# Tagged Questions

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32 views

### Instability problem in NLMS adaptive algorithm

I have been used NLMS algorithm to equalize 4x4 MIMO signals, but the bit-error-rate (BER) after equalization is unstable with iterations. I don't know if it is the normal behavior of the adaptive ...
59 views

### RLS or another way to solve Ax=b in batches

I need to solve a system of linear equations to do the imaging. My A is 60k by 10k or so and not full-rank. What are the ways to proceed? I tried matlab built-in LSQR algorithm, which allows ...
31 views

### Are the RLS filter and Kalman filter gradient methods?

I would like to extend my previous question What is difference between LMS and gradient-descent adaptation? with this other question. I found out, that RLS and Kalman filter learning seems to be ...
68 views

I found algorithms that seems the same to me, but they are described with different names (in field of adaptive filtering). For example: LMS - least-mean-squares seems to be GD - stochastic ...
53 views

### Best DSP algoritms for ultrasonic background noise cancellation

I am looking into detection of pressurized gas leaks by means of the broadband hissing sound (white noise) generated from pressurized leaking gas. The instrument will have a broadband microphone ...
28 views

### Cost function for adaptive algorithms

I am having little difficulty to understand that why most of the adaptive algorithms use error power or addition of error power as cost function/minimization criterion. I have read that minimization ...
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### Estimate $s$ from $y=s+n$

Thank you in advance. My question is: Now I receive $y=s+n$, $s$ is the signal and $n$ is the white guassion noise. Everytime $s$ will be change irregularly, have some methods to get a estimation ...
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### Variance of output signal

I have the White Gaussian noise v[n] with zero mean and variance of v = 1 is filtered by the FIR filter F(z) with impulse ...
95 views

### Modeling ADC in Active Noise Cancellation

I'm tinkering in Matlab with a problem that's very similar to active noise cancellation. In the literature, the secondary path is described as the transfer function from the output of the adaptive ...
19 views

### Feedback Loops for Computer Vision

What image shape-detection algorithms exist that look in the neighborhood of starting parameters, rather than trying to find the "best possible fit" for image. For instance, I'd give a starting x-...
72 views

### Echo cancellation supporting long delays and without frequency domain processing

AEC algorithms mostly rely on LMS adaptive filtering, i.e. you update FIR filter coefficients then perform the filtering. Theoretically, the FIR must be as long as the maximum echo length you want to ...
27 views

### Null Steering using MVDR for a 4 antenna array

I am trying to get a null in the interference direction using MVDR. MVDR requires a matrix inversion. When i am implementing it, i am getting two nulls, one in the desired direction and one more in ...
614 views

### MATLAB : Proper estimation of weights and how to calculate MSE for QPSK signal for Constant Modulus Algorithm

I had asked conceptual Question about Constant Modulus Algorithm. I am implementing the simple steps of the algorithm, as I do not have the cma() built in module. ...
59 views

### Beginner level : Help with terminologies : smooting length, length of channel, channel equalization delay, blind system identification, equalization

Say the channel model is an univariate FIR filter with true coefficients $h=[1,a_1, a_2 ]$. I am learning algorithms for system identification and channel equalization. For this, I am implementing ...
181 views

### Constant Modulus Algorithm and the gradient operation

CMA is a blind channel equalization algorithm with the details presented above. I am facing 3 difficulties and shall appreciate help Q1: Does $H$ and the bar over $\bar{y_k}$ represent the Transpose ...
40 views

### non-standard error function for adaptive filter

I want to create an adaptive filter. Its coefficients have this general shape: When the input signal for the filter is a sine wave, the filter behaves the desired way if the look-back window is set ...
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### Auto/cross correlation of a cosine in the context of an adaptive beamformer

I am currently reading chapter 13 of 'Adaptive Signal Processing' by Widrow and Stearns, so if anyone happens to have a copy of the book to hand it could be helpful. I am reading the chapter on "...
221 views

### Questions about Active Noise Cancellation

Being new to ANC, this is my understanding of how ANC works: Ambient noise (n) is entering a geographically small zone. To suppress the noise, an interfering (corrective) sound is injected ...
218 views

### Adaptive equalizer for IIR channel?

I am quite new to the idea of equalization. I have a few queries regarding the same. In my application I require to equalize a channel whose impulse response is an IIR response. Is it possible to ...
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I have 3 sensor inputs: $a(t)$, $b(t)$ and $c(t)$. I want to design a filter such that the weighted linear combination of the three is always a constant. Kind of like: w_1(t)a(t) + w_2(t)b(t) + w_3(...
201 views

### Best signal processing method for this application?

I have a signal I'm getting from a sensor (shown below in the photo of an excel plot) and I need to process it to get it to look something like the red line I've overdrawn on it. Sort of a moving ...
109 views

### Need a fast algorithm of adaptive convolution

I have to apply some kind of adaptive filter to my function $f(x).$ I present each point of my signal as a Gaussian, whose bandwidth depends on its location (not the point of observation $\textbf{x}$) ...
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### What could an algorithm look like that iterates through all combinations of two variables to aim at a certain number of entries? [closed]

For background information, see "Some background" further down. I have a list that looks like this: Start-Time-In-Seconds;End-Time-In-Seconds 1;2 4;6 12;15 ... ...
910 views

### Difference between 'conventional' and 'adaptive' beamformers?

This might be a terminology question but I am not sure. Basically, what is the difference between conventional beamformers, and adaptive beamformers? I thought that all beamformers were inherently ...
971 views

### Applying Photoshop's “Shadow/Highlight” correction using standard image-processing algorithms

Adobe's Photoshop has an excelent filter called "Shadow/Highlight" used to correct, in one step, dark areas AND overexposed areas of a photo. By simple analysis, I suppose it uses some radius-...
4k views

### Kalman filter in practice

I have read the description of the Kalman filter, but I am not clear on how it comes together in practice. It appears to be primarily targeted at mechanical or electrical systems since it wants linear ...
237 views

### Convolution involving turning each pixel value to the most represented pixel value of the neighbourhood

In order to correct gradual changes of intensities in the background of grey-scales images, I have been blurring them and then subtracting the original images from the convolved one. In some cases, I ...