LMS algorithm vs. adaline neural network

Started by Lance123 in comp.dsp11 years ago

I am looking at using an adaptive filter for noise cancellation. I was wondering whether there was any advantage to using a neural...

I am looking at using an adaptive filter for noise cancellation. I was wondering whether there was any advantage to using a neural network approach such as the ADALINE in the Matlab Neural Net toolbox vs. a typical LMS algorithm? Is the expected performance very similar or is there an advantage of one approach over the other?


equalizer output issue - eqout.jpg (0/1)

Started by Muzaffer Kal in comp.dsp11 years ago 5 replies

Hi everyone, I'm working on an LMS adaptive filter which is behaving in somewhat of an unexpected way. The attached image shows the histogram of...

Hi everyone, I'm working on an LMS adaptive filter which is behaving in somewhat of an unexpected way. The attached image shows the histogram of the equalizer output after convergence; my slicer thresholds are at 0.5 and -0.5 (ie anything above 0.5 is sliced to 1, anything below -0.5 is sliced to -1 and anything in between is sliced to 0; this is a 3 level code.) Then I use an error generate...


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?


Detect wide band noise

Started by Vladimir Vassilevsky in comp.dsp10 years ago 7 replies

Hello All, I need to detect the bursts of the wide band noise in the sampled signal. The detector should ignore the narrow band pulses or the...

Hello All, I need to detect the bursts of the wide band noise in the sampled signal. The detector should ignore the narrow band pulses or the stationary signals. This is intended for blanking of the signal processing in the instrument. A solution could be based on the FFT, LPC or some sort of adaptive filter. However I am looking for less demanding method, which can be very approxi...


PNLMS filter required!!!!

Started by Sharmin in comp.dsp10 years ago

Hi , I am working on adaptive filter algorithm. I have already implemented the NLMS algorithm but when I wrote the code for PNLMS algorithm ,I am...

Hi , I am working on adaptive filter algorithm. I have already implemented the NLMS algorithm but when I wrote the code for PNLMS algorithm ,I am not getting the desired output. If anyone already worked with PNLMS algorithm plz help me by sending the matlab code for PNLMS filter.


Convergence of Linear Equalizer

Started by cpshah99 in comp.dsp10 years ago 6 replies

Hi All In Haykin book of adaptive filter, he has explained tracking of LMS in non-stationary environment. In that he says that the tracking is...

Hi All In Haykin book of adaptive filter, he has explained tracking of LMS in non-stationary environment. In that he says that the tracking is problem specific i.e. tracking of system identification is different problem than equalizing. I get what he is saying. And then he derives all the math for system identification problem where he models the time varying environment as first order Marko...


FFT computation complexity

Started by HyeeWang in comp.dsp10 years ago 6 replies

Consider next the fast LMS algotithm. Each N-point FFT (and IFFT) requires approximately N log2 N real multiplication (Oppenheim and Scafer...

Consider next the fast LMS algotithm. Each N-point FFT (and IFFT) requires approximately N log2 N real multiplication (Oppenheim and Scafer 1989),where N = 2M. Above, it cited from page 454 , < < Adaptive Filter Theory> > ,Third edition by Simon Haykin. 1. The contents in brackets, ie., Oppenheim and Scafer 1989, what does it mean? Does it refer to the famous textbook "Discrete-time Sign


What decides Number of Taps of FIR filter in Adaptive applications?

Started by bharat pathak in comp.dsp9 years ago 4 replies

Hello, If I am designing an adaptive filter to remove narrowband interference from wideband signal, how can I decide on the order...

Hello, If I am designing an adaptive filter to remove narrowband interference from wideband signal, how can I decide on the order of the FIR filter? Regards Bharat


Adaptive Filter for Binary Signal?

Started by jerothb in comp.dsp9 years ago 26 replies

Hello, I'm taking an adaptive filter course, and have been given a desired signal and a distorted signal. The desired signal is...

Hello, I'm taking an adaptive filter course, and have been given a desired signal and a distorted signal. The desired signal is non-return-to- zero purely random binary data, i.e. -1, 1, 1, -1, 1, -1 etc. The distorted is this exact same signal, but filtered and added with noise. We are to filter the distorted signal using adaptive filter methods that we learned, namely steepest descent...


Highly Non-Stationary Signals for Adaptive Filters

Started by pacman101 in comp.dsp8 years ago 8 replies

Hello, I encountered a problem with Noise Cancellation. The interfering signal that I am trying to cancel goes on and off really fast...

Hello, I encountered a problem with Noise Cancellation. The interfering signal that I am trying to cancel goes on and off really fast (noise of a switch). I have never quantified how long it turns on and off but it it is less than 1 ms or so. I am attempting to cancel its noise by applying an adaptive filter and my application works for stationary signals such as band-limited white Ga...


