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Discussion Groups | Echo Cancellation | New Member seeking help to master Echo Cancellation Techniques.
RE: New Member seeking help to master Echo Cancellation Techniques. - Dharmendra Lingaiah - May 13 3:39:00 2001
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Hello Madhu, I have tried to answer your questions below ... 1. Why 4-wire system is used between Hybrid and PSNT and 2-wire system is used as subscriber loop. I believe ...the choice of 2-wire for local loop was purely a COST CONSIDERATION Factor, it worked out cheaper to provide a 2-wire connection to every subscriber..rather than 4-wire. 2. How single tone detection is done at Echo Suppressors. Most implementations use BANDPASS Filters for single tone detection. 3. What is the major advantage of Echo Cancellor over Echo Suppressor. An Echo Suppressor acts like a attenuator providing a fixed attenuation level for signals.... An Echo Cancellor on the other hand is adaptive... it estimates the echo and substracts the echo. 4.What is meant by Non-Linear Echo and howit is taken care over by NLP? NLP or the NON-LINEAR PROCESSOR acts on the signals provided by the ADAPTIVE FILTER in the ECHO CANCELLER. It tries to nullify any additional echo present in the residual signal. NLP is so called because the "Describing Function" of the Non-Linear Processor is a NON-LINEAR CURVE. Regards, Dharmendra P.S :- I request the members of the group to correct me wherever I am wrong..if at all. -----Original Message----- From: d_madhu_rao [mailto:] Sent: Friday, May 10, 2002 12:37 PM To: Subject: [echocancel] New Member seeking help to master Echo Cancellation Techniques. Hello Friends, I am a new member to this group and am eager to understand theoretical and practical aspects of echo cancellation techniques. Firstly can u plz give me certain site addresses which cover extensively the above mentioned aspects of Echo Cancellation Techniques. I have not fully understood certain issues like, 1. Why 4-wire system is used between Hybrid and PSNT and 2-wire system is used as subscriber loop. 2. How single tone detection is done at Echo Suppressors. 3. What is the major advantage of Echo Cancellor over Echo Suppressor. What is meant by Non-Linear Echo and howit is taken care over by NLP? _____________________________________ ___________________________________________________________ "This comunication is for the exclusive use of the intended recipient/s and may contain confidential & legally privileged information. Any unauthorised use, disclosure, dissemination, printing, forwarding or copying of this email is strictly prohibited and unlawful. Visit us http://www.cranessoftware.com Cranes Software International Pvt Ltd |
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New Member seeking help to master Echo Cancellation Techniques. - d_madhu_rao - May 10 7:07:00 2002
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Hello Friends, I am a new member to this group and am eager to understand theoretical and practical aspects of echo cancellation techniques. Firstly can u plz give me certain site addresses which cover extensively the above mentioned aspects of Echo Cancellation Techniques. I have not fully understood certain issues like, 1. Why 4-wire system is used between Hybrid and PSNT and 2-wire system is used as subscriber loop. 2. How single tone detection is done at Echo Suppressors. 3. What is the major advantage of Echo Cancellor over Echo Suppressor. What is meant by Non-Linear Echo and howit is taken care over by NLP? |
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