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I am trying to find the Fourier transform of a set of data points that equate to the change in absolute magnitude of a certain star. When I graph the data points in Excel, I can obtain the following graph.

I understand that I am supposed to use Non-uniform Discrete Fourier Transform, but whenever I try to perform calculations with it, I obtain a graph looking like this. I am not sure what I am doing wrong, since I followed the instructions perfectly.

I am using the following formula for calculating the terms:

$$X_k=\sum_{n=0}^{N-1} x_n \cdot W^n $$

where $x_n$ is the value of the data point, $W^n$ is $W^n=e^{-\Omega \cdot j}$, N is the number of total data points.

Am I doing something wrong which is causing the error in the graph? Or am I missing a step in my calculations, leading to an incomplete graph? Any help is appreciated!

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    "Non-uniform Discrete Fourier Transform" is a big word for saying DFT applies only to uniformly sampled signals. So why don't you make a uniformly sampled signal from your data ? – 2017-01-29
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    Thank you for your response! However, I'm a little unsure as to how I would do this. Is there a way to get Excel to do this for me? Google searches yield no significant results :( – 2017-01-31

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