[asterisk-users] The High Performance Echo Canceller (HPEC)

Andrew Kohlsmith akohlsmith-asterisk at benshaw.com
Wed Feb 14 15:12:14 MST 2007


On Wednesday 14 February 2007 4:12 pm, shadowym wrote:
> The algorithms may be similar but EC is an infinitely variable
> non-linear(analog) process.  A CPU cannot do that.  You can fake it by
> performing cpu intensive rapid calculations one after another but it is
> fundamentally not an analog processor.  HWEC is designed to deal with the
> analog process on an instant by instant basis performing parallel
> computations.  A CPU cannot do that at ANY clock speed.

I think you are very sorely mistaken.  I've done DSP work on general-purpose 
CPUs for many years.  All current processors have SIMD, which, until the i586 
(for Intel), was more or less only in DSPs.  Steven Critchfield has been 
doing DSP work (spandsp) for much longer than I have, and is much better at 
it than I will ever be.  :-)

Anything a DSP can do, a general-purpose CPU can do, but very likely slower.  
There is no magic.  There is nothing particularly "special" about ASICs or 
DSPs that general-purpose CPUs can't do; it's all a matter of how quickly it 
can do it and how much you're willing to consume in system resources.

-A.


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