Reply by Manish Bajpai July 9, 20042004-07-09
HI BJC,
 
There are a couple of sources you can refer to depending on what your project exactly demands from you.
 
On the theory of Adaptive Signal Processing, there is an excellent book by Simon Haykin named Adaptive Filter Theory (Third Ed) brought out by Prentice Hall.
 
There are a couple of Applicaion Notes by TI and a couple of good research papers by Bell-labs which are freely available over the net.

Digital Signal Processing Solutions September 1996 SPRA322 By TI is good to begin with, but not very good if you want to implement a commercial grade EC.

A good paper which talks about AEC but is equally good in situations where LEC needs to support higher tail lenghts like 64-256 ms is:

"Residual Echo Signal in Critically Sampled Subband Acoustic Echo Cancellers Based on IIR and FIR Filter Banks"

On Subband Decomposition and Multirate PP Vaidyanathan has written a classic named "Multirate systems and filter banks"

If you search on the net, you will get a couple of open source EC implementations which are nothing but copy of various TI app notes. These will give you good idea.

Cheers

Manish

 

----- Original Message -----

From: bojuchen2000
To: e...@yahoogroups.com
Sent: Thursday, July 08, 2004 9:35 PM
Subject: [echocancel] Re: Acoustic echo simulator

Manish:
Thanks for your explanation about my question.
i'm going to have a project about line echo cancellation.
The documentation i have is only G.168.
Could you have any documentation, book or paper that tells more
details about line EC?
Any suggestion is welcome.
BJC--- In e...@yahoogroups.com, "Manish Bajpai"
<manish_bajpai@i...> wrote:
> G.168 talks about Network echo cancellation. It is different from
acoustic EC. As far as I know, there is no ITU-T standard for
accoustic echo. However, the test framework suggested in G.168 can
be used to test an accoust EC also. Please note that the standard
does not give much information about the implementation of the
network EC.
>
> Accoustic EC is more difficult to implement because longer delayes
involved (of the order of 128ms or more). This calls for adaptive
algorithms which are more efficient. One popular technique is
subband filtering. You can search for the research paper:
> "Residual Echo Signal in Critically Sampled Subband Acoustic Echo
Cancellers Based on IIR and FIR Filter Banks"
>
> This paper has a very good discuussion on AEC.>
> Cheers,
>
> Manish
>
>   ----- Original Message -----
>   From: bojuchen2000
>   To: e...@yahoogroups.com
>   Sent: Tuesday, July 06, 2004 10:16 PM
>   Subject: [echocancel] Re: Acoustic echo simulator>   Hi:
>   I have a question.
>   What is the difference between acoustic echo cancellation and
G.168?
>   Are they the same?
>   BJC>   --- In e...@yahoogroups.com, "Vladan Bajic" <vbajic@a...>
>   wrote:
>   > Hi Anandh,
>   > Try http://www.esat.kuleuven.ac.be/~rombouts/demo/aec.html or
>   > http://www.ee.ucla.edu/~dsplab/index.html
>   > There is a lot of them on the web.  Hope it helps.
>   > Vladan
>   >
>   > -----Original Message-----
>   > From: panandh74 [mailto:panandh74@y...]
>   > Sent: Thursday, June 10, 2004 5:01 PM
>   > To: e...@yahoogroups.com
>   > Subject: [echocancel] Acoustic echo simulator
>   >
>   > Hi all,
>   >
>   > I'm working on acoustic echo cancellation. I need help in
>   simulating
>   > acoustic echo. Can somebody give me any site or suggestions?
>   >
>   > Anandh.
>   >
>  


