Am 09.07.2012 12:09, schrieb David Nečas (Yeti): > On Fri, Jun 29, 2012 at 11:28:14AM +0200, Martin Engler wrote: >> I am wondering which convetion is used for the wavenumber k in the FFT >> output? It looks like that k=1/lambda, if lambda is the wavelength, in >> the output of the FFT. As this is not clear from the documentation. I am >> not sure if it is not k=2*pi/lambda as usally defined in mathematics. > It is actually 2π/λ in Gwyddion (you can easily verify this by looking > at the ACF and PSDF of a periodic surface). I would not dare to call > any of the conventions ‘usual’... > > Considering the PSDF values (and units), they follow from considering > that we sample an infinite continous finite-mean-power surface and > impose Plancherel/Parseval theorem and samling independence of the PSDF > (i.e. different samplings of the surface must lead only to different > samplings of the same PSD function). > > Regards, > > Yeti > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Gwyddion-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/gwyddion-users Thanks for the information. It would be nice if you can state this in the documentaion.
Regards Martin -- Martin Engler Universität zu Köln II. Physikalisches Institut Zülpicher Str. 77 50937 Köln, Deutschland Telefon: +49 221 470-3658 Telefax: +49 221 470-5178 ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Gwyddion-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/gwyddion-users
