comfort noise’ is output. In order for the encoder
to output coded silence frames the VAD feature must be enabled (see Section 6.4) yet
the decoder will report the receipt of a silence frame regardless of the VAD being
enabled or disabled. This flag will also report the decoder outputting a silence frame as
a result of setting the Force Decoder Silence bit in the Control_0 field of an input frame
to the decoder (see section 4.1.12).
Find Sync : The Find Sync Flag only has relevance when operating in Unframed
(serial) mode. This flag is set to 1 during the period of time when the decoder is still
trying to synchronize with the embedded frame bit of the Unframed data format.
Once synchronization has occurred (normally takes 10-15 frames of uncorrupted data)
this flag will return to 0.
Encoder Silence Detected : The Encoder Silence Detected Flag is relevant only when
the VAD feature is enabled (see Section 6.4). This flag is set to 1 when the encoder
detects no voice activity in the speech data. The corresponding voice data bits will
contain a ‘silence frame’ which will convey (in-band) to the receiving decoder to insert
‘comfort noise’ during this frame.
DTMF Detected : The DTMF Detected Flag will be set to a 1 when the encoder detects
a DTMF tone according to the requirements in Table 4-C. When this flag is set to a 1
then a code corresponding to which DTMF tone has been detected will be output in
Status_2 along with amplitude information (see Section 4.1.6 below).
Unused : 0
6
The AMBE-1000 is not recommended for new designs.
Please refer to the AMBE-2000/2020 product line.
Repeat
Frame
5
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Status_0 (see Table 4-A)
Decoder
Silence
Output
4
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Unused : 0
3
Find Sync
2
Detected
Encoder
Silence
1
Detected
0 : LSB
DTMF
A