## Forums Search for: adaptive

## Adaptive equalization and synchronization

inHow does one maintain synchronization when one is using adaptive equalization? I'm currently working on a highly dispersive, varying channel,...

How does one maintain synchronization when one is using adaptive equalization? I'm currently working on a highly dispersive, varying channel, that needs adaptive equalization to work well. But I've come to realize that one thing that adaptive equalization adapts for is the exact timing of the signal. This means that you can't really used the output of the equalizer as a phase refere...

## problem understanding LMS noise whitening alg.

Hi. I am self-studying adaptive signal processing. I've read C.R. Johnson's Adaptive Signal Processing, and some parts of Haykin's. I am...

Hi. I am self-studying adaptive signal processing. I've read C.R. Johnson's Adaptive Signal Processing, and some parts of Haykin's. I am reading this paper "Self adaptive decision feedback equalization: Application to high order QAM signal" In the paper, adaptive whitening filter is applied to the received signal. The whitened signal is then fed to another adaptive FFE equalizer to recov...

## adaptive quantization and transmission errors

inHi I am working on a backward adaptive non-uniform quantizer for use in wireless transmissions. More precisely my quantizer currently consists...

Hi I am working on a backward adaptive non-uniform quantizer for use in wireless transmissions. More precisely my quantizer currently consists of an adaptive compader (currently atan-based) and a simple uniform quantizer. This works very well. Trouble is: I am going to transmit data over a noisy wireless channel. As of now the errors are bringing the adaptive expander on the decoder side ...

## adaptive precoding and pre-equalization

inI was trying to search through literature in order to find advantages and disadvantages of adaptive pre-coding and pre-equalization...

I was trying to search through literature in order to find advantages and disadvantages of adaptive pre-coding and pre-equalization over adaptive post-equalization. I failed. Can anyone point to a good reference. 2ndly on adaptive pre-equalization there are only three papers when we search ieeexplore. I was thinking of using indirect learning architechture as a pre-equalizer mentioned in D....

## Echo Canceller: Measuring Performance

inI'm simulating an echo canceller in Matlab, using a FIR adaptive LMS filter. I'm using the standard noise cancelling approach: -adaptive filter...

I'm simulating an echo canceller in Matlab, using a FIR adaptive LMS filter. I'm using the standard noise cancelling approach: -adaptive filter input u(n) = far end speech -adaptive filter output is y(n) -impulse response of echo path is h(n) -near end speech is ne(n) -d(n) = ne(n) + u(n) (*) h(n) ----> where (*) denotes convolution -adaptive filter error single e(n) = d(n) - y(n) -In

## adaptive beamforming

I'm trying to simulate a adaptive beamformer. I refered to the block diagram of GSC in "adaptive filter theory" of S.Haykin,P.257.I'm a...

I'm trying to simulate a adaptive beamformer. I refered to the block diagram of GSC in "adaptive filter theory" of S.Haykin,P.257.I'm a little confused with the constraint matrix and quiescent weight vector. I'm wondering about how to built the signal-blocking matrix 'Ca' and how to determine the constraint matrix numerically. Any help is appreciated!

## books on adaptive filtering

inhi everybody. I'm looking for one (or more) textbook on adaptive filter theory. I'm not interesting in advanced topics, I'm interesting in a...

hi everybody. I'm looking for one (or more) textbook on adaptive filter theory. I'm not interesting in advanced topics, I'm interesting in a well explained book able to drive the beginner inside the matter. a book with some examples or solved exercises would be appreciated. does anyone studied the subject on a such valuable book? e.g. I implemented some adaptive notch filters startin...

## Adaptive Comb Filtering

inAnyone out there familiar with "Adaptive Comb Filtering for Harmonic Signal Enhancement" by Nehorai and Porat? I'm attempting to implement the...

Anyone out there familiar with "Adaptive Comb Filtering for Harmonic Signal Enhancement" by Nehorai and Porat? I'm attempting to implement the recursive algorithm described by equations 30a-30t, but having problems with initial conditions for some of the variables. Failing that, does anyone have a better reference for adaptive comb filtering? Thanks, Greg

## Gear shifting for adaptive filters

inDear All, Recently I had posted a thread where I asked about SNR penalty due to linear interpolation. I managed to solve that problem but there...

