Regarding double talk detection in Acoustic Echo Cancellation

Started by Aparna Ram in comp.dsp12 years ago 2 replies

Dear Sir, I am working on Acoustic Echo Cancellation using LMS algorithm in time domain.I have written the code for this.It is...

Dear Sir, I am working on Acoustic Echo Cancellation using LMS algorithm in time domain.I have written the code for this.It is working fine that its output signal has only the near end signal with a very very small hiss sound in the situation when both farend and near end signals are talked simultaneously. As large eigen value spread and double talk situation are two major d...


Line echo cancellation - conditions for freezing adaptation

Started by Anonymous in comp.dsp12 years ago 3 replies

Hi com.dsp-ers, I know that there are some scenarios in which a line echo canceller should suspend the process of adapting its...

Hi com.dsp-ers, I know that there are some scenarios in which a line echo canceller should suspend the process of adapting its coefficients: 1. Double talk (the most obvious case) 2. Narrow band reference signal detected 3. Numerical overload detected I wanted to broadcast a call for ideas for detecting scenarios 2 and 3. For 2, I am currently thinking of putting in an 8 channel filte...


TMS320C6711-Real Time Implemantation of Echo Cancellation (LMS) Algorithm

Started by singla in comp.dsp12 years ago 3 replies

Hello Everyone As the Final Year Engineering Project we are Implementing Echo Cancellation (LMS) Algorithm in Real Time using TI's TMS320C6711...

Hello Everyone As the Final Year Engineering Project we are Implementing Echo Cancellation (LMS) Algorithm in Real Time using TI's TMS320C6711 DSK. The project is in final stages and we are experiencing the following problems: 1) At the RUN time or BUILD time the following pops up "DISK IS FULL". The system we are using is having 512 MB RAM and enough disk space. What do you...


Regarding Acoustic Echo Cancellation with subbanding

Started by Aparna Ram in comp.dsp12 years ago

Dear Sir, I am working on Acoustic Echo Cancellation. I have implemented both AEC without subbanding and AEC with subbanding in...

Dear Sir, I am working on Acoustic Echo Cancellation. I have implemented both AEC without subbanding and AEC with subbanding in C+ +. For subbanding of AEC I used Polyphase IIR filter(with 70dB attenuation). AEC without subbanding is working fine. But in the outputs of AEC with subbanding there exists some slight disturbance(but echo is cancelling for all recorded...


Regarding Delay estimation in Acoustic echo cancellation

Started by neelufar.2005 in comp.dsp12 years ago 6 replies

Hi, I am a fresher to the DSP field, I am going through the acoustic echo cancellation. I want help regarding delay estimation in acoustics...

Hi, I am a fresher to the DSP field, I am going through the acoustic echo cancellation. I want help regarding delay estimation in acoustics echo cancellation. Can any one suggest me a good algorithm for this. Help me for getting good papers on this. Thanks in advance. Regards, Neelufar. _____________________________________ Do you know a company who employs DSP engineers? Is it a...


Need argent help regarding delay estimation

Started by neelufar.2005 in comp.dsp12 years ago 1 reply

I am going through Average Magnitude Difference Function (AMDF), while exploring on this I found a good PDF Enhancing Echo Cancellation via...

I am going through Average Magnitude Difference Function (AMDF), while exploring on this I found a good PDF Enhancing Echo Cancellation via Estimation of delay By Youhong lu,Ronald Fowler,Wenshun Tian and Leland Thompson. In which the delay estimation is done. I am going through this paper to understand the mathematical steps used for estimation of delay. I have got struck with the n...


Low Standby Current DSP

Started by Steve4DSP in comp.dsp12 years ago 12 replies

Hi Im trying to find a DSP that meets a few different requirements. In short, it has to be the following: -

Hi Im trying to find a DSP that meets a few different requirements. In short, it has to be the following: -


Regarding Linear prediction analysis.

Started by neelufar.2005 in comp.dsp12 years ago 3 replies

Hi, I am working on the linear prediction analysis implementation,I have one question which is regrding windowing which is done before LCP,...

Hi, I am working on the linear prediction analysis implementation,I have one question which is regrding windowing which is done before LCP, where we have a frame of size 240 samples i.e 40 samples from past, 80 samples of present frame and 40 samples from future. I am using the linear prediction analysis for decorrelation of signal after acoustic echo cancellation. I can store the 40 sample...


Bypassing residual echo suppression module.

Started by neelufar.2005 in comp.dsp12 years ago 1 reply

Hello All, I am searching for the method to detect if there is residual echo or not in the output of acoustic echo cancellation. So that if the...

Hello All, I am searching for the method to detect if there is residual echo or not in the output of acoustic echo cancellation. So that if the acoustic echo cancellation does 100% cancellation of echo then there is no need of using residual echo suppression module after the acoustic echo cancellation module. Can any one help regarding bypassing the residula echo suppression module. Thanks in ...


Residual echo activity detection.

Started by neelufar.2005 in comp.dsp12 years ago 2 replies

Hi All, Can any one help me to get documents related to Residual echo activity detection i.e, to detect weather the output of acoustic echo...

Hi All, Can any one help me to get documents related to Residual echo activity detection i.e, to detect weather the output of acoustic echo cancellation contain residual echo or not. Thanks in advance Regards, Neelufar.


