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AMBE-2020
Vocoder Chip
Digital Voice Systems, Inc.
The Speech Com pression Specialists
Features
· Half-Duplex Operation
· AMBE+
· User selectable bit rate (2.0 kbps to 9.6 kbps)
· Integrated convolutional and block code
Forward Error Correction (FEC)
· Viterbi Decoder (1/4
bits of soft decision decoding
· High performance Voice Activity Detection
(VAD) with adaptive Comfort Noise Insertion
(CNI)
· DTMF North American call progress tone
detection, transmission and regeneration
· Low delay (~52 ms)
· Echo Cancellation (16 ms)
Low Cost
· Ideal for wireless and consumer products
· No licensing fees or royalties
· Low power consumption (65 mw @ 3.3v)
· Single IC Solution (100 pin TQFP)
Simple Integration
· Flexible A/D-D/A interface that works with
most low cost codecs
· User selectable speech and FEC rates for
flexibility in system design
· Serial channel interface with independent
Encoder and Decoder rates
· Built on the success of DVSIs AMBE-1000
Vocoder Chip
· Inter-operates with DVSIs 16 channel
Computer Telephony MultiMux
Board
TM
Vocoder - Toll quality @ 4.0 kbps
< rate < 1) with up to 4
Benefits
TM
Vocoder
TM
Digital Voice Systems AMBE-2020 Vocoder Chip is an extremely
flexible, high performance half-duplex voice compression solution
that provides exceptional voice quality at rates as low as 2000
bps. The AMBE-2020 Vocoder Chip is a low cost, DSP based voice
codec for half-duplex, real and non-real time voice compression
applications.
The AMBE-2020 Vocoder Chip implements DVSIs patented AMBE
Voice Compression Algorithm. The field-proven success of this
technology has resulted in it being recognized as the standard for
voice quality in communications systems around the globe.
Satellite systems such as Iridium, ICO, Inmarsat, Thuraya, ACeS,
Optus and AMSC/TMI use this technology because of its superior
voice quality at low bit rates.
DVSI has packaged this advanced vocoder technology onto a
proprietary chip from the worlds leading DSP manufacturer. This
single chip solution achieves a level of performance and reliability
typically associated only with customized ASICs but without the
risks and high development costs.
DVSI developed the AMBE-2020 Vocoder Chip to offer the latest
AMBE® Voice Compression Technology with no licensing fees,
royalties or engineering expense typically associated with custom
DSP software implementation. With off-the-shelf availability this
DSP provides low risk cost effective voice compression.
The AMBE-2020 Vocoder Chip supports bit rates from 2000 to
9600 bps, formed from the combination of compressed speech
data and Forward Error Correction (FEC) data . The AMBE-2020
can change speech and/or FEC rates within one frame for on-thefly flexibility.
With variable rate high performance FEC built-in, the AMBE-2020
Vocoder Chip provides exceptional robustness to background noise
and bit errors. Offering block and convolution codes with up to
four bits of soft decision decoding, the AMBE-2020 Vocoder Chip
can achieve peak performance in degraded channel conditions
that include significant bit errors. The Viterbi decoder offers
rates as low as R=1/4 for intelligible speech at up to 20% BER.
This level of performance can lead to the successful development
and deployment of wireless communication systems in the most
demanding environments.
The AMBE-2020 Vocoder Chip also includes a number of advanced
features such as automatic Voice/Silence detection (VAD),
adaptive comfort noise generation, DTMF and North American
call progress tone detection and signaling, 16 ms echo cancellation
and low power consumption.
®
Digital Voice Systems, Inc.
Tel: (978) 392-0002
234 Littleton Road
Fax: (978) 392-8866
Westford, MA 01886
Web site : www.d v s in c .com
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The AMBE-2020 Vocoder Chip is easily configured to transmit
and receive digitized speech to and from most linear, a-law,
or u-law A/D-D/A codecs through its serial interface. The
digitized speech from the external A/D is converted into
compressed digital data (encoded) by the AMBE-2020
Vocoder Chip and output to the channel interface.
The serial channel interface may use a processor, controller,
modem or similar device to handle the transmission of the
compressed voice data across a channel. Simultaneously,
the AMBE-2020 Vocoder Chip receives data from the other
side of the channel. This data is (decoded) by the AMBE2020 Vocoder Chip, then reconstructed into a digital speech
signal and sent to the D/A. The encoder and decoder functions
are fully asynchronous for maximum flexibility.
Specifications
Electrical
Supply: 3.3 Volts
CMOS I/O Levels: 2.5 V < High < 3.6 V
-0.3 V < Low < 0.8 V
Power Consumption
Operating: 65 mW (typical)
Sleep: 33 mW (interface streams active)
3.3 mW (clocks inactive)
Physical
Package: 100 pin TQFP (industrial grade)
Temperature Range:
-40°C to 85°C (Operation)
-55°C to 150°C (Storage)
Humidity: <95% RH
Serial Interfaces
Codec (passive):
8 bit ulaw @ 8 kHz.
8 bit alaw @ 8 kHz.
16 bit linear* @ 8 kHz.
16 bit linear* @ 32 kHz.
(*recommended for optimum performance)
Channel (active or passive):
The AMBE-2020 Vocoder Chip employs DVSIs latest AMBE+
voice coder technology providing toll quality speech at rates as
low as 4.0 kbps. Along with improved performance and
enhancements such as convolutional FEC coding, exists an
operational mode that provides a seamless migration path into
systems already using DVSIs AMBE-1000 Vocoder Chip.
Packetized or
Unformatted (1, 2, 3, 4 bit per baud)
Contact DVSI
The AMBE-2020 Vocoder Chip offers the affordability, mobility
and power efficiency required by virtually all personal
communication devices. The chip is designed for an endless
array of computer telephony and wireless communication
applications.
The value of DVSIs 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 DVSIs Voice Compression
technology has been implemented worldwide for more than ten
years delivers the added security of a field proven technology
that can play a key role in making any communication system
an overall success. 234 Littleton Road
AMBE® Voice Compression is a registered trademark of Digital Voice Systems, Inc.
The dedicated staff at DVSI bring years of
experience in vocoder technology including
Digital Signal Processing, computer software
generation and hardware development. DVSIs
expertise and unique technology offers
significant benefits.
For more information on how to get the best
quality voice compression, contact DVSI today.
Digital Voice Systems, Inc.
The Speech Com pression Specialists
Westford, MA 01886
Tel: (978) 392-0002
Fax: (978) 392-8866
email: info@dvsinc.com
(Specifications subject to change without notice.)