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

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Detect gradual increase then decrease in slightly noisy data

I have data thats not too noisy and I am trying to detect a pattern where it gradually increases then decreases in a short period of time (20 ticks? it should be roughly similar per session but can ...
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1answer
31 views

Covariance matrix associated with random DC level in Gaussian noise

Given a signal $x[n] = A + w[n]$ where $A$ is a Gaussian random variable and $w[n]$ is Gaussian white noise, then the covariance matrix of the signal is given by $[C(\sigma^2_A)]_{ij}=E[x[i-1]x[j-...
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0answers
23 views

orthogonal base of chirp [on hold]

Do you know a method to construct an orthogonal base of chirp?
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5answers
79 views

How can telecommunication system know which part is signal and which is noise? [closed]

When signal is received how can receiver know which part of received signal is signal and which part is noise??
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1answer
37 views

Is there noise that is multiplied with the signal? [closed]

In most cases, additive noise is considered. I was asking myself: Is there type of noise when we multiply input with noise? My current approach: Yes! In the case of the mobile communication, we ...
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2answers
48 views

Why use $\chi^2$ test to determine the presence of white noise?

I want to test for the presence of broadband noise in a snapshot 1000 complex baseband samples recorded by a software defined radio. As a follow-up to this post, why was the $\chi^2$ test used? How ...
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0answers
28 views

Simulating Phase Noise: How to do it?

I have a system that I am simulating, and I want to add phase noise to the process. I didn't know how to do it, so I have been conducting an literature review. I found a good reference with an "easy ...
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1answer
84 views

What is the noise whitening process?

I came across this process when working on OFDM in wireless communication. It's mentioned if we have two copies of a signal resulted from SIMO system (Single Rx Multiple Tx), we can process the noise ...
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1answer
42 views

Remove multiplied white noise from periodic signal

I need to remove noise that is multiplied to a periodic signal using a maximum of 7 periods having no information about the noise. I have tried to use auto-correlation - abs(ifft(fft(signal.*noise).*...
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1answer
27 views

Best digital noise reduction in optical spectra measurement

I am using an optical spectrometer to measure the reflectance of some surfaces; the output is essentially a set of photodiodes' signals: for each photodiode I have a discrete time signal every $T$. ...
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1answer
33 views

Spectral Subtraction python implementation error

I am trying to implement Spectral subtraction in python. I am new to DSP. I used this article as reference and below code is what I can come up with. Of course I did not get the expected output. I ...
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0answers
21 views

Backgroun noise in voltage vs time graph

I am analyzing a voltage vs time graph and I am coming across sinusoidal background noise in the cathode. I was wondering what the best method of getting rid of this noise would be on python. So far I ...
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0answers
28 views

How to add overlapping frames after processing a signal

I have to perform spectral subtraction on a signal in python. I have followed the steps specified in this link http://practicalcryptography.com/miscellaneous/machine-learning/tutorial-spectral-...
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0answers
17 views

Multiplicative Input-Dependent Noise [closed]

This question might not be exactly suitable to the question format of StackExchange but I couldn't find a better way to put it forward. Lately, I have been dealing with ECG Signal processing and due ...
2
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1answer
42 views

Linear Predictive coding vs AR modeling

I'm looking for a suitable explanation of the circumstances in which the LPC error polynomial for a discrete time process x[n] is replaceable with an error polynomial categorized under the AR model? I ...
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0answers
30 views

Noise removal and speech enhancements

I am working with peak extraction from audio files (something like shazam) in python. I only need to focus on human speech. Audio is recorded from single channel common mic. Can someone help me with ...
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1answer
86 views

Designing an experiment to show blue noise not adding noise below nyquist and not aliasing above

I read this paper from 1983 "Spectral Consequences of Photoreceptor Sampling in the Rhesus Retina". This paper talks about blue noise sampling patterns in the retina and says that: The results (...
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1answer
15 views

What are the most robust implementations of passive/self-localization assuming high noise and reverberation?

