Questions tagged [noise]

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

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18 views

AWGN noise variance in upsampled BPSK signal

When I simulate BER for basic PSK schemes, I set the IQ complex noise variance to $\sigma^{2} = \frac{E_{s}}{2*R_{m}*R_{c}}*\left( \frac{Eb}{No}\right)^{-1}$ where $E_{s}$ = Energy per modulated ...
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46 views

How this convolution integral is solved to obtain autocorrelation function of current for shot noise?

I am studying shot noise characteristics from this source: Here the author writes that autocorrelation function is given by: $$R_I(\tau)=\bar{h}*h*R_Z(\tau)$$ where $R_Z(\tau)=q^2(\lambda^2+\lambda \...
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Calculating threshold in white noise for multiple pulses

I want to calculate the threshold for a given probability of false alarm (PFA) in a system, in which the noise is given by a coherent summation of three white Gaussian noise signals. Of course, there ...
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35 views

Remove Noise from Discrete Signal with given Noise Model

I am interested in finding the true signal $p \in \mathbb{R}^D$ of an observed discrete signal $t \in \mathbb{Z}_{+}^D$. I know that each observed $t_{i}$ with $1 \leq i \leq D$ is the result of a ...
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116 views

The power of signal processing when faced with hardware constraints

I am currently studying interferometry, but I have only just begun studying signal processing. I want to better understand the effect signal processing can have in maximising signal detection from ...
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32 views

Classification of very noisy EMG signals

I'm an absolutely newbie to signal processing. I'm trying to classify EMG signals which are very noisy (decibel values are more than -70 dB in some cases). After applying EMD technique these values ...
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1answer
57 views

How to extract noise from a signal in order to get both noise power and signal power

I have to implement a function to get an accurate SNR value. For that, I would need a separate noise signal to get the signal power and noise power but I have only one noisy signal (a .wav file.) ...
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33 views

How to Remove Temporal and Fixed Pattern Noise and Apply Tone Mapping?

I have a video, whose frames I have extracted and require to work with. 16 bits and grayscale images. My task is to improve the quality of the images, by removing the noise + adding tone mapping and ...
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38 views

Change spectrum and normalization

I have a question about magnitude of a spectrum. My task is to build the spectrum and make IFFT - the result waveform should have unity amplitude. For example: Create 2 arrays with Magnitudes and ...
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26 views

Noise Removal and Signal Decomposition

I am quite new to DSP but its tools are required for my current project. I need advice on how to approach certain issues. I have multiple experimental datasets, which can be split in to three ...
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48 views

How to write a complex symmetric gaussian signal [closed]

In my work I need to use this signal of complex symmetric gaussian noise signal represented as $w$. But I don't know exactly how to represent it
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41 views

Given a noise power spectral density, how long does it take for the underlying process to deviate by a given amount?

Assume we are given a noise power spectral density $S(f)$ for a stochastic process $x(t)$. What can be said about how long it takes for the underlying stochastic process to deviate by a given amount $...
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51 views

What is the meaning of magnitude of the noise power spectral density?

Say we have a noise power spectral density that has the following form (I think the question is the same for more general forms as well) $$ S(f) = Af^\alpha, $$ In experiments people usually discuss ...
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Dividing two non-noisy signals by each other increases noise

I am doing some signal processing on spectrum data. A methodology I am following requires a ratio of a measured signal S and a reference signal R. Both of these signals are quite clean but since both ...
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31 views

Can Goodness-of-fit increase while noise also increases?

I saw a tweet with a good slide. It has a Goodness-of-fit curve that goes up with Model Complexity. There is a Generalizability curve. Noise is cited as the difference between the GOF and ...
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Static noise which changes based on which usb port I've audio interface connected to?

