User`s manual
AMBE-2000™ Vocoder Chip
User’s Manual Version 4.9
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Decoder Silence Detect: When the Decoder Silence Detect flag is set to 1, the decoder is reporting that the last frame decoded
was a comfort noise frame.
Encoder DTMF Detect: The Encoder DTMF Detected Flag will be set to a 1 when the encoder detects a DTMF tone.
Encoder Silence Detect: The Encoder Silence Detected Flag will be set to 1 when no voice activity is detected. The Silence
Detect option is controlled by and can be disabled by the VAD as described in section 5.2.9.
5.3.4 Framed Output: Words 2-6 : Rate Information
Rate Info 0, Rate Info 1, Rate Info 2, Rate Info 3, Rate Info 4.
Words 2-6 in the packet indicate the rate at which the AMBE-2000™ encoder is operating. These words are output. See tables
5-C and 5-D for corresponding values.
5.3.5 Framed Output: Word 7 : Bit Error Rate
This status field is used for the decoder to report bit error information. The 16 bit number output is used to compute the BER
using the following calculation
% BER = (Word 7) / (32768) x 100
This status field works in conjunction with the RIS bits in control word 2. Every time the RIS bits are set to any value other
than 0x3, this field is reset. The BER is calculated only when using FEC provided by the AMBE-2000
™.
5.3.6 Framed Output: Word 8 : Soft Decision Distance
This status field is used in conjunction with hardware pin 79 SOFT_EN. This field is used to report the soft decision distance
for the most recent decoded frame.
This status field works in conjunction with the RIS bits in control word 2. Every time the RIS bits are set to any value other
than 0x3, this field is reset. The Soft Decision Distance is calculated only when using Soft Decision decoding provided by the
AMBE-2000
™.
5.3.7 Framed Output: Word 9 : Detected Bit Errors
This status field is used to report the number of detected bit errors in the most recent decoded frame.
This status field works in conjunction with the RIS bits in control word 2. Every time the RIS bits are set to any value other
than 0x3, this field is reset. The number of bit errors is calculated only when using FEC provided by the AMBE-2000
™.