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Questions tagged [python]

Python is a high-level interpreted general programming language. Python has popular numerical and scientific libraries/packages, most notably numpy and scipy. The scipy.signal package is a powerful signal processing software collection. This tag covers the use of numpy, scipy, and other Python packages often used for SP computations.

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Unstable high-pass filter on mouse-generated signal

I am making a Desktop application using PyQT as the app is a Digital Filter You can add zeros and poles to a unit circle and apply the filter to the data the data can be of two types 1- saved data on ...
Mohamed Hazem's user avatar
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71 views

Discrepancy between time & frequency domain RMS magnitude

I'm looking at complex baseband RF at a sample rate of 2.56 MHz. I've plotted the FFT of the entire spectrum, a 16 kHz segment of that spectrum, and the output of 160 decimation low pass filter that ...
Deepstop's user avatar
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Unstable high-pass filter on mouse-generated signal using Python

I am practicing some DSP techniques along with desktop application development using Python and PyQt. In my filter design application, I am able to create a filter by placing zeros and poles on a unit ...
Kafka's user avatar
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1 answer
154 views

What is wrong with this sinc interpolation? (Zero padding in frequency domain)

I'm trying to pad $N=16$ zeros to the DFT of a $16$ point sinewave, but something is wrong either with my code or with my method. The method is this : I create a new $32$ point DFT where $F'(0),...,F'(...
In the blind's user avatar
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Remove noise from lung sound wav

I am working in this dataset data.mendeley.com/datasets/jwyy9np4gv/3? aiming to develop a machine learning model for classifying various diseases based on lung sounds during both expiration and ...
Zayo's user avatar
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1 answer
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2D Fourier downsampling to even number of points gives incorrect modes in the last column

I would like to downsample an image in the frequency domain to an even shape, similar to what is described in this post. I have been able to do this successfully with a 1D signal to both an odd and ...
Jacob Helwig's user avatar
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29 views

Issues obtaining Clarke Park transform

I have a three-phase electric signal and I've been asked to obtain its Clarke-Park transform (also called direct-quadrature-zero or dq0 transformation). I'm using this Python library, and I've gotten ...
J. Maria's user avatar
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2 votes
1 answer
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what does librosa.stft do that makes it different?

My understanding of the Short Time Fourier Transform is that first I need to frame the signal and window it, after that apply an fft on these windowed frames. Using Librosa: ...
kulon one's user avatar
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EMD in Python vs. Matlab

I want to move an analysis pipeline from Matlab to Python. I'm noticing a slight difference between the IMFs generated by the emd function in Matlab and those ...
Riley N. Boecher's user avatar
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1 answer
52 views

Noise (in dB) added to a signal but within range limits

I have a sine wave signal to which I add noise in terms of dB. This is based on https://stackoverflow.com/questions/14058340/adding-noise-to-a-signal-in-python The signal is sent to a DAC and there ...
Mart's user avatar
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scalogram shows black image

my goal is to generate scalogram from .wav file and save as jpg or png format,i used following code : ...
dato's user avatar
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2 answers
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How to normalize the FFT?

I want to normalize my FFT signal. From this page it says that we can normalize it by dividing the FFT result by the lenght of the signal in time domain. On the other hand, my supervisor told me that ...
Apinorr's user avatar
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2 answers
113 views

Visually identifying audio noise

I have an audio file consisted of a sole 440 Hz sinusoidal wave, which can be heard here. After some manipulation, I've added a noise to it, resulting in a second audio file, avilable here. The noise ...
JohnCalms's user avatar
1 vote
2 answers
211 views

How can I apply a filter to remove reverberation with python?

I am developing an algorithm that automates the processing of audio files for the assembly of datasets of machine learning models. Among the steps to be followed for the processing of the files is to ...
JouseJG's user avatar
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Detect GUI Buttons in every application window with python

I want to detect every buttons in every application windows. For example, in explorer window, I want to detect every Tags, folders, files and Buttons like "page back", "page forward&...
roy's user avatar
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104 views

Using python to remove Gaussian noise and a high frequency signal from a audio file

I have an audio file where people are talking, and Gaussian noise and high-frequency signals have been added to the file. My goal is to remove the noise from this file using Python. For this ...
Joe's user avatar
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1 answer
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Scaling plots after FFT

I have multiplexed 32 signals into 1 signal with python. Now I want to plot that signal in time domain and to plot it's amplitude spectrum. Professor gave us his plots so we can look up to it. These ...
3d014's user avatar
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1 vote
1 answer
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Impulse response and amplitude-frequency characteristic of a communication channel

