Questions tagged [noise]

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

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28 views

Channel noise - A misnomer?

I was discussing with a colleague with background in communication about white Gaussian (WG) channel noise. He said noise is not added by the channel and it's just a misnomer. Noise, which is thermal ...
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1answer
30 views

Fourier transform of a noisy signal

Let's suppose i have a sensor that measures the output of a process and this cause a not negligible noise that affects my signal. My goal is to analyze the process signal in order to find faults. How ...
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27 views

lock in detection based denoising using matlab?

What are the limitations of implementing the lock in detection technique in matlab? I have time varying data with known frequency with huge background noise. The reference signal is also available. ...
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31 views

Information entropy of Poisson noise

I would like to calculate the information entropy of the channel with additive Poisson noise. The model consists of an input signal, an optical image, an image acquisition device, and the output ...
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17 views

Filtering noise from periodic time series

Apologies if this is answered elsewhere, but I'm not a signal processing expert and am probably not using the right words to describe my problem or search for answers. I'm tracking people's feet ...
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1answer
155 views

Does mixing brown noise and white noise create pink noise?

What happens if you take a white noise generator, run it through a one-pole LPF set to a low cutoff frequency, and then mix the two together? Do you get pink noise? Say you have this code: ...
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1answer
27 views

Normalizing white noise to match pink noise's amplitude at a given frequency?

I have a pinking filter which I am running white noise through to get pink noise. I would like to then mix the white noise with this pink noise, where the amplitude of the white noise will match the ...
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1answer
46 views

Difference between “scaled white noise ” vs. “unscaled white noise”

I have been searching Matlab user-guide for Wavelets. In their graphical user interface for denoising, there is an option for "unscaled white noise" and "scaled white noise" for the noise structure. ...
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1answer
31 views

What is the type of each 4 different noise signals that are shown below?

Dear signal processing experts, I am looking at four different noise signals.I got them in a time domain and they are different. I went to the frequency domain and found the fft for all four signals....
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1answer
70 views

Positive slope of BER with a greater frequency deviation?

I am trying to implement a frequency-modulated communication channel on MatLab. However, there is something I don't understand about the sensitivity of the frequency modulator (or the frequency ...
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1answer
35 views

Adding White Gaussian noise to a voice signal

I'm trying to add White Gaussian Noise to an audio file. However; the energy of the noise should be 1/10th of that of the signal. My first attempt is as following: ...
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1answer
27 views

SNR estimation prior to demodulation?

What are the standard ways to measure SNR, particularly before demodulation/synchronization?
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1answer
34 views

Auto-correlation of C/A code with 30dB noise

I've a C# program that generates a GPS C/A code consisting of -1s and +1s. Auto correlating the code with rotated versions of itself shows that the peak is 1023 and the next maximum value is 63 which ...
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2answers
36 views

Transforming digitized noisy signal before applying cross-correlation

I'm trying to grasp the concept of cross-correlation as it applies to CDMA in the GPS C/A signal where noise is involved and the SNR is low. My understanding is that before calculating the cross-...
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1answer
30 views

Adding Poisson noise to a time series signal

I'm working on a radiation detection problem. I have simulated some measurement count data and want to add an amount of Poisson background noise to achieve a certain SNR. Radiation count measurement (...
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27 views

Minimum statistics noise estimate - how to calculate the underestimation factor?

I have implemented a basic noise estimator using the minimum statistics method. Noise power estimate is obtained as a minimum of the short time power estimate within a window of subband power samples. ...
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29 views

FFT response for noisy signal, averaging the response and

I try to analyze a system's state with acceleration sensors by measuring the frequencies and amplitudes. Since a cheap sensor is used, I have a noisy signal in the beginning (up to 40Hz - see below). ...
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1answer
32 views

How to measure the “correctness” of a pink noise generator?

