Regarding acoustic echo cancellation using frequency domain LMS algorithm and subband LMS algorithm

Started by Aparna Ram in comp.dsp13 years ago 12 replies

Dear all, I am working on the acoustic echo cancellation.I have implemented the time domain LMS algorithm for acoustic...

Dear all, I am working on the acoustic echo cancellation.I have implemented the time domain LMS algorithm for acoustic echo cancellation and it is working fine only for some audio files and not working for some other audio files which has the large eigen value spread.So to avoid this eigen value spread now I am working on the subband LMS algorithm in frequency domain for aco...


Matched filter and LMS equalizer

Started by Richard_K in comp.dsp13 years ago 2 replies

Hi, Is it possible for a LMS equalizer in multipath environment to achieve better BER performance as compared to matched filter in AWGN...

Hi, Is it possible for a LMS equalizer in multipath environment to achieve better BER performance as compared to matched filter in AWGN channel?


LMMSE (non-adaptive) equalizer and LMS equalizer

Started by Richard_K in comp.dsp13 years ago 1 reply

Hi, If we compare LMMSE (non-adaptive) equalizer and LMS adaptive equalizer in time-invariant channel, which equalizer should achieve better...

Hi, If we compare LMMSE (non-adaptive) equalizer and LMS adaptive equalizer in time-invariant channel, which equalizer should achieve better performance in terms of MMSE and BER? Why? Thanks.


BER of multipath channel

Started by Richard_K in comp.dsp13 years ago 4 replies

I wrote a program to calculate the BER of LMS equalizer in AWGN and multipath channel. The tap weights of the mobile radio channels...

I wrote a program to calculate the BER of LMS equalizer in AWGN and multipath channel. The tap weights of the mobile radio channels are normalized to 1 (the exact value is 1.0062). Surprisingly, I found out that the performance of the equalizer in multipath channel is better than the one in AWGN. Is this acceptable? Or anything that might be wrong in my simulation? Or the performance gain of ...


LMMSE equalizer

Started by Andrew2006 in comp.dsp13 years ago 3 replies

From some technical papers, I found out that non-adaptive MMSE block equalizer has been used to equalize for time-varying channels. Since adaptive...

From some technical papers, I found out that non-adaptive MMSE block equalizer has been used to equalize for time-varying channels. Since adaptive algorithm (LMS, RLS,....) is not applied here, then how the researchers simulate for the BER performance? Can anyone please help? Thanks.


quantization for RLS and LMS design

Started by Anonymous in comp.dsp13 years ago

I want to implement the quantization technique in matlab for RLS and LMS design !! Please recommend something !! I know about the fixed point...

I want to implement the quantization technique in matlab for RLS and LMS design !! Please recommend something !! I know about the fixed point toolbox to do quantization !! Please tell me where can i get it and for free !! dont tell me mathswork cause it sucks !!


Regarding double talk detection in Acoustic Echo Cancellation

Started by Aparna Ram in comp.dsp13 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...


Adaptive Notch Filter - LMS Algorithm

Started by zrimkunas in comp.dsp13 years ago 4 replies

Hi everyone, I am working on a simple adaptive notch filter that will be used to cancel one sinusoid. Additionally, the filter coefficient is...

Hi everyone, I am working on a simple adaptive notch filter that will be used to cancel one sinusoid. Additionally, the filter coefficient is complex (I am looking after the error envelope). So what I have is one zero and one pole. The zero is fixed to the unit circle and the pole is very close to the unit circle at the same angle as the zero. The transfer function is: H(z) = (1 - (1


Time Delay Estimation - LMS

Started by Anonymous in comp.dsp13 years ago 1 reply

I know how to estimate time-delays using FFTs and generalised cross- correlation but I was wondering if LMS offers any advantages. eg if I have...

I know how to estimate time-delays using FFTs and generalised cross- correlation but I was wondering if LMS offers any advantages. eg if I have say two acoustic sensors I would know the delay by assuming there are 'zeros' in the leading coefficients of the LMS (ie the weights). What mechanism would be used to say what is near to zero? Practically you might have something obvious like 0.01,...


Wiener solution for equalization

Started by Richard_K in comp.dsp13 years ago 4 replies

In order to find the Wiener solution for equalization purpose, do I need to provide delay to the desired signal as in the case of LMS...

