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Girly_girl
Joined: 14 Oct 2009
Posts: 5
Location: UK
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 15 Oct 2009 10:23 Echo Cancellation Project |
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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
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Girly_girl
Joined: 14 Oct 2009
Posts: 5
Location: UK
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16 Oct 2009 22:33 Echo Cancellation Project |
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| Any IDeas anyone?!!
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zorro
Joined: 06 Sep 2001
Posts: 380
Helped: 47
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19 Oct 2009 13:33 Re: Echo Cancellation Project |
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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
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Andrelee
Joined: 03 Nov 2009
Posts: 1
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03 Nov 2009 8:21 Echo Cancellation Project |
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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
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Google
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03 Nov 2009 8:21 Ads |
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Aya2002
Joined: 12 Dec 2006
Posts: 1409
Helped: 254
Location: Iraq
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03 Nov 2009 19:03 Re: Echo Cancellation Project |
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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
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