Echo Cancellation Project

[Girly_girl]

Hello

Can some one possibly suggest me some projects to do with the echo cancellation?

I have chosen this area , but I dono what practical things i could do ?!

Thank you

 

[Girly_girl]

Any IDeas anyone?!!

 

[zorro]

Hi Girly_girl,

Practical applications in telephony are:

a) Line echo cancellers: for cancellation of near- and far-end echo in telephone links (don't confuse with echo suppressors). There are ITU-T reccomendations in series G (ITU-T G.168 and others) that specify them.

b) Acoustic echo cancellers: for use in speakerphones.

Regards

Z

 

[Andrelee]

Here are some practical and interesting directions worth you to spend time on.

1. Adaptive filter types: Kalman, LMS, NLMS, RLS…..
2. Double talk detector: correlation, recursive correlation based, or even combine with signal talk detector
3. Adaptive step size control
4. Divergence protection with background and foreground filters

BRs

 

[Aya2002]

During a normal PSTN land to land call, no echo is apparent because the
delay is too short and the user is unable to distinguish between the echo and
the normal telephone “side tone”. However, without the EC and with the
GSM round trip delay added, the effect would be very irritating to the MS
subscriber, disrupting speech and concentration. The standard EC will
provide cancellation of up to 68 milliseconds on the “tail circuit” (the tail
circuit is the connection between the output of the EC and the land
telephone).
The generation of Echoes at 2-Wire to 4-Wire interface is
shown in the figure below

 

[Girly_girl]

During a normal PSTN land to land call, no echo is apparent because the
delay is too short and the user is unable to distinguish between the echo and
the normal telephone “side tone”. However, without the EC and with the
GSM round trip delay added, the effect would be very irritating to the MS
subscriber, disrupting speech and concentration. The standard EC will
provide cancellation of up to 68 milliseconds on the “tail circuit” (the tail
circuit is the connection between the output of the EC and the land
telephone).
The generation of Echoes at 2-Wire to 4-Wire interface is
shown in the figure below

Thank you very much for your explanation..

I have decided to gather some practical results by recording some voice as the Acoustic echo and implement them using some algorithms such as Kalman, LMS, NLMS, RLS and adaptive filter...

But i still dont know how to gather some data for the Hybrid echo.. What would u suggest?

Thank you

 

[Aya2002]

do search on google using this words (GSM echo problem solution), in the first page of results there are four pdf documents , download them all, these documents will help you too much.

 

[Girly_girl]

Thanks so much....I have now gathered the results. Thanks

Will someone please help/guid me on how to start writing a software for Adaptive or Kalman filter using MATLAB.

Thanks guys