I am doing research on a related subject that requires the use of TDOA estimation of two signals in an environment with a great deal of noise and reverberation. If anyone had any expertise on (or ...
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0answers
27 views

Noise PSD and sampling rate relation

Let's consider generating samples of a random process like white Gaussian noise (AWGN). Let's assume I am generating $N$ samples of AWGN with variance $\sigma ^2$ in MATLAB by using randn() funtion i....
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1answer
17 views

What kind of noise is city noise?

White, pink, brown...? In general, to what category does it subscribe the spectrum of city noises, like traffic noise, ambulance/police siren, alarms, etc, put together? If the question is too broad, ...
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0answers
8 views

Voice masking for removing voice and not birdsong

First the problem I'm tyring to solve: I'd like to find a way of removing any potential noise from audio files recorded in noisy environments where we are trying to record birdsong. This is for the ...
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2answers
61 views

Power spectrum density and frequency

if i have some random signals (sampling rate = 10Hz, 0.1s per data) Using python library i transformed it to power spectral density power spectral density forms = f, psd (using mlab.psd) I'm really ...
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2answers
49 views

Expectation of deterministic signals

Maybe this a stupid question, but I came along with this point and I would like to confirm that I am not wrong. I found some similar posts in StackExchange, like: Expectation and Auto-correlation of ...
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1answer
50 views

What's the relationship between the parameters of this noise generator and the gaussian curve it produces in the frequency domain?

This algorithm produces a sequence $y$ having a magnitude spectrum that resembles a normal distribution, peaking at frequency $\omega$: $$b[n]=(1-\sigma)b[n-1]+\frac{\sigma}{\omega} C$$ $$p[n]=p[n-1]+...
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0answers
24 views

How do i estimate the momentary white noise out of three signals sampled at different frequency and phase?

I have three signals sampled at different three frequencies $Fs_1, Fs_2, Fs_3$. They all suffer from the same white noise source. I allow my self, if needed, to sample at a higher frequency than ...
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1answer
34 views

Measure 3-D length using smart-phone's accelerometer

I'm wondering if we can measure 3-D length only by our smart-phone's accelerometer. And we all know these low cost IMUs are not accurate. You can model accelerometer's error this way: $$ a = f*a' + g ...
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2answers
87 views

Understanding PSD: Why Does Power at High Frequencies Affect Low Frequencies?

I'm trying to wrap my head around power spectral density on a conceptual level, but I am having some difficulty. Suppose I have a communication system where I am receiving and sampling white Gaussian ...
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1answer
35 views

Group delay using cross correlation?

An input signal + (thermal) noise travels through a channel and can be measured at its output. Is it possible to use cross correlation between input and output signal to measure group delay? If not, ...
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2answers
30 views

improving pre-processing (noise removal) orange seven segment display for OCR reading

About this project: Older images have the date they where taken placed on the image, in the bottom left hand corner. The goal is to extract this date and put it in the EXIF data of the scanned photo. ...
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0answers
44 views

Plot Background Noise

I am a total newbie in signal processing. I have been trying to plot on simulink a time/frequency domain noise in PLC (Powerline Communication) that matches a real-world research "...
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0answers
15 views

Removing known audio signal from unknown stream

I am looking for a way to remove a known signal, A, of fixed length, from an unknown audio stream, B, when signal A can be mixed into signal B at any point in time. I may be mistaking but converting ...
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0answers
66 views

frequency spectrum of a sampled signal, PSD and power discussion

Before I go into my question, I first want to review the basics of sampling a signal and at the same time I build the basics of my questions so that they make more sense. I know I have asked couple of ...
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1answer
142 views

How Does the RMS of White Noise Change with Sampling Frequency?

