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

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Advice for creating differential microphone array

For a school project I'm required to create a differential microphone array that can filter out background ambience, so a clear voice signal can be recorded in noisy environments. The plan was to use ...
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7 views

WAV files are going defect (by white noise overwrite) [on hold]

I have some problems with WAV files and maybe you can help me or you have an idea. Last year I ripped my whole CD collection to WAV. In summer-holiday I often listened all PLACEBO records over and ...
3
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1answer
70 views

What is the connection between analog signal to noise ratio and signal to noise ratio in the IQ plane in a quadrature demodulation system?

We would like to compute the quantitative relation between analog noise near the LO frequency and the statistics of points found in the IQ plane after IQ demodulation. In order to completely ...
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3answers
53 views

EQ - Calculate the power per Octave of a signal through FFT

I'm working on a audio Equalizer, and I'm not sure if the way I obtain the power per octave of my signal is good. Here is the code I have : (I use the third octave bands, which is initialized earlier ...
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1answer
26 views

What noise will change the frequencies components of a signal?

Normally, when talking about adding noise to simulation data, the choice are AWGN, pink noise and so on. However, in practice, the noise in the experiments changes the locations of frequency peaks as ...
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18 views

How to detect impulse noises in audio recording?

How do you detect impulse noises in audio recordings of speech? By "impulse noise" I am thinking about noises like: Typing on a keyboard A door slamming Somebody bumping into a table Tapping on a ...
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0answers
27 views

SDR Signal processing - noise filtering

I'm looking for an advice with noise filtering using digital singal processing. I've been pointed here in my original question posted on Stack Overflow. So whats the problem: 1. I am using my SDR ...
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1answer
40 views

What is the statistics of the discrete Fourier transform of white Gaussian noise?

Consider a white Gaussian noise signal $x(t)$. If we sample this signal and compute the discrete Fourier transform, what are the statistics of the resulting Fourier amplitudes?
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1answer
51 views

Spectral density of modulated noise process

Suppose we have a noise process $F(t)$. Suppose $F$ is stationary and we know its autocorrelation function $$\rho_F(\tau) \equiv \langle F(0)F(\tau) \rangle$$ where the average is over realizations of ...
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1answer
47 views

Can realizations of a filtered Gaussian white noise process be represented as a Fourier transform?

Suppose we have a noise process $V(t)$ which is the result of passing Gaussian white noise through a filter with frequency response function $H(\omega)$. Can we represent realizations of this process ...
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1answer
33 views

Removing a non linear noise trend from data

I have a dataset that looks as follows Now, this is from an actual measurement (of the reflection coefficient of a microchip with four LC resonators connected in a periodic fashion) so there is ...
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1answer
41 views

How to remove gaussian noise and poisson noise?

I want to remove the noise gaussian and poisson noise. But I'm unfamilier with noise remove methods but from my understanding it's similler to average filter which is median filter. But I want to know ...
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0answers
19 views

What is difference noise reduction technic on additive gaussian noise and poisson noise?

As I know the camera noise are consisting like poisson noise and additive gausian noise. I want to know about What is difference noise reduction technic on additive gaussian noise and poisson noise? ...
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34 views

ECG noise filtering using FIR Bandpass Filter

I am new to signal processing and examine ECG data corrupted with noise. The clean data has a frequency spectrum like this. And the corrupted one looks like this (sorry for the different scale) ...
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1answer
28 views

Smooth (not) equally-spaced signal strength data

I'm currently trying to reduce the noise in/smooth sampled signal strength data. The context is that I collected data from a transmitting device using bluetooth - the available data is basically a ...
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1answer
26 views

How to form Kalman filtering matrices for a problem with variable acceleration?

Assuming we have time vector $T$ with constant time step $dt$ position vector $X$ velocity vector $V$ acceleration vector $A$ All vectors $X, V, A$ have noise on their measurement ( $n_x$ , $n_v$ ...
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1answer
151 views

What is the difference between i.i.d noise and white noise? [closed]

I want to know the difference between independent and identically distributed (i.i.d) noise and white noise. In my short knowledge, i.i.d is that there is no relationship about time dependancy. White ...
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1answer
95 views

What does clipping gaussian noise mean?

I found the subject at here like this "Does clipping noise colour the spectrum" When I researching for clipping noise. But I can't understand because typically something has clipped means something ...
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1answer
57 views

What does standard deviation of noise 1 mean?

In theory of noise,Typically, the standard deviation of noise has 1 and mean has 0. I think that the reason of noise mean has 0 that we can assume that all noise signal go to zero when we sum it all. ...
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1answer
82 views

What does zero-mean noise mean?

I don't know where to start from. and this question might be very silly, I have found such as comment from someone at here, "I think if you noise is zero-mean it doesn't matter, if not it does (you ...
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1answer
37 views

Kalman filter - understanding the noise covariance matrix

What is the significance of the noise covariance matrices in the Kalman Filter framework? I am referring to: process noise covariance matrix Q, and measurement noise covariance matrix R at any ...
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1answer
47 views

Does clipping noise colour the spectrum

Does extreme clipping white noise colour the audio spectrum? I thought (and hoped!) not on the basis of this from research.net Clipping is mathematically equivalent to the addition of impulse ...
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0answers
37 views

What is spectral subtraction? [closed]

I have to write some simple examples in Matlab which use spectral subtraction. These examples will be included in a paper to help a friend understand spectral subtraction. But I don't know where to ...
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0answers
18 views

Simulate noise on the x axis for raw time-of-flight mass spectrometry signals

I am analyzing raw mass spectra produced by a time-of-flight mass spectrometer. These spectra are 2 dimensional signals that consist in intensity values with respect to mass/charge values. Here is an ...
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2answers
84 views

Noise removal from audio using FFT/Spectral editing

I have a noisy recording with some letters spoken out loud. I've noticed that the noise is easily recognizable when looking at a spectrogram of the audio. Is there anyway to set a power/frequency ...
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1answer
145 views

What do we espect Likelihood function used for?