Re: echo cancellation

Started by Mark in comp.dsp11 years ago

> > > >    I've been hunting around for an echo cancellation plug in; vst or > > > > directX; to use with sound forge - it's probably...

> > > >    I've been hunting around for an echo cancellation plug in; vst or > > > > directX; to use with sound forge - it's probably right under my nose... > > can > > > > somebody throw me a few pointers ? > the folks at comp.dsp might be able to help you Mark


echo cancellation by solving linear equations

Started by pal.debabrata123 in comp.dsp11 years ago 12 replies

Ok , assume echo tail length is less that or equal to 64 sample. Is it possible to get coefficient of the adaptive filter by solving 64 linear...

Ok , assume echo tail length is less that or equal to 64 sample. Is it possible to get coefficient of the adaptive filter by solving 64 linear equation? Input is known, output is known , only unknon is coefficient? Has anybody tried this ? Is it too inefficient?


estimation

Started by mmoctar in comp.dsp10 years ago 1 reply

Dear all, My question is about estimation I found in many algorithms. x(n)=b*x(n)+(1-b)*x(n-1);-----> (DCT and DFT LMS, power...

Dear all, My question is about estimation I found in many algorithms. x(n)=b*x(n)+(1-b)*x(n-1);-----> (DCT and DFT LMS, power normalized-NLMS) and sometimes its: x(n)=b1*x(n)+(1-b1)*x(n-1) if x(n)> x(n-1); x(n)=b2*x(n)+(1-b2)*x(n-1); I'm working in echo cancellation... I want to know how derive it and the effects on my x(n) signal... References are welcome... thank you


Developer required for server-side multiple echo cancellation software

Started by kseggie in comp.dsp10 years ago

I am looking to hire a developer to create some code to cancel multiple echos on server-side Flash/Speex audio from pairs of laptops with built...

I am looking to hire a developer to create some code to cancel multiple echos on server-side Flash/Speex audio from pairs of laptops with built in speakers and microphones. This is pretty much what we need: http://ieeexplore.ieee.org/iel1/26/2235/00061439.pdf Please contact me kseggie at gmail.com for more info. Regards


'black box', echo and Voip

Started by johnstokes in comp.dsp10 years ago 2 replies

I have a practical question about echo cancellation and Voip. I have made a 'black box' which contains analogue electronics of a phone earpiece...

I have a practical question about echo cancellation and Voip. I have made a 'black box' which contains analogue electronics of a phone earpiece and mic. However i have problems when connected to Voip. This black box is plugged into a major manufacturers Voip device + PC which converts the analogue voice into a Voip signal for input then across the Voip network. However When a far end caller u...


wav file

Started by mmoctar in comp.dsp10 years ago 5 replies

Hi all, I'm working on acoustic echo cancellation, my question is; When I test an algorithm like LMS or NLMS should I change the scale of...

Hi all, I'm working on acoustic echo cancellation, my question is; When I test an algorithm like LMS or NLMS should I change the scale of my wave signal? As pcm file are Q15 between 1 and -1, do I need to multiply my signal by 2^15 for test under matlab. Like input=2^15*wavread('input.wav'). My question is relative to the fact that signal level have an impact on algorithm performances. tha...


Acoustic echo cancellation

Started by createdon2003 in comp.dsp10 years ago 16 replies

Hi all, I am working on acoustic echo canceler for mobile telephony. I have two doubts to clarify: 1) Avi perry in his book "Voice Quality...

Hi all, I am working on acoustic echo canceler for mobile telephony. I have two doubts to clarify: 1) Avi perry in his book "Voice Quality Engineering in Wireless Networks" has mentioned that although speech signal power is distributed almost uniformly across the entire spectrum, the acoustic echo power concentrates most of its energy in the 1700-2500 Hz range. Anybody having any idea of th...


Undo frequency change by audio device before echo cancellation?

Started by roschler in comp.dsp9 years ago 3 replies

I am squarely in the camp of knowing barely enough DSP to be dangerous. I have successfully coded up some FIR filters to assist in sample rate...

I am squarely in the camp of knowing barely enough DSP to be dangerous. I have successfully coded up some FIR filters to assist in sample rate conversions between audio files but that's about it. My ambition could easily exceed my capacity here. I want to do echo cancellation of audio coming into a microphone that is positioned right next to an output speaker on an audio device I own. W...


Acoustic Echo Cancellation

Started by John McDermick in comp.dsp8 years ago 10 replies

Hello, If I model the microphone signal, y, as the output, y_hat, of an FIR filter H(z) and the input to that FIR filter is the speaker signal...

Hello, If I model the microphone signal, y, as the output, y_hat, of an FIR filter H(z) and the input to that FIR filter is the speaker signal x, is the following then the principles of acoustic echo cancellation: Initialize H(z) to an all pass filter Intialize estimated delay to 0 0. Buffer block of microphone data 1. Buffer block of speaker data 2. If near-end speaker is talkin...


Which algorithm would you choose?

Started by John McDermick in comp.dsp8 years ago 2 replies

Say you have two signals, x and y, where y is the output of an unknown FIR filter. The only thing which is "known" about the FIR filter is that...

Say you have two signals, x and y, where y is the output of an unknown FIR filter. The only thing which is "known" about the FIR filter is that it has N filter coefficients. The above relates to acoustic echo cancellation for speech signals sampled at 8kHz. I guess you can call it a channel estimation problem? Or a deconvolution problem? I don't know.... Anyways....As a pre-liminary expe...