Interdependent Coefficients and LMS

Started by taken in comp.dsp8 years ago 4 replies

Hi , Can LMS algorithm deal with an adaptive filter with coefficients that depend on each other such as : y=...

Hi , Can LMS algorithm deal with an adaptive filter with coefficients that depend on each other such as : y= x(n)+(W1+W2)*x(n-1)+(W1.W2)x(n-2); In my experiments it does not converge. Can anyone point me in the correct direction to solve such problems? Thanks much


Adaptive Filter Reference Constructed From the 2 Noisy Signals To Be Filtered

Started by Bret Cahill in comp.dsp8 years ago 47 replies

Is this situation/solution common? There is at least one example in electronics. Bret Cahill

Is this situation/solution common? There is at least one example in electronics. Bret Cahill


genetic algorithm

Started by ABU BENAZIR in comp.dsp7 years ago 11 replies

am doing project in genetic algorithm.... i need to design an adaptive filter using this genetic algorithm... am working in matlab........

am doing project in genetic algorithm.... i need to design an adaptive filter using this genetic algorithm... am working in matlab..... if anyone can help me???? thanks in advance..........


help in filter coefficients

Started by asik nisha in comp.dsp7 years ago 9 replies

hi i'm doing my project in genetic algorithm.... i need to find the best filter coefficient value using this genetic algorithm........

hi i'm doing my project in genetic algorithm.... i need to find the best filter coefficient value using this genetic algorithm..... i already designed one adaptive filter and also find its coefficients...... So by using GA the mean square value of the filter coefficient is calculate and compare the error values and find the best value among it.... i tried it in optimization tool... i...


NLMS and ERL above 0dB

Started by Mauritz Jameson in comp.dsp7 years ago 27 replies

Hi I'm playing around with a traditional NLMS algorithm for acoustic echo cancellation. It seems like the NLMS algorithm have a hard time...

Hi I'm playing around with a traditional NLMS algorithm for acoustic echo cancellation. It seems like the NLMS algorithm have a hard time cancelling the echo as soon as the ERL level creeps above 0dB. Is that to be expected? The speaker signal is pure speech (no noise) and I have linearly filtered the speaker signal to have a simulated microphone signal. The adaptive filter order i...


Why is the original gradient of cost function increase in steepest descent algorithm

Started by fl in comp.dsp6 years ago 3 replies

Hi, I read a book on adaptive filter. In part of steepest descent algorithm, it says that the gradient vector at any point of a cost function...

Hi, I read a book on adaptive filter. In part of steepest descent algorithm, it says that the gradient vector at any point of a cost function points toward the direction in which the function is increasing. I do not find the explanation about that in that book. Could you explain it to me? Thanks


Adaptive Filter Convergence

Started by RIH7777 in comp.dsp6 years ago 5 replies

Hello, Some basic questions about behavior of a FIR LMS adaptive filter. In Matlab I'm using their supplied adaptfilt.lms function. ...

Hello, Some basic questions about behavior of a FIR LMS adaptive filter. In Matlab I'm using their supplied adaptfilt.lms function. let: mu = adaptation constant = .08 for all experiments x(n) = filter input d(n) = desired filter output y(n) = filter output e(n) = error signal = d(n) - y(n) h(n) = impulse response of system to be modeled afilt(n) = value of filter taps at end of data...


Adaptive filter

Started by Jim craig in comp.dsp6 years ago 1 reply

Hi I am using a classic nlms adaptive filter to minimize the error between an unknown LTI system and the output of an adaptive FIR. However I...

Hi I am using a classic nlms adaptive filter to minimize the error between an unknown LTI system and the output of an adaptive FIR. However I have no control over the stimulus, which is a mix of sinusoids that change slowly over time. I know that with this input, the filter may not adapt to the true impulse response, but as long as the error goes to a small value I don't really c


detecting an echo in DTMF tone in echo canceler

Started by alpha1 in comp.dsp4 years ago 4 replies

I am facing some issue with my echo cancellation module. I am having a correlator and an adaptive filter modules. My correlator will detect...

I am facing some issue with my echo cancellation module. I am having a correlator and an adaptive filter modules. My correlator will detect presence of echo in the DTMF tones and will activate the adaptive filter. The adaptive filter will remove the echo present in the DTMF tones. Activation of adaptive filter is done only if the correlation is above a certain threshold. My issue is t...


subtraction of two speech signals

Started by abhi5491 in comp.dsp3 years ago 8 replies

I am working on project on Adaptive filter using TMSC6713. I have to calculate the snr ratio at the output.SO what i did is ,I gave only the...

I am working on project on Adaptive filter using TMSC6713. I have to calculate the snr ratio at the output.SO what i did is ,I gave only the speech signal to the adaptive filter and recorded the output,The second thing I did is I gave both speech signal and the wind noise to the adaptive filter and recorded the output. So now I have 2 signals. 1. Clear speech signal 2.Speech signal+noise(ve...