Questions tagged [frequency]
The frequency tag has no summary.
30 questions
5
votes
2
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426
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Frequency identification via Fourier when wave period is larger than dataset length
The following code is taken from the manual
...
- 2,072
1
vote
1
answer
152
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How can I use fast Fourier transform to divide into low and high frequency components? [closed]
I have this data (where x is time (seconds) and y is diopters (D)):
...
- 119
0
votes
1
answer
131
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How to plot time-frequency evolution based on zero crossings?
In a paper that analyzes the data from GW150914, a time-frequency plot was shown.
The paper proposes that, quote:
An approximate version
of the time-frequency evolution can also be obtained
directly ...
0
votes
1
answer
125
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Find FWHM from a plot of real part of complex equation
I am plotting the Real part of a complex equation which looks like this:
for now, using the FindMaximum function I can get the max y and max x of the plot, any ideas on how to get the FWHM of this ...
- 9
0
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1
answer
247
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amplitude frequency response in mathematica
I am solving the Rayleigh-Plesset equation, which includes the forcing. I want to plot a frequency-amplitude relation numerically in Mathematica, but I am unable to do it. I am providing the Non-...
- 91
3
votes
1
answer
447
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Time domain to Frequency domain: Simple question
I have an input sine wave of:
f=60 Hz.
a[x_]= Sin[(2*\[Pi]*f) * x];
If I want to have an input, the same sine wave but in the frequency domain, how it can
be ...
- 887
-1
votes
1
answer
166
views
Fourier transform on analogue signal to frequency domain
Hi I have a question regarding the Fourier transform of an analogue signal measured in time domain.
The current 3 data is normalised, and it is expressed in percentage.
I have tried using this line of ...
- 322
0
votes
1
answer
776
views
How can I get the power spectrum density and separate low and high frequencies?
Good day everyone,
I'm new in mathematica.
I got these values over time (each value was obtained every 100 milliseconds):
...
- 119
3
votes
0
answers
529
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Chladni experiment verification
I refurbished my post in order to be more understandable.
After computing simulations of Chladni patterns with Mathematica (see my previous topics), I finally went to practice. I realized my own ...
- 195
0
votes
1
answer
263
views
What is the syntax for using Reap and Sow and WhenEvent with derivative = 0 with interpolating function?
I have a system of three ODEs. This system oscillates. I need to determine the frequency of each of the three solutions.
My file. You can download and modify this.
I'm new to Mathematica and I know ...
- 187
0
votes
2
answers
251
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Input a frequency distribution with unequal class widths and estimate the mean and median
The websites I have visited and the texts available to me determine the mean of an unequal frequency distribution using
mean = Sum(class marks x frequency) / Sum(frequency).
This is an example I ...
4
votes
2
answers
420
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How to determine the frequency of oscillations in system of three ODEs?
I want to determine the frequency of oscillations in a system of three stiff ODEs (Oregonator model). That model describes a chemical oscillator.
I have a slightly more advanced model of the default ...
- 187
2
votes
1
answer
208
views
FindFit low speed when fitting polynomial coefficients: is it possible to significantly increase the speed?
I work in Mathematica with a Butterworth filter, the transfer function of which depends on the selected order and cutoff frequency.
I want to evaluate the change in the location of the roots on the ...
- 2,687
0
votes
1
answer
328
views
Identifying the three frequencies using fourier transform
The following simple function has clearly three frequency components:
...
- 954
-1
votes
2
answers
654
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How can I add two sin waves of different amplitude and frequency? [closed]
I've been tearing up the internet, but I can only find explanations for adding two sine waves of same amplitude and frequency, two sine waves of different amplitudes, or two sine waves of different ...