5,666 questions
0
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1
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38
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ESP32 + INMP441: Frequency response measurement fails despite chirp sweep playback from Python
I'm trying to measure the frequency response of an INMP441 microphone using an ESP32 and a Python script. The ESP32 captures 6000 samples via I²S and sends them over serial. I play a 62.5 ms ...
- 1
0
votes
0
answers
63
views
Why am I getting mirrored peaks in Javascript AudioContext AnalyserNode frequency spectra around specific frequencies?
I've been having a problem with the Javascript AudioContext using AnalyserNode to get frequency data from a microphone on a HTML page. Using getByteFrequencyData() to get the frequency info and a ...
1
vote
0
answers
75
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 ...
- 11
0
votes
0
answers
64
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What is the fastest way to compute a filter in Fourier space?
I am currently working on a beam propagation code. The code basically consists of a transversal profile (a 2000x2000 array) which is propagated a small distance, then has its borders filtered, then ...
13
votes
2
answers
2k
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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 ...
- 314
1
vote
0
answers
57
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Is it possible to reduce the memory requirements for (I)FFT by chunking?
I'm trying to run an IFFT on a very long signal (10^9 data points) and I'm running into RAM constraints. I'd like to be able to chop up the signal and run it in batches (as I am not time constrained ...
- 454
0
votes
1
answer
57
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Restore an image through Matlab with noise and psf
I'm trying to solve a problem where I'm given the magnitude and phase spectrum of an image. I know the spectrum information is centered and compressed, so I'm working backward, but I'm getting lost ...
3
votes
1
answer
151
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How to compute the power spectral density of a vector-valued process without mirroring the autocorrelation function?
I'm simulating a 2D Ornstein-Uhlenbeck process (Langevin equation for velocity), and I'm interested in computing the power spectral density (PSD) of the vector-valued velocity process.
Following the ...
- 509
0
votes
0
answers
75
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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)
...
2
votes
2
answers
143
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What is the correct way to perform 4D FFT in Cuda by implementing 1D FFT in each dimension using cufftPlanMany API
Cuda does not have any direct implementation of 4D FFT. Hence I want to decompose a 4D FFT into 4 x 1D FFTs into X, Y, Z, and W dimensions. I understand that the cufftPlanMany API is best suited for ...
- 183
0
votes
1
answer
67
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Incorrect modeling of the spectrum of a sequence of pulse signals [closed]
I have a task to simulate a sequence of rectangular pulses. As a result, I wrote Python code, but the end results are not encouraging.
#!/bin/python
import numpy as np
from numpy.fft import fft
...
- 49
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
80
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 ...
2
votes
1
answer
68
views
How to Apply Band Pass Filter to a 3D Stack in DigitalMicrograph
In Gatan software, I found that the Band Pass Filter in Process Image can only be applied to a single 2D image or a specific frame of a 3D image. My dataset is a 3D stack (multiple frames), and I need ...
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1
vote
0
answers
51
views
Why CuFFT throughput increases as the transform size gets larger?
(Updated) I am trying to understand how CUDA parallelism works in CuFFT while learning CUDA coding.
I wrote my version of 1-D FFT in CUDA C++ and compared it with cuFFT. Below are the throughputs I ...
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0
votes
0
answers
37
views
Is this code and answer is correct ? (EMG data with FFT)
I'm wondering if I got some errors in my emg data + fft code
[I got 0Hz filtered emg data]
plt.figure(figsize=(20,10))
sns.lineplot(data = DF_newemg, x = DF_newemg.index, y = 'emg[2]', label = '...
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5
votes
1
answer
368
views
How to do fft based convolution with long doubles/float128s quickly and accurately
On my linux system I have:
np.finfo(np.float128)
info(resolution=1e-18, min=-1.189731495357231765e+4932, max=1.189731495357231765e+4932, dtype=float128)
So that is an 80-bit long double. I want to ...
- 21.5k
0
votes
1
answer
70
views
Pyserial and fft
I want to read real time data from my arduibo, plot it in time domain and then do fft of that data and plot that (frequency domain) but I have no clue how to do it.
can’t seem to transfer data array ...
4
votes
1
answer
327
views
How to accelerate the cross-correlation computation of two 2D matrices in Python?
I am using Python to compute the cross-correlation of two 2D matrices, and I have implemented three different methods. Below is my experimental code along with their execution times:
import numpy as ...
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3
votes
1
answer
98
views
Inverse Fast Fourier Transform (ifft2) of scipy not working for fourier optics
I'm following a tutorial on youtube on Fourier Optics in python, to simulate diffraction of light through a slit.
The video in question
Source Code of video
Now, I'm trying to implement the get_U(z,...
- 165
0
votes
1
answer
117
views
STM32C031C6 - FLASH Overflow Error During FFT Implementation with ARM CMSIS-DSP
I am working on an embedded project with the STM32C031C6 microcontroller using STM32CubeIDE. My goal is to perform an FFT on ADC input data and transmit the results over UART. I am utilizing the ARM ...
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0
votes
0
answers
76
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 ...
- 1
2
votes
0
answers
142
views
How to identify an specific Beep frequency on audio files (.Wav, .Mp3)?
I have a problem where I have a dataset of audio's files, and I need to cut every single of it in 2 pieces: one piece after and one before a determined "beep" sound.
I examined some audios ...
- 884
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0
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61
views
I want to compute FFT and IFFT on a large image via GPU. But my GPU is low on memory
I’m working on a MATLAB project that requires FFT and IFFT computations on large images using GPUs. Currently, the image size is
32000×25600 with double precision data. Although we need to process ...
- 11
0
votes
0
answers
55
views
Defining length for fft in Matlab
I have a question to the command fft in Matlab. By using the default settings Matlab assumes the signal to be periodic with a periodicity of 2π. However, for my problem I need to apply the FFT to a ...
