Thanks for that. Does this affect how I should extract the magnitude & phase from the transform? Or is it OK to throw the second half away for that purpose?
Why does a discrete Fourier transform seems to produce two peaks for a single sine wave? It seems to be the case that the spectrum ends halfway through the transform and then reappears as a mirror image; why is that? And what is the use of this mirror image? If I want to recover the frequency...
The software used to control the AFM and produce the output was Park Systems' XEP. Since the GPL'd Gwyddion is able to view the files it created, I'm presuming the format of AFM ouput must be standardised... how can I find out what exactly this format is?
I have recently started using an AFM machine, and have some issues with the way it saves the data. The people who maintain the machine haven't been very helpful with my concerns, so I'm hoping somebody here might be able to help me.
I have been using Gwyddion to display the raw data images...