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

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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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24 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
58 views

how to create synthetic $1/f$ noise?

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
14 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
38 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
27 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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36 views

how to calculate noise power [closed]

I want to calculate the noise power after getting received N samples of noise, I should implement this in C++. Here is my code and I think that is not correct ...
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1answer
19 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
31 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
70 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
77 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
26 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
44 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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1answer
97 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!
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1answer
64 views

Tinnitus Masking with broadband Noise

I have the problem of masking tinnitus. I have the following questions: Can broadband noise mask tone tinnitus, or any kind of tinnitus (such as narrowband, or chirp)? Assume an audiogram test has ...
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0answers
30 views

Can sample aliasing of strictly white noise lead to random walk (drift) in the sampled signal?

Aliasing of tones higher than the Nyquist frequency, and where the tone may have some degree of nonlinear distortion can appear as low frequency 'drift' or even near static bias in the sampled signal. ...
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3answers
184 views

Removing unwanted square-wave noise from a signal

I have a signal, s, given at the end of this message. I need to remove the square wave shape from it. The desired signal is actually very small and it has been contaminated by a strong square-shape ...
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1answer
34 views

Noise power transient at output of RC filter

Consider a simple first-order RC filter with AWGN input noise with single-sided density of No. We know the output noise power is No/(4RC). What is rarely noted is that this is true after steady-state ...
2
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1answer
39 views

Gaussian noise generator algorithm trouble

I stumbled upon the following algorithm for Gaussian noise generation and I just can't figure out how this is supposed to work at all. The algorithm is as follows: First of all: j = argmin_i (q_1 ...
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0answers
34 views

Generating Gaussian noise uncertainty?

How can I generate non-stationary Gaussian noise (noise uncertainty) using Matlab? where the noise power fluctuate between $(1+p)^{-1}$ to $(1+p)$ where $p$ is the uncertainty factor in dB. Best
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62 views

Removing background noise (sound) by attenuation below certain amplitude (loudness) in MATLAB

I have to write a MATLAB code that attenuates sound at low amplitudes to zero, in VoIP. Meaning I have to reduce low amplitude sound to zero E.G. while speaking I have some background noise (like the ...
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2answers
83 views

carrier frequency difference

Papers use wireless device-dependent radio-metrics as fingerprints. A radio-metric is a component of radio signal, amplitude, frequency and bandwidth. Each device creates a unique set of radio-metrics ...
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0answers
48 views

filter out an expected but not regular signal

I am stuck with a case where I need to get rid of a portion of sinusoidal signal that suddenly appears in my main signal (sine wave). my total signal will look like: $ s(n) = \begin{cases} ...
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1answer
88 views

Equalizing 1/f noise

I am recently acquiring data through ADC on signals ranging from 0.1 Hz to 50 KHz (Fs = 128 KHz). I noticed that apart from the white noise, I have something similar 1/f noise with a cutoff near 1 Hz. ...
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2answers
201 views

How to remove the noise without destroying the main edge?

I am working on a project. I want to segment a logo from a car and the picture's size is 3648*2432. The logo is selected by the red rectangle. I extracted this area and turn into gray level. The ...
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2answers
138 views

Fourier transform possible on non-rectangular part of an image

Dear Signal Processing readers, I want to introduce 'noise' into parts of images. Until now, I worked with rectangluar images for a similar purpose and did the following, using (inverse) Fourier ...
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2answers
97 views

Simulating noise in OFDM

I'd like to simulate a certain $E_s/N_0$ in a baseband OFDM MATLAB modem to generate SER curves. I randomize 50 QAM symbols with $N$ subcarriers each in frequency domain, add null frequencies (guard ...
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3answers
116 views

How to determine SNR from FFT of measured data?

I am doing impedance measurements, where I do a frequency sweep of a test current, and I measure the resulting voltage. Offline, I compute the FFTs of the voltage and current, and I want to make sure ...
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34 views

Estimate Image power spectrum of the noise

I want to implement Wiener filter. I have original image and image blured with linear motion. The one thing I am lack of(to implement it) is Noise power spectrum. I know that it is hard task. I've ...
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5answers
178 views

Improving Digitization by Adding White Noise Before Oversampling

I was reading a physics book and it said that when digitizing a signal white noise was added to improve the process. I don't understand how this works. Therefore my question is: When digitizing an ...
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3answers
92 views

