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Questions tagged [equalization]

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Hisotgram equalisation error, help with my code

Iam working on implenting a histogram equalisation of an image without using inbuilt functions specifcally imhist and histeq, I have, for the most part understood what do during a histogram ...
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32 views

Correlation function in RLS-based equalization

In the Recursive Least Square (RLS) algorithm , the correction applied to the previous estimate consist of the product of two factors: the prior information error and the kalman gain vector, which ...
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24 views

Training Fractionally Spaced Channel Estimator and Equalizer

If you are attempting least squares channel estimation with a fractionally spaced channel estimator, do you want the training sequence to also be fractionally spaced or symbol spaced? It looks like ...
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61 views

Digital Communications block diagram question

I am new to digital communications and trying to understand the basic underlying concepts of digital comm systems. So far , studying the course , I have some questions which if anyone can answer would ...
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14 views

Amplifying the difference of luminance between pixels of color images?

I'm doing some research on digital watermarking and came across an article that embeds QR codes on mostly grayscale images and the extraction part for color images is quite confusing the article ...
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74 views

The Definition of Q Factor by an Equation and How to Graph

I am currently building an EQ in an music app, and it's relatively simple: 6 bands of fixed center frequency, and a Q knob to control the Q of all bands, because we do not currently have space for ...
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1answer
47 views

Is CMA equalization applicable for OFDM

I have a question regarding the constant modulus algorithm (CMA), as you know it's one of the known algorithms used for blind equalization. The cost function of the CMA is build blindly, it means ...
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1answer
53 views

Where in the signal chain is Channel Equalization applied?

I am reading about channel equalization and I am somewhat confused on where in the signal chain channel equalization is normally applied and if it's before or after a correlator detector or matched ...
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1answer
129 views

What is the difference between an equalizer and a channel estimator?

I was wondering what is the difference between channel estimator and channel equalizer? Thanks!
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1answer
32 views

Need information about following channel model

The following research paper is for blind channel equalization and the author has modeled the channel as 7 tap weights https://ieeexplore.ieee.org/document/1096877 On page 3 it has shown the ...
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1answer
28 views

Equalizing a temporal sound signal with a convolution

This question is more or less the following of a previous question. The aim is to equalize some sounds signals. By equalizing, I mean increasing or decreasing some frequency ranges, a bit like an ...
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1answer
38 views

Inter-Symbol Interference (ISI) channels

Is there any open and free data-set for digital ISI channels? I want to have a variety of ISI channels' taps, such as $h[k]$ here. Especially looking for BPSK channels.
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42 views

Is the Channel shortening similar to Time domain Equalizer (TEQ)

I used to read about Time domain equalizer (TEQ) in many lectures, i.e here , But in many other papers, that's called Channel shortening i.e here . However, in the a two above links, the cost ...
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1answer
43 views

how to set Equalizer's coefficient using generalized eigenvector.

In that paper https://jwcn-eurasipjournals.springeropen.com/articles/10.1186/1687-1499-2012-72 .. Equation 3, $J(w) = w^HBw/w^HCw$ .. $B$ and $C$ are matrices, $w$ the filter coefficients vector ...
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1answer
205 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
39 views

BER performance of fractional equalizers for colored noise

I am trying to compare the BER performance of fractional and symbol spaced equalizers for channel equalization in colored noise scenario. I have found from simulation that for positively correlated ...
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1answer
62 views

What's the difference between Channel shortening and time-domain equalizer

I'm asking about the difference about channel shortening and time-domain equalization. I have checked on-line and tried to get something clear but I couldn't. What I found is that channel shortening ...
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0answers
48 views

Implementing Fractionally Spaced Equalizer

I have been searching for robust algorithm that can be implemented for avoiding the ISI (Inter-Symbol interference), I came across two types of channel equalizations are there. One is data Aided (...
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1answer
107 views

What is the difference between pulse shaping and equalizers when used to cancel Inter-symbol Interference (ISI)?

According to Nyquist, to transmit R symbols/sec without ISI, the minimum bandwidth required is R/2 Hz, and the sinc pulse shape satisfies this condition. If we use equalizers instead of pulse ...
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2answers
180 views

Inter Symbol Interference (ISI) / Equalization in Digital Signal Processing

I am studying the OFDM system and before to start I have decided to study the main concepts of modulation. And I have spent yet a lot of time to understand the concept of an equalization to reduce ISI....
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148 views

Blind equalization with constant modulus algorithm in GNU Radio

I'm currently simulating the effect of multitap channel on BPSK as well as its remedy i.e. equalization. The modem is expected to work with satellite TT&C transponder. The communication channel ...
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1answer
168 views

how can I generate SIMO underwater acoustic channel

I'm working in underwater acoustic channel, then I need to generate SIMO channel to use it for simulation in MATLAB, how can I generate SIMO channel? thank you
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0answers
123 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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68 views

Satellite receiver suite

I'm in the process of implementing a general purpose baseband system for modulation schemes (Linear + CPM) commonly used satellite and deep-space TT&C as shown in the functional flow block diagram ...
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1answer
456 views

Precursor ISI - causality violation?

