Questions tagged [noise]
In signal processing noise can be considered random unwanted data without meaning.
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Related to Additive white Gaussian noise (AWGN)
In my research work regarding wireless communication, I came across many research papers wherein AWGN is assumed to be modelled as "complex Gaussian with zero mean and unit variance".
I ...
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Removing multiplicative noise (signal) in FFT
I've read up a little here on how to deal with multiplicative noise vs additive noise, with the most simple approach to take the logarithm of the signal to remove the noise. I'm wondering how this ...
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Imitate noise audio file with math function
Is it possible to reverse engineer a short white noise audio file and imitate it with a function instead?
The file doesn't contain pure white noise, there has been EQ applied to it, also some ...
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Removing fixed phase offset noise
This feels like a real basic question but I'm struggling to find a clear answer.
I have PSK signal that subjected to a fixed phase shift noise, introduced between the transmitter and receiver - so the ...
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How to understand "independent sample rate" of windows?
A window metric called independent sample rate is given in a book that I recently read. It says that in spectral estimation, the variance of power-level estimates is inversely proportional to the ...
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Thresholding algorithm for separating skin from clothes in python
I have an several images that look like the following:
I would like to separate the skin from the trousers here without specifically training a segmentation model. Can anyone suggest any such ...
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I need help deciphering an audio file .mp3 file to get an answer. From a game
I was given a .mp3 audio file needed to be deciphered however I don't know how.
I found the spectrogram which outlines the words "youtube", so I suspect the final answer might have a youtube ...
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Kalman Filter - Gaussian representation
I'm trying to understand well the kalman filter, as a result i'm having this question :
Why do we represent noise with a Gaussian ? what does this really mean intuitively ?
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Estimate Image power spectrum of the noise
I want to implement Wiener filter. I have original image and image blurred with linear motion. The one thing I am lack of(to implement it) is Noise power spectrum.
I know that it is hard task. I've ...
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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 ...
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Modelling MEMS accelerometer noise
I am trying to compare two MEMS accelerometers in terms of their noise for ground motion monitoring applications. I would like to take some "clean" data (recorded by good quality ...
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Noise on microscopy data
I have to analyze beating cardiomyocytes. In order to do so, I have written a Matlab script to replicate the method found in Béland et al., Front. Physiol. (2022) (doi: doi.org/10.3389/fphys.2022....
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Allan deviation correct with one-side noise but wrog with two-side noise. Why?
I'm developing a Simulink model for noise according to the description of the algorithm of Accelerometer in this page: IMU simulation model.
My system takes the RandomWalk (defined in [unit], being ...
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Smoothening Noisy FFT
I've got the following FFT with a sampling frequency of 192 kHz that has around 17.000.000 samples. The signal is a hiss of escaping gas. This looks noisy and i want to determine the characteristic &...
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Periodogram Formula for sampling noise
The formula I know for the periodogram is
$$I\left(f\right)=\frac{1}{NT}\sum_{n=0}^{N-1}\left|x\left[n\right]\exp\left(-2\pi fjnT\right)\right|^2$$
but for this one question I have which states that $...
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Frequency content of a noisy signal
To find the frequency content of a noisy signal (PSD), there are two methods below:
#1 Take the fourier transform of its power signal (square the noisy signal)
#2 Find the autocorrelation function of ...
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Noise reduction for 2D advection scheme
I am modelling the path of a rock deposited onto a glacier and its englacial flow with the ice within the glacier in MATLAB. I am doing this with the 2D advection equation. However, I do get some ...
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How to detect faint, dense grains on an image?
I have a bunch of images similar to the following:
As you can see, there are faint grains in a roughly ellipse-shaped area, along with a few bright ones. I need to identify the location and density ...
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What's the distribution of the DFT of a real-valued, zero-mean, normally distributed random vector?
Suppose $X$ is a real-valued N-dimensional Gaussian vector, $X \sim \mathcal{N}(\mathbf{0}, C_X)$. The discrete Fourier transform can be obtained by left-multiplying with the unitary DFT matrix, i.e. $...
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Proper audio noise and artifact detection approach
I'm working on developing an audio device testing suite (for speakers and like). I'm looking for approaches to detecting two types of noise: static such as white or pink noise and artifacts such as ...
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Can white noise be correlated to a random signal
For an random signal $X$ (does not matter if it is correlated or uncorrelated), given lag $τ$. If white noise is added to this signal, then can the summation of them be a correlated signal? Also, even ...
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Help figuring out how to extract audio content correctly from a file that produces spiky waveform with audible hiss/noise
I'm trying to extract PCM wave sequences from different files (files that are NOT audio files but contain audio data, and other data all in one file), and while this code does extract the expected ...
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Determine Noise Level by Convolving N Signals
I using a microphone to determine (air) leakage characteristics. The signals need to be filtered to reduce the noise level and i thought of using the Spectral Subtraction Technique. Since im having 4 ...
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Extracting transfer function from output measurement
Let's say I am generating pure sine oscillations with a laboratory instrument on which vibration frequency and amplitude are tunable (there are uncertainties +/- 1 % with my inputs), and I get my ...
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How to convert the phase noise spectrum density to frequency spectrum density?
Following the answer in this post: Phase noise and frequency noise relationship, I can calculate the phase noise spectrum density with the unit from $\frac{dB_{c}}{Hz}$ to $\frac{rad}{\sqrt{Hz}}$. ...
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Extract a signal from noise, so I can view noise spectrum only?
I have a perfect modulated signal.
I have the same signal but with noise, this noise is from non linear amplification.
Is it possible, to extract the clean signal so it's just leaving the noise? The ...
