[Asterisk-Users] more cpu intensive echo cancellers ?

[Paul Hewlett]

On Saturday 11 February 2006 19:36, Steve Underwood wrote:
> Matthew Fredrickson wrote:
> > On Feb 10, 2006, at 10:25 PM, Steve Underwood wrote:
> >> Matthew Fredrickson wrote:
> >>> On Feb 10, 2006, at 1:21 PM, Gerard Saraber wrote:

> DC in the signal through the echo canceller represents a signal the
> canceller's adaption can never eliminate. It fights; it fails; it many
> get very upset trying. DC needs to be eliminated before cancellation.
> A-law/u-law ports are not supposed to give you any DC, but some do. The
> following will estimate and remove DC from the signal. Prime
> "dc_estimate" with zero.
>
> int 16_t dc_removal(int32_t &dc_estimate, int16_t sample)
> {
>     dc_estimate += ((((int32_t) sample << 15) - dc_bias) >> 9);
>     sample -= (dc_estimate >> 15);
>     return sample;
> }

   Shouldn't it be *dc_estimate ?

Paul
>

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Paul Hewlett - CottonPickinMinds - www.cottonpickinminds.co.za
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