Reply by Tapas Guha Neogi _98007017_ ●August 14, 20012001-08-14
hi all..
I had worked on a project on acoustic echo cancellation and would like
to share my knowledge in the field with each of you.I had used an
algorithm to detect double talk while using the NLMS algorithm.Though it
worked fine with the NLMS algorithm it didn't perform well with the other
algorithms I had worked on.
The algorithm I had followed was as follows.
1.determine presence of farend and near end speech by using
appropriate values of SNRs on each side.While chosing the SNR the expected
signal and corresponding noise energy on each side was taken itno
consideration.
2.set up a counter say cnt.
3.adapt the filter coefficients only if far end signal present.cnt=cnt
4.if far end signal and near end signal present than stop
adaptation.cnt=cnt+1.
5.if cnt > num then increase cnt by a greater factor say 50.dont adapt.
6.if cnt > highnum then flush all the filter coefficients.restart.
this algorithm worked for me with the NLMS algorithms under certain test
conditions.I dont have a good exposure in this area, so it would be really
adisable to seek advice from more knowledgeable people around.However i
thought I would bring forth my algorithm so that i get feedabcks about
drawbacks that exist in the model.Waiting for your kind feedbacks.
Regards,
Tapas Guha Neogi
Senior Undergraduate,
Electrical Engineering Department,
Indian Institute of Technology,Bombay,
India On Sat, 11 Aug 2001, Fuliang yin wrote:

> Hi,
>
> An echo canceller must include the double-talk module. But in acoustic
> echo canceller, the energy of the acoustic echo often is larger than that of
> far-end speech because of effect of power amplifier in TV. This situation
> often occurs in the videoconference system. Can anybody tell me how to
> efficiently detect the double-talk ? Any information (Article, Patent,
> software, resource, etc) will be appreciated.
>
> Thanks
>
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Reply by Fuliang yin ●August 11, 20012001-08-11
Hi,

An echo canceller must include the double-talk module. But in acoustic
echo canceller, the energy of the acoustic echo often is larger than that of
far-end speech because of effect of power amplifier in TV. This situation
often occurs in the videoconference system. Can anybody tell me how to
efficiently detect the double-talk ? Any information (Article, Patent,
software, resource, etc) will be appreciated.

Thanks

Fuliang Yin