AMBE-2000™ Vocoder Chip

User’s Manual Version 3.0

page 6

Confidential Proprietary, Subject to Change

1. Product Introduction

1.1 General Information

Digital Voice Systems Inc.’s AMBE-2000™ Vocoder Chip is an extremely flexible, high-performance, single chip, speech

compression coder. It provides superior voice quality at low data rates. It provides a real-time, full-duplex implementation of

the standard-setting AMBE

has been proven to outperform CELP, RELP, VSELP, MELP, ECELP, MP-MLQ, LPC-10, and other competitive technologies.

Numerous evaluations have shown its ability to provide performance equal to today’s digital cellular systems at under half the

data rate. The AMBE

of digital mobile communication systems.

The AMBE-2000™ Vocoder chip provides a high degree of flexibility in selecting the speech and FEC (Forward Error

Correction) data rates. The user can separately select these parameters in 50 bps increments for total rates from 2.4 kbps to 9.6

kbps. Typically for higher error rate channels, the user will apportion a greater percentage of the total bit rate to FEC coding.

The AMBE-2000™ voice coder maintains natural voice quality and speech intelligibility at rates as low as 2.4 kbits/sec. The

AMBE

2000™ Vocoder Chip.

The AMBE-2000™ Vocoder Chip offers similar features as to DVSI’s AMBE-1000™ Vocoder Chip allowing it to be

incorporated into systems already design for the AMBE-1000™ and is interoperable with other DVSI products. The AMBE-

2000™ Vocoder Chip delivers improved performance and enhanced modes such as 4.0 kbps toll quality speech and

convolutional FEC coding. Along with these enhancements the AMBE-2000™ Vocoder Chip employs a control interface

along with the variable data rates and FEC selection as found in .

1.2 Advantages

•

Superior Voice Quality

•

Low Cost

•

No External Memory Required

•

Robust to Bit Errors & Background Noise

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Variable Data Rates - 2.0 kbps to 9.6 kbps

•

Variable FEC Rates - 50 bps to 7.2 kbps

•

Very Low Power (65mW @ 3.3V, 0.11mW Deep Sleep)

•

Compact Single Chip Solution: 100 pin TQFP

Features

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High Quality Low Data Rate Speech Coding

•

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Supports Data Rates of 2.0 kbps to 9.6 kbps in 50 bps increments

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User Selectable Forward Error Correction rates

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Viterbi Decoder (rate 1/4 or more)

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16 Level Soft Decision Decoding

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Voice Activity Detection (VAD) / Comfort Noise Insertion

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16 ms. Echo Cancellation

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Single and Dual Tone (DTMF) Detection and Generation