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Search options not deleted user 5119

This tag means the asker is new to the DSP field and is requesting extra guidance. It has similar connotations to the homework tag, but this lets potential answerers know they should probably do more than guide the self-studier compared with the homework requester.

0 votes
1 answer
257 views

Beginner level confusion regarding symbols used in modulation

For 4-QAM symbol sequence, each symbol can be represented by $k=\log_2(4) = 2$ bits. 4-QAM constellation can be generated using s = round(rand(1,T)*2 -1) For 16-QAM, the symbol sequence takes 4 ampli …
Srishti M's user avatar
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0 votes
1 answer
332 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 schem …
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4 votes
1 answer
4k views

Design of equalizer for wireless communication

I am having difficulty in trying to understand the working mechanism of an equalizer. Please correct me where wrong. Mechanism of an Equalizer - The purpose of an equalizer is to reduce intersymbol …
Srishti M's user avatar
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0 votes
1 answer
78 views

Is there a rule of thumb for selecting the variance of the input?

Considering an estimation problem, where I want to estimate the unknown input $x$ using the known channel parameters. This estimation problem can be solved by Least Squares. Thus, the model is $$\hat …
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0 votes
1 answer
104 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 ch …
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1 vote
1 answer
229 views

Performance of adaptive filters

Can somebody please provide an intuitive answer or reference for the following questions? Q1: Dependence of estimation performance on number of data points -- I could not find any information whether …
Srishti M's user avatar
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2 votes
1 answer
149 views

How to represent the nonlinear model as a state space in Unscented Kalman Filter

There is an Autoregressive model of order 1 (AR(1)) that is excited by a non-linear signal as the input: $$x_t = \rho x_{t-1} + u_t \tag{1}$$ The time series $u_t$ is generated from a nonlinear map, $ …
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  • 616
0 votes
1 answer
591 views

Proper method for generating Channel coefficients in MATLAB

I am trying to estimate the coefficients of a Moving average model using popular estimation method such as Least Squares (LS). For educational purposes, I am trying to see if LS can work well when the …
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1 vote
0 answers
324 views

What is the difference between entropy and entropy rate and which one is important in inform... [duplicate]

By entropy I understand the uncertainty or randomness. But if the uncertainty is high then what is its implication and advantage in transmitting information or as an information source or is high entr …
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3 votes
2 answers
153 views

Why use parametric based estimation methods - confusion regarding terms

Using the probability density function (pdf) we can estimate an unknown parameter using methods such as Maximum Likelihood estimation. If the pdf is not available, then Least Squares can be used. Oth …
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1 vote
1 answer
1k 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 sha …
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2 votes
1 answer
710 views

Concepts: Ideal and Non Ideal Channel Resulting in Inter Symbol Interference

I am following the book: Blind equalization and Identification by Zhi Ding and Ye Li. In Chapter 2, the concept of T spaced equalizers is presented. It is mentioned that the output of the channel is $ …
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1 vote
1 answer
256 views

Doubts and some confusion on variance for complex rv

This question is in continuation of the one asked here. Let's say that the measurement noise $w$ or any random variable is circularly Gaussian complex. If the imaginary and real components each ha …
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1 vote
1 answer
140 views

Notations to Use in Formulating of Maximum Likelihood Estimation

The received noisy signal $y_n \in \mathbb{R}$ is expressed as: \begin{align} y_n = \mathbf{h}^\mathsf{T}\mathbf{u}_n + w_n. \tag{1} \end{align} $\mathbf{h} = [h_0,h_1,\ldots,h_{p-1}]^\mathsf{T} \in …
Srishti M's user avatar
  • 616
4 votes
1 answer
268 views

Relationship between information retrieval and source separation in signal processing

In machine learning, for the task of classifying input data (called an example) which are in binary representation, $\mathbf{x}\in \mathbb{R}^D$, $\mathbf{x} \in \{0,1\}^D$ into its multiple class lab …
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