5,898 questions
0
votes
0
answers
58
views
How to correlate packets?
I'm trying to simulate a transmission chain in GNU radio and send an audiofile, my output file has very loud pure noise but the original audio can be heard underneath. Looking at the output wave shows ...
1
vote
1
answer
65
views
Raman spectral data format for MCR-ALS [closed]
I have a chemometrics project where I need to put Raman Spectroscopy data files into a Multivariate Curve Resolution model. I have been given .CNF files which came off the instrument, converted into ....
3
votes
0
answers
91
views
Error calculation for a time series using autocorrelation
I'm trying to calculate the autocorrelation time for a time series generated from molecular-dynamics trajectory frames. I used several methods to estimate the autocorrelation time because I need it to ...
2
votes
1
answer
63
views
Release section of ADSR envelope not working
I'm trying to make a digital audio synthesizer from scratch in C++ using a combination of resources. I'm using functions from raylib to play a raw audio stream. Here's the code:
#include <iostream&...
0
votes
1
answer
58
views
How to decode the bidirectional DShot eRPM telemetry waveform from an ESC?
I’m working on decoding the bidirectional DShot (bidir DShot) telemetry signal from an ESC.
I’ve read the article DSHOT - the missing Handbook, which explains that the ESC sends back a 21-bit ...
2
votes
1
answer
139
views
FFT-based quasi-steady detection issue
I am trying to detect the beginning of a quasi-steady regime in time series data representing drag (Fx) and lift (Fy) forces after an initial transient.
Initially, I used a slope-based method, but it ...
1
vote
0
answers
82
views
How to implement range doppler map on Infineon CY8KIT-062S2-AI
Recently, I have been trying to take the raw output from the Infineon BGT60TR13C mmWave radar on the CY8KIT-062S2-AI board and process it into a Range Doppler Map using the onboard CPU.
One issue that ...
5
votes
0
answers
128
views
Why does my real-time FFT of a logarithmic sweep keep sinking — and why does this weird normalization fix it? [closed]
I’m building an open-source audio spectrum analyzer for loudspeaker manufacturing. The “killer feature” is using a logarithmic sweep as the excitation signal, and analyzing the response as the sweep ...
13
votes
2
answers
2k
views
What's wrong with this Python assignment on signal processing - mostly Fourier series and transform
In this assignment I created the basic rect signal a[n] such that over the domain [-1000, 1000] it's 1 only at |n|<100, meaning it's an array (complex one with zero in the imaginary part) that ...
1
vote
2
answers
106
views
Issues with boundary layers in step propagation
I am trying to create a function which receives the transversal profile of a beam and outputs the transversal profile propagated by some distance. To exemplify the task, here is the profile of a ...
1
vote
2
answers
119
views
finding zeroes in complex polynomial taking forever in sympy, pathological case?
I'm new to sympy and python, I should have used R but wanted to try some AI generated code. This seems to work ok for other test polynomials but this eventually generates some symbolic results but ...
9
votes
1
answer
314
views
Generating blue noise with values sampled from a log normal distribution
Aim
I am trying to generate random signals with the following two properties:
The values should be approximately log-normally distributed (any long-tailed distribution bounded form below with non-...
2
votes
1
answer
121
views
Unable to understand product of Sinusoid signal with Hann window function in MATLAB R2024b
I'm writing a script for a certain signal processing application in MATLAB and have to multiply with the Hann window. Here's my code snippet:
Fpoints = 1e9;
d = 1e-7;
t = 0:1/Fpoints:d;
w1 = hann(...
0
votes
0
answers
95
views
Costas Loop Block in GnuRadio 3.8 Failing to Lock Phase Correctly on a Perfect Signal
I'm testing the Costas Loop block in GnuRadio (version 3.8.x) using a simple sine wave signal. The Costas loop is expected to lock the phase to a known value (ideally 0 for a perfect signal), but the ...
0
votes
0
answers
51
views
Exponential swept sine signals and amplitude scaling
I calculated the transfer function of a system in Frequency Domain by division of Y and X. Since I only deal with exponential sweep sines (ESS) as excitation, I want to reproduce the transfer function ...
1
vote
1
answer
64
views
Why do results from adjustable quadratic Volterra filter mapping not enhance dark/bright regions as in the paper?
Based on this paper Adjustable quadratic filters for image enhancement, Reinhard Bernstein, Michael Moore and Sanjit Mitra, 1997, I am trying to reproduce the image enhancement results. I followed the ...
2
votes
2
answers
113
views
desired frequency in discrete fourier transform gets shifted by the factor of increasing sample duration
I have written a python script to compute DFT of a simple sin wave having frequency 3. I have taken the following consideration for taking sample of the sin wave
sin function for test = sin( 2 * pi * ...