I've audio interface umc22. I thought I could hear some static noise Even with 0 gain. I recorded audio sample without any gain or even microphone attached. Yet there was still static white noise. I ...
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22 views

Verifying if noise is gaussian in non-time series data

I'm trying to figure out if the noise in my experiments is gaussian or not. I don't have time series data. I first configure my system and then run some software application's and measure the average ...
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44 views

Optimal Combination of received signals from two antenna

I really appreciate an answer or any hint how to approach this problem: Problem: A receiver has two antennas. The first antenna receives $Y_1=hx+n_1$, where $x\in\{-A,+A\}$, $h$ estimated channel, and ...
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37 views

How can I add complex WGN to a complex damped signal for a specified SNR?

I want to add complex wgn to a signal for a specified SNR. I have been using the following lines: ...
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1answer
20 views

Filter Ranking based on Noise

I spent a good amount of my time searching but I can't seem to find any straightforward answer. I want to know the comparison/ranking of the filters (Butterworth, Chebyshev I, Chebyshev II, Elliptic) ...
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53 views

How to get rid of noise in audio files?

Is there any method to get rid of noise in wite circles of the spectrogram? I have done the high pass filter for a cut-off frequency of 1 kHz. And I'v also done a adptive noise reduction in adbobe ...
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33 views

Is this noise a heartbeat or something else?

I tried to make a quick casual recording of rain and thunder outside the window today by setting my Zoom H4n on my desk (internal mics, 96 kHz, 24-bit stereo, lithium batteries). When I loaded the WAV ...
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Maximum Likelihood for Colored Noise: Implementing using Viterbi Algorithm

I have a question regarding the ML estimation in presence of colored noise, i.e., Additive Colored Gaussian Noise. I want to implement this using a Viterbi algorithm, since I need to take the '...
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46 views

Ideally Lowpass-filtered White Gaussian Noise: question about a derivation of variance and covariance

Consider white gaussian noise $\omega(t)$ that has passed through and ideal lowpass filter with bandwidth $B$. This filter has the impulse response $$h(t) = 2B\text{sinc}(2Bt)$$ Sampling the filter ...
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27 views

Differentiate betwee sibilant “sssh” voice sounds and instruments like hi-hat?

How would I differentiate betwee sibilant "sssh" voice sounds in a music track and a similar sounding instrument sounds like hi-hat or cymbals?
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39 views

Timing Jitter in PLLs

Regarding white (uncorrelated) and coloured (correlated) timing jitter. I know that for free-running oscillators (such as VCOs), various kinds of noise causes the jitter, for example (1/f) coloured ...
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Why are some Shannon's limit plots exponential rather than logarithmic?

This diagram again. This is clearly not the shape of $\log_2(1+SNR)$ but I very frequently see this instead of this: But this is also a stupid diagram because it doesn't cross at the origin. Also why ...
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28 views

FFT Frequency-Spectrum has noise

I am plotting a Frequency-Amplitude Graph using openGL for the graph and Rosetta FFT implementation for the FFT calculations, I generated a 2 waveform, applied Hanning window, applied FFT and ...
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42 views

Can we differentiate between observed sequences of IID and uncorrelated noise?

Given a realization $\{z_{i}\}_{i}$ of some noise process $\{Z_{i}\}_{i}$ that is either a White-Noise process or an IID process, i.e. both are uncorrelated however the former also is independent, can ...
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33 views

How to add complex WGN to complex damped exponential and compute SNR?

I am new to the Signal processing domain, So my question might sound basic. I am trying to reproduce the results from the paper Decimative subspace-based parameter estimation techniques by Geert ...
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46 views

Why is Power spectral density of random walk noise defined despite it being non-stationary? [duplicate]

While reading up on oscillator stability, I noticed that authors characterize random walk noise (Brownian noise) as having a PSD of $S_y(f) = h_{-2} f^{-2} $ where $h_{-2}$ is some constant. This is ...
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115 views

periodic noise detection in image's frequency domain

Since I'm learning frequency domain and I'm really curios about this topic, I'm trying to solve a problem (that I have already solved it using morphology [detecting lines by their thickness]) in ...
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171 views

Allan Variance vs Autocorrelation - Advantages

I am currently studying oscillator stability and have come across the Allan variance. I gather that it was developed as an alternative to the standard variance as it doesn't necessarily converge for ...
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24 views

Speed measurement calibration

I have a sailing yacht where speed is measured using a peddle wheel. It measures speed through water (STW). This measurement contains a measurement error whose magnetude is dependend on both speed (it ...
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1answer
54 views

Can Oversampling help to mitigate the effect of additive white gaussian noise?