Dear All, Recently I had posted a thread where I asked about SNR penalty due to linear interpolation. I managed to solve that problem but there are some more doubts. My receiver has adaptive doppler correction and adaptive DFE using LMS. Now, the filter update constants that I had kept intially are as follows: Training mode: mu1=0.01 -> for Feedforward filter mu2=0.003 -> for

## Adaptive filter

inHi 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

inI 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...

## Adaptive arrays

inHey, I need to design an adaptive array for automatic interference rejection using the LMS algorithm in MATLAB. There is a target...

Hey, I need to design an adaptive array for automatic interference rejection using the LMS algorithm in MATLAB. There is a target signal cos(2*pi*f0*t) and three interference signals cos(2*pi*f0*t) coming in at angles of 45, -30 and -60 degrees. The adaptive array will consist of eight elements. The input signals are sampled at Ts=2*10^-10 s where t=0,Ts,2Ts,3Ts,4Ts...f0=3*10^8 Hz,lambda=1 ...

## Any good practical book on Adaptive filtering?

inHi, I'm looking for a good book on adaptive filtering, in the style of Richard Lyon's 'Understanding digital signal processing'. So far,...

Hi, I'm looking for a good book on adaptive filtering, in the style of Richard Lyon's 'Understanding digital signal processing'. So far, everything I've found involves quite complicated formulas straight from page 1, with very little clear and intuitive description of how this all works. Number one on this list would be 'Fundamental of Adaptive Filtering' by Sayed. I understand this book prob...

## LMMSE (non-adaptive) equalizer and LMS equalizer

inHi, 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.

## pls give some hints on the tuning of adaptive algs

inWill the adaptive algs achieve the same performance as the direct computation of the optimal weights may achieve, especially when data is...

Will the adaptive algs achieve the same performance as the direct computation of the optimal weights may achieve, especially when data is short? Is it necessary to estimate the variance of the input data when initilizing the adaptive algs, like RLS? How to monitor the stationariness and take what measure to counteract non-stationariness? Is there any common practices not mentioned in textbo...

## Litterature on adaptive MISO systems.

inHello group, I have been assigned a bachelor project (final thesis) and I'm looking for litterature for some particular subjects. Mainly, the...

Hello group, I have been assigned a bachelor project (final thesis) and I'm looking for litterature for some particular subjects. Mainly, the objective is to cancel noise using an adaptive filter. The system consists of two noise sources and one primary signal, in short, an adaptive MISO filter. I've googled for abstracts, litterature reference and for books at Amazon that describes such sys...

## Convergence of adaptive DFE

inHi All I am trying to demodulate real time data using adaptive DFE. The channel is highly time varying and the multipath spread is approx....

Hi All I am trying to demodulate real time data using adaptive DFE. The channel is highly time varying and the multipath spread is approx. 50 - 100 symbols at the data rate of 4ksps. I have 1000 symbols long training sequence. The problem is that adaptive DFE is not able to converge. The algorithms that I am using is LMS and NLMS. I have been palying with filter lengths and step sizes. I ...

## What's difference between Active NC and Adaptive NC

inI am doing a project on removing noise from speech signal, but in the survey stage. I noticed that there are two kinds of subjects on ANC, which...

I am doing a project on removing noise from speech signal, but in the survey stage. I noticed that there are two kinds of subjects on ANC, which could be either Active Noise Cancellation/Control, or Adaptive Noise Cancellation. Would anybody tell me what difference is between these two? I know the adaptive noise cancellation is that the algorithm adapts to continuously cancel the noise to giv...

## Adaptive filtering

inHi everyone I'm trying to do adaptive filtering with Matlab (LMS adaptive filtering). But with this method, it seems that I need to know the...

Hi everyone I'm trying to do adaptive filtering with Matlab (LMS adaptive filtering). But with this method, it seems that I need to know the original signal form (without noise). And I don't have information about the original signal (it's a large band signal, ofdm modulation). Do you know if it's possible to reduce noise with this method? Thanks a lot.

## adaptive beamforming

inHi, I am doing a project on robust adaptive beamforming. I wanted to know if there are any open source tools/softwares available for this...

Hi, I am doing a project on robust adaptive beamforming. I wanted to know if there are any open source tools/softwares available for this purpose.I need it at the earliest. So, I would really appreciate if someone could help me out in this regard. Thanks, suhas