1
vote
2
answers
150
views
One frequency is absent from fourier transform representation of the addition of two cosine wave of same amplitude and phase
I have wrote a general python code in Sage-math to find out the Fourier transform of the addition of two different frequency cosine wave in order to plot the frequency domain in a graph. The function :...
0
votes
0
answers
75
views
Trouble implementing a super resolution algorithm with a frequency method
I'm currently trying to implement the following algorithm for image super resolution https://ieeexplore.ieee.org/document/56062 (doi:10.1109/29.56062) (there is a paywall but it's available on scihub)
...
0
votes
1
answer
78
views
subtract parabolic average from image (vignette removal)
I have to process the images I acquire with the microscope with a vertical binning, to obtain the distances between the dark/bright regions.
Images are like this:
I defined a threshold function that ...
0
votes
1
answer
71
views
Why is the numerator coefficient array returned by scipy.signal.cont2discrete two dimensional?
I'm converting a continuous-time dynamical system to discrete time using the function cont2discrete from Scipy's signal processing library.
dt = 0.1
num, den, dt = scipy.signal.cont2discrete(([1], [5, ...
2
votes
1
answer
169
views
CPU bilinear filtering output same results than point sampling
I am adding bilinear filtering to my C++ rendering software. To validate that it works I am trying to downscale a test image.
This is the 1024x1024 test image:
When I perform point sampling resizing ...
0
votes
0
answers
176
views
What's causing this weird jump in these phase graphs of Fourier coefficients?
This is from an assignment in signal processing in Python. It's all done in Python (through Google Colab) with the libraries cmath, numpy, and matplotlib alone.
Signal a is a window signal, and I ...
1
vote
1
answer
114
views
Why is the convolution of two different frequency sine waves not 0? (Windowing help)
I'm trying to figure out how to window two different frequency sine waves in such a way that their convolution produces a 0 signal.
I have code that works for sine waves with integer periods:
T = 1000
...
0
votes
1
answer
94
views
Real time audio processing iOS
I'm trying to get sound from the microphone, process the sound with some function and then output the processed sound to the speakers.
I need to be able to process buffers of 1024 samples. but for now ...
0
votes
1
answer
290
views
Does Pico 2, utilizes SIMD-instructions or just loop-unrolling during arm_dot_prod_f32?
The title says almost everything. Does (Cortex-M33) RP2350 rasberry-pi-pico 2 utilizes any SIMD-instructions (at all) via DSP during arm_dot_prod_f32 or does it simply loop-unrolls? I know for certain ...
1
vote
2
answers
99
views
FFT Does Not Detect Expected Frequencies in Experimental Data with Known Periodicities
I am analyzing experimental data where resistance Rxx is measured as a function of an angle Phi, which ranges from 0 to 360 degrees in steps of 2 degrees. The dataset consists of two columns:
Phi (...
0
votes
1
answer
77
views
Discrepancy Between NumPy and TensorFlow FFT Outputs: Missing Imaginary Components in TensorFlow
I am working on a project where I need to perform Fourier Transform on synthetic periodic data using both NumPy and TensorFlow. However, I am encountering a discrepancy between the FFT outputs of ...
-1
votes
1
answer
83
views
How to calculate the phase response?
Good afternoon. I want to write a code to output experimental frequency response for system identification. For verification I use the modeled sinusoid and the response of the modeled system. To ...
1
vote
1
answer
80
views
The error of manually computed inverse-FFT increase along x_axis
I am manually compute the inverse FFT using the NumPy FFT components by the below code, to compare the rebuild signal with the original signal (sin function). As shown in the results, the error (...
1
vote
0
answers
179
views
How to Draw a Solid 3-Band Waveform Like Rekordbox Using Canvas in JavaScript?
I’m trying to replicate Rekordbox’s 3-band waveform display (low, mid, high frequencies as solid, color-coded shapes) in JavaScript using canvas. I’ve already created a Python script that extracts ...
1
vote
1
answer
75
views
IT++ and Matlab randomness
How can I get the same random results in IT++ and Matlab?
For example, the default random generator algorithm in Matlab is "twister" which is "Mersenne Twister" with the keyword ...
0
votes
0
answers
82
views
using SciPy.signal.filtfilt but an exception occurred at the beginning or boundary position
I'm learning on signal process and I'm trying to simulate a First-order low-pass filter as the equation below:
(1+ω)y[n]=x[n]+ωy[n-1]
where y[n] denotes the output and x[n] denotes input.
So I try to ...