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Reply by bojuchen2000 July 8, 20042004-07-08
Manish:
Thanks for your explanation about my question.
i'm going to have a project about line echo cancellation.
The documentation i have is only G.168.
Could you have any documentation, book or paper that tells more
details about line EC?
Any suggestion is welcome.
BJC --- In , "Manish Bajpai"
<manish_bajpai@i...> wrote:
> G.168 talks about Network echo cancellation. It is different from
acoustic EC. As far as I know, there is no ITU-T standard for
accoustic echo. However, the test framework suggested in G.168 can
be used to test an accoust EC also. Please note that the standard
does not give much information about the implementation of the
network EC.
>
> Accoustic EC is more difficult to implement because longer delayes
involved (of the order of 128ms or more). This calls for adaptive
algorithms which are more efficient. One popular technique is
subband filtering. You can search for the research paper:
> "Residual Echo Signal in Critically Sampled Subband Acoustic Echo
Cancellers Based on IIR and FIR Filter Banks"
>
> This paper has a very good discuussion on AEC. >
> Cheers,
>
> Manish
>
> ----- Original Message -----
> From: bojuchen2000
> To:
> Sent: Tuesday, July 06, 2004 10:16 PM
> Subject: [echocancel] Re: Acoustic echo simulator > Hi:
> I have a question.
> What is the difference between acoustic echo cancellation and
G.168?
> Are they the same?
> BJC > --- In , "Vladan Bajic" <vbajic@a...>
> wrote:
> > Hi Anandh,
> > Try http://www.esat.kuleuven.ac.be/~rombouts/demo/aec.html or
> > http://www.ee.ucla.edu/~dsplab/index.html
> > There is a lot of them on the web. Hope it helps.
> > Vladan
> >
> > -----Original Message-----
> > From: panandh74 [mailto:panandh74@y...]
> > Sent: Thursday, June 10, 2004 5:01 PM
> > To:
> > Subject: [echocancel] Acoustic echo simulator
> >
> > Hi all,
> >
> > I'm working on acoustic echo cancellation. I need help in
> simulating
> > acoustic echo. Can somebody give me any site or suggestions?
> >
> > Anandh.
> >
> >


Reply by L. Hao July 7, 20042004-07-07
If my memory serves me right, acoustic echo cancellation is defined in G.167.

bojuchen2000 <n...@ms94.url.com.tw> wrote:
Hi:
I have a question.
What is the difference between acoustic echo cancellation and G.168?
Are they the same?
BJC--- In e...@yahoogroups.com, "Vladan Bajic" <vbajic@a...>
wrote:
> Hi Anandh,
> Try http://www.esat.kuleuven.ac.be/~~rombouts/demo/aec.html or
> http://www.ee.ucla.edu/~~dsplab/index.html
> There is a lot of them on the web.  Hope it helps.
> Vladan
>
> -----Original Message-----
> From: panandh74 [mailto:panandh74@y...]
> Sent: Thursday, June 10, 2004 5:01 PM
> To: e...@yahoogroups.com
> Subject: [echocancel] Acoustic echo simulator
>
> Hi all,
>
> I'm working on acoustic echo cancellation. I need help in
simulating
> acoustic echo. Can somebody give me any site or suggestions?
>
> Anandh.> ------------------------ Yahoo! Groups Sponsor --------------------
~~-->
> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
> Now with Pop-Up Blocker. Get it for free!
> http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/sVPplB/TM
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>
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author
> of this message will receive your answer.  You need to do a "reply
all"
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-----------------------------------
Li Hao
h...@yahoo.com

__________________________________________________

Reply by Manish Bajpai July 7, 20042004-07-07
G.168 talks about Network echo cancellation. It is different from acoustic EC. As far as I know, there is no ITU-T standard for accoustic echo. However, the test framework suggested in G.168 can be used to test an accoust EC also. Please note that the standard does not give much information about the implementation of the network EC.
 
Accoustic EC is more difficult to implement because longer delayes involved (of the order of 128ms or more). This calls for adaptive algorithms which are more efficient. One popular technique is subband filtering. You can search for the research paper:

"Residual Echo Signal in Critically Sampled Subband Acoustic Echo Cancellers Based on IIR and FIR Filter Banks"

This paper has a very good discuussion on AEC.

 

Cheers,

Manish

----- Original Message -----
From: bojuchen2000
To: e...@yahoogroups.com
Sent: Tuesday, July 06, 2004 10:16 PM
Subject: [echocancel] Re: Acoustic echo simulator

Hi:
I have a question.
What is the difference between acoustic echo cancellation and G.168?
Are they the same?
BJC--- In e...@yahoogroups.com, "Vladan Bajic" <vbajic@a...>
wrote:
> Hi Anandh,
> Try http://www.esat.kuleuven.ac.be/~rombouts/demo/aec.html or
> http://www.ee.ucla.edu/~dsplab/index.html
> There is a lot of them on the web.  Hope it helps.
> Vladan
>
> -----Original Message-----
> From: panandh74 [mailto:panandh74@y...]
> Sent: Thursday, June 10, 2004 5:01 PM
> To: e...@yahoogroups.com
> Subject: [echocancel] Acoustic echo simulator
>
> Hi all,
>
> I'm working on acoustic echo cancellation. I need help in
simulating
> acoustic echo. Can somebody give me any site or suggestions?
>
> Anandh.
>
>



Reply by Saraj July 7, 20042004-07-07

BJC,

G.168 is ITU Recommnedation for Line Echo Cancellation while for Acoustic
Echo Cancellation it is G.167.

