307 views

### Wrong frequency in Fourier

I have a file, filled with data like this: As you can see the approximate frequency is about $5/1000 = 0.005$, then angular frequency is about $2 \pi \times 0.005 \approx 0.03$. Then I use discrete ...
496 views

### FFT of data to obtain resonance frequencies and correct amplitudes

I have often to do with experimental data (with a certain length and given sampling frequency) where I obtain trajetories of moving objects in 2d. Then I am interested to find out what the ...
334 views

### Fourier Transform accelerogram seismic

I have a seismic accelerogram. I tried to apply the Fourier Transform to interpolate function, but dosn't work. So, i applied the ...
279 views

### Parseval identity in one side Fourier Transform

Is there any posibility to apply Parseval identity(energy in time domain is equal to freq. domain) on One/Single-side Fourier transform? In other word for "standard" FT the test Mathematica can be <...
214 views

### Ideal/Brick wall Low/High-pass filters: Fourier approach not working

I am trying to take a signal (as a list) and separate it into the low frequency and high frequency parts around some split frequency f. Given that what little signal processing I ever studied is now ...
92 views

### Finding frequency from Fourier transform [closed]

I tried to find frequency using Fourier Transform, but notice that my code have some mistakes which I can't find. So, my code is below: ...
138 views

### Frequencies doubled in fourier transform [duplicate]

With this code I get a nice plot of the Fourier transform, but the frequencies are doubled. By this I mean that when using a sine wave I generated at 220 Hz, the plot gives me a single peak at 440 Hz. ...
198 views

### How to find the Fourier Transform of a list?

I have a list (list) in the form of {x,y} as ...
195 views

### DataRange in plotting Fourier

I'm trying to estimate a frequency spectrum of a given discrete function. I have a file which is filled of values of Sine-function $sin(t)$, where $t$ runs from $0.0$ to $100.0$ and a discrete step is ...
206 views

### Perform a Fourier Transform on a wavelength scan

I have a plot of the power transmitted through a device as a function of wavelength, from 1500 to 1600nm. There is some Fabry-Perot noise, plus I suspect some other regularities. I would like to ...
120 views

### Periodogram local maximum

I want to find dominant frequencies of periodogram exactly. ...
154 views

### Get frequency axis in Fourier transform (and save them)

I am trying to get the Fourier transform of a light-curve (with an even number of points, 300, and equally spaced in time, 6.9 seconds) and my problem is to get the frequency on the x-axis. I can ...
105 views

### Discrete Fourier transformation from ASCII (for noob)

I am not familiar with Mathematica (I am a physicist programming in Fortran) and my knowledge of it is very limited, unfortunately. I would like to perform the Fourier trasform of a lightcurve which ...