In my understanding, I let make a example. For example, you can see in the following picture. Consequently, We want to find ^sigma. and We have already known the observation data(which is random ...
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2answers
27 views

FIR Filter matlab command

i'm trying to understand the fir1 filter but i still don't get it. For example here i got an audio signal that i consider noise, i'm passing it through a low pass filter. ...
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29 views

time domain non stationary time series individual colored noise identification algorithm

One of the methods for identification of modulated colored (stationary) noises is that of lag 1 autocorrelation power law noise identification algorithm. This method can determine the dominant noise ...
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2answers
64 views

adding noise to a signal

I have an audio file. I took an extract of the file called variable "CALL", and I took another extract from the file which is just filled with background noise, called "BACKGROUND". Using matlab, I ...
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1answer
59 views

Matlab: if given nothing but an audio file, how do I modify it to produce incrementally lower signal to noise ratios?

I have an audio file with a high sampling rate of 250khz. It contains animal noises. I've built a program which counts all the animal noises. However, I want to find out how robust the program is and ...
3
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2answers
97 views

How do can we cancel out noises while listening voice on headphones?

It's a common problem that while talking with the another person on Smart phones with the help of regular headphones,we get very annoying sounds at background . The opposite person's voice gets mixed ...
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1answer
14 views

Concepts Surrounding First Two Samples in Difference Equation

I'm attempting to construct a difference equation in matlab for the function u(n) and find the auto-correlation matrix R. I'm following the technique as is defined by my text below: The system I'm ...
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2answers
54 views

how to estimate the noise of a signal?

please can someone help me to define a method that allows me to estimate the power of noise in any signal? the signal is received by usrp and the problem that it is variable all the time in the FM ...
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1answer
56 views

How to estimate the noise of an image?

I want to know how to estimate the noise of an image? Also is this represent the camera's noise? Does anyone know how to estimate the noise of an image or camera? Update: Especially, I want to ...
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24 views

How to estimate noise level and actual intensity of image from a noisy image?

The image I have is corrupted with random (natural) noise. So I would call it Gaussian noise. I am thinking of the following approaches for denoising: Mean filter Non-local means filter Averaging ...
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1answer
30 views

Can we decompose a correlated random variable into correlated plus uncorrelated?

Assume a random sequence $ Y_k = X_k \cdot H_k + W_k $ where $X_k$ is a deterministic quantity, $H_k$ is a correlated random sequence, $W_k$ is Additive White Gaussian random sequence. Can we ...
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0answers
7 views

use of recurrence quantification analysis for deterministic signal identification and classification

The recurrence quantification analysis (RQA) is a method of nonlinear data analysis which quantifies the number and duration of recurrences of a dynamical system presented by its state space ...
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0answers
49 views

Kalman filter - mathematical model for signal strength based tracking

I'm currently trying to wrap my head around Kalman filters. I've read some tutorials/introductions on this subject and am trying to apply it to a problem to get a better understanding of the mechanics ...
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0answers
25 views

Is it possible to calculate the variance of signal in real time implementation? [duplicate]

In communication system, when we received some signal which contain our message of known variance sigma_s which is corrupted in noise of unknown variance. If I need the variance of the signal in ...
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1answer
64 views

how to create synthetic $1/f$ noise? [duplicate]

I am writing an app to work with synthetic time series data from a physics experiment. In our experiments we always have $1/f$ noise in our time series, but I haven't been able to find code/packages ...
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2answers
28 views

Noise modeling and reduction in Video when we have just noisy video

We would like to send a video (sequence of images), we have limit bandwidth. If there is a lot of noise, the required bandwidth (bitrate) is needed to send the video+noise becomes high that is not ...
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1answer
49 views

1D filter for speed input and noisy position sensor

I was tasked with designing a filter to smooth out a translating table. The system, we command a speed and a desired position, and measure it with two noisy position sensors. The commanded speed is ...
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1answer
29 views

Notch filtering line noise outside of frequency band of interest

Practically speaking, if one is interested in a frequency band well-separated from the line noise (say, for example, the 10-20 Hz band, with 60 Hz line noise), would it be advisable to notch out this ...
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1answer
52 views

Diagonal vs non diagonal processing for audio denoising

I am going through a technique for audio denoising by block thresholding. Here is the paper: http://www.di.ens.fr/~mallat/papiers/AudioBlock.pdf According to the definition in the paper for ...
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1answer
42 views

Adaptive Digital Filter Block Diagram Question

I'm currently attempting to study up on adaptive digital filters. My book presents the diagram I've included below and I'm having trouble understanding conceptually what it's indicating. The problem ...
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3answers
99 views

How to remove heart beats interference from pectoralis major electromyogram?

I am using electromyography to detect activity on pectoralis major, however I found an interference from heart beats that is affecting my posterior analysis. The sampling rate is 2000 Hz, and the time ...
4
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1answer
80 views

How can noise be good?

It seems like (controlled) noise can sometimes be good: dithering in an image, or a softer sound in audio, or white noise alone. Here's a paper on noise improving detectability. My intuition also says ...
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1answer
32 views

What type of sensors have complex Gaussian noise?

What type of sensors have complex Gaussian noise? Do strain gauges also exhibit such noise?
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1answer
51 views

How to find out whether guassian or salt& pepper noise present in an image, Is there any algorithm

Is there any algorithm for identifying the noise in an image I have to identify whether the noise present in a mammogram image is guassian or salt& pepper.
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157 views

What is the type of noise in this image?

what reason could make the noise/effect in this image? Below is the original Thanks!