Questions tagged [equalization]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
2 votes
1 answer
198 views

Help in deriving the update rule for equalizer

Considering an FIR system excited by an input $s_n$. If the input is derived from a mapping, and a +1/-1 BPSK signal is derived. Considering the Constant Modulus Algorithm (CMA). The channel is ...
SKM's user avatar
  • 611
2 votes
0 answers
24 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 ...
user43523's user avatar
2 votes
0 answers
153 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 ...
user1113242's user avatar
2 votes
0 answers
151 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 ...
Abdul Rehman's user avatar
1 vote
2 answers
3k views

Making an EQ from cascading filters

I hope this isn't a dublicate . I checked but maybe didn't see everything. Here goes : I've been scratching my head over some EQ related questions. I read a lot of papers but my limited math and ...
Dinaiz's user avatar
  • 373
1 vote
3 answers
530 views

How are the reflections in a quarter wavelength transformer dealt with in signal processing?

I haven't seen this issue ever explicitly discussed. Briefly, reflections cannot be avoided in a quarter wave transformer due to the characteristic impedance not matching the source or the load. In ...
Lewis Kelsey's user avatar
1 vote
1 answer
152 views

The use of LS estimation with Vector OFDM

I work in Vector OFDM, but I had an issue in channel estimation in that scheme. For example, I try to use LS channel estimation but I can't get the performance back. However, in conventional OFDM, I ...
Fatima_Ali's user avatar
1 vote
1 answer
453 views

Adaptive equalization vs inverse of transfer function

I have the following equalization problem as shown in the figure below: Now I can compute the coefficients for my adaptive FIR filter c (dim(c) = N) the following: $\mathbf{c_{opt}} = (\mathbf{H}^T\...
Phobos's user avatar
  • 425
1 vote
1 answer
415 views

Why do the OFDM training (and payload) symbols have silent sub-carriers (aka virtual carriers)?

I am examining an OFDM signal. Training symbol: The first two OFDM symbols are training symbols, they are 2PSK modulated (within the subcarriers). In the first OFDM symbol the $(0+18N)^{\rm th}$ ...
jhegedus's user avatar
  • 247
1 vote
1 answer
6k views

Histogram matching (specification) in Python

I'm trying to implement an algorithm in which I first pad each row of the image with a fixed amount of new pixels in a certain range, apply Gaussian smoothing to the row cumulative histograms in ...
chronosynclastic's user avatar
1 vote
1 answer
61 views

LTE PSS Channel Estimation for coarse SSS Equalization

In LTE the Primary Synchronisation Signal (PSS) can be detected by taking a correlation with the known 3 zadoff chu sequences (roots: 25,29,34). Once the peak has been detected the receiver knows ...
Sonny Wandel's user avatar
1 vote
1 answer
58 views

ISI and RRC basic concepts

I've been studying a kind of "introduction" for a few days now to get to talking about equalizers and ISI, and I would like to know if I have understood the things correctly or if I got ...
KaleM's user avatar
  • 115
1 vote
2 answers
1k views

Equalizing audio under linux / Raspberry Pi

I have an audio streaming receiver written in Python running on a raspberry pi. This receiver writes the streamed audio out to an alsa device, which in turn passes it to an amplifier which is driving ...
Paul Wieland's user avatar
1 vote
1 answer
101 views

The cost function of LS algorithm

I'm trying to understand the derivation of LS algorithm for channel estimation in OFDM. Could anyone explain why do we need complex conj transpose in the below equation?
dcs's user avatar
  • 45
1 vote
1 answer
176 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 ...
FourierFlux's user avatar
1 vote
1 answer
679 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 ...
SKM's user avatar
  • 611
1 vote
2 answers
1k 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....
LenaPark's user avatar
1 vote
1 answer
243 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 ...
gerrgheiser's user avatar
1 vote
1 answer
121 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 $\mathbf{h}=[h_0 h_1 \cdots h_{\mu}]$...
NAASI's user avatar
  • 187
1 vote
1 answer
33 views

Separating an audio file into "N" frequencies

I'm working on an audio visualizer using Blender, and I'm wanting to separate input audio files into their respective frequencies to allow my models to react based on the amplitude at different ...
Devin Gardner's user avatar
1 vote
1 answer
89 views

Equalization with FSK

What are the downsides of using an LMS (or least squares) equalizer with FSK signals? What are the tradeoffs on doing equalization pre-demoduation vs post-demodulation? Most literature I can find ...
BigBrownBear00's user avatar
1 vote
1 answer
137 views

main idea of Adaptive histogram equalization (AHE)

I want to understand the main idea behind AHE and the way for applying it manually with my hands. Wikipedia says: In its simplest form, each pixel is transformed based on the histogram of a square ...
hasanghaforian's user avatar
1 vote
1 answer
475 views

What phase rotation occurs when you take the derivative of an audio signal?