I've implemented a pink noise generator for audio applications. How can I measure how close of an ideal pink noise is my output? I do not have access to Matlab or Mathematica. I would prefer a ...
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2answers
67 views

Understanding Voss-McCartney pink noise generation algorithm

I'm implementing the Voss-McCartney pink noise generation algorithm. If you follow the link above, you can read: from James McCartney 2 Sep 1999 21:00:30 -0600: The top end of the ...
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1answer
65 views

Variance of a signal

How to calculate the variance of noise samples modeled as follows: $n_a(t)$ is a Gaussian zero-mean white noise process with (two-sided) power spectral density $\frac{N_0}{2}$. $n_a(t)$ is passed ...
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20 views

Randomly Generate Synthetic Noise in an Image Text Document

I'm working on denoising dirty image document. I want to create a dataset wherein synthetic noise will be added to simulate real-world, messy artifacts. Simulated dirt may include coffee stains, faded ...
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1answer
29 views

How exactly is analog Signal to Noise Ration (SNR) defined?

Say, my ADC reads noise signal only, not sure how to define a threshold. Let's say my noise is sitting at 0V (zero mean), oscillating between +5 mV to -5 mV, so Vnoise = 10 mVpp. I'm looking for 20 dB ...
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14 views

How can I cluster signales by their different noise patterns?

Given be a set of signals (e.g. images) coming from one or more sources (e.g. different types of cameras) is it possible to find out, which signals come from which source? I consider this question ...
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1answer
54 views

Amplitude estimation of sinusoid in known spiky spectral noise

What is the "best" way to estimate amplitude of a known-frequency sinusoid in the presence of known spiky spectral noise (i.e. noise comprising a few spectral peaks at known frequencies)? By "best", ...
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1answer
48 views

How to describe correlated noise after the signal is oversampled?

The Gaussian noise in discrete signal models is usually assumed to be independent and identically distributed variables (i.i.d.). Does this mean that the signal must be sampled with the sampling rate ...
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24 views

Is fundamental frequency information present in speech-shaped white noise?

I am using a so-called speech-shaped stationary white noise, which means so much as a white noise that has been filtered to match the long-term spectrum of a female speaker. The way it was generated ...
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18 views

Alone MFCC can identify difference between sound?

I am doing a project to identify different drum beats. There are lots of features like MFCC, Chroma Values, Spectral Bandwidth, Spectral Centroid, Zero Crossing Rate, etc. But most of the projects are ...
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21 views

how to reduce signal noises

I am trying generate guided waves on simple metallic plate through piezo-ceramic material, I place two piezo on the surface of the plate at the different location and through Arbitrary pulse generator,...
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16 views

Is there a way to filter out low volume content in an audio sample?

Imagine you are listening to a digital file that contains some random speech. Now, while you are listening to it, you also hear in the background (spatially) some low volume content, either noise, ...
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1answer
61 views

Reduce noise of sensor by combining two

I've had the basics of signal in university but little real-life practice. I've got an acceleration sensor with a digital output signal (signed 16 bit value). This signal is a little noisy. The ...
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1answer
119 views

How to filter a white noise or random noise in Matlab Simulink?

I am working on a sun-synchronous satellite Simulink model wich determines its attitude from a Sun sensor and a star sensor whom measure the sun and star direction in the satellite body reference ...
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1answer
130 views

Problem converting from Eb/N0 to SNR

I'm doubtful about which of these is correct: $\frac{E_b}{N_0}=\frac{SNR}{k}\frac{T_{symbol}}{2T_{sampling}}=\frac{SNR}{k}\frac{L}{2}$ $\frac{E_b}{N_0}=\frac{SNR}{k}\frac{T_{symbol}}{T_{sampling}}=\...
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0answers
11 views

Effect of filtering on Energy of a Digital Signal

I am trying to detect (not remove) noise from the digital signal to get meaningful information out of it. The signal I need is in the frequency range of 0.1 Hz to 10 Hz. Anything beyond this is just ...
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2answers
57 views

