Stateful FIRFilter

[TacHawkes]

I am having troubles setting up the stateful FIRFilter with the information given in the docs.
How can I properly construct a FIRFilter from a designed filter using e.g. Lowpass and design method Butterworth? Could someone provide an example?

Thanks!