Hello Cheng Wei,

It is not mentioned in the WIKI, which I will update, but the nuisance variable regression included detrending.  Also the "highpass" part of the bandpass filter is there to remove the low frequency noise (i.e. linear trend).

Which data are you performing the FFT on?  If the filenames begin with a sn* then they have NOT been filtered.  If they begin with sf* then they have.  Also there is another iconsisntency on the WIKI, the bandpass filter is 0.009

Could you give me more information on this problem?  What subject are you looking at the data of?

Cheers,
Cameron