On Wed, Nov 5, 2008 at 4:55 PM, Ryan May <[EMAIL PROTECTED]> wrote: > Hi, > > How much freedom would I (and my colleague) have in changing up some of > the behavior/API of mlab.psd? My current issues with the function: > > 1) Returning one-sided or two-sided depends on whether the data is > complex. I'd like that to be controlled by a keyword parameter (could > take strings, such as 'two-sided' like matlab)
Sounds good > > 2) We'd like to add a parameter to control how many points are used for > performing the FFT (automatic zero padding for increased plotting > detail). The obvious name for this would be nfft, but this seems to > conflict with the NFFT parameter. NFFT, confusingly, is used to specify > the blocksize used for averaging. If we can't outright change names > here, I'd love for suggestions on a good way forward. I wrote this function a *long* time ago, so my memory is a little hazy, but I don't find the terminology confusing. The method breaks the sequence into NFFT sized chunks and does an fft on each NFFT length piece, so that is the length of the fft. Perhaps an addition pad argument if you want to zero pad the chunks? I intended to replicate the matlab function when I wrote this, and vaguely recall that I did some close comparisons on the output, but if I am misusing this parameter let me know. Some (possibly dated) matlab docs are here: http://www.mathworks.com/access/helpdesk/help/toolbox/signal/index.html?/access/helpdesk/help/toolbox/signal/periodogram.html > 3) Can we remove the requirement for even NFFT (blocksize)? Sure A while back someone on the list said that the amplitude scaling for psd was of, but I never delved into it. Something you may want to check into while you are poking around in there. http://www.nabble.com/forum/Search.jtp?forum=2906&local=y&query=psd+amplitude JDH ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
