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Questions tagged [lms]

Least Mean Square adaptive filter.

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27 views

Estimating Parameters (Coefficients) of Autoregressive (AR) Equation using Least Means Square (LMS) Algorithm

I want to do two things. Estimating Coefficients of AR model using LMS filter Using Coefficients found in step 1 and predict future samples of a signal using AR equation. I don't have a desired ...
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0answers
13 views

NLMS Echo Cancellation: How do we estimate when the time-step at which the Far-End Echo will be generated?

I'm new to this domain. From my understanding, we do the following in our algo: ...
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1answer
72 views

estimate the impulse response after equalization

I want to estimate the impulse response of the channel at the receiver. Assuming some arbitrary impulse response: h=[1 0.2 -0.4 0.0 0.6]. Once the equalizer is ...
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1answer
72 views

Recursive Least Square Adaptive Linear Equalizer

For the adaptive filter to work properly, a desired signal d(n) needs to be provided. The output from the equalizer y(n) is subtracted from d(n) to produce an error signal, which is used to adjust the ...
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1answer
37 views

Fair performance comparison betweem LMS & NLMS

How can I choose the step size $\mu$, when I'm comparing different algorithms such as LMS, NLMS and transform domain adaptive filters, regarding their convergence speed, to get a fair comparison ...
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30 views

Are the update equations for LMS in Real Time System Identification being handled correctly

Question: Are the Least Mean Squares (LMS) coefficient update equations and step size being handled correctly? Some background information: This algorithm is implemented on the ezdsp5535 on which ...
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2answers
62 views

what is an alpha filter?

Currently, I'm working on adaptive beamforming using LMS approach, so they change the value of the step factor adaptively in which one of the steps is to pass the weight vector through an alpha filter....
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0answers
48 views

Generalized Sidelobe Cancelling performance

I'm tinkering with different adaptive beam-forming algorithms for a research project in which I want to use a Uniform Rectangular microphones Array (URA) to isolate speech in a room. I am determining ...
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0answers
99 views

Equalizer design for spectral gain flatness

I'm trying to design an equalizer for spectral flatness over a 100MHz signal for an LTE channel emulator. A channel emulator simply multiples channel coefficients with an external signal from a signal ...
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1answer
78 views

Block LMS with overlapping blocks

In the Block LMS algorithm, the input is partitioned into nonoverlapping blocks of size $L$ and the filter coefficients are updated once every $L$ samples. Would convergence improve if we used more ...
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0answers
54 views

How to implement a LMS filter bank using multi-threading in python?

Since it involves parallelism and concurrency I planned on using multi-threading in python. Is it possible to do it this way if so how?
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1answer
165 views

Why does block LMS have the same performance as LMS?

The block LMS and conventional LMS have the same convergence rate and the same misadjustment. I am having trouble wrapping my head around this. The block LMS uses a more accurate estimate of the ...
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1answer
109 views

Doubts on LMS derivation

I have been trying to follow the Least Mean Square(LMS) algorithm derivation given by Wikipedia here and have the following questions. Here I expected $y(n)$ is to be computed by convolving $x(n)$ ...
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1answer
105 views

Equalizer coefficients and channel coefficients

Blind channel equalization methods equalize the channel without using the source data and without knowing the impulse response of the channel. Consider the channel to be a single input single output ...
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1answer
299 views

What do the filter coefficients in digital filter represent?

Could you help me? How can I understand the function of the filter coefficients practically? In the simple case, it is the impulse response of the LTI system. but how do they work?
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1answer
39 views

Error plot between known and estimated data

The channel is an FIR model with input $u$. The input takes in values which are symbols from some constellation. Using an equalizer such as the Least Mean Squares (LMS), I estimate the input to the ...
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0answers
36 views

Normalized LMS with a posteriori Error and Woodburry's Matrix Inversion

I was going through this paper and the author mentioned that we can prove the following using the Matrix Inversion Lemma (AKA Woodburry's Matrix Inversion Identity): Using matrix inversion lemma we ...
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1answer
104 views

Recursive DCT implementation

I am trying to understand the recursive implementation of the DCT on the input signal (used for LMS filtering) according to the pictures below. The pictures and formulas are taken from the paper: "...
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1answer
196 views

Model validation after estimation — system identification — help with an example in Matlab

QUESTION: I want to determine how well the estimated model fits to the future new data. How do I validate the estimated model...what is the procedure? After system identification, how to do model ...
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1answer
213 views

Unable to understand the derivation of the update equation for LMS

I am trying to follow the derivation of the Least Mean Square https://en.wikipedia.org/wiki/Least_mean_squares_filter#Proof but I cannot get the update rule. I am stuck in the following steps and ...
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2answers
240 views

Explain the Adaptive Part of Adaptive Algorithms - Kalman Filter and Least Mean Square / Constant Modulus

General questions: Is the Kalman filter (they have used Unscented Kalman Filter) adaptive or not? Is the Unscented Kalman Filter used in the paper an adaptive algorithm? Adaptive algorithms such as ...
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1answer
394 views

Maximum Likelihood Estimator (MLE), MMSE and LS - Are All of Them Regressor, Estimator and Predictor?

Can all three criteria ML, MMSE, and LS be called regressor, estimator, and predictor ? If not, an intuitive explanation of why they can't be would be good.
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1answer
110 views

Two type of calculating R in steepest-descent modeling algorithm

I have wrote this algorithm for steepest descent: ...
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1answer
538 views

LMS algorithm for modeling step-size ambiguity!

Behrouz Farhang-Boroujeny in his adoptive filters, 2nd ed., p. 155 ,told: It is sufficient for stability: 1/(3*tr(R)). But his book have attached mfile for ...
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2answers
45 views

Stochastic approximation algorithm

The goal is to find the FIR filter coefficients $\mathbf{h} = [5;3]$ with the help of the adaptive FIR filter $\mathbf{w}$ of order $p = 2$. I have implemented the Stochastic approximation algorithm ...
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1answer
217 views

LMS and delta impulse response- Equalization concepts

I have been reading about equalization and channel estimation in order to apply to my application of estimating trajectory path for a two-wheeled robot. The application is quite similar to ...
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0answers
46 views

the result of LMS filter is too small

What I wanna do is system identification through LMS filter or NLMS filter. I get 3 audio files.1 input(x)and 2 outputs(y and z). I want to get an optimal filter that can get the similar output of y ...
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1answer
192 views

Why is my NLMS filter off by +/- 2?

I haven't done any signal processing in a while, but I'm completely stymied by the instability and bias in my implementation of a normalized least mean squares filter. I checked the usual things: Am ...
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2answers
60 views

Upsampled input to an Adaptive filter?

I will try to explain the issue I am having as clearly as possible without going into my coding or maths. I have my own and a MATLAB Central implementation pf standard LMS in MATLAB. Fixed step size. ...
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0answers
88 views

Gradient descent applying chain rule in state space setup

Trying to perform system identification in the following state-space model $$ \begin{bmatrix} x_{1}(n)\\ x_{2}(n) \\ x_{3}(n)\end{bmatrix}=\begin{bmatrix} a_{11} && a_{12} && a_{13} \\ ...
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1answer
331 views

Variable step size LMS vs Leaky-LMS adaptive filter algorithm

What is the advantage of Variable step size LMS over Leaky-LMS adaptive filter algorithm? Which one has a better performance?
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0answers
1k views

Adaptive LMS (Least Mean Square) Equalization in OFDM

I have a problem with the adaptive LMS frequency domain equalization in OFDM. When I assume that the receiver knows the channel perfectly and apply zero forcing equalizer, there is no problem. Also ...