# Tagged Questions

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

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### Flattening out a power spectral density

The situation is as follows. I am generating a white noise voltage signal with a certain power spectral density amplitude of choice, from 0 to some cutoff frequency, for example 200 MHz. This proceeds ...
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### Remove noise from linear signal

This signal represents the distance in an experimental device. As the speed is constant, the signal should be linear (untill it drops). However, for some reason the device showed interferences as ...
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### remove static noise from audio

I have a recording with a static noise added throughout the audio. the longest silence period I could extract was this: audio_file however, it contains some moments of new sounds of flipping pages. ...
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### Adaptive filter with two inputs

I have general theoretical questions: Is it true that an adaptive filter with two inputs (one normal and one delayed by the single time increment) can completely get rid of any single frequency ...
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### How do we detect presence of background noise in audio?

The problem I am facing to solve is detect background hissing or humming sound in any audio stream. The audio stream can be of any type ranging from movies to talk shows. The background noise is ...
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### SNR After Multiplying Two Noisy Signals

If I have two noisy signals where the noise is not correlated and I know the SNR of each signal, how would I find the SNR after multiplying the two signals together?
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### detect what is noise in audio signal

I'm trying to filter noise from an audio signal. The signal was and is going to be recorded in a city environment which always contains some white/pink noise. At this moment I'm using two options to ...
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### Difference between a digital lock-in amplifier and a FFT when extracting phase of a signal?

I am trying to measure the relative phase of a sine wave fixed at a particular frequency in a noisy environment. My initial approach is to simply collect $N$ samples, take an FFT, and then just ...
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### Active noise cancellation using kalman filter

I am doing signal processing on audio data sampled at 8Ksps in matlab but it is corrupted with random noise. Therefore, I decided to use LMS and RLS ANC algorithms to remove overlapped frequency ...
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### Noise detection

I was wondering if someone could suggest a method to differenciate between two signals, on algorithmic scale for example a criterium to calculate, that shows how noisy a signal is, i have found a post ...
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### Decorrelating Stationary Colored Gaussian Noise — Effect On The Desired Signal

So given stationary colored gaussian noise $\mathbf{n}$, I know that I can decorrelate it by first finding it's autocorrelation $R_{nn}$ and performing $R^{-\frac{1}{2}}_{nn} \mathbf{n}$. In ...
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### Additive Gaussian white noise - bandwidth

The average power at output when additive Gaussian white noise is present is given by the formula below: $$P_0 = \int\limits_{-B}^{B} \frac N2\ df ,\quad \text{with B being the bandwidth.}$$ My ...
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### SNR and noise in Simulations

I've always taken the definition of noise and SNR for granted in doing BER simulations in an AWGN channel. I would usually use the AWGN noise function and make a loop with varying SNR values. However,...
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### Concept question - What is noise?

I've been studying image processing methods (without signal processing background) and many things are interesting to me. I was think about noise. In many definitions noise is unwanted and without ...
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### What is the value of the standard deviation $\sigma$? [closed]

I am using the following formula to add the additive Gaussian noise. noise= (x/255)*(randn(size(image))), where x is the ...
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### generating white gaussian noise in matlab using two different functions

I want to know the difference between the two Gaussian noises generated below? Which one is white and how can i make the other one white? y=wgn(1,10000,0) and <...
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### Image averaging for impulse noise

I understand the mathematics behind the use of image averaging for gaussian noise. Why can't it be used for impulse noise ? Would it be because there is no way to prove that impulse noise is additive ?...
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### Segmentation of small artifacts - Image Processing

I am working on a task of segmenting small artifacts from a set of images like below: I am looking for a generic approach, but unsure of what to search? I tried looking at density flow analysis, but ...
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### Resources on Non-Gaussian Channels

I understand why most of the classic textbooks only consider Additive White Gaussian Noise channels in digital data transmission. Unfortunately in my case noise is not Gaussian and it might even be ...
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### What is the difference between a'mixer' and a ' multiplier' used in modulation process?