Today, in my lecture on intersymbol interference (ISI), there was a discussion on postcursor ISI, and precursor ISI. Postcursor ISI is caused by the past bits, whereas, precursor ISI is caused by the ...
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53 views

Best equalizer for a perfect CSI

Assuming a MIMO system and a perfect CSI (the channel matrix is known), what can be the best equalizer? ZF or others?
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42 views

Constructing Contour for Star QAM Equalization

I am trying to equalize the 16 Star QAM using known blind channel algorithms such as CMA,MMA,SCA,RCA,IRCA,CXA,SCXA.I now need to contruct a new contour for equalizing the 16 Star QAM.As it is in ...
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2answers
83 views

MATLAB's $\tt dsp.ParametricEQFilter$ bandwidth question

Consider the following code: ...
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0answers
55 views

Applications for adaptive and non adaptive histogram equalization

I have a question regarding histogram equalization and adaptive histogram equalization. In which circumstance would it be preferable to use adaptive histogram equalization over histogram equalization ...
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1answer
211 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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0answers
136 views

Speaker equalization for white noise

I need a speaker to play broadband white noise for my scientific application. I would like to know whether my relative naive implementation is correct or not. The speakers I use have a large frequency ...
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1answer
213 views

Entropy of enhanced image more than the original image

It is said that the entropy of an image is the information that it contains. Let us assume, that the entropy of an image f(x,y) is ...
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2answers
73 views

Besides computational costs, is filtering, decimating, then filtering different from just filtering?

Background: I have a variety of BPSK which uses a raised cosine transmitted pulse shape: $$ h(t) = {1 \over 2}\, (1+\cos(\pi t))\, \Pi(t/2) $$ After matched filtering in the receiver, the end result ...
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0answers
153 views

SNR for channel after equalization

Suppose I have a channel described by $h[n]$ or $H(z)$ over which I send a simple PAM2 signal. After the channel AWGN is added. What is the best possible SNR with equalization? As suggested in the ...
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1answer
90 views

Determining pulse shape for Viterbi Equalization

I believe I understand well enough how the Viterbi algorithm can reverse the effects of ISI when the combined impulse response (transmit filter, multipath, receive filter) is known. I've read How I ...
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1answer
269 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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2answers
252 views

Magnetometer coil equalization

I have a search coil magnetometer with two coils, one at each end of a ferromagnetic core of high magnetic permeability: Figure 1. Double search coil magnetometer. (Modified from a drawing CC BY-SA 3....
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1answer
186 views

Two-sided impulse response and its inverse in real life

Dear StackExchange gurus, I would like to pose this question from a practical standpoint rather than a theoretical one, although perhaps some context in the latter might come useful. Real-life ...
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1answer
119 views

Constant modulus algorithm - performance poor?

The question is based on a research article titled, "Novel Robust Blind Equalizer for QAM Signals Using Iterative Weighted-Least-Mean-Square Algorithm" The Authors have proposed an equalization ...
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1answer
419 views

Zigbee Transceiver Using OQPSK Modulation under Fading Channels

I am working on transmitting ECG signal over wireless body area networks. According to IEEE802.15.4 standards , I am using ZigBee transceiver at 2.4 GHZ . Complex baseband equivalent channel model is ...
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1answer
444 views

What Is the Difference between RLS, LMS and Wiener Filter? When Is One Preferred Over Another?

I'm dealing with a channel equalization problem where the channel is modeled as a WSS process. I understand LMS utilises a Wiener-like approach, ie it converges to the optimal (wiener) solution. I ...
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1answer
285 views

Fequency Domain Oversampling - decimating when going back to time domain

I'm currently trying to simulate Frequency Domain Equalization, and the effect that over sampling in the frequency domain has on the affect of the equalization. If I understand things correctly this ...
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1answer
78 views

spectral factorization method

So I'm trying to figure out a method to do spectral factorization, where we take some function $X(D) = (1+cD)(1+cD^{-1})$. I believe this is used in equaliation I can do this if I just plugging in ...
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0answers
57 views

Help me out in finding the problem in my given MATLAB code of Rectangular Contour Algorithm(RCA)

I am implementing the Rectangular Contour Algorithm (RCA) used for blind channel equalization on 32 Rectangular QAM Signal, polluted with noise and channel effects. It is described in: Khan Q. - ...
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2answers
581 views

CMA Equaliser and FSK

I'm looking into equalisation for FSK over HF channels for Digital Voice applications. As a starting point, I am trying to understand the CMA algorithm. I found a nice CMA Matlab example for BPSK in ...
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1answer
96 views

How to equalize an ISI channel when the transmitted symbols are unknown?

I am using MATLAB to simulate transmission of binary data sequence, $\mathbf{x}={x_k\in\{+1,-1\}\forall 0\leq k\leq N}$, over an ISI channel whose impulse response $\mathbf{h}=[h_0 h_1 \cdots h_{\mu}]$...
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1answer
209 views

Conceptual Question on equalization technique in rayleigh fading channel based on a paper

Question Link http://www.raymaps.com/index.php/theoretical-ber-of-m-qam-in-rayleigh-fading/ gives theoretical expressions for BER in Rayleigh fading channel. Can I use the expression for 64-QAM in ...
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1answer
76 views

When and how can multiple EQ filters be merged into one?

As I understand it, it should be possible to merge similar filters, e.g. if I have two shelving filters with the same Q and frequency but different gains, I can just merge them into one by adding the ...
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2answers
134 views

Equalizing frequency response in software

I'm playing audio through a speaker which I know to have a non-flat frequency response, with particularly poor response in the low ($<1\textrm{ kHz}$) ranges. My plan to get around this problem is ...
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2answers
1k views

Equalize Speaker using Frequency Response Curve

I have a speaker for which I know the frequency response curve (-5dB at 600Hz, -3dB at 700Hz, ... +5dB at 10kHz). This response curve is not as flat as I would like, and so I want to write a script ...