If you take the derivative of an audio signal, it provides a 6 dB/oct upward sloping filter (increasing high frequencies / cutting low frequencies) all the way across the spectrum. What is the result ...
mike's user avatar
  • 523
1 vote
1 answer
99 views

Mathematical expression of Multicarrier frequency equalizer

I have a signal $X$ with length of $N$, multiplied with any unitary matrix, i.e the transpose of DCT matrix as: $x = D' X$ where $D'$ is the transpose of the of DCT matrix. Then let's add $CP$ guard ...
New_student's user avatar
1 vote
1 answer
141 views

Is DFE equalizer always blind or can we use reference signal?

I have made a blind DFE Equalization, I mean decision directed . But I am not sure how to make an implementation based on reference signal known by receiver and emitter. In the back forward filter ...
user avatar
1 vote
1 answer
114 views

How to use matlab toolbox for 2qam dfe equalizer?

I made Channel equalization with matlab, You can find the code below. ...
user avatar
1 vote
1 answer
38 views

Question about image equalization

Let $f$ be an $N \times M$-image and suppose that $g$ is its equalization. Question - Why the equalization does not change the objects, why a car on $f$ does not convert into a bus on $g$?. It is ...
Leox's user avatar
  • 111
1 vote
2 answers
94 views

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

Consider the following code: ...
CyDe's user avatar
  • 23
1 vote
1 answer
454 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 ...
Navdeep's user avatar
  • 265
1 vote
1 answer
477 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 ...
Ria George's user avatar
1 vote
1 answer
534 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 ...
LucrativeSasquatch's user avatar
1 vote
2 answers
6k views

Decibels conversion into amplitude ratio

I want to convert db into amplitude ratio. I did some research but I only found online convertor, and I don't understand what's on Wikipedia very well... Here is a little of backstory : I am a ...
Khaz42's user avatar
  • 55
1 vote
1 answer
3k 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 ...
eduardo.sufan's user avatar
1 vote
0 answers
35 views

decision feedback equalizer building blocks (from Adaptive Filters: Theory and Applications” a book by Behrouz Farhang-Boroujeny)

Here you can see building blocks of DFE from "Adaptive Filters: Theory and Applications” a book by Behrouz Farhang-Boroujeny in chapter 17. Figure 17.9 shows the overall building blocks of DFE ...
Sadeq Ebrahimi's user avatar
1 vote
0 answers
83 views

Channel equalization in uplink

I have a multiuser uplink signal $$ Y=h_1x_1+h_2x_2$$ where, $h_1$ and $h_2$ are channels for user 1 and user2 respectively. At the receiver how can I equalize the signal $Y$, assuming known $h_1$and $...
Digi1's user avatar
  • 161
1 vote
0 answers
152 views

Matching two different type of equalizer responses

AutoEq (by Jaakko Pasanen) is an utility for headphone equalization. I'm trying to make a EQ converter for SuperEQ (source code for implementation found in DeadBeef), which can be found on few ...
Juha P's user avatar
  • 917
1 vote
1 answer
106 views

Fractionally spaced equalizer - LMS algorithm

I am doing a project in MATLAB about the fractionally spaced equalizer. The method that i have chosen to update the tap weight coefficients is the LMS algorithm. Here is the block scheme that i have ...
Obsidian's user avatar
1 vote
0 answers
50 views

fractionally spaced channel equalizer code [closed]

I want to write a program in matlab for an adaptive fractionally spaced equalizer with lms algorithm.consider each packet with 150 bits that 25 first bits are pilot and used to train weights of the ...
Mahtab's user avatar
  • 11
1 vote
1 answer
295 views

All-pass phase compensation only in a specific frequency range

I am trying to design an all-pass filter in order to compensate the phase distortion at the output of an equalizer. To do so, I take the phase vector of the output, compute the real and imaginary part ...
skateskate's user avatar
1 vote
0 answers
197 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 ...
Rokai's user avatar
  • 63
1 vote
0 answers
44 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 (...
pacific's user avatar
  • 11
1 vote
0 answers
295 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 ...
Nicholas's user avatar
  • 121
1 vote
0 answers
471 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 ...
Moses Browne Mwakyanjala's user avatar
1 vote
0 answers
320 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 ...
Naveen's user avatar
  • 418
1 vote
0 answers
76 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 ...
Faizan Zaheer's user avatar
1 vote
0 answers
161 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 ...
user367640's user avatar
1 vote
0 answers
207 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 ...
J. R. C.'s user avatar
  • 111
1 vote
0 answers
498 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 ...
divB's user avatar
  • 473
1 vote
2 answers
3k 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 ...
jon_simon's user avatar
  • 185
1 vote
0 answers
201 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 ...
M. F.'s user avatar
  • 41