[asterisk-dev] Zaptel Echo Cancellation

[Andrew Kohlsmith]

On Thursday 03 August 2006 12:49, Hans Petter Selasky wrote:
> Hardware echo cancellers perform no better than software echo cancellers.
> What you need is good timing and ringbuffers. Then you compute exactly how
> many bytes are in the buffer, and just "skip" those before doing any echo
> cancelling. In this case the buffer delay does not matter at all. For
> example I have 50ms buffering working very well with 32ms echo-cancelling !
> You might think this was very difficult and ureliable, but no. All you need
> is a ring buffer, and a good timing source.

That's the best explanation I have heard and yes, it makes perfect sense now.  
So long as the buffer size doesn't change without the echo canceller knowing 
about it it makes very little difference.  

Thanks!

-A.