Normalization purpose in signal processing

What is the purpose of normalizing the signal? If we have two signals on hand, how is it used when comparing these two signals?
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1answer
50 views

Frequency of a noisy signal with fixed width pulses

My electricity meter has a front panel LED which pulses in proportional to the current energy rate. The frequency changes but the pulse width is set at 250ms. Due to environmental conditions there's ...
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2answers
91 views

'A priori' and 'a posteriori' SNR

I am reading this paper about speech enhancement using a minimum mean square error short time spectral amplitude estimator for our speech enhancement project. Basically in the paper they mix a clean ...
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1answer
18 views

Expected value of coupled signals is zero

Suppose there are two vector signals, $u$ and $v$, which are functions of time. Given, $E[uv^T]=0$, what is the physical significance of this statement. For clarity, assume $u$ and $v$ are noises in a ...
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17 views

Noisy omni-directinoal UWB radar

I am working with an omni-directional UWB radar and need to make meaningful sense of the data to distinguish objects that could represent an obstacle. It is interfaced and giving me data, but I was ...
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1answer
105 views

Improving an auto-correlation based guitar pitch detector

I've seen many questions on this forum regarding pitch detection for musical instruments (commonly guitar), and spent a while reading through the answers to create a basic implementation of ...
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2answers
175 views

What is the rms value of a signal and how to use it

In some papers/books I found infos about a signal given as RMS value. What is the RMS value and what information does it contain? How can I compute it? Moreover, if they say that the signal is a ...
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1answer
61 views

Variance of white noise and the STFT

I hope someone can help me understand the meaning of variance in this case. I am reading an old research paper by Ephraim and Malah (for my DSP project) and it says: Knowing that $D_k$ is the FFT ...
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1answer
47 views

filter design for ECG

I would like to ask how to design a digital filter to remove $50$ Hz interference on an ECG signal. Do I need to use notch filter? Thanks.
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113 views

Generate band limited white noise to be used as excitation in ODE

I am trying to repeat an example I found in a paper. I have to solve this ODE: $25 \ddot{x} + 15 \dot{x} + 330000 x = p(t)$ where $p(t)$ is a white noise sequence band-limited into the 10-25 Hz ...
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96 views

How to calculate SNR of noisy signal?

Say, I have a noisy signal (clean signal + AWGN). When I pass this signal through my noise reduction program, I get the clean signal. My question is how to calculate the SNR before and after passing ...
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3answers
286 views

How does averaging increase the Signal to Noise ratio?

When attempting to spot activities on an EEG waveform given a stimuli, it is recommended that several trials be taken and their average is done to increase the SNR. Intuitively, since noise is not ...
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2answers
408 views

How is RMS and Peak-to-peak of white noise calculated

I have seen some devices which specify their internal noise in RMS or Peak-to-peak value. How does one calculate RMS or p2p values for white noise?
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1answer
85 views

Is it possible that adding noise to a signal can increase detection possibility?

I am simulating a feature detector in noisy environment which consist of AWGN Noise and Impulsive Noise. But I am getting a strange result as Signal with Impulsive+AWGN noise has better detection ...
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1answer
91 views

Digital low-pass filters; best practice application

I have time domain strain gauge data from a structure which is subjected to low frequency, random loading. The signal / noise ratio is pretty good, but I would like to try to improve on it as much as ...
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1answer
63 views

Confusion about how to calculate signal to noise ratio(SNR)?

I searched a lot but I didn't find a good answer. According to wikipedia SNR page, SNR can be calculated by both ratio of Power of clean signal to its noise Power either ratio of variance of clean ...
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26 views

Noise Figure And Amplifier Equation

I'm trying to understand how a particular equation works. The scenario is: there is a load of some resistance connected onto an amplifier with some noise figure. The thermal noise of the load alone ...
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22 views

Derivative of a noisy signal with multiple samples

I am trying to find the best way to get a derivative from the shown signal. It consists of a number measuring positions, which each have been sampled 50 times and then gone to the next point. My ...
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15 views

Estimating plant parameters from noisy frequecy response data

I have to estimate the parameters of a 1st order transfer function, namely, the coefficients, through experiment. I ran a few experiments and I have a bunch of input-output data vectors. The ...
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25 views

Unable to reproduce same quality results - Motion (Video) Magnification by MIT

I'm exploring the Eulerian Video Magnification for Revealing Subtle Changes in the World paper and trying to reproduce the same results they obtained, but in my own videos rather than the ones ...