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PSNR decreases while denoising
I currently am trying to portray PSNR's ability to measure noise in an image. The PSNR is said to be high (around 40 dB) if there is a low amount of noise in the 2D signal.
In my experiment I have ...
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Noise color in multidimensional frequency space - is there an angular effect or dependence?
I understand that if there is a non-constant level of noise in one-dimensional frequency space, e.g. noise variance increasing linearly with frequency gives "blue noise" in the iFFT space. ...
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DSM Model Not Producing Expected Noise Shaping
I am trying to design a 2nd Order CIFB DSM ADC on Simulink based off the values I have extracted from Richard Schreier's Delta Sigma Modulation Toolbox. However, when I ran the model according to the ...
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Noise only from TDM input from ICS-52000 MEMS mics on board NotWired NW-AUD-ICS52000
If this is not the right StackExchange group, please advice.
I seem to have the same problem as 1 (2019, on the miniDSP forum, unanswered) with the NotWired NW-AUD-ICS52000 boards. I have had no other ...
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AWGN model of Quantization Noise
[Edit answer moved from OP edit to "Answers" as per comment suggestion]
I'm trying to create a simple model of a signal chain (image sensor) that includes an ADC but I'm failing to observe ...
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How to calculate The Signal-to-Noise Ratio (SNR) in dB (different units)?
Recently, I've ventured into a new domain that I intend to incorporate into my work. After thorough research and consultation, I've found this model to calculate the data transmission rate (Capacity).
...
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Difference between ADC dynamic range and voltage resolution?
Say I have a 10-bit SAR ADC with a $5 \ \text{V}$ reference. I calculate its resolution to be
$$\Delta V_\text{lsb} = \frac{5 \ \text{V}}{2^{10}} = 4.88 \ \text{mV} \approx 5 \ \text{mV}. $$
So for a $...
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Time-varying shot noise generation
I'd like to model the behavior of photodiodes, the input is like data bits (0 & 1) where each bit is represented maybe with 100 samples / bit and the bit rate is $B$ bits/sec with period $T_{bit}=\...
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Pop sounds at intersection of overlapping envelopes
I am currently dabbeling with programming a real-time audio software and I already got a simple pipeline where notes can be played and released and each note has its own envelope so that the amplitude ...
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Generating time-domain noise from PSD
I have a question regarding generating a time-domain noise from the power spectral density (PSD), this was addressed in this question (How to generate time-series from a given one-sided PSD?) but I ...
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How to determine Transmission Rate for Task Offloading in edge computing?
I am new to communication systems and am working on a model for task offloading on edge computing. One key parameter I'm aiming to determine is the data transmission rate. While I am familiar with ...
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Noise spectral density and windowing
I am wondering about the definition of Power Spectral Density, in the context of measuring noise, i.e., Johnson-Nyquist (thermal) noise.
Usually a windowing method, like Welch's method, is used to ...
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What am i doing wrong?
How do I remove the noise (long vertical lines) from signal? I am applying AC voltage via function generator which is amplified by the power amplifier to a 6mm thick steel specimen. The signals are ...
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Power spectral density convergence for finite samples
Suppose a sequence $\{a_k\}_{k=0}^{\infty}$ has power spectral density
$$
S_{\mathbf{a}}(f) := \lim_{n\to \infty}\mathbb{E}\left[\frac{1}{f_0 n}\left| \sum_{k=0}^{n-1} 2\pi f_0 a_k \exp(-2\pi ikf/f_0) ...
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Weird Pattern in the Power Spectrum diagram (i.e. the frequency domain of the signal)
I am quite a newbie to signal processing. I convert the time-domain signal to the frequency domain with the automated power-spectrum generator in the matlab app. The frequency domain has this ...
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Audio Classification
Most of the paper about audio classification has worked like this they have specific sounds class wise and the did classification. What if the audio files i have collected have two different sounds at ...
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How Does the RMS of White Noise Change with Sampling Frequency?
There is an analog system which includes the continuous-time linear equalizer (CTLE). With some .noise analysis the power-spectral density (PSD) of the noise in that system is provided. So let's not ...
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PLL in noise-free and noisy channels
I'm trying to evaluate the performance of PLL in compensating the phase noise in the absence and presence of AWGN noise, and the counterintuitive result I consistently get is that PLL performs better ...
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removing spikes from spectrum
I am working on 50 samples obtained from time domain signal by FFT. It appears at certain frequencies which are -- according to our experimentalist -- due to some issues with their oscilloscope. What ...
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Probability distribution of phase of fourier transform of white noise, colored noise (1/f noise in particular)--- Definitions and standards
What is the probability distribution of phase of fourier transform of white noise and colored noise (1/f noise in particular) ? Is there a standardised definition?
Often, the colored noise is derived ...
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How to determine the CRLB for FFT based estimator with MATLAB?
I am trying to determine the CRLB for FFT-based frequency estimation in MATLAB. For this, I am simulating a single sinusoid in white noise with different amplitudes and constant noise power. Here is ...
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noise synthesis arbitrary PSD
I have noise measurements for a circuit, in units of noise power (measured in Watts against a known load), per frequency bin.
For simulation purposes, I wish to synthesize noise with the same spectral ...
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Correlated phase noise
I am trying to find a mathematical model to understand the correlated phase noise.
Here, I see the reference phase noise is almost the same after up-conversion and then down-conversion. How does ...
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Will a DC offset drift create any noise?
Transducers have a certain DC offset and it can drift relatively quickly. After a high-pass filter is used (say 0.1 Hz) will there be any noise in the frequency bands of interest (eg. 30Hz-200Hz) ...
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