modeling of echo path

Started by shiv8groups in Echo Cancellation16 years ago 8 replies

Dear friends, I want to model an echo path in matlab. This problem is different from estimation of echo path. In fact Echo ...

Dear friends, I want to model an echo path in matlab. This problem is different from estimation of echo path. In fact Echo Estimator will adapt to this echo path. but the first thing is to implement that echo path itself. I am trying it by implementing an all pass


Reflections & multiple tail circuits

Started by Mark Antony in Echo Cancellation17 years ago 1 reply

Hello, I have one question regarding 2, 3 or more reflections and multiple tail circuits. Is the double reflections or three...

Hello, I have one question regarding 2, 3 or more reflections and multiple tail circuits. Is the double reflections or three reflections overall can be called as single tail circuit? Or Can we consider 3 reflections as 3 small dispersive regions in a echo pat


How to Specify TailLen

Started by Suryadi in Echo Cancellation17 years ago 2 replies

I read about echo cancell that it can can cancell echo between 30 ms and 62 ms. These number get from the delay in Hybrid 30 ms...

I read about echo cancell that it can can cancell echo between 30 ms and 62 ms. These number get from the delay in Hybrid 30 ms (240 samples) and the tailLen 32 ms. tailLen is defined as "The length of the echo spread in the number of samples. Echo spread is also so


Does anybody know where I can get C source code for the AEC?

Started by zhang_zhh in Echo Cancellation17 years ago 4 replies

Hi all, I am working on the H323 VoIP terminal in the PC environment. but in order to cancel the echo from speaker even from...

Hi all, I am working on the H323 VoIP terminal in the PC environment. but in order to cancel the echo from speaker even from the headset(I am not sure if this is acoustic echo or line echo. but we do hear a faint echo intermittently, any idea? ), I need a basic acoustic echo


Re:Re: Does anybody know where I can get C source code fo r the AEC?

Started by Anonymous in Echo Cancellation17 years ago

Hello Maximus, There are algorithms that do not rely on level differences to determine if double-talk is present. These algorithms...

Hello Maximus, There are algorithms that do not rely on level differences to determine if double-talk is present. These algorithms do not suffer from input level differences. I would suggest you do a patent search on echo canceller double-talk detectors. One detector I k


RE: New Member seeking help to master Echo Cancellation Techniques.

Started by Dharmendra Lingaiah in Echo Cancellation17 years ago 1 reply

Hello Madhu, I have tried to answer your questions below ... 1. Why 4-wire system is used between Hybrid and PSNT and...

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 worke


Power measurement

Started by vinprakash366 in Echo Cancellation17 years ago 7 replies

Hi all, In the G.168(2000) standard, under section 6.4.1.2.1, level measurement device, i am a little confused abt the...

Hi all, In the G.168(2000) standard, under section 6.4.1.2.1, level measurement device, i am a little confused abt the detector-indicator block. How should this be implemented in order to decect the power in dBm0??. Also, is the 1-pole exponential filter mentioned in the block


Automatic Gain Control

Started by shiv8groups in Echo Cancellation17 years ago 3 replies

Hi friends, Can anybody tell me how to implement -Automatic Gain Control -Pre-emphasis Any help will be highly...

Hi friends, Can anybody tell me how to implement -Automatic Gain Control -Pre-emphasis Any help will be highly appreciated. Best Regards, Shiv


error signal

Started by John Lai in Echo Cancellation17 years ago

Hello All, Suppose I want to test if echo is induced during transmission through a network. I send a predetermined messsage from...

Hello All, Suppose I want to test if echo is induced during transmission through a network. I send a predetermined messsage from the farside and on the nearend, I compare this transmitted predetermined message (from the farend)with the original message. From there I try to detect if


Re: Training sequences in hybrid echo cancellers

Started by Maurice Givens in Echo Cancellation17 years ago

The hybrid is not connected until the connection is made when the called is off hook. Therefore, the called party would hear the...

The hybrid is not connected until the connection is made when the called is off hook. Therefore, the called party would hear the training sequence. This is considered annoying and unacceptable by the carriers. Maurice Givens (one of those G.168 authors) On


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