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Questions tagged [noise]

In signal processing noise can be considered random unwanted data without meaning.

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31 views

AWGN interpretation of bit error rate in time domain

I'll consider a 20 MHz bandwidth between 1.99-2.01 GHz. The carrier has been modulated by an OFDM signal (I/Q modulation) and is passed through a narrowband filter at the receiver. The noise that is ...
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17 views

Noise power for decorrelating detector

I have the following setup: $\mathbf{y}=\mathbf{R}\mathbf{s}+\mathbf{w}$, where the details of each entity can be found at http://bard.ece.cornell.edu/downloads/sim_tools/spanc_me/report/node12.html. ...
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20 views

The difference between the variance of white noise and narrow-band noise in Matlab

In Matlab, we can generate noise with zero-mean and unit variance by using "n = randn()". But in fact, the variance is not really equal to 1, but there is a slight error. Assume that the length of ...
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0answers
15 views

How to plot noise shaped spectrum of First order Incremental Sigma Delta ADC's output?

A little background: This question is about viewing the output spectrum of incremental delta sigma modulators (IDSM). IDSM is a subcategory of general delta sigma modulators where the integrators are ...
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2answers
33 views

Noise power and bandwidth

$$N=kTB$$ In this formula for calculating noise power, why do we use the total bandwidth of the system? I mean our signal is at $f_0$ carrier frequency, why is it effected by a large bandwidth and ...
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1answer
34 views

Will noise cancellation with playstation eye improve my spectral analysis?

Im doing some beginners spectral analysis for a homemade reactive RGB LED project and was thinking of ways to improve the accuracy of the audio analysis. Im using a Playstation eye with a Raspberry Pi ...
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26 views

$E(X(t)X(t))=\sigma^2\delta(\tau)$ or $E(X(t)X(t))=\sigma^2$

(Question already asked on Math StackExchange) Let's say we have a white noise process $x(t)$ such that: $E(X(t)X(t+\tau))=N\delta(\tau)$ $E(X(t))=0$ In particular, with $\tau=0$, $E(X(t)X(t))=E(X^...
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what is the statistical corrleation between the velocity and position errors outputed from an alpha beta filter

Attempting to do an error budget for robotic arm of which one component is alpha-beta filter using noisy position measurements. To get the future state the estimated positin and velocity(multiplied ...
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0answers
14 views

Reduce non-uniform 16 bit thermal image (infrarred)

I have a thermal detector that produces 16 bit grayscale images. The detector is 384*288 size. So my problem is that when I have a static scenery, each pixel variates an amount of counts. So if in ...
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1answer
30 views

What do you mean by noise vairance and mean in an image?

I know the sudden variation in the intensity level of an image is termed as noise. But I couldn't understand what do mean and variance of noise in an image refer to? What is the role of noise variance?...
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2answers
89 views

CT corrupted by Poisson noise, weighted least squares, how to calculate in detail

I've trained a convolutional neural network to recognize ellipses. I took random generated ellipses as ground truth images and applied radon and inverse radon transform for the noisy images. Now I ...
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1answer
18 views

Bias instability in Gyroscopes : AVER / ADEV

I am attempting to implement allan variance to determine the amount of bias that is shown in my IMU's gyroscope ( BMI160 ). I am doing this with the following formula, that was captured in the ...
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1answer
35 views

Modulation and Noise

I am fairly new to studying communication systems. When it comes to different digital modulation techniques, does the effect of an additive complex noise (a) introduced by the system, and (b) by the ...
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0answers
33 views

Improving efficiency of the Prony's method

I employ the Prony's method on very complex signal with a relatively high amount of noise (signal-to-noise ratio of approximately 20 dB), predominantly in the high-frequency range (above 5 kHz) while ...
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1answer
36 views

How to interpret Allan Deviation plot for gyroscope?

