AMBE-3000™, AMBE-3000-SAT™ and AMBE-3003™ Vocoder Chips

Proven Technology at rates from 2.0 to 9.6 kbps

Introduction

The AMBE-3000™ Vocoder Chip implements DVSI's patented AMBE+2™ Voice Compression Algorithm. The AMBE-3000™ Vocoder Chip can operate at virtually any data rate from 2.0 to 9.6 kbps. This allows designers to optimize speech and/or FEC rates within their system requirements to provide excellent voice quality with superior robustness to bit errors and acoustic background noise. The success of this vocoder technology has resulted in it being chosen by many mobile radio manufacturers in North America and in Europe. In addition, satellite systems prefer this technology because of its superior voice quality at low bit-rates.

The AMBE-3003™ Vocoder Chip is the multi-channel version of Digital Voice Systems, Inc. (DVSI)'s successful AMBE-3000™ vocoder chip. The AMBE-3003™ Vocoder Chip offers three separate encoder/decoder operations to provide the capability of up to three full duplex channels. The voice coding rate and the FEC rate for each of the three channels can be specified independently for integration into a variety of design configurations.

By incorporating this advanced vocoder technology, into proven DSP technology the AMBE-3000™ vocoder chip achieves a level of performance and reliability typically associated only with customized ASICs, but without the associated risks and high development costs. With small quantity, off-the-shelf availability and no licensing fees or royalties, engineers and original equipment manufacturers are able to efficiently design and affordably produce high-performance, narrow-band, communication equipment.

Operation

To allow for easy integration, basic communication to/from the AMBE-3000™ Vocoder chip is designed to be as flexible as possible. The AMBE-3000™ offers users four separate physical interfaces: SPI (speech data samples interface only), McBSP serial port, UART, and a parallel port. Selecting the interface that best fits system requirements is made easy with two operating modes.

In Codec mode the AMBE-3000™ Vocoder Chip is configured to transmit and receive digitized speech to and from most linear, a-law, or u-law A/D-D/A codecs through either its SPI or McBSP serial port and the compressed channel data uses one of the remaining interfaces. Alternatively, the AMBE-3000™ Vocoder chip can be set-up to operate in packet mode, where both the speech and compressed channel data are on the same interface. Packet mode also allows for vocoder configuration, vocoder status information, as well as the transferring of speech and compressed data bits to/from the chip's internal encoder and decoder.

The AMBE-3000™ chip boasts numerous advanced design features such as automatic Voice/Silence Detection (VAD), noise suppression, adaptive comfort noise insertion (CNI), DTMF and Call Progress Tone detection/regeneration, echo cancellation, low power modes and frame-by-frame "on-the-fly" rate switching. Additionally, the chip includes variable rate Forward Error Correction (FEC). The built-in FEC supports block and convolution codes with up to four bits of Viterbi soft decision decoding. The quality of this FEC provides exceptional robustness to background noise and intelligible speech in degraded channel conditions, even with bit errors (BER) of up to 20%. This level of performance can lead to the successful development and deployment of wireless communication systems in the most demanding environments.

These features, combined with the chip's low power consumption and small form factor (128 pin LQFP of BGA package), make the AMBE-3000™ Vocoder Chip an ideal solution for wireless applications where bandwidth is at a premium and low-data-rate, high-voice-quality is imperative. As the latest addition to DVSI's family of voice compression products, the AMBE-3000™ has inter-operable modes that provide a seamless migration path from systems already using DVSI's AMBE-2000™ and AMBE-1000™ Vocoder Chips.

The value of DVSI's AMBE® Voice Compression Technology goes beyond low bit rate and voice quality. It has been thoroughly evaluated and tested by international manufacturers under various conditions using a variety of languages. This assures the user is getting the best vocoder available and makes the DVSI vocoder the logical choice without the need for additional comparison tests. Plus the fact, that DVSI's Voice Compression technology has been implemented worldwide for more than 19 years, delivers the added security of a field proven technology that can play a key role in making any communication system an overall success.