VC-20-PRJ25 IMBE™ Vocoder Board
User’s Manual
Page 1
Section 1- Introduction
DVSI Confidential Proprietary
Product Introduction
General Information
The Digital Voice Systems, Inc. (DVSI) VC-20-PRJ25 voice codec is a full-duplex real-time voice
processing board. The VC-20-PRJ25 contains proprietary software which implements the Improved
Multi-Band Excitation™ (IMBE™) voice coding algorithm. DVSI grants a license to its customers to
use this software according to the terms established in the attached IMBE™ Software END USER
License Agreement. Use of the VC-20-PRJ25, or any portion thereof, signifies acceptance of these
licensing terms.
The VC-20-PRJ25 operates by digitizing an analog speech signal using an on-board A-to-D converter.
This digitized speech is then processed by the encoder and converted into a 7.2 kbps data bit stream.
This bit stream is output to a modem or similar device. Simultaneously, the VC-20-PRJ25 receives a
7.2 kbps data bit stream from a modem or similar device. This received bit stream is processed by the
decoder and converted into a synthetic speech signal which is then converted into an analog signal using
the on-board D-to-A converter. The encoder and decoder are fully asynchronous
The VC-20-PRJ25 is capable of supporting advanced features such as external codecs and
downloading custom software. Please contact DVSI for more information on these features.
