Questions tagged [equalization]

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Block CMA algorithm

The Constant Modulus Algorithm is a common equalization method which adapts at every sample in an attempt to give a filter which produces a fixed power output. Divergence/convergence of the CMA ...
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19 views

How to exploit auditory masking to boost intelligibility

I am currently working on a dynamic equalizer to improve a synthesized voice's intelligibility in noisy environments. The current implementation of my algorithm simply applies a parametric EQ to the ...
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1answer
56 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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134 views

Fractional equalizer with non-integer oversampled signal as input

I would like to know how the output sequence from a fractionally spaced equalizer, with a non-integer oversampled input signal, is generated. For example, for $T=T_{sym}/2$, my actual code is ...
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141 views

TDE, OFDE and FDE equalizer simplest exmple in matlab

I want to implement the equalizer in matlab. I am just learning this. I want a good kick start code that can help me to learn it further. I searched a lot on Google but do not find a good reference ...
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62 views

Is MMSE equalizer necessary?

For observation $y$, channel coefficient $h$ and gaussian noise $w \sim \mathcal{CN}(0,\sigma^2)$, $$y = hx + w \tag{1}$$ Note that for OFDM system, (1) is assumed channel input-ouput equation on ...
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25 views

Converting the equalizer coefficients from VSA at 2 sample/Symbol to 1.5 sample/Symbol

I was looking for some feedback on conversion of equalizer/filter coefficients at different sampler rate. Problem Statement: We have built a transmitter system whose output is at 1.5 sample/symbol (...
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198 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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315 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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177 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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59 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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91 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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189 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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301 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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165 views

Instability Problem in Normalized Least Mean Squares (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 ...
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1answer
2k views

DFE for QPSK in MATLAB

I need to do a DFE for QPSK simulation in MATLAB. The system consists of a QPSK signal transmitted with power = 1 which is then pulse shaped with a square raised-cosine filter. Add AWGN and a filter ...
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882 views

Local histogram equalization

I want to learn computer vision and so I downloaded image processing slides from my university archive. I'm on histogram equalization. Learning about local histogram equalization points me out to this ...
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88 views

MATLAB model for equalizer using LMS algorithm adaptive filter and unexpected output curve

The MATLAB code below is for equalizer using lms algorithm adaptive filter and then plotting MSE (Mean Square Error) Vs Iteration numbers ...
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20 views

Compensating for poor illumination across a specific image axis - possible solutions?

A friend of mine is working at an institute for nano-membranes. Currently they are using ImageJ and do a lot of manual (in my opinion inaccurate) work to process some membrane "photos" (...
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8 views

quantification of histogram equalization improvement

My project consist of classification of images using ML. The images are microscopic slices. For the feature extraction phase, I am using multiple filters and got a good result. So I decided to do a ...
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68 views

Zero padding OFDM equalization

In ZP-OFDM, The convolution is linear. it's different from CP-OFDM which is circular convolution leading to have one tap equalizer in frequency domain. if I have a ZP-OFDM system, and we have a signal ...
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24 views

Time Reversal OFDM

I am trying to understand the Time Reversal OFDM where ,According to my opinion, the channel is reversed in time domain at receiver side and then equalized. what I found online is something similar ...
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13 views

chromatic and polarization mode dispersion compensation in electrical dmain

I am currently working on adaptive compensation of chromatic and polarization dispersions in the electric domain using LMS (least squares method) and CMA (constant module algorithm) algorithms. I am ...
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44 views

How to implement Minimum mean-squared error (MMSE) equalization?

I have the channel estimation and noise power estimation and I need a matlab implementation of time domain siso channel Equalization. Theory: Consider the FIR filter of length $N+1:$ $$ \hat{s}_{k}...
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42 views

On the channel estimation based on vector

I have a matrix $X$ of size .i.e $(8,8)$ with $M$ columns and $N$ rows. Suppose I took it's $iFFT$ column wise resulting matrix $x$ of size $(8,8)$ too, $x = F^HX_{(:,m)}, $ ...... (1), where ...
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48 views

How to compute the DFE based MMSE equalizer FF and FB coefficients in a non adaptative way?

I seek your assistance, I am reading the Proakis 5th edition and I came across a paragraph explaining the tuning of DFE filters, i.e, how to compute the FF(FeedForward) and FB (Feedback Filter) ...
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69 views

Clip wav by PSD

I have the following two things. sequence_1: Sound file in the wave format. PSD_1: Some PSD (Power Spectral Density). I want that the PSD(sequence_1) < PSD_1 for all indices. How I think about ...
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87 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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88 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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80 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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100 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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1answer
46 views

MMSE- Channel estimated based - DFE Equalization

For HF ionospheric channels ( frequency range 3 up to 30 MHz), I Want to make channel equalization in time domain, using MMSE criterion. I have to do it using the channel estimation. I have some ...