Fourier Transform of a signal for which no function exists

[Gavin Harper]

I have the readings from a signal in a file (floating point values) that I wish to apply the Fourier Transform to.

The samples (mV) were taken every 4 milliseconds and I wish to transform them into the frequency domain.

How would I apply the FT to a set of values without knowing any function that can describe even a discrete sample of it?

Thank you to anyone who can offer any insight!

 

[AlephZero]

Use a digital Fourier transform (DFT) instead of the continuous Fourier transform defined using an integral. You can get he details from textbooks or websites on digital signal processing.

The term "FFT" (Fast Fourier transform) is often used as another name for "DFT", but that is not quite accurate. The FFT algorithm is one of several ways to calculate a DFT (and usually the quickest way), not the DFT itself.

 

[Gavin Harper]

Thank you!