The task is to implement communication system for transmission of 32 multiplexed signals through communication channel represented by copper cable whose frequency characteristic is given by: $$H(f) = ...
3d014's user avatar
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1 answer
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Finding the impulse response between two microphones

I have made recordings of a single source (musical instrument) with multiple microphones and in the interest of limiting the size of the final project, I would like to find a way to get the impulse ...
arno sica's user avatar
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41 views

Looking for paper about applications of using phase screen to model space laser communication

A phase screen is a concept used in wave optics to model the statistical properties of wavefront aberrations caused by a medium. In the context of light propagation through atmospheric turbulence, for ...
138 Aspen's user avatar
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176 views

Plot an eye diagram with a cmap 'hot'

I'd like to plot an eye diagram with a 'hot' colormap that becomes clearer not when the signal has high values, but when the signal is dense at an instant in time, see picture below. Here is what I'...
user70072's user avatar
1 vote
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How to get Power Spectral Density of file using this research paper method?

I came across this research paper. In this they have mentioned power spectral density calculation of various file. I have read the paper and try to calculate and plot the graph, don't know it correct ...
i_am_learning's user avatar
1 vote
1 answer
560 views

How to calculate a 3D Fourier Transform?

I am currently employing a centered finite difference method to simulate the excitation of a circular membrane by a forcing term in Python, and the code is functioning as intended. To further enhance ...
Manuel Borra's user avatar
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1 answer
97 views

How to play sound at specific location (horizontal/azimuth) using wav and python ? without libraries

how to set sound location left/right (in mono audio) and azimuth (up/down) of the wave? I know there are a lot of different libraries doing that, but I'm interested in some minimal examples to ...
tempdeltavalue's user avatar
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31 views

Python - CV, contour and measurements

I have small problem with cv in Python and rhombus. I can read frame from the camera and create contours... ...
Krzysztof's user avatar
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17 views

Face Detection real-time with Local Binary Pattern

I'm writing for code to detect human face by Local Binary Pattern algorithm in webcam, but with my limited knowledge in optimization code, I having to struggle in detect in each frame , I want to say ...
Hau Chung's user avatar
0 votes
1 answer
58 views

Sound having lower rms values but higher loudness.What are the possible reasons?

I have some noise datas which are having lower RMS values. But don't know why they are very loud when I am normalizing and playing them. After normalizing the audio remain still low rms values. But ...
Bisnu Sarkar's user avatar
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0 answers
117 views

FIR Filter Design in python

This is mine code for fir_filter_design in python. But I'm getting wrong output for low-pass, band-pass, and high-pass magnitude response. ...
Mr Superfluous's user avatar
2 votes
1 answer
84 views

Problem by designing and filtering a Bessel-Thomson filter in Python

I have an issue when I want to filter a signal with a 4th order Bessel-Thomson filter with a cutoff frequency at 18 GHz. 1. Generate data at 50 Gbps (T-spaced) ...
user70072's user avatar
1 vote
0 answers
46 views

Local Binary Pattern rotation

How does LBP work? To learn that, I decided to calculate by hand for the matrix but the problem is about the rotation pixel over the image based on the radius and neighbor of LBP. I do it clockwise ...
chews's user avatar
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1 vote
0 answers
29 views

Get FFT from a Wav after a hanning filter with 25% overlap?

I have a program that allows me to record wav and get the FFT all at the same time. However, the FFT I have I can't export it to work with. So I need to make a script to get it from the wav. Can ...
THORNADOR's user avatar
1 vote
0 answers
54 views

what is the meaning of the second line in the code?

what is the meaning of the second line in the code , i am not understanding the meaning of it
Nabanko Das's user avatar
1 vote
1 answer
109 views

Frequency spectrum of interpolated sine

When interpolating a sine wave in Python, it seems I get a lot of additional frequencies closely around the fundamental. Why is that the case? I would have expected a more or less similar spectrum, ...
MisterFilter's user avatar
0 votes
1 answer
120 views

Time-varying shot noise generation

I'd like to model the behavior of photodiodes, the input is like data bits (0 & 1) where each bit is represented maybe with 100 samples / bit and the bit rate is $B$ bits/sec with period $T_{bit}=\...
Mohamed Osama's user avatar
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0 answers
78 views

How to adjust the length of the window of the Fourier transform with respect to the length of the signal in Python

