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Questions tagged [time-frequency]

Time-frequency methods provide more viable solutions than Fourier methods for signals that are shorter in time and not necessarily periodic. Methods such as Wavelet and Gabor transforms are considered to be T-F techniques.

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Why Time-Frequency plane is reversed?

I'm trying to build my own code implementation for Continuous Wavelet Fourier Transform. But when I compare the time-frequency plot created with my function with time-frequency plot created with the Matlab function, it seems time…
Edoardo De Gaspari
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How to get a range of frequency bins for PSD

I am computing PSD of a signal, and I want the power from frequency range 0Hz to 20Hz. This is what i tried using linspace df = pd.read_csv(path) df = pd.DataFrame(df) x = np.linspace(0, 20, 41) dt = x[1] - x[0] fs = 1 / dt f,P = signal.welch(df,…
Rashma N
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Plot PLC Background Noise

I am a total newbie in signal processing. I have been trying to plot on simulink a time/frequency domain noise in PLC (Powerline Communication) modem that matches a real-world research, however, I failed to plot such noise. If anyone knows how to…
Sam Al-Ghammari
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define an interval for frequency of STFT outputs

As you know the STFT has a matrix result, with the dimension given by: number of frequency bins * number of time frames. For example, suppose that I have a signal with characteristics and I want to apply STFT method with the following input…
roan
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MPU 6050 SD Writing Frequency Arduino is not constant , how to have a constant writing frequency?

I am a noob and i am from civil engineer, I apologize in advance. I have a MPU6050 connected to my Arduino Uno and I write the data on an SD. I can write at a sample rate of 20millis. Why i have this default frequency? This is part of the code //…
Andrea Ciufo
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Creating Artificial Signals

I've tried posting this on the Signal Processing StackExchange, but with little avail, as it is rather sparsely populated. Since I am using MATLAB, I hope someone here can help just as well. I'm trying to design a sample signal that has two…
Franz Hahn
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How to determine trough in time-series data?

I am receiving a stream of time-series data/events from a manufacturing process machine. I need to be able to calculate the start of a cycle and pinpoint this event based on the trough of the data. What would be a recommended way to do…
Phil Boyd
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Convolution by Dirac Delta on Xlinx FPGA

I am trying to convolve a 16-bit input data stream with a Dirac Delta on a Xilinx Virtex 7. More specifically, instead of multiplying my input stream by a cosine in the time domain, I would like to convolve it with the following expression in the…
asonnino
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To create Hamming window of length 64 with overlap 60% in Matlab

I am trying to give for Wigner-Ville Distribution Hamming Window of length 64 with 60% overlap here. I can create Hamming window of length 64 by h=hamming(64); Here is some theoretical pieces of advice about the issue. The window seems to be some…
Léo Léopold Hertz 준영
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how to transform frequency domain into time domain

I had created a 3 three different frequency signal and filter out the signal i don't want. But when i using ifft in matlab, it shows a wrong graph.How to transform my frequency domain spectrum back into my 3 second time domain graph? Below my code…
Ambbie
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Variational Mode Decomposition for time series forecasting

I'm currently working on a time series project, and I intend to employ the VMD+CNN technique for forecasting the output.Upon applying VMD to the training data, I obtained a total of 14 Intrinsic Mode Functions (IMFs). Consequently, I constructed my…
nad66
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Frequency and time-freqeuncy domain features for a sinusoidal signal in Python

I have the following sine wave signal created in Python: # Import libraries import numpy as np import matplotlib.pyplot as plt Fs = 1000 # Sampling frequency (Hz) T = 10 …
NN_Developer
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Why does this code not return the correct fft frequencies?

I'm writing a code and I want to create a function that receives the amplitudes, frequencies and shifts and the points to be evaluated and returns a sum of sines with such amplitudes, frequencies and shifts on the points. The code I used is: import…
Kuku
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what are the good metrics that I can compare the performance of the result of several time-frequency transformations result quantitatively?

I generated a non-stationary signal and I want to apply several time-frequency transformation methods such as STFT, Continous Wavelet Transform(CWT), Wigner-Ville Distribution (WVD) to this signal and compare the performance of the results…
Sebastian Fischer
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How to use tftb library in Python to plot a spectrogram?

I have an audio signal in wav format. I have to plot its spectrogram using Winger-Vill distribution. I have tried other libraries and other options to plot the spectrogarm like librosa, scipy and matplotlib spec but to compare the differences…
Malahat Mehraban
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