All Questions

16,591 questions
5 views

Sigma Value change after down-sampling

I am I have an image with a specific sigma(say 2). I downsample the image. Will thr be any change in the sigma for the downsampled image?
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Change durration/tempo of a .Wav file without introducing pops or pitch shift?

I am attempting to develop a similar function as Audacity's Effects>Change Tempo effect. Or more specifically: I am in need of a way to create a funciton in my ...
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I need to read two .wav files. One of them is a song, and the other one is impulse response. Then, I have to convolve them. In fact, I have read them by using ...
14 views

-6db low pass filter and synthesised tone

I want to synthesis a harmonic sound with fundamental frequency of f0 and 20 partials with amplitudes of a0, a1, a2, a3 ....a20. The amplitudes should reduce a - 6db per octave like a low pass filter ...
30 views

Intelligent Noise Removal in Data

This question is linked to this question: I have this data: ...
26 views

Bandpass filter for audio wav file

How do I apply a bandpass filter on an audio file which is in wav format? And write back the filtered data in a new wav file for further analysis.
14 views

Elimination of image blurring using noise model restoration techniques

How can the blurring be eliminated from image using the noise model restoration process techniques? To my knowledge the answer must be filter.If yes,then which filter is used?
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dft of sampled sine using python

I'm trying to write a python script to perform a 100-point DFT over a finite length sample of a sinewave at 1/8 the sampling frequency. I'm curious why my DFT magnitude plot has two spikes in it when ...
43 views

PSD subtraction

I am interested seeing the difference between two power spectral densities (PSD) as a noise reduction exercise The blue line is the psd of my signal, and the the orange line is the psd of the ...
17 views

Multi channel signal enhancment inequality proof

Assume that $\mathbf{h}(f)$ is a spatial filter coeff vector, and $\mathbf{d}(f)$ is the steering vector. $\mathbf{\Phi_v}(f)$ is the correlation matrix of noise. How do i proof the following ...
37 views

How is the Gaussian kernel related to the Euclidean distance of the neighbourhoods in the non-local means algorithm?

I am reading the paper A non-local algorithm for image denoising that describes the original non-local means algorithm. They define (p. 3 of the pdf) the distance between two square fixed ...
14 views

Signal ECG Noise correction

in order to make the correction of an ECG signal full of collector noises from a sensor, I use the fast Fourier transform (FFT) method and it sends me complex numbers, my problem is that I do not know ...
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ECG raw signal problem

I am getting this raw signal. cannot understand why its going up and then down again, like a cycle. Any suggestions?
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Possibility of using Power allocation with Maximum likelihood estimation

I have a basic question about maximum likelihood (ML) estimator and its implementation with power allocation. Suppose we are using $MIMO$ system with $4$x$4$ transmit and receive antennas, so the ...
18 views

Effect of down mixing on complex demodulation method

As I know, IQ demodulation (complex demodulation) consists of three steps: Down mixing X(complex demodulation)(t)=X(real signal)(t).{exp⁡[(-i2π(f_demodulation).t)]} low pass filtering decimation ...
20 views

FIR filter window method [duplicate]

In the window method for filter design it is explained that we do an ideal filter and then we pass it to time domain, but it will be time limited and then... Why don't we filter directly in the ...
41 views

How to find location of impedance in electrical (transmission line) network using reflectometry?

I am trying to find the location of impedance mismatch on the transmission line network using sequence time-domain reflectometry through MATLAB Simulink. In this work, I can find the location of some ...
29 views

What is the technical term for the product of “number of pixels” and “number of channel per pixel”?

Assume I have m x n pixels of an RGB image. If I calculate 3mn, what is the name of quantity for this value?
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Relationship between Frequency response, magnitude spectrum and gain

I have been reading quite a lot of DSP related materials online and offline (books etc.) lately. I come across the terms frequency response and ...
22 views

Remove Powerline interference from an Electrocardiogram(ECG)

how do i go about removing 50Hz powerline interference from an ECG using filter design techniques such as pole zero placement and Butterworth filter design?
35 views

How do I denoise a microscope image?

I'm working in a computer vision project, where the goal is to detect some specific parasites, but now that I have the images, I noticed that they have a watermark that specifies the microscope ...
81 views

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How to realistically represent antenna elements in phased array system alongside it's 3D gain response?

Please find the figure below where I've plotted a 3D gain response(in dB) of an antenna array system for beam-steering application and overlaid the actual antenna element(in red X marks surrounded by ...
19 views

QPSK signal 'passthrough' - not working as expected

as a fun project I am trying to build Quadrature Phase Shift Keying (QPSK) modulator & demodulator for a Digital Video Broadcasting (DVB) application. I am using the LimeSDR mini as my hardware ...
31 views

Prefix code of symbol pairs

An input sequence consists of two symbols, each independently and randomly chosen from a set of symbols with known associated probabilities. Each symbol is independently encoded using a prefix code ...
47 views

Delay in Savitzky-Golay filtering

I am applying a Savitzky-Golay filter to a signal, using the scipy function. I need to calculate the lag of the filtered signal, and how much is it behind the original signal. Could someone shed ...
7 views

Is the WTST-NST filter available as a module in some python library?

I need to implement the WTST-NST filter (wavelet transform based stationary non-stationary filter) to denoise some sound files (preferably in Python). I am from a Mechanical Engineering background ...
25 views

What is energy in image processing?

There are several web articles on the topic, but, after having read them, I still don't know what "energy" is, in the context of computer vision (CV) and image processing (IP). It is related to ...
25 views

I want to plot a gaussian pulse in MATLAB in the frequency domain, with its centre at the highest value

I have tried one way but i am getting 2 peaks at the edges as shown in the picture. I have used 1 part of my code for the signal generation where i used the gauspuls command (reference: www.simsonic....
11 views

what waveform using to send qpsk signal with IQ tranceiver

I have an SDR tranceiver (AD9361 on fmcomms3) working with IQ channels, i wanted to make a c++ software that modulate and send a digital QPSK signal but i'm a beginner in digital signal processing and ...
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How to relate power spectral density with the number of resource blocks in LTE?

I am running a simulation with 100 Resource blocks for LTE OFDM and I plotted a PSD for it. Now I am able to bring down the out of band emissions when I perform an algorithm on it. Based on the ...
13 views

Interpreting results of multiplying signal and wavelets in the frequency domain

I have followed a lot of stuff on mike cohens website and have managed to make a filterbank of Morlet wavelets and convolve with an incoming block of samples. This of course is a computationally heave ...
16 views

Signal ECG , collecte & visualize data

I am currently working on a sensor that visualizes an ECG signal and visualizes its data. Its principle is that it has 3 electrodes that must be placed in specific parts of the body .... I would like ...
12 views

Term for signal waveform correction or demodulation

Let say a periodic signal waveform $v(t)$ can be modeled as: $v(t) = f(\phi) A \sin(2\pi ft + \psi)$ where $A$ is a constant amplitude, $f$ is signal frequency, $t$ is time and $\psi$ is a constant ...
46 views

How is the decay of a signal exemplified in a Fourier Transform?

Is there any way to tell if a signal is decaying from its fourier transform?
34 views

Speech processing using matlab

My teacher gave me a project speech processing using matlab. I've completed up to point 6 but I do not know anything about points 7 and 8. Is there anyone who can help me please
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Scipy Deconvolve help

I was playing with the deconvolve method in scipy and I can't seem to get it working properly (I am still really new to DSP/deconvolution). I convolved a gaussian with a fwhm of 2.0e-9 with a ...

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