If flt.filt_order is zero or negative, a the edge filters defined by the other " flt.filt_..." parameters are hard-edged. That is, they change from zero to one without any intermediate values. If flt.filt_order is larger than zero, the edge filters are soft-edged Butterworth filters with order given by the value of this parameter. An order of 1 is the softest, and will thus produce least ringing, at the expense of poorer frequency response. Higher orders produce sharper filters that have better frequency response but at the expense of greater ringing. [0]

MAKEMAP, CALCQU