Regards,

-Saraj

-----Original Message-----
From: bojuchen2000 [mailto:]
Sent: Tuesday, July 06, 2004 10:16 PM
To:
Subject: [echocancel] Re: Acoustic echo simulator Hi:
I have a question.
What is the difference between acoustic echo cancellation and G.168?
Are they the same?
BJC --- In , "Vladan Bajic" <vbajic@a...>
wrote:
> Hi Anandh,
> Try http://www.esat.kuleuven.ac.be/~rombouts/demo/aec.html or
> http://www.ee.ucla.edu/~dsplab/index.html
> There is a lot of them on the web. Hope it helps.
> Vladan
>
> -----Original Message-----
> From: panandh74 [mailto:panandh74@y...]
> Sent: Thursday, June 10, 2004 5:01 PM
> To:
> Subject: [echocancel] Acoustic echo simulator
>
> Hi all,
>
> I'm working on acoustic echo cancellation. I need help in
simulating
> acoustic echo. Can somebody give me any site or suggestions?
>
> Anandh. > ------------------------ Yahoo! Groups Sponsor --------------------
~-->
> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
> Now with Pop-Up Blocker. Get it for free!
> http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/sVPplB/TM
> -------------------------------
-~->
>
> _____________________________________
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author
> of this message will receive your answer. You need to do a "reply
all"
> if you want your answer to be distributed to the entire group.
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Reply by bojuchen2000 July 6, 20042004-07-06
Hi:
I have a question.
What is the difference between acoustic echo cancellation and G.168?
Are they the same?
BJC --- In , "Vladan Bajic" <vbajic@a...>
wrote:
> Hi Anandh,
> Try http://www.esat.kuleuven.ac.be/~rombouts/demo/aec.html or
> http://www.ee.ucla.edu/~dsplab/index.html
> There is a lot of them on the web. Hope it helps.
> Vladan
>
> -----Original Message-----
> From: panandh74 [mailto:panandh74@y...]
> Sent: Thursday, June 10, 2004 5:01 PM
> To:
> Subject: [echocancel] Acoustic echo simulator
>
> Hi all,
>
> I'm working on acoustic echo cancellation. I need help in
simulating
> acoustic echo. Can somebody give me any site or suggestions?
>
> Anandh. > ------------------------ Yahoo! Groups Sponsor --------------------
~-->
> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
> Now with Pop-Up Blocker. Get it for free!
> http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/sVPplB/TM
> -------------------------------
-~->
>
> _____________________________________
> Note: If you do a simple "reply" with your email client, only the
author
> of this message will receive your answer. You need to do a "reply
all"
> if you want your answer to be distributed to the entire group.
>
> _____________________________________
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Reply by Vladan Bajic June 11, 20042004-06-11
Hi Anandh,
Try http://www.esat.kuleuven.ac.be/~rombouts/demo/aec.html or
http://www.ee.ucla.edu/~dsplab/index.html
There is a lot of them on the web. Hope it helps.
Vladan

-----Original Message-----
From: panandh74 [mailto:]
Sent: Thursday, June 10, 2004 5:01 PM
To:
Subject: [echocancel] Acoustic echo simulator

Hi all,

I'm working on acoustic echo cancellation. I need help in simulating
acoustic echo. Can somebody give me any site or suggestions?

Anandh. ------------------------ Yahoo! Groups Sponsor --------------------~-->
Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
Now with Pop-Up Blocker. Get it for free!
http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/sVPplB/TM
--------------------------------~->

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Reply by panandh74 June 10, 20042004-06-10
Hi all,

I'm working on acoustic echo cancellation. I need help in simulating
acoustic echo. Can somebody give me any site or suggestions?

Anandh.