Regions with different slopes correspond to different types of noises in Allan Deviation plot of a steady gyroscope at steady temperature. My doubts are: What is significance of x axis in this plot, ...
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0answers
36 views

FIR Audio Equalizer Crackling Noise

I've implemented a few FIR filters into a song equalizer, but there seems to be a crackling that I'm unsure how to fix. Heres a video for reference: https://www.youtube.com/watch?v=IlzWRYpv0rk. Noise ...
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1answer
67 views

State of the art algorithms for estimating noise variance

Suppose I have a signal $X[n]= f[n] + W[n]$, where $W$ is uncorrelated Gaussian white noise satisfying $E\{W[n]W[k]\} = \sigma^2 \delta[n-k]$. What are the state-of-the-art algorithms for determining ...
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1answer
32 views

Questions about reproducing results of a paper on Communication Systems and Wireless Communication

I'm trying to reproduce the results of a paper on Device-to-Device Communication, channel assignment and mode selection (G. Yu, L. Xu, D. Feng, R. Yin, G. Y. Li and Y. Jiang, "Joint Mode Selection and ...
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55 views

Input and Output SNR Calculation in AM receiver input and output

For the FOM calculation of an AM receiver, the input and output signal powers are respectively, $$P_{in} = \frac{A_c^2(1 + k_a^2P_m)}{2}$$ $$P_{out} = k_a^2A_c^2P_m$$ These are obtained from the input ...
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0answers
25 views

Why are componets of Complex baseband noise uncorrelated?

Many articles and papers on digital communications use the assumption of an AWGN environment. They write that after the signal is converted to baseband the resulting In-Phase and Quadrature components ...
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0answers
8 views

Imposing constraints in mixture modeling of correlated data?

For 1-D signals (spectra) or 2-D signals (images), is there a way to impose the constraint that the data within a group is uncorrelated? I am iteratively applying background correction model fitted to ...
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0answers
49 views

Band Limited White Noise

How do I create in simulink a true white noise? The block 'Band Limited White Noise' asks for power, step and seed. The power must be choosed accordingly to the step time. As a reverse proof I've ...
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0answers
30 views

Noise Shape Digital Filter

My objective is to build a noise shape filter from a given transfer function (in one case) and from a given PSD (for another case). Checking my precedent questions you can see that this argument is ...
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1answer
39 views

How to add additive noise to an image?

I have the following image I and I want to add additive noise using the array N below. Can you please give me a calculation example of how to achieve this? Do I have to move from image space to ...
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5answers
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Why is random noise assumed to be normally distributed? [duplicate]

From residual in the linear regression to noise in signal processing are assumed to be normally distributed? By considering them as normally distributed we are kind of telling the pattern in the noise ...
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2answers
46 views

Accurate description of the spectrum of sinusoid waveform added with WGN?

The transmitting signal is $$ s(t) = \sin(20\pi t)+\sin(40\pi t)+\sin(60\pi t) $$ The received signal after AWGN channel is $$ r(t) = s(t)+n(t) $$ where the variance of noise $n(t)$ is $\sigma^2$. ...
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1answer
35 views

edge detection of 1-D signals

Would you please introduce me to some methods (or references) to do edge detection on some pulses (rectangular pulses embedded in noise). At first I apply some filters to smooth the signals, then I ...
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0answers
55 views

Why I don't get the right PSD

I need to model a noise with a given PSD. To do this, I am starting from a white gaussian noise (WGN) and feed with the WGN a transfer function, which will act like a filter. In fact,it's easy to ...
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0answers
34 views

Simulating 1D correlated Gaussian noise

I have some sensor which shows a Gaussian error distribution around the true value. I can simulate uncorrelated measurements via a list of RNG samples from a normal distribution with known mean and ...
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0answers
64 views

Noise Shape Filter to obtain a given PSD

I have experimental PSD data of disturbances in terms of acceleration on a mass. My first problem is that these data are presented as $ (m/s^2)/\sqrt(Hz)$ which is not the PSD unit. Those unit should ...
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2answers
102 views

Measuring microphone Signal to Noise ratio (SNR) with A-weighting

Foreword: I have already read Applying A-weighting and user @endolith's A-weighting code I would like to measure the SNR of a microphone with the same method applied by the main manufacturers, that ...
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0answers
60 views

Generation of Noise-shape filter from Power Spectrum Density

This is my very first time in dealing with signal processing, so I am sorry if I will not use a rigorous terminology. I am dealing with some issues about noise modeling in matlab. I'm trying to ...
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0answers
21 views

What is the signal-noise model of laser induced fluorescence?

The following image is an example of a fluorescence signal trace from the photomultiplier tube detector (PMT). Each spike represents one fluorescently labeled cell. This signal model is definitely ...
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2answers
82 views

Modeling the human perception of noise

Add together some sinusoids with irrational or "nearly" irrational frequency ratios, and you get something pseudoperiodic. If there aren't too many, you can hear that it has only pitched components, ...
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1answer
73 views

Why a DFT of two sinusoids is very noisy even with frequency sampling 5 times higher?

I've set up this case to try to understand DFT implementing a real case in Excel Frame Size $\;\color{blue}{(T = 5 \; s})$ Time Sampling $\;\color{blue}{(T_S = 0.1 \; s})$ Block Size $\;\color{blue}{(...
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1answer
18 views

SNR in one-dimensional additive channel with uniform noise and binary antipodal input

A one-dimensional addictive noise channel, $Y=X+N$, has uniform noise distribution $N \sim U(-\frac{L}{2}, \frac{L}{2})$ and binary antipodal input constellation with equally likely input values $x=\...
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2answers
57 views

Why is distorted / quantized white noise still white noise?

White noise can be created by setting every sample in the time domain to a random number with a gaussian distribution. Every sample is random, so the frequency response is obviously random. Easy ...
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1answer
63 views

What's the expression of the noise for a RF signal?

I am confused about how to give the expression of noise. Can someone tell me if my equations are correct? If the received RF signal is expressed as: where If I want to add a AWGN, can I give the ...
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0answers
26 views

Detection of interesting structure in images?

I'm looking for methods of computing some measure of structure in an image. (I do not have a rigorous definition of "structure" though........) Consider the 15 image blocks below: Suppose for each ...
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1answer
47 views

Fluctuation of autocorrelation of a signal due to signal's noise

I have a question about the fluctuation of autocorrelation of a signal due to signal's noise. I have a signal defined in $-1\leq t \leq 1$ as the following: $V(t)=kt+R(t)$, where $R(t)$ is the random ...
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1answer
26 views

Filter for denoising a signals using a known (noisy) derivative of that signal

I have a signal and it's derivative simultaneously measured, both including additive noise. The measurement is completed before the analysis, so it can be looked ahead. Now I want to reconstruct a ...
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2answers
109 views

How the white and colored noise differ in time domain

I know the white noise is uncorrelated. So a perfectly white signal has an autocorrelation equal to an impulse at zero. This implies that the corresponding signal in the time domain is any function ...
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1answer
72 views

Are two jointly stationary white noise processes independent?

I am currently dealing with a problem concerning beamforming, where two "jointly stationary zero-mean white noise processes" form the input of an adaptive system. One of those processes resembles the ...
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1answer
55 views

How does harmonic distortion occur in ADCs?

We are currently testing an ADC at my workplace and the Total Harmonic Distortion is an important spec. It got me to thinking as to how it occurs in the first place 1) Can there be harmonic ...
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0answers
46 views

What would be an appropriate method to filter the noise from the following data?

I have a paralleled potentiometer and capacitor connected to the digital pin of a micro controller. I am using the micro controller to discharge the cap and then measure the time it takes for it to ...
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0answers
55 views

Accounting for Mechanical Vibration in Accelerometer Readings

I am very new to DSP so please forgive any ignorance within this post. I am working on a device which has a 6-axis IMU measuring acceleration and rotation. The device itself is attached to a ...
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1answer
69 views

What is the name of this very simple spectral subtraction technique?

Let $S = X + N$ be the sum of two audio signals $X$ and $N$ which are both stationnary (let's think X is a constant volume 440 Hz sinusoid and N is constant volume noise). If the sum S has a -20 dB ...
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2answers
148 views

Properties of Up- and Downsampling

Given a gaussian white noise with mean 0 and $\sigma = 1$. I'm interested in the PSD (power spectral density), when the signal is plain up- or downsampled. No interpolation, no filtering nothing. ...
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3answers
69 views

Using white noise to test filter freq. response?

If I want to test a digital filter, is using white noise a good way? I mean input white noise to the filter, and visualize the frequency out from the output. Is that procedure the same as testing a ...
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2answers
62 views

Calculating a NRR of an IIR

I'd like to calculate the Noise Reduction Ratio of a system. The system I have is $$ H(z)= \frac{z^{-5}}{1-0.1z^-1}.$$ For FIR Filters this can easily done by $$ \sum h[n].$$ For an IIR Filter this ...