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.
Questions tagged [time-frequency]
87 questions
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Interpolating data fails: grid vectors do not define a grid of points that match the given values
I have some time/frequency data and I try to interpolate it using the interp2 function of Matlab. The data [F,T,data] is obtained from a different Matlab routine of Matlab, spectrogram in case you are interested.
[~,F,T,data] =…
WG-
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Python time module - imprecise adding
DISCLAIMER: Unsure if title even fits and this is my first post so I'm learning how to organize this
CODE BACKSTORY:
I create fractal flames (iterated images) using Apophysis7x and open the .flame file (this file is not rendered, it simply holds the…
BHerna
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Wavelets: how to determine scales from frequencies?
In the following code sample, I would expect the rows of the printed output to match each other, at least approximately. But they don't.
% input data
y = rand(10000,1);
dt = 1/500; % 500Hz is the sampling rate
% wavelet transform
f = 1:50; …
Jonathan H
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TF Plot in MATLAB
I want to divide 5 low frequency of EEG data. Here I am using EMD to obtain that. What I want to ask is how we can create a line which will separate each frequency like this picture below. For example, delta is 0-4 Hz, theta 4-8 Hx, alpha is 8-12…
nafilatur2724
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Dividing a signal in channels
I have a signal in time domain (6000 samples from -100 to 1100 ps). I have to convert it into frequency domain and divide it into 100 channels, and find the center frequency of each channel.
I am not good in "MATLAB" so how to do that, help will be…
Farhan
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How to increase the no of points in a FFT Narrow band for 1/3 octave analysis
I am calculating Sound pressure level of a Pressure-Time signal.
The number of samples per second is 9831.(dt = 0.0001017 sec)
Totally 749 samples are collected for a simple example case.
I am using 512 FFT points for this example case,so the…
Balaji Spades
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Why black surf from this Matlab command?
Code
tfr = abs ( tfr ); [row_size, column_size] = size(tfr);
tfr = tfr(1:round(row_size/2), 1:row_size);
surf(tfr); view(2);
I get in R2014b of OSX 10.10.3 Yosemite
but rotating around shows that the cells should not be black
Why is the output…
Léo Léopold Hertz 준영
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Python - aggregating financial transactions with closest time in window
Suppose I collected (in a list) all trades that occurred within a certain period of time (say first 5mins after 11AM) for n stocks (I'll make n=2 for simplicity and adapt later). Say we have firm AAA and firm BBB (if it helps, liststocks=['AAA',…
Eduardo Hinterholz
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Frequency calculation in Beckhoff TwinCAT3.1
I am trying to determine the frequency of a pulsing input, which is tacho feedback of a pump. I have tried to create two timers which are a second each, and counts up every time there is rising edge. Based on the number of rising edges in a second,…
Vinny
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Matlab- Get the max or second max value of frequency from text file
I have a text file like…
Vu Ngo Thanh
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compute S transform and its square value in matlab
let us consider following code taken from
http://www.mathworks.com/matlabcentral/fileexchange/45848-stockwell-transform--s-transform-/content/stran.m
to compute S transform, here is my code
function ST=stran(h)
% Compute S-Transform without for…
user466534
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how to use ifft function in MATLAB with experimental data
I am trying to use the ifft function in MATLAB on some experimental data, but I don't get the expected results.
I have frequency data of a logarithmic sine sweep excitation, therefore I know the amplitude [g's], the frequency [Hz] and the phase…
Rhei
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3 answers
Checking if function was not called for x amount of time
I didn't find this kind of question anywhere so I'm going to ask it here.
How can I check if some specific function written by me wasn't called for some x amount of time?
Satoshi
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Two time-frequency pictures in one picture in Matlab
I have two figures which have same spaces in domain and range:
and
I follow the manual here about subimage
image1 = imagesc(T*t, F*fs, abs(B));
subimage(T*t, image1);
image2 = imagesc(T*t, F*fs, abs(B'));
subimage(T*t, image2);
but I get…
Léo Léopold Hertz 준영
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7 answers
To make all peaks clearly visible in Matlab
I finally solved my problem here with lennon310.
I have a picture of thousands of thin peaks in Time-Frequency picture.
I cannot see all the same time in one picture.
Depending on the physical width of my time window, some windows appear and some…
Léo Léopold Hertz 준영
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