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

[Jean-Marc Valin]

Hi,

Not sure what your actual question is, but Speex seems appropriate for
what you are trying to do. It can operate at many bit-rates, including
3.95 kbps and 5.95 kbps and it can be compiled to use fixed-point
instructions.

	Jean-Marc

Andre Melo Carvalhais Dutra a écrit :
> 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
> system.
>      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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