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

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comparing different signals

I have some noise measurements and 4 different models that can generate a similar noises using estimated parameters from the real measurements. To compare the estimated noises I calculated the PDF, ...
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22 views

comparing statistical destributions and non-gaussian noise measeruments

I have some non Gaussian noise measurements and I want to find a statistical model that best represents those measurements. The statistical models that I used for comparison are Middleton Class A , ...
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1answer
35 views

Why use Wavelet Denosing instead of Band pass Filtering

What is the important advantage of adopting a wavelet based denosing scheme such as SURE, SUREshrink, etc. than using approaches involving low pass, high pass, band pass, band reject filter for signal ...
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22 views

How to smooth out a noisy signal?

I've been waiting for an answer to my question here therfore I decided to ask the question in a different way. Could anyone please help me to smooth out the signal below!!. I've no experience of ...
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1answer
31 views

how to detect signal noise

I have data from a power transformer that has a frequency of 60 hz. Sometimes there are faults in the system and causes a large spike in the reading of the transformer. What I want to do is run the ...
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0answers
14 views

is there a specific band for noise in eeg

i want to know is there any specific band in eeg signal for noise? i have read all the related posts on this forum . one of them make me know that there is noise with 50 hz in eeg. some suggest to use ...
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1answer
83 views

Picking out a signal that appears to be noise inside a large signal

I have a signal from a photodiode sensor that has two types of noise. One type of noise is ambient light white noise that gets introduced just from the surrounding environemnt. The other type of noise ...
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1answer
38 views

Phase angle operator, Implemention and drawbacks

Let assume we have a signal as: $\color{blue} {x(t)=M e^{(-\beta.t)} e^{j(\sigma .t+\delta )}}$ By applying phase angle operator we have: $\color{blue} {Phase[x(t)]=Phase[M e^{-\beta.t} e^{j(\sigma ...
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1answer
32 views

How is LMS/FXLMS noise cancelling different than simple polarity inversion?

Consider a noise-cancelling headphone: If I have a noise signal from the outside world, mic it, flip the polarity by multiplying by -1 (with an op-amp or digitally), delay by the appropriate amount, ...
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75 views

why adding noise enhances the accuracy sometimes?

I am applying simple FFT to estimate the frequencies of the oscillations. The real values of frequencies are known to me as I made a synthesis signal for simulation.Thus, I can calculate the error ...
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1answer
59 views

why derivative and logarithm operators amplify the noise effects?

It is said, do not use derivative operator in a the control system. because it will amplify the noise effect. Can someone explain it and give some mathematical reference about it please? Also I heard, ...
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471 views

why Gaussian noise is usually used?

Gaussian noise with different SNR levels are usually used in research works to simulate a realistic environment. How can researchers guarantee that Gaussian noise can simulate the reality of a System? ...
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2answers
90 views

what is the unit of SNR?

SNR is defined as: $$SNR=10 \log_{10}\left(\frac{\sigma_s^2}{\sigma_n^2}\right)$$ When we say SNR of 10db is 10 times higher that 20db, it is higher in what? amplitude, power or what? also tell me ...
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3answers
58 views

comb filter - attenuation

I have a signal and from 'standard information' I know the predominant frequency is at 1Hz and then there should be three harmonics at lower amplitudes. My signal however has a lower amplitude at 1Hz, ...
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1answer
49 views

Fixed SNR with unitary noise variance

I've just one question : How can I write a model like y = x + w,( with w a white gaussian noise) with a fixed SNR and a noise variance equal to 1. What coefficient may I have before x ? Thanks !
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0answers
139 views

How to estimate PSD, and time delay of a random signal?

I'm trying to estimate the power spectrum and time delay for random signals. the signals were taken from two sensors, 10 cm apart. My aim is to estimate the PSD first then estimate the time delay in ...
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1answer
61 views

Effect of noise and entropy

Relation of Entropy and SNR : Based on this question and answer, I had another question that struck me and I am curious to know, if somebody can shed some light, on the following situation: $y= ...
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1answer
55 views

white noise filtering

If I have a white noise fed into a filter what would be the output of the filter - what would you expect to see? I know that white noise has a unit power spectral density (PSD), how these thing relate ...
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1answer
45 views

Long burst of high amplitude noise removal

I have a setup with an embedded DSPIC. This is used to link multiple audio inputs to the outputs and changed between them either when told to, or when one is active. This changing takes place on a ...
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1answer
87 views

How to simulate AWGN in communication systems for specific bandwidth

I am trying to generate a AWGN waveform to add it to the signal of my simulated communication system. The operating bandwidth of the communication system is about ...
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0answers
56 views

Noise analysis with periodogram. problem with different resolutions

I don't understand what happened in my simulation. I would like to perform a trade off between 2 ways to estimate power in frequency bands. I want to detect spurious frequencies. First method: I ...
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1answer
52 views

What is best practice to remove static noise?

What is best practice/algorithms to remove static noise from speech ? static noise aka Stationary Signal/static noise due to 1.humming sound due to of telephonic line/channel, 2.moving Vehicle,or ...
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1answer
84 views

Autocorrelation of white noise

Autocorrelation of white noise should have a strong peak at '0' and absolutely zero for all other $\tau according to this. Then why is output of this code a cone shape(with the expected 'strong peak' ...
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2answers
150 views

Denosing signal using soft and hard thresholding

Let us consider following code: fs=100; N=1000; t=0:1/fs:N-1; y=10*sin(2*pi*100*t)+0.5*randn(size(t)); plot(y) plot(t,y) I have applied following threshold ...
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1answer
115 views

Digital Gaussian White noise signal generation in C++

I am trying to generate a band limited noise signal on a Raspberry Pi. I calculate samples at every 1/48000 sec on the Pi. If I generate normally distributed random numbers as data points at every ...
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1answer
49 views

Parameters for signal analysis

I am extremely new to signal analysis. And before posting I did a lot of reading on signal analysis, FFT and windowing. I am working on my thesis which involves comparison of speech signals lets say ...
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52 views

What is OSNR in Fiber Optics?

