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G726 on TMS320C62xx

Started by Unknown February 2, 2001
Hello All:

I am working on ADPCM G.726 Coder for dual channel.
After completeing coding and testing sucessfully , MIPS(MCPS)
performance is found to be around 15( for full duplex).
The assembly code is fully optimized as it's almost completely serial
and without any software pipeling.
I wanted information from anyone who has worked on this before as to
how many MIPS that had done it in. Also Radisys Comm.,claims to have
done ADPCM in 7.5MCPS (full duplex)!!!!!!!!!!!!!.
Any suggestions on how I can improve on the performance
figures.

Thanks in advance
Arvind





Arvind wrote:

> I am working on ADPCM G.726 Coder for dual channel.
> After completeing coding and testing sucessfully , MIPS(MCPS)
> performance is found to be around 15( for full duplex).
> The assembly code is fully optimized as it's almost completely serial
> and without any software pipeling.
> I wanted information from anyone who has worked on this before as to
> how many MIPS that had done it in. Also Radisys Comm.,claims to have
> done ADPCM in 7.5MCPS (full duplex)!!!!!!!!!!!!!.
> Any suggestions on how I can improve on the performance
> figures.

Am I right to recall that g726 is almost the same as g721
but with a selection of rates? If not, ignore the rest of this
message.

A couple of years ago, I wrote a g721 for a processor almost
the same as a 320c55. It took about 4.5 mips, duplex.

I can't tell you details of the tricks I used because the
work was done for a client who now owns all the detailed
implementation information. However, there is one general
point:

I spent nearly a month fiddling with C code for the algorithm
before going near an assembler. This mostly consisted of
experimenting with different ways of performing the arithmetic,
checking which alternatives were possible without breaking
the bit-exactness.

I always write my own C code, even when code already exists
as part of the standard. I think it's the only way of getting
sufficiently familiar with the algorithm.

Tim.

------------------------
Tim Thorpe Tel: +44 1223 240366
Fax: +44 1223 414402
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