Digital Voice Systems AMBE-2000 User manual

Benefits
Low Cost
·Ideal for wireless products
·No licensing fees or royalties
·Low power consumption (65 mw @ 3.3v)
·Single I Solution (100 pin TQFP)
Simple Integration
·Flexible A/D-D/A interface that works with
most low cost codecs
·User selectable speech and FE rates for
flexibility in system design
·Serial channel interface with independent
Encoder and Decoder rates
·Built on the success of DVSIs AMBE-1000TM
Vocoder hip
·Inter-operates with DVSIs 16 channel
omputer Telephony MultiMuxTM Vocoder
Board
The Speech Compression Specialists
Digital Voice Systems, Inc.
Westford, MA 01886
Web site: www.dvsinc.com
Digital Voice Systems, Inc.
Tel: [phone] Littleton Road Fax: [phone]
Features
·AMBE+TM Vocoder - Toll quality @ 4.0 kbps
·User selectable bit rate (2.0 kbps to 9.6 kbps)
·Integrated convolutional and block code
Forward Error orrection (FE )
·Viterbi Decoder (1/4 < rate < 1) with up to 4
bits of soft decision decoding
·High performance Voice Activity Detection
(VAD) with adaptive omfort Noise Insertion
( NI)
·DTMF  North American call progress tone
detection, transmission and regeneration
·Low delay (~52 ms)
·Echo ancellation (16 ms)
AMBE-2000
Voco er Chip
Digital Voice Systems AMBE-2000 Vocoder hip is an extremely
flexible, high performance voice compression solution that
provides exceptional voice quality at rates as low as 2000 bps.
The AMBE-2000 Vocoder hip is a low cost, DSP based voice
codec for full or half-duplex, real and non-real time voice
compression applications.
The AMBE-2000 Vocoder hip implements DVSIs patented AMBE®
Voice ompression 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, I O, Inmarsat, Thuraya, A eS,
Optus and AMS /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 worlds leading DSP manufacturer. This
single chip solution achieves a level of performance and reliability
typically associated only with customized ASI s but without the
risks and high development costs.
DVSI developed the AMBE-2000 Vocoder hip to offer the latest
AMBE® Voice ompression 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-2000 Vocoder hip supports bit rates from 2000 to
9600 bps, formed from the combination of compressed speech
data and Forward Error orrection (FE ) data . The AMBE-2000
can change speech and/or FE rates within one frame for on-
the-fly flexibility.
With variable rate high performance FE built-in, the AMBE-2000
Vocoder hip 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-2000 Vocoder hip
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-2000 Vocoder hip 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.

The Speech Compression Specialists
Digital Voice Systems, Inc.
Contact DVSI
The dedicated staff at DVSI bring years of
experience in vocoder technology including
Digital Signal Processing, computer software
generation and hardware development. DVSIs
expertise and unique technology offers
significant benefits.
For more information on how to get the best
quality voice compression, contact DVSI today.
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 ange:
-40° to 85° (Operation)
-55° to 150° (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):
Packetized or
Unformatted (1, 2, 3, 4 bit per baud)
The AMBE-2000 Vocoder hip 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-2000
Vocoder hip 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-2000 Vocoder hip receives data from the other
side of the channel. This data is (decoded) by the AMBE-
2000 Vocoder hip, then reconstructed into a digital speech
signal and sent to the D/A. The encoder and decoder functions
are fully asynchronous for maximum flexibility.
The AMBE-2000 Vocoder hip employs DVSIs 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 FE coding, exists an
operational mode that provides a seamless migration path into
systems already using DVSIs AMBE-1000 Vocoder hip.
The AMBE-2000 Vocoder hip offers the affordability, mobility
and power efficiency required by virtually all personal
communication devices. The chip is designed to be fully inter-
operable with DVSIs MultiMux Vocoder Board which provides
sixteen full duplex channels of voice compression. The
integration of these two devices creates a complete system for
an endless array of computer telephony and wireless
communication applications.
The value of DVSIs AMBE® Voice ompression 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 ompression
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
Westford, MA 01886
Tel: [phone]
Fax: [phone]
email: [email protected]
(Specifications subject to change without notice.)
AMBE®Voice Compression is a registered trademark of Digital Voice Systems, Inc.