I am not sure if it is valid to conclude that a mixer produces a difference/sum of frequencies at output ,while multiplier produces multiples of frequency at its output. I am keen to know how far I ...
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### Sox, mixing mono inputs into mono output (efficiently)

I want to mix two mono files, signal.wav and noise.wav, into a single mono file, signal_noise_mono.wav. Currently, I know how to mix the two input files into a stereo file and then remix it to mono, ...
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### Should S-Matrix components for scattering response in a Polarimetric Radar be Real or Complex?

I am trying to implement some polarimetric decomposition algorithms on my MIMO polarimetric radar. At first, I will try the Pauli Decomposition algo. But instead of doing signal processing on the ...
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### Filter for noisy accelerometer data

I tried to read up and get a filter for a 3-axis accelerometer but this is more confusing than I thought. I have an IMU with a 3-axis accelerometer on the end of a robot link which is rotated around ...
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### Calculation of an autocorrelation function

A sample of a random process is given as: $$x(t) = A\cos(2\pi f_0t) + Bw(t)$$ where $w(t)$ is a white noise process with $0$ mean and a power spectral density of $\frac{N_0}{2}$, and $f_0$, $A$ ...
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I have to quantify the broadband noise of an audio track. I've seen lots of things around and the only viable option to estimate the broadband noise (without having any information about it) is ...
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### Looking for low-noise audio data to benchmark some noise-processing techniques

I'm looking for a source of very low-noise audio data for use in benchmarking various methods of random noise correction methods. My intention is to have a very clean signal to which I can add known ...
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### Finding the Amplitude of a Sinusoid in Noise

I'm trying to solve for the amplitude and frequency of a sinusoid embedded in zero-mean gaussian white noise. I am supplied a sample file of a 40000 element array. I first took the autocorrelation ...
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### Noise Robust Linear Prediction

So it appears that Linear Prediction as performed via Durbin Recursion is sensitive to additive noise. What are some techniques for linear prediction that may be more robust? Can anyone supply a link ...
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### Fourier transform of a Fourier transform

I generate a Gaussian noise and then I filter it with a passband FIR Kaiser window filter. When I perform the Fourier transform of the output of the filter and plot its magnitude spectrum, it is ...
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### In signal averaging, will the noise be reduced if the noise is not Gaussian?

My understanding is that signal averaging works this way. If we take the average of the waveform, we get the average of the signal component (which is the magnitude of the signal) and the average of ...
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### 1/f noise parameter characterization

I would like to characterize 1/f noise in some time series data. I would like to estimate the 1/f noise corner, and the standard deviation of the 1/f noise component and white noise component. The ...
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### Generating 3-dimension $1/f^\alpha$ noise

I'm stumped trying to find a way to generate a 3-dimensional $1/f^\alpha$ noise time series. Basically I want simulate a forcing that is $1/f^\alpha$ in the 2 space dimensions and $1/f^\beta$ in time, ...
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### Adding two audio files at a predefined SNR level

I have two speech audio wav files. file1 is primary speech, file2 is supposed to be interference. I want to add them so that ...
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### Adding “realistic” noise to signals of different amplitudes

I have a question regarding basic signal processing, which I have to start using since I have started studying fault isolation. The thing is, I have three computed signals, which are gathered in the ...
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### Approximation of Step Response from Data with delay

How can I approximate a Step Response curve from a measured data of a single input and a single output using Matlab while the delay between the input and the output is 30 minutes?
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### How to measure noise, consonance, dissonance of a sound?

How can I make a graph of the noisiness of some audio durations of 100ms - 10s with 100% being white noise and 0% being a sine wave. I have FFT at the moment, are there other ways to know the ...
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### Determine whether a signal is increasing or decreasing over time

I have a signal (x-axis: Time, y-axis: Data) which has more than 10000 samples per second. The signal itself represents some physical data (e.g. speed, acceleration, etc.) and has some noise on it. ...
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### What does it mean by “Adding Gaussian Noise to a 2D Image”? [duplicate]

As far as I understand, Suppose, we have a 2D image of pixel resolution 200 x 300. That means, the image has 60000 pixels in it. Now, we would generate $n$ random values and add those values to $n$ ...
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### Why is Gaussian noise called so?

Can you please explain: why is a specific type of noise called "Gaussian noise"? Why is it relevant to call it Gaussian? Please, explain in layman's terms.