Indicates the shape of the filter FILT_ORDER
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filt_..."
parameters are hard-edged. That is, they change from zero to
one without any intermediate values. If 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]