# Questions tagged [noise]

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

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### detect what is noise in audio signal

I'm trying to filter noise from an audio signal. The signal was and is going to be recorded in a city environment which always contains some white/pink noise. At this moment I'm using two options to ...
964 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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### 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 ...
121 views

### Relative beat detection for two audio recordings

I'm trying to synchronize (overlap) two audio recordings of the same song: a complete HQ version, and an incomplete, noisy version (phone recording for example). The noisy recording may have had its ...
83 views

### How to understand "independent sample rate" of windows?

A window metric called independent sample rate is given in a book that I recently read. It says that in spectral estimation, the variance of power-level estimates is inversely proportional to the ...
110 views

### How to extract human voice from cluttered signal?

I have a signal which has human speech, background voice and noise as it can be seen in below figure. I have calculated its power spectral density (PSD) using many different methods which can be seen ...
105 views

### Pop and buzz noises caused by the signal process

There is a measurement called waterfall effect in audio systems. When you apply a sweep signal starting from 50Hz to 20KHz, it shows how long the resonance of the speaker goes. For example in the ...
495 views

### How to determine the CRLB for FFT based estimator with MATLAB?

I am trying to determine the CRLB for FFT-based frequency estimation in MATLAB. For this, I am simulating a single sinusoid in white noise with different amplitudes and constant noise power. Here is ...
141 views

### What is the difference in the algorithm for noise reduction in SoX and Audacity?

I've looked at this question, and I understand that SoX works way FFT of the noise, then subtracting that from the FFT audio, and then resynthesizing using FFT, but I don't quite understand how this ...
289 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 ...
144 views

### Energy Detection in Presence of Colored Gaussian Noise

Before asking my question, let me introduce the context: For spectrum sensing based on energy detection, which has been widely studied in presence of AWGN, the optimal detection threshold is computed ...
484 views

### Connections between quantum field theory and signal processing

I've been working with quantum field theory on the basis of it being a stochastic signal processing formalism for a number of years. The projection to fourier components within the forward light-cone ...
568 views

### Estimate Image power spectrum of the noise

I want to implement Wiener filter. I have original image and image blurred 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 ...
355 views

### Remove the extra peaks by lag

Suppose that we have some peaks of a signal and we know the time lag between dominant peaks. How is it possible to remove the extra peaks by applying time lag ? Lets say it in MATLAB ...
1k views

### Why PSNR decreases for Ultrasound Images?

I am working different types of filters to remove speckle noise in ultrasound image. I have taken the below paper as my base paper and trying to reproduce the results of this paper: My Base Paper I ...
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### Calculation of an autocorrelation function

A sample of a random process is given as: $$x(t) = A\cos(2\pi f_0t) + Bw(t)$$ where $w(t)$ is a white noise process with $0$ mean and a power spectral density of $\frac{N_0}{2}$, and $f_0$, $A$ ...
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### Modelling of quantization noise with logarithmic steps

I have to modell the quantization noise of ADC. I only know that the maximum relative error is 1 dB. Since this is logarithmic, I find it hard to formulate an appropriate model for the quantization ...
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### Check if I has right: Is this the Extended Kalman Filter

I have learn the Kalman-Buncy filter for the LQG controllers. I know that this is a signal processing forum and not robotics not math forum. But Extended Kalman Filters are daily discussed here. ...
277 views

### AWGN Build vs Randn noise do not match

I am generating noise in two different cases with the same SNR once using AWGN command which is a built in command and second time using randn function with the correct scaling however I am getting ...
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### Kalman Filter - Gaussian representation

I'm trying to understand well the kalman filter, as a result i'm having this question : Why do we represent noise with a Gaussian ? what does this really mean intuitively ?
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### 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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### 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 ...
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### Extended kalman filter for accelerometer data on shaking table

I am using an accelerometer to record the motion of a shake table (a rocking table) which moves forward and backward in one direction. The signal is very noisy and decided to use Extended Kalman ...
81 views

### Smoothing data from a 3D camera

The camera uses two cameras and reflective infrared markers to compute 3D positions. For recognized marker configurations, the camera computes a translation and an orientation (quaternion). For stray ...
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### Equivalent number of looks (ENL) calculation

As stated in gagnon1997speckle in paragraph 2.2, under the unit-mean noise assumption one can say that: \begin{equation} ENL = \left(\frac{\bar{y}}{\sigma_{y}} \right)^2 = \frac{1}{\sigma_{n}^2} \end{...
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### Finding circle in binary image (R, not matlab)

How would I extract the circular area of a binary image which looks like: The two rods emerging from the side of the circle are noise. I know of the hough transform in Matlab. However, I am using R ...
1 vote
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### Smoothening Noisy FFT

I've got the following FFT with a sampling frequency of 192 kHz that has around 17.000.000 samples. The signal is a hiss of escaping gas. This looks noisy and i want to determine the characteristic &...
1 vote
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### Frequency content of a noisy signal

To find the frequency content of a noisy signal (PSD), there are two methods below: #1 Take the fourier transform of its power signal (square the noisy signal) #2 Find the autocorrelation function of ...
1 vote
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### Help figuring out how to extract audio content correctly from a file that produces spiky waveform with audible hiss/noise

I'm trying to extract PCM wave sequences from different files (files that are NOT audio files but contain audio data, and other data all in one file), and while this code does extract the expected ...
1 vote