But just how well does it compare to a FFT of the same data.
The bandpass plot is based on 4000 points and the FFT on 4096.
All 5 frequencies were found in both Band pass and FFT forms.The FFTs show correct amplitudes but the filtering shows a drop off with frequency
Next a comparison on hadcrut4 NH data 1850 to 2011 data length 1930 months
The interpretation of the band pass filtered for is easier but is it more reliable? The reported frequency needs an offset adjustment
This test at least proves that the bandpass plugin works!
Bandpass plugin is available from Web:reg:
This site has other useful goodies!