I ran the following code in Python, setting the window length to 5s, but he reports an error as the window length does not match the signal length. How should I adjust it please? code: ...
BaiYueChu's user avatar
1 vote
0 answers
55 views

Simulate Op-Amp low-pass transfer function in Python

I am struggling to simulate the frequency response of a simple op-amp low-pass transfer function in Python. The results I get are not accurate. The transfer function is $H(s)=\frac{1}{1 + s\tau}$, ...
MisterFilter's user avatar
2 votes
0 answers
208 views

Detecting the piano notes using python

I am trying to build a small application that is very similar to simply piano, where I am trying to detect the piano notes, my program will be listening and when a key gets pressed it will estimate ...
Sanju Reddy's user avatar
1 vote
0 answers
52 views

PyWavelets CWT : error when differentiating after convolution?

I'm trying to understand the implementation of CWT in PYWT. This topic has already helped me quite a lot but there is still a thing that is unclear to me : why is the result differentiated only after ...
Tanguy Jonv's user avatar
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0 answers
11 views

How to reconstruct MMW image using electrical field in each direction at Receiver points using Back projection algorithm

I have used a structure including 109 Receivers and 4 transmitters in order to do MMW imaging(multistatic imaging). Imaging was done in 3 different frequencies. So, now I have electrical field in each ...
mohammad rezza's user avatar
3 votes
2 answers
549 views

Given two low-pass digital IIR filters, find bandpass coefficients

In the case of FIR filters it is easy to get a band-pass filter by subtracting the coefficients of two low-pass filter filters or by convolving a high-pass and a low-pass filter: ...
nopeva's user avatar
  • 133
0 votes
0 answers
37 views

I have a distorted signal and want to achieve a perfect wave in the output. What am I doing wrong?

I've been told to use a digital filter, but this solution achieves what I've been told to do. It is so simple it is dumb, what am I missing here? I want to be more scientific about it. ...
kovyakov's user avatar
6 votes
1 answer
896 views

Implementing logarithmic AGC (automatic gain control)

I'd like to implement the Log(arithmic) AGC from Understanding Digital Signal Processing But with ...
ge45mue's user avatar
  • 163
1 vote
1 answer
84 views

Unexpected frequency components after applying bandpass filter in python

When I apply a bandpass filter in python to a pure sinusoidal signal, it seems that after filtering I get different frequency components across the spectrum (see orange line below). It looks like ...
MisterFilter's user avatar
2 votes
1 answer
134 views

Help with Implementation of Transfer Function using Python or MATLAB

Relatively new to the DSP side and wanted some help to implement this approach using Python (with NumPy, SciPy libraries) or via MATLAB. Background of the problem: I'm running a linear dynamic loads ...
ganondorf29's user avatar
1 vote
1 answer
84 views

What is the best method of describing the effects of downsampling on a chromatographic signal?

I am in the process of compressing a set of chromatograms to develop a preprocessing pipeline, that will end with DTW for peak alignment. During this process I have downsampled a signal from 0.4 ...
jstathakis's user avatar
0 votes
0 answers
25 views

Incorrect epoch labelling

I am processing an EEG signal acquired by showing 10 image of each of 40 classes. I want to label the signals converted to epochs to their corresponding class labels. The ...
madiha Rehman's user avatar
1 vote
2 answers
318 views

Overall spectrum computation from Short-Time-Fourier-Transform

I am trying to computing the overall spectrum of a given signal from its Short-Time-Fourier-Transform. I am using python to do this and I wrote my function to compute the STFT: ...
Ciccios_1518's user avatar
1 vote
0 answers
176 views

Is lock-in amplifier a correct approach?

I have a noisy signal which is the voltage output from a photodetector circuit. I have researched about extracting signals, and found that lock-in amplifiers are one of the main approaches for the ...
Teena's user avatar
  • 21
1 vote
1 answer
298 views

Lock-in Amplifier: How to improve the output of lock in amplifier?

I tried to extract a pure signal from the noisy signal using a lock-in amplifier with the help of python code. The output is from a photodetector circuit. These are the reference signal, expected ...
Teena's user avatar
  • 21
1 vote
1 answer
68 views

Periodicity problem with FFT for generating "starburst" from aperture

I am following a paper on computationally modeling optical phenomena within a lens. (https://resources.mpi-inf.mpg.de/lensflareRendering/) At some point they use the Fourier power spectrum of an ...
geloescht's user avatar

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