In order to find the Wiener solution for equalization purpose, do I need to provide delay to the desired signal as in the case of LMS algorithm? Will the result of the Wiener solution become better if I provide some delay to the desired signal? Thanks.


LMS in C code needed

Started by Bergen in comp.dsp13 years ago 10 replies

Anybody knows where to find LMS filter code written in C/C++ ??? I need it to implement it on old ADSP 21061 to finish my diploma and get outta...

Anybody knows where to find LMS filter code written in C/C++ ??? I need it to implement it on old ADSP 21061 to finish my diploma and get outta school (freedom !!!). Google don't know what's all about. Please, help !!! -- Bergen


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

Started by singla in comp.dsp13 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...


project echo canceller

Started by zalix in comp.dsp13 years ago 1 reply

I have seen your work on an echo canceller and I was impressed. Am a graduate student at Kyambogo university trying to implement a simulation of a...

I have seen your work on an echo canceller and I was impressed. Am a graduate student at Kyambogo university trying to implement a simulation of a echo canceller using C++ builder the background code for the lms algorithm has totally refused to work out because the filter cant run until a minimum mean square error is got but raises an overflow error here is my code please look through it and help ...


Regarding Real Time Problems of AEC

Started by Aparna Ram in comp.dsp12 years ago

Dear All, I have implemented AEC with and with out subbanding using NLMS algorithm and that code is working fine for all recorded...

Dear All, I have implemented AEC with and with out subbanding using NLMS algorithm and that code is working fine for all recorded audio files. But for real time audio files this algorithm is not effecting. If any one know the reason behind this then please give me your valuable suggestions. Thanks in advance. Regards, Aparna Ram.K.


LMS vs Wiener

Started by gabinet in comp.dsp12 years ago 2 replies

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise...

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise v(n) with known variance and mean x(n) = d(n) + v(n); the goal is define an optimal Wiener filter of 101 coefficients. (I call it "toy situation" because I have at the same time the value of the noisy signal and the value of the original signal) ...


LMS vs Wiener

Started by gabinet in comp.dsp12 years ago 1 reply

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise...

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise v(n) with known variance and mean x(n) = d(n) + v(n); the goal is define an optimal Wiener filter of 101 coefficients. (I call it "toy situation" because I have at the same time the value of the noisy signal and the value of the original signal) ...


LMS with quantized data?

Started by gct in comp.dsp12 years ago 9 replies
LMS

OK so I wrote an LMS algorithm using floating point numbers. But I switched the signals I'm operating on to ones that are complex-integer (from a...

OK so I wrote an LMS algorithm using floating point numbers. But I switched the signals I'm operating on to ones that are complex-integer (from a 12-bit ADC). My problem is that the algorithm refuses to converge now. It acts like it's going to, but then it just hits a stead states and oscillates. Anyone know a good way to fix this?


LMS Algorithm

Started by Stacy in comp.dsp12 years ago 6 replies
LMS

Question 1: eq. 1) W(k+1) = W(k) + 2*u*e(k)*X(k) eq. 2) W(k+1) = W(k) + u*e(k)*X(k) I've seen the LMS algorithm written both ways....

Question 1: eq. 1) W(k+1) = W(k) + 2*u*e(k)*X(k) eq. 2) W(k+1) = W(k) + u*e(k)*X(k) I've seen the LMS algorithm written both ways. Which one is correct? (the difference between 1 & 2 above is multiplying e(k)*X(k) by 2) Question 2: Is there a formula for calculating u, the step size?


c code for lms adaptive filtering

Started by mohsen5052 in comp.dsp12 years ago 3 replies

hi Anybody knows where to find LMS filter code written in C/C++ ??? I need it to implement it on old ADSP 21061 to finish my diploma and get...

hi Anybody knows where to find LMS filter code written in C/C++ ??? I need it to implement it on old ADSP 21061 to finish my diploma and get outta school (freedom !!!). Google don't know what's all about. Please, help !!! mohsen


Noise Cancellation

Started by Stacy in comp.dsp12 years ago 13 replies

If you have a recording with people talking in a room and a radio playing at the same time, how do you remove the sound of the radio? I am...

If you have a recording with people talking in a room and a radio playing at the same time, how do you remove the sound of the radio? I am aware of adaptive noise cancellation with LMS. However the noise there is white noise or noise from an airplane cockpit, waterfall, etc.