0
votes
2
answers
88
views
GNU Octave stereo recording, how?
I'd like to use GNU Octave for signal processing; one channel would be the audio, the other would be a sync signal input.
This is the default recorder object in Octave:
BitsPerSample = 8
...
1
vote
0
answers
52
views
How do I simulate image magnification using Angular Spectrum Method?
I have written a code that forms the image of an input image at some distance z. All the parameters I have used (pixel size, no. of pixels, z, etc.) are mentioned later in the question. The objective ...
0
votes
0
answers
48
views
STM32 frequency identification giving wrong results using analog input
I am trying to use stm32f411 and libopencm3 with CMSIS DSP lib to identify sine wave generated by a function signal generator but without sucess, I just cant compreend what I am doing wrong, i know ...
0
votes
0
answers
38
views
Trying to obtain coefficient matrix of Bspline matrix then obtaining its quasi-diagonal matrix?
I tried to obtain the coefficients of B-spline matrix using the following code:
function C_matrix = calculateBsplineCoefficientMatrix(s)
% Number of input samples
N = length(s);
% Construct Alpha ...
0
votes
1
answer
58
views
Wireless nodes receive packets even though they are allocated with different Channels in OMNET++
I have implemented TDMA using a network of wireless nodes in OMNet++. I tried to change the channel Number in the .ini file.
**.radio.typename = "Ieee80211UnitDiskRadio"
*.node[0].wlan.radio....
1
vote
0
answers
48
views
Issues with MP3-like Compression: Quantization and File Size
I’m trying to implement an MP3-like compression algorithm for audio and have followed the general steps, but I’m encountering a few issues with the quantization step. Here's the overall process I'm ...
4
votes
1
answer
240
views
Most efficient way to wrap 32 bit integer to 16 bit value?
I am writing some DSP code that performs wavefolding distortion on an input signal. This code applies amplitude gain (multiplies input by a gain value) then wave folds the input such that the final ...
1
vote
0
answers
116
views
How to calculate the cross-correlation between two 2D numpy arrays along a given axis
Currently the SciPy's scipy.signal.correlate function supports computing the cross-correlation between two 1D arrays. However, there is no direct support for axis-wise cross-correlation between two 2D ...
0
votes
1
answer
114
views
trouble on making GNURADIO C++ OOT sync block
i'm trying to implement a block that process chunks of 512 bytes and return chunks of 480 bytes. At first i'm trying to work with 512 input/512 output instead to grasp the in/out mechanism of GNUradio....
0
votes
2
answers
379
views
Phase of two signals by correlation slightly off, scipy signal.correlate
I want to get the phase shift of two signals via the correlation function. In general I set up a sine with frequency f0 and a 2nd sine (with noise) and a given phase phase_deg. I correlate both ...
0
votes
0
answers
76
views
Heart rate detection with FMCW radar
I have this data set which is recorded from 50 children with FMCW radar to detect their heart rate and respiration rate. I am using this data set and I want to just calculate the range FFT and after ...
-1
votes
3
answers
271
views
How to do a gaussian blur without modifying the original pixels?
Given an image such as below, I want to blur it such that none of the original black pixels change in value. The blur should have a nice S curve fade-off to white.
If I apply a 15px gaussian blur to ...
1
vote
0
answers
62
views
How to calculate magnitude for a filter to specific dB level?
I'm using fir2 function (and then filter with basic settings filter(fir2,1,audio) ) to filter audio files to specific values in each spectrum band. I have two sets of dB values:
the original spectrum ...
0
votes
0
answers
80
views
Inverse Fast Fourier Transform from One-Sided Fourier Amplitude Spectra at Matlab
I am writing down a code that first apply Butterworth (low pass filter) to a earthquake time history and then create the one sided fourier amplitude of the filtered motion and multiply it with a ...
0
votes
0
answers
54
views
SPIDEV on raspberry pi for TI DAC8568 producing distorted signals
I’m working on a Raspberry Pi project where I’ve transitioned from using an I2C-based HiFi DAC HAT (PCM5122) to an SPI-based DAC (Boost 8568). My goal is to output analog signals from processed EEG ...
0
votes
0
answers
75
views
How can I create an FIR from difference of two impulse responses?
I am trying to create an FIR and associated waveform for a transfer function that is the magnitude difference between the two impulses responses. I have recorded both IR's but am struggling with ...
0
votes
0
answers
126
views
Getting error with obspy reading reftek130 files on python 3.13.0 windows 11
I have some problems to read reftek130 files on python 3.13.0 & windows 11 with obspy.
Although it has to work before reinstalling windows 11 & VS code & Python.
I did not understand the ...