There is an analog system which includes the continuous-time linear equalizer (CTLE). With some .noise analysis the power-spectral density (PSD) of the noise in that system is provided. So let's not ...
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1answer
41 views

Play with a Gaussian random set in the frequency domain to obtain desired effect in the time-domain

Please assume we have a set of 100 random numbers obeying Gaussian PDF in time-domain. Let's index them 1-100. Within a time-accurate simulation, I apply four operations on this dynamic set every ...
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1answer
49 views

Adaptive filter to scale and phase shift two sensors output

One way of separating downgoing and upgoing wavefields in offshore seimic processing is to add signals from hydrophone and vertical component of the geophone (they are co-located). Hydrophone only ...
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0answers
45 views

filtering 1D signal with very low SNR(<2)

I have recorded speech using a microphone(with 16bit A/D converter). The signal has a frequency range of 300Hz to 1000Hz, I have recorded 3.5 seconds of the speech and 1.5 seconds of the baseline(no ...
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1answer
55 views

Audio transfer function modelling with pink noise + signal

I'm trying to model a transfer function for a noisy audio system, specifically to measure delayed system response. Before I can confidently apply control, I need to verify that I can exert control ...
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1answer
60 views

Zero padding effect on a FFT of gaussian noise

I have a gaussian noise $\nu(t)$ with variance $\sigma^2$. After a FFT I get $X(\omega)$. If now I do the IFFT on the $X(\omega)$ can I say that the result is still a gaussian noise of variance $\...
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1answer
69 views

efficient Noise cancellation & suppression algorith to use in VoIP for low latency

I am working on Noise suppression and cancellation in VoIP media engine. I am looking for noise cancellation & suppression algorithms and its implementation available with real-time low latency ...
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3answers
98 views

Extracting common signal without knowledge about noise [closed]

Given two noisy time series thought to contain a common signal, $$ x_1(t) = s(t) + n_1(t), \quad x_2(t) = s(t) + n_2(t), $$ what is the best way to determine $s(t)$ without assuming any distribution ...
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0answers
28 views

Computing Power spectral Density

Acronyms: Power spectral density, PSD Autocorrelation, AC Hey so I'm in my first ever DSP class and thoroughly enjoy the material, but absolutely suffer in the HW. I have this question ...
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1answer
19 views

Uncorrelated model error

A dynamical system evolves according to $x_{k+1} = M_k x_k + w_k$ $w_k$ denotes the model error. In a textbook, it is specified that $w_k$ is temporally uncorrelated and $E[w_kw_j^T]$ = $Q_k$ if j=...
2
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1answer
46 views

Does a collection of Gaussian random variables necessarily constitute a Gaussian Process?

If $\{X(t)\}$ is a Gaussian Process then the random variables $X(t_k)$ where $k = 1,2,3...n$, are jointly Gaussian. If each random variable $X(t)$ is a Gaussian variable, then will the random ...
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2answers
56 views

What is the value of $0.01\log_{10}$?

I have posted this question in math.stackexchange.com, [can be found here], which I originally thought it is a math question. I now believe this would fit more to the Signal Processing community. For ...
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1answer
57 views

Condition for modelling noise as white noise

I am reading a book on Communication System by Simon Haykin. In the topic of white noise there is a paragraph "We may state that as long as the bandwidth of noise process at input of a system is ...
2
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0answers
15 views

Evaluation of Jacobian for Extended Kalman Filter

For the non-additive noise case, \begin{equation} x_k = f(x_{k-1}, u_{k-1}, \xi_{k-1}) \\ y_k = h(x_k, \nu_k) \end{equation} the EKF takes into account the jacobian wrt to the noise terms $ L_{k-1} =...
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2answers
93 views

Problem with convolution

For a flat fading channel (SISO system) we have: $y=h \star s+n$ But for a mimo system, we have: $y=Hx+n$ with $H \in \mathbb{C}^{N_r \times N_t}$ Why is there not the product of convolution for a ...
3
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2answers
143 views

How detect signal from noise?

I'm trying to detect when a signal is "on" from samples I have. Those samples come from a software defined radio, if that matters, and the signal i'm trying to detect is a WiFi signal. The problem is ...
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0answers
19 views

non-eccentricity pattern noise

non-eccentricity pattern noise is a noise distortion applied to images, used in TID2013. I would like to know what "eccentricity" and "non-eccentricity" means in this context. Thank you.
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1answer
44 views

How much noise gets through my raised cosine filter?

I want to figure out how much of my total noise is getting through my filter. To see this, I generated a noise vector, applied the filter, and measured the output variance. However, the output ...