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

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What are the best algorithms to detect fundamental frequencies of noisy signal [on hold]

I am using FFT to detect fundamental frequency but unfortunately it is not working correctly. I have written FFT code in C and my signal is too noisy but when I see it in oscilloscope a clear pattern ...
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1answer
13 views

What is the difference between photon shot noise and salt and pepper noise?

I am currently working on an application which deals with the restoration of fluorescent beads examined using widefield microscopy. There are two major sources of noises that are being encountered in ...
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6 views

Valid non stationary non parametric white noise tests for non strick stationary time series

I could not find a question where testing for white noise for non strick stationary non parametric time series is adressed. Traditionally testing for white noise is done via multiple tests for the ...
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2answers
36 views

how do i calsulate SNR of a noisy signal without having the noise?

i want to calculate the SNR value of a speech signal in matlab having only the clean and the noisy one and not the noise.what should i do?
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1answer
37 views

Noise cancellation for known sources

Creating a noise cancelling earphones that cancel/suppress speech is a huge challenge , maybe even impossible. But what happens if we change the goals a bit: We need to cancel the ...
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3answers
69 views

3dB and 6dB Per Octave Rolloff Digital Filters / Generating Pink and Brown Noise

So I would like to have a design method for filters with 3dB and 6dB per octave roll off -- for generating pink and brown noise respectively. I know the following 'pinking' filters exist: Filter to ...
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1answer
29 views

Channel Estimation / Equalization - Estimate Channel Inverse Using White Noise Statistics Only

Given the system defined in the following figure: We have a system $ G \left( f \right) $ which is unknown yet can be defined by $ {N}_{p} $ poles and $ {N}_{z} $ zeros. The signal $ x \left( t ...
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21 views

What kind of reference signal would be preferable when identifying a closed loop process?

Given the following reference signals constant Gaussian white noise sequence a sequence of sinusoidal signals of different frequencies or a PRBS signal Which one would be preferable when trying to ...
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11 views

Calculating a Matched filter for 2.4GHz ISM band: does it make sense to take the noise auto-correlation into account?

If my goal is to demodulate a GFSK encoded signal at 2.4GHz ISM band, does it make sense to take the noise auto-correlation into account when calculating the matched filter as it described here : ...
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1answer
23 views

How the noise in time series can be reduced?

I have asked the question in the following link: Are time series data always contain noise? I wonder if we could use variational methods to denoise the time series data just as in computer vision? ...
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2answers
39 views

Are time series data always contain noise?

I wonder if every time series data should contain noise or not. For example I am taking the price of a ticker, say Yahoo, every hour and noting the values. Does this data contains noise or not?
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1answer
31 views

Low Pass Filter - pixel correlation

I am trying to understand low pass filters for image processing, I came across an article that stated that low pass filters effect noise more than the real data due to that the image Noise always ...
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2answers
77 views

Filtering noise from FFT, where noise is known to be shifted delta function

I have an input sequence $x=\{x_1, x_2 , ... x_n\}$ of reals, where $n=2^m$ for some $m$. I wish to calculate FFT of $x$. $X=FFT(x)$ However, before I calculate the FFT, the signal $x$ gets ...
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27 views

Regarding maximizing signal to noise ratio

If I have 3 recordings, each of speech (recorded in a relatively silent room), speech+background noise and background noise then is there a way to utilise the data from all the three to extract clear ...
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0answers
25 views

Filtering an audio file using IIR filter on Matlab

First of all, sorry for my English. I'm quite lost with Matlab, I'm not comfortable at all and I have to create an IIR filter using Matlab. The thing is I'd like to remove background noise from an ...
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25 views

Empirical Distribution White Noise Tests

All common tests for testing if a time series is white noise are based on common distribution assumptions from which inference is made that a process is white noise. However, in the case for most ...
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1answer
60 views

Simulate packet loss in internet video streaming

i have encoded H.264 video using ffmpeg . I want to apply packet loss model like Gilbert Eliot model to depict video transmission over unreliable network. Like in this thread TV noise is simulated. ...
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18 views

Calculation of snr at output of Adaptive Filter

I am working on Spectram Digital DSK having Texas Instruments c6713 DSP Processor. I have run the sample code of adaptive filter. I have to calculate the SNR ratio at the output in MATLAB. I can get ...
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1answer
38 views

Quantization SNR of bipolar signal

I want to estimate the SNR of a bipolar signal. I know that each bit increases the SNR at 6 dB. Do i have to subtract one bit for sign, so that for bipolar signals the SNR is (n-1) x 6 dB ?
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27 views

Noise due to Fluorescent light in a signal from a LED

I measured a signal coming from a LED using a sensor. The signal is Amplitude Modulated, so I expect its spectrum to be moved by the carrier frequency. I am trying to explain the symmetric harmonics ...
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2answers
44 views

what is a Gaussian signal?

I am learning Wiener filtering for 2D images by myself. From one book, it reads It should be noted that the study of the more general problem of signal denoising dates back to at least Norbert Wiener ...
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1answer
46 views

AWGN and Rayleigh fading in slow flat fading channels in MATLAB

I wanted to add Additive White Gaussian Noise (AWGN) and involve effect of slow flat fading on my transmitted signal in Matlab. I created noise with zero mean and variance of one by ...
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1answer
56 views

What is the difference between MSE and PSNR of images?

I have some doubts. What is the difference between quality parameters MSE and PSNR? Which is used when? Is there any advantage of PSNR over MSE or vice versa? Also I have heard people saying that ...
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20 views

estimating noise by projection

I have a MATLAB code that want to estimate SNR of a matrix R as below: ...
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48 views

Kalman filter to filter noise from acceleration data

I would like to apply a Kalman filter to remove noise from my measured acceleration data. The idea is then to compare the results obtained in this way whit the results obtained by applying a low-pass ...
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43 views

Multiplication of two noise

I have a question on the multiplication of two noise. Suppose I have two noise $n_1[n]$ and $n_2[n]$. I only know their power spectral density $N_1[k]$ and $N_2[k]$. How can I get $N_3[k]$, where ...
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1answer
73 views

How to filter almost periodic noise?