Idea for Noise Level Estimation / Automatic Thresholding in the Presence of Peaks

I have the fft of some signal, and want a rough estimate of the noise level in order to choose an appropriate threshold for our peak detection algorithm. In general, the fft contains mostly noise with ...
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10 views

Local noise intensity in an image

Noise can be assessed in uniform regions of an image, by subtracting a lowpass-filtered version of it. Then from the histogram of intensities, a global measure can be obtained (such as the average ...
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4answers
835 views

Noise reduction using multiple recordings of the same signal

I have two (audio) recordings of one analog signal, I used two separate devices (smart-phones) recording from two different locations. Each recording device is pretty crappy, lot's of electrical hum ...
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15 views

how to calculate power spectrum of Gaussian noise from the known variance of it?

can someone explain me the following paragraph, i tried to understand it but i am not getting it exactly, Thank you ! Since you know the variance, you can predict the energy of the noise image, ∑x∑y|...
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24 views

Which filters can I use to remove Poisson Noise from data?

I have a (continuous) function f and a vector v with values of f over an interval of integers as components, v = [f(0), ..., f(n)]. v is affected from Poisson noise such that the components are not ...
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1answer
66 views

Estimate Variance of Additive White Gaussian Noise (AWGN) Given Multiple Realizations with Different Mean

Given $ N $ images of the same scene, where each image is corrupted by additive white Gaussian noise of the same variance $ {\sigma}^{2} $. How can $ {\sigma}^{2} $ be estimated? So we have an Image $...
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14 views

Validating tapping and singing

I have a recording of someone tapping while singing and need to check that this someone is tapping the right rhythm and singing the right notes. My intuition is to detect tapping through amplitude of ...
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0answers
37 views

Measure How Much Pattern Is Present In Signal

I have some pattern signal. This pattern signal will be played in noisy room. Then it will be recorded and processed. I need to show that my processing algorithm improves the signal. My idea is to ...
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0answers
29 views

Determine Gaussian distribution parameters from the signal-to-noise ratio

Is there a straightforward formula for determining the mean and standard deviation of the gaussian distribution followed by noise applied on an image, knowing the signal-to-noise ratio between the ...
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0answers
23 views

How to remove non-periodical high frequency noise from signal in python3?

I am trying to get rid of the noise in my data. You can find the python file and signal.csv here ...
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0answers
17 views

Is splitting single white gaussian noise samples-stream in multiple sample-streams still gaussian noises?

Suppose I have a random generator that generates gaussian distributed samples (mean = 0, variance = sigma) at a rate of 4*N samples per second. I want to generate 4 different streams from this ...
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48 views

AWGN for a specific dBc

I have a square-ware signal with 1V peak-to-peak (alternating between -500 and +500mV, so its absolute value is a constant 500mV) and I would like to add to this an AWGN expressed in dBc ("decibels ...
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77 views

Signal Averaging

Note I also asked this in math stackexchange I was reading a wiki page about signal averaging specifically in the section Signal power for sampled signals. At least at first glance the information ...
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18 views

Adding Symmetric alpha stable noise to channel

I am doing GFDM in underwater acoustic channel with symmetric alpha stable noise. My GFDM signals is in frequency domain. I generate a symmetric alpha stable noise wish to add in to the channel. I am ...
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2answers
111 views

how to remove noise from heart sounds?

i have .wav files acquired through putting android cell phone MIC directly on chest of person.For feature extraction, i have to made them noise free. These recordings were taken in rooms with no noise ...
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1answer
68 views

White noise in range of frequencies [duplicate]

If I have this function: while (true) { frequency = 8000; wave = sin(sampleNumber*2*PI*frequency/sampleRate) sampleNumber++; } it will produce an ...
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29 views

How to reduce noise in plot of velocity calculated from GPS points?

I'm interested to see if it's possible to compute the velocity given only GPS data and so, I calculated the distance between GPS points and computed the velocity by dividing it by the time interval ...