I have seen that the SNR is measured for optical fibers "OSNR". What is the difference? Is there any equivalent?
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2answers
64 views

noise cancellation of non-repetitive noise

There are a new noise cancellation headphones that almost fully cancel human noise. What kinds of algorithms could achieve that ? EDIT:by human noise , i mean talking. In general, previous audio ...
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1answer
56 views

simulating range-bearing sensor with Matlab with Gaussian noise

I would like to simulate a sensor that provides range and direction of a beacon. This is for EKF localization, so the noise must be Gaussian (i.e. $\mathcal{N}(0, \sigma^{2})$. Also, I would like to ...
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1answer
78 views

Maximum likelihood estimation in presence of colored noise

I am trying to test system identification in presence of measurement noise (1) A white Gaussian noise (2) Colored noise - pink, violet. When we are estimating parameters we do so in presence of iid, ...
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1answer
106 views

How to filter uniform noise in a microcontroller?

By uniform noise I mean a band of a fixed width, no spikes, etc. This has to be one of the simplest examples. I'm looking for the appropriate theoretical approach as much as something relatively ...
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1answer
152 views

What is obtained from the cross correlation plot?

Let’s assume that we have two audio signals, x(t) and y(t) affected by the noise as shown below. And we would like to cross-correlate these two signals and the cross-correlation plot is shown as ...
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1answer
55 views

How to implement simple noise filter based on the frequency domain information?

Brief introduction: I am working on my university project. My task is to develop application that captures sound from mobile phone and removes/reduces noise (this simpilied version of task). I never ...
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1answer
61 views

What is uncorrelated noise

In many applications such as estimation theory, when we need to estimate a parameter then we usually consider in presence of white gaussian noise of zero mean and some standard deviation. During ...
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47 views

Noisy Signal auto/cross-correlation

I am trying to understand the basics of the cross/auto-correlation if the noisy signal $y(t)$ which is received from the channel at the receiver. Here at receiver we want to estimate the noise in the ...
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50 views

Spectral estimation from noisy time-series data

This is the first time I'm posting a question on here so I hope I'm doing it right. I've tried searching on here for an answer but haven't found anything particularly relevant. I have some data ...
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2answers
143 views

Derivative of noisy signal

My input signal is phase vector. I want to differentiate it to get frequency vector. My input signal is somewhat noisy. Here is the input signal. This is the derivative of the input signal as ...
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1answer
44 views

Extract signal from big gaussian noise

I have signal, periodic with amplitude 10 with frequency about 10 kHz. It is hidden in Gaussian noise with standard deviation 100. Some idea how to extract periodic signal? Thanks in advance.
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2answers
61 views

Reason of circular conv in OFDM

In OFDM system, after IFFT a CP is added at the beginning of the OFDM symbol by copying it from the end of the symbol.My question is that with CP why we use cyclic convolution instead of linear ...
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2answers
72 views

A [Very] Rough Approximation to “White Noise” with Sine Waves

This might be a silly question, but I'm pretty rusty on my signals. The problem is the following: I'm using a program which does not have a random signal generator, but I can sum up sines; and I need ...
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1answer
95 views

Adding measuruments noises to kalman filter

I'm implementing navigation system for my robot. There are two ways to get data from it: odometry(encoders from motors) and camera. Both of information sources can give me estimate of robot's ...
2
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1answer
67 views

Determining power of white noise component of an incomplete time signal

I want to determine the power of the noise component of a time dependend signal x(t) (similar to picture below) With constant sampling rate I use Parceval's Therorem and calculate the standard ...
2
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1answer
124 views

Removing baseline drift from ECG signal

I am trying to design a high pass filter to remove baseline drift from an ECG signal. the baseline drift is of very low frequency like 0.3Hz or so with an amplitude of 25% of the ECG signal. But the ...
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2answers
55 views

Adaptive gaussian filter for noise image

I am looking for methods to enhance noisy images, where: some pixels in the image are very noise, some other pixels do not contain so much noise. My first thought is to build an adaptive Gaussian ...
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0answers
49 views

Performance of adaptive signal processiong algorithm in noise not working

I am taking a course on signal processing and have been looking at various algorithms performance in presence of additive noise of different SNR. I was implementing Least Mean Square (LMS) algorithm ...
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2answers
235 views

Adding white noise to complex signal (complex envelope)

Good day everyone. So, i run in to trouble - how to add white noise to signal samples? For now i'm working with MSK signal - quadrature modulator and quadrature demodulator + viterbi processor. My ...
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1answer
53 views

Forecasting noisy data with polynomials

What's the best way to incorporate polynomials or sinusoidal equations into a linear model to predict a future amplitude in this sort of data? You can see that if those polynomials continued to go on, ...
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2answers
110 views

Poisson noise and curve fitting - denoise first?

If I have an image that is severely corrupted by Poisson noise, and I want to fit a function to the image, is it "better" to attempt to denoise the signal first before fitting, or should I move ...
2
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1answer
75 views

Generating a time series given a transfer function

I'm trying to work my way through a paper I found online, titled "Three Models of Wind-Gust Disturbances for the Analysis of Antenna Pointing Accuracy" by W. Gawronski, 2002. ...
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2answers
283 views

How to find peaks and periods?

I am looking at data like this: Source data: http://pastebin.com/raw.php?i=L6cd8d5K The data is quasi-periodic, there is a distinct cycle but it is not an exact repeat, and the period changes ...