I have signal that looks like this: As you can see there are some almost periodic pulses at the background with amplitude about 1000. I am saying almost, because, if you zoom in, you may see that ...
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16 views

Denoising of Images capture by digital camera using Butterworth Filter

Right now, i am doing a research on how the Butterworth filter can reduce the noise in images captured by digital camera. For start, what i need is images which contain noise in it. My question is; ...
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19 views

Sum of the variances of the real and imaginary parts

I have a noise $\eta[k]$ and I performed IFFT to this discrete function to get $Z[n]$. In other words, $Z[n] = \textrm{IFFT}[\eta[k]][n]$. I have also found the expression for the variance of ...
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26 views

Noise level estimation

I'm trying to estimate a noise level within every 1024 samples of the AM modulated, 5kHz, complex signal. My current approach is to perform some filtering (bandpass, median) and then deduct the power ...
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25 views

Apply noise in H.264 Stream

I have Encoded H.264 bitstream using JM. I want to pass this stream to the common noisy channel or packet loss models. So that i can check effect of packet loss on perceptual video quality. My ...
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1answer
19 views

Baseband vs Passband simulation in terms of noise impact

From other posts I understood that it is normally no problem to simulate a communication system in the baseband though it is carrier modulated in reality. It just speeds up the simulation. But what ...
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2answers
57 views

Removing Bounded Noise from an Audio Signal

I'm currently trying to remove some noise from a "contaminated" audio file. From what's given, I know that the noise is isolated to a specific frequency band - that is, from ~1400 Hz - ~1800 Hz. The ...
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38 views

How to remove or filter the drift problem in measured Strain signal?

I have the strain signal of a lateral beam of a car measured at sampling rate 1,200Hz from data acquiring system. Even after using temperature compensation in strain gage, we are getting drift. So I ...
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60 views

Standard deviation of the spectrum of white noise

I have a temporal signal which looks like $f(t) = t\eta(t)$, where $\eta(t)$ is a white noise with the mean $\eta_m$ and STD $\sigma$. I want to calculate the corresponding spectrum, $F(\omega)$, take ...
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1answer
52 views

How to eliminate noise that has the same frequency of my signal

I have an audio signal , and I want to remove noise from it. I have applied a bandpass filter in order to remove frequencies that are not part of mi signal. But if there is background noise (some ...
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2answers
99 views

Fourier transform of certain noisy function

So, I have a noisy signal in time domain, $f(t) = t \eta(t)$ where $\eta(t)$ is white noise with variance $\sigma$ and mean zero, and that it has the property $\langle \eta(t)\eta(t') \rangle = ...
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2answers
89 views

Compute the time derivative of a noisy digital signal?

The issue is that my signal is very noisy. I need extract its time derivative as accurate as possible. P.S. I do not have any prior knowledge on the signal (black box). On forums some suggested ...
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38 views

Noise level in voice recordings

I'm conducting a phonology research and I have recorded some speech segments. I would like to know how can I report the noise level I get in my recordings? I used Rightmark Audio Analyzer to analyze ...
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49 views

detect pattern of noise / sound from pcm data

First of all, I'm very new to this field, I've never learnt anything related to sound processing. So I have a case that requires me to detect noise inside audio files (16bit 8khz mono wave file). ...
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42 views

Is there a general name for this kind of filter?

I have a signal with some high frequency noise. At first was just adding a low pass filter which removes the noise very well but has two drawbacks: First there is a delay (which I try to avoid in my ...
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2answers
100 views

reducing pepper noise

For an image with pepper noise, presuming it is desirable to reduce the pepper noise, which operations, in which sequence, would you apply? Find an image, add pepper noise, and demonstrate your ...
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1answer
78 views

salt noise in an image

Suppose an image has noise, but it is exclusively salt noise. What effect will dilation have? I am looking for a reference so I can answer this question. anyone has any idea?
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2answers
75 views

Why power and not amplitude?

I'm reading 'The Scientist and Engineer's Guide to Digital Signal Processing'. It says for a noisy signal, the important parameter is not the deviation from the mean, but the power represented by the ...
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0answers
44 views

Median Filter for salt and pepper noise removal

Why median filter is considered as good for removal of salt and pepper noise? What are the other filters used for the same?
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31 views

Remove microphone rustle / clothing rustle from raw audio data

Thank in advance for the help. I have several GB's of raw audio data that I have collected as part of a research study. This audio is divided up into individual samples approximately 30 seconds in ...
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0answers
12 views

x shift impulse noise?

Is it possible to add some form of gain to an image, such that an impulse noise get shifted along the x-axis.. I have these two histogram of an image with noise and the original image. As you ...
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2answers
69 views

Is the Kalman Filter a Best Linear Unbiased Estimator (BLUE) for Heteroscedastic Noise?

According to the Gauss-Markov Theorem, a ordinary least squares estimator is BLUE if the noise entering a system is uncorrelated with zero mean and is homoscedastic (has a constant finite variance). I ...
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1answer
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Can I model process noise as a known “error” in my dynamics while designing a Kalman Filter?

Consider I am modelling the dynamics of a robot and using a Kalman filter to obtain estimates of some state. I have certain terms in my equation which correspond to data not accessible to this robot ( ...
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49 views

1/f noise generation

Recently I was reading a paper about the pink noise generation. But I don't have any background of this field. I am confused with some part in the paper. First, the Voss's algorithm generated a ...