And  and , you know , it will , uh , if you have an IIR filter for instance , it will , um , uh , not behave in the steady - state way that you would like it to behave until you get a long enough period , but , um , uh , by just constraining yourself to have your filter be only a subtraction of the mean , you 're kind of , you know , tying your hands behind your back because there 's  filters have all sorts of be temporal and spectral behaviors.
Mm - hmm.
And the only thing , you know , consistent that we know about is that you want to get rid of the very low frequency component.
Hmm.