AMBE-4020-HDK™ Hardware Development Kit Featuring the AMBE-4020™ Vocoder Chip


The Digital Voice Systems, Inc. (DVSI) AMBE-4020-HDK™ is a comprehensive, evaluation, test and development platform that can demonstrate the capabilities and benefits of the AMBE-4020™ vocoder chip in real time, without investing much time in engineering and product prototype development. It is also the ideal reference design for evaluation and test of DVSI's AMBE-4020™ vocoder chip performance.


The heart of AMBE-4020-HDK™ is DVSI's patented AMBE+2 Voice Compression technology that provides exceptional voice quality. Embedded in the AMBE-4020™ vocoder chip are voice compression bit rates from 2000 to 9600 bps that are inter-operable with DVSI's family of Vocoder chips. Forward Error Correction (FEC) is included to optimize robustness to background noise and channel bit errors. Also, the AMBE-4020™ vocoder chip includes a number of advanced features such as: Voice Activity Detection (VAD), adaptive Comfort Noise Insertion (CNI) and support for the detection and generation of single and DTMF tones. This level of performance has resulted in the successful deployment of wireless communication systems in the most demanding environments.

The AMBE-4020-HDK™ is a completely functional system that can be used as a stand-alone voice processing board. It is equipped with connections for analog audio I/O, a Digital Microphone interface and a UART port communication channel interface.

The AMBE-4020-HDK™ vocoder board uses a variety of industry standard connections for fast and easy setup and operation. An RCA jack and a handset connection allow analog voice input/output for encoding/decoding real-time speech. A UART serial port is the data channel that delivers the compressed bit stream between two AMBE-4020™ HDKs for real-time half-duplex communication. With the USB interface users can connect the AMBE-4020-HDK™ to a PC, to configure the channel interface, encode (record) an analog input to a compressed data file, and decode (playback) previously encoded files. Additionally, the HDK can be used to batch process files for evaluation of the vocoder.

The AMBE-4020-HDK™ specifically uses inexpensive, widely available circuit components with easily attainable development tools so that designers can understand how to produce low cost AMBE-4020™ vocoder chip products with a quick time to market. Once a new product design is complete and manufacturing begins the AMBE-4020-HDK™ can then be used to simulate actual system conditions as a quality control reference standard.

The AMBE-4020-HDK™ is a cost-effective vehicle that reduces the time and up-front engineering expenses associated with new product development. The value of DVSI's AMBE-4020™-HDK goes beyond just simple hardware design. The integrated AMBE+2 vocoder technology has been thoroughly evaluated and tested by international manufacturers under various conditions, using a variety of languages, and has been implemented worldwide. This field proven voice compression technology assures that the developed end product is utilizing the best low-bitrate high-quality vocoder available, leading any communication system to be an overall success.

The AMBE-4020-HDK™ is a complete hardware and software package solution with off-the-shelf availability. The development kit includes the evaluation board, reference circuit design schematics, as well as, example software.

AMBE-2000™ Chip Rates YES
AMBE-3000™ Chip Rates YES*
APCO Project 25 Half Rate NO
APCO Project 25 Full Rate NO
TerreStar NO
MexSat NO
GlobalStar NO

(* NOTE: The following AMBE-3000™ built-in rates are not supported: 33-37, 47, and 51-55. As a result, MotoTRBO, DMR, dPMR, NXDN and APCO Project 25 Half Rate are not supported as indicted above.)

DVSI's dedicated staff combine years of experience in vocoder technology, with expertise in Digital Signal Processing, computer software generation and hardware development. For more information regarding our high-performance, extremely flexible voice compression solutions, contact DVSI today.

Key benefits of the AMBE-4020 HDK™ Vocoder Board are:

  • Flexible Bit Rate Selection - High Quality, Speech Compression Data and FEC rates from 2000 bps to 9600 bps.
  • Full Control of AMBE-4020™ Vocoder Chip advanced capabilities - Soft decision decoding, FEC, Voice Activity Detection (VAD), adaptive Comfort Noise Insertion (CNI) and support for DTMF tones.
  • Easy to Duplicate Design - schematic details, example software and reference documentation, provides engineers details for designing custom circuits.
  • Standard UART Serial Interface - provides a Real-time half-duplex communication between two HDK boards
  • 5 Volt DC power - Low power requirements with minimal circuit complexity.
  • Additional analog audio I/O interface - Daughter board connection allows for easy integration of an external codec board of your own design.
  • Integrated 16-bit ADC / 12-bit DAC and vocoder in one chip - provides high quality analog audio I/O to an RCA jack (4-wire) and interface and to a handset (2-wire).

AMBE-4020 HDK™ Vocoder Board Technical Specifications:

Input Voltage 5V DC
Physical Size: 3.9 X 3.17 inches

Design Flexibility/Low Cost Integration

  • Superior voice quality, DVSI's latest generation half duplex AMBE+2™ Vocoder Technology
  • Maximizes channel bandwidth efficiency supports data-rates from 2.0 kbps to 9.6 kbps
  • User selectable forward error correction rates - 50 bps to 7.2 kbps
  • Excellent performance at low data rates and harsh environments
  • Robustness to acoustic background noise and channel bit errors
  • Advanced features like Noise Suppression, Improved Error Mitigation, and Soft Decision FEC Decoding
  • Supports a-law and u-law companding via I2S interface
  • DTMF detection and regeneration with North American call progress tones
  • Integrated 16-bit ADC / 12-bit DAC and vocoder in one chip
  • Works with most low-cost A/D-D/A codecs
  • Input Interfaces available internal ADC or digital mic or I2S
  • Output interfaces available: internal DAC or I2S
  • Interface for low-cost digital microphone
  • Push-to-talk Half-duplex Operation
  • Very low power consumption - Ideal for portable mobile devices
  • Small compact footprint design
  • 80 pin 12mm x 12mm LQFP or 121 ball 8mm x 8mm BGA package available
  • No licensing fees or royalties
  • Off-the-shelf availability for quick delivery