Oversampling the signal at the receiver's ADC is a common technique to improve the ADC's resolution, dynamic range and to improve the signal to noise ratio (SNR) due to ADC quantizaiton noise, thermal ...
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38 views

Keysight ADS Gaussian noise + understand signal plan (BPSK-Mapping a. Demapping)

I have already created the circuit in the Schematic.I am concerned with the understanding of the diagram. In the diagram you can see the Gaussian noise before and after the addition and the question ...
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2answers
62 views

Application of MAP criteria

This question has been asked in GATE 2019. I am unable to understand how MAP criteria is "applied" here. I've read about MAP but I'm unable to get how they're solving it by graphical method. ...
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How to solve this question on communication lines?

The Question asked is as follows: A communication link operates at a bitrate of 20 Mbps. The receiver is expected to perform at a $BER$ of $10^{-6}$ or better using $QPSK$ modulation scheme. [Note: $...
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29 views

What happens to the audio of a reconstructed signal if we remove too much frequency?

Assuming we have an audio with noise embedded in it, I was wondering what happens theoretically if we remove (filter out) too much frequency when we pass LPF with a cutoff frequency lower than the ...
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1answer
44 views

What is meant by “omega suppression” in a lock in amplifier context?

Can anyone explain what is meant by "Omega suppression" in lock-in amplifier discussions or specifications. I'm usually very good at web-searching, but have been unable to find anything that ...
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2answers
187 views

signal of $\frac{1}{f}$ Noise

I am working on kind of signals that can be classified as 1/f Noise. In this article is explained that the time history of 1/f noise follows a power law proportional to $t^{-\alpha}$. I am very ...
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30 views

Can complex envelope be writen in the form of quadrature components when it has symmetric spectrum?

I am reading a chapter on VCO noise in "Design of CMOS phase-locked loops from circuit level to architecture level by Behzad Razavi";I am confused when the upconverted noise is writen as $...
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59 views

GPS | Retain Signal Tracking after Noise Bound

I have an IF data, 2 seconds signal sample from only one GPS satellite, I know the PRN number of the satellite. ...
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1answer
35 views

How to calculate mean and Variance of Gaussian-distributed random noise?

I have been given a Gaussian-distributed random noise n(t) which has an average power of 5 mW. How can I calculate the mean and variance of noise n(t)? Any suggestions? Thanks!
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Adding noise in frequency domain while solving an SPDE

I’m implementing a numerical solver to a certain kind of a 2D stochastic PDE using Fourier Transforms. So, this solver is a Galerkin type method, which means that choosing the right basis functions I ...
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15 views

Adaptive removal of structured noise

I am trying to use a scanner with vertical banding. The scan head's black and white point calibration numbers have a modulation pattern on top of them. I am not sure if the calibration's banding is ...
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47 views

Comparing a clean, noisy and enhanced signal

I was doing some experiments on analyzing few audio samples and I'm stuck with this. Suppose we have a clean audio signal ($y_{clean}$), a noisy version of it ($y_{noisy}$) and an enhanced version ($...
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when exposure time is longer, the Poisson noise become Gaussian

Can we have an explanation of why exposure time is longer, the Poisson noise become Gaussian? Or any reference? Please provide a reference and I like to dig into more. Thanks in advance!!
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55 views

Finding optimal decision threshold for binary comm system

I'm trying to solve the following exercise: Given a system that transmits bit $b$ with probability $p_b$ and $-b$ with $p_{-b}$ and the transmission is degraded by AWGN $N(0,\sigma^2)$. What is the ...
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55 views

Adding noise to frequency response

I have the dynamics of a 2nd order system, mass-spring-damper for example, in the transfer-function format. For the analysis that I am doing, I am calculating the frequency response of the system by ...

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