[Speex-dev] Implementation of a Speex based hardware VOCODER

Andre Melo Carvalhais Dutra amcd at ita.br
Fri Oct 26 06:53:19 PDT 2007

Hi everyone,

     I´m a graduate student in a Brazilian Intitute of Technology, and I´m 
doing some academic research regarding secure voice transmission over phone
lines. One of our reserach goals is to implement a hardware vocoder, with low
bit rates, and a preferably free algorithm, to be used in this secure voice
     Actually, there is a functional system using a proprietary AMBE board
(also a very expensive one) with a bit rate of 4800bps. When I found this
project, I tought the vocoder hardware could be implemented based on the Speex
code, since it works with similar bitrates.
     Is speex suitable for that? What are the main hindrances? I thought in
using some high speed uController (code would be implemented in C and ASM), or
a low cost FPGA (in wich the vocoder would be implemented in some hardware
description language, such as VHDL); what do you thing about this?
     Thanks in advance. Wishing to hear from you soon,

     André Melo Carvalhais Dutra.

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