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

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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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38 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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variance of the product of two samples with awgn

i am multiplying two samples and i want to figure out how to calculate the variance of the results, my statistics & probability knowledge is very rusty so i'd appreciate it if anyone could check ...
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22 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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56 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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20 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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69 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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68 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
10 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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48 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
50 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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22 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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38 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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15 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
58 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
56 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
33 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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40 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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27 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
62 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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36 views

Removing noise from time series with known sigma?

I have an instrument producing time series data with significant noise (the noise is about 3x larger than the signal). Here is an example plot of simulated data and noise (data here): I want to ...
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2answers
89 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
59 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
55 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 ...
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1answer
58 views

Calculating SNR from Frequency-time domain

I tried to analyse the time-frequency of specific appliances. As it shows in the following frequency-time graph I have High frequency noise from different appliances here. 4096 is the number of ...
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1answer
30 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
95 views

Generate Complex White Gaussian Noise in MATLAB

n_3=sqrt(0.1)*randn(1,K); n_4=sqrt(0.1)*randn(1,K); beta_NLoS=(n_3+1i*n_4); % CN(0,0.1) I want to create a $CN(0,0.1)$,does my code have any problem?
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Open Source Synthetic (but Realistic Sounding) Sounds

I have seen a few JavaScript libraries that demonstrate white noise, but that is a pretty basic natural yet synthetic sound, similar to rain. I'm wondering though if there are any "open source" sound ...
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1answer
48 views

Maximum Likelihood Detection of Signal Vectors in Gaussian Noise

Consider a binary-input additive white Gaussian noise channel. Let $\mathbf{x}_0 = (\sqrt{Es},\sqrt{E_s},⋯,\sqrt{E_s})$ and $\mathbf{x}_1 = (-\sqrt{E_s},-\sqrt{E_s},⋯,-\sqrt{E_s})$, be two codewords ...
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1answer
31 views

Detect gradual increase then decrease in slightly noisy data

I have data thats not too noisy and I am trying to detect a pattern where it gradually increases then decreases in a short period of time (20 ticks? it should be roughly similar per session but can ...
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1answer
34 views

Covariance matrix associated with random DC level in Gaussian noise

Given a signal $x[n] = A + w[n]$ where $A$ is a Gaussian random variable and $w[n]$ is Gaussian white noise, then the covariance matrix of the signal is given by $[C(\sigma^2_A)]_{ij}=E[x[i-1]x[j-...
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95 views

How can telecommunication system know which part is signal and which is noise? [closed]

When signal is received how can receiver know which part of received signal is signal and which part is noise??
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Is there noise that is multiplied with the signal? [closed]

In most cases, additive noise is considered. I was asking myself: Is there type of noise when we multiply input with noise? My current approach: Yes! In the case of the mobile communication, we ...
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58 views

Why use $\chi^2$ test to determine the presence of white noise?

I want to test for the presence of broadband noise in a snapshot 1000 complex baseband samples recorded by a software defined radio. As a follow-up to this post, why was the $\chi^2$ test used? How ...
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Simulating Phase Noise: How to do it?

I have a system that I am simulating, and I want to add phase noise to the process. I didn't know how to do it, so I have been conducting an literature review. I found a good reference with an "easy ...
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106 views

What is the noise whitening process?

I came across this process when working on OFDM in wireless communication. It's mentioned if we have two copies of a signal resulted from SIMO system (Single Rx Multiple Tx), we can process the noise ...
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1answer
55 views

Remove multiplied white noise from periodic signal

I need to remove noise that is multiplied to a periodic signal using a maximum of 7 periods having no information about the noise. I have tried to use auto-correlation - abs(ifft(fft(signal.*noise).*...
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1answer
33 views

Best digital noise reduction in optical spectra measurement

I am using an optical spectrometer to measure the reflectance of some surfaces; the output is essentially a set of photodiodes' signals: for each photodiode I have a discrete time signal every $T$. ...
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1answer
64 views

Spectral Subtraction python implementation error

I am trying to implement Spectral subtraction in python. I am new to DSP. I used this article as reference and below code is what I can come up with. Of course I did not get the expected output. I ...
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Backgroun noise in voltage vs time graph

I am analyzing a voltage vs time graph and I am coming across sinusoidal background noise in the cathode. I was wondering what the best method of getting rid of this noise would be on python. So far I ...
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How to add overlapping frames after processing a signal

I have to perform spectral subtraction on a signal in python. I have followed the steps specified in this link http://practicalcryptography.com/miscellaneous/machine-learning/tutorial-spectral-...
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Multiplicative Input-Dependent Noise [closed]

This question might not be exactly suitable to the question format of StackExchange but I couldn't find a better way to put it forward. Lately, I have been dealing with ECG Signal processing and due ...
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1answer
67 views

Linear Predictive coding vs AR modeling

I'm looking for a suitable explanation of the circumstances in which the LPC error polynomial for a discrete time process x[n] is replaceable with an error polynomial categorized under the AR model? I ...
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70 views

Noise removal and speech enhancements

I am working with peak extraction from audio files (something like shazam) in python. I only need to focus on human speech. Audio is recorded from single channel common mic. Can someone help me with ...
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1answer
87 views

Designing an experiment to show blue noise not adding noise below nyquist and not aliasing above

I read this paper from 1983 "Spectral Consequences of Photoreceptor Sampling in the Rhesus Retina". This paper talks about blue noise sampling patterns in the retina and says that: The results (...
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1answer
26 views

What are the most robust implementations of passive/self-localization assuming high noise and reverberation?

I am doing research on a related subject that requires the use of TDOA estimation of two signals in an environment with a great deal of noise and reverberation. If anyone had any expertise on (or ...
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Noise PSD and sampling rate relation

Let's consider generating samples of a random process like white Gaussian noise (AWGN). Let's assume I am generating $N$ samples of AWGN with variance $\sigma ^2$ in MATLAB by using randn() funtion i....
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What kind of noise is city noise?

White, pink, brown...? In general, to what category does it subscribe the spectrum of city noises, like traffic noise, ambulance/police siren, alarms, etc, put together? If the question is too broad, ...
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1answer
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Voice masking for removing voice and not birdsong

First the problem I'm tyring to solve: I'd like to find a way of removing any potential noise from audio files recorded in noisy environments where we are trying to record birdsong. This is for the ...
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2answers
70 views

Power spectrum density and frequency

if i have some random signals (sampling rate = 10Hz, 0.1s per data) Using python library i transformed it to power spectral density power spectral density forms = f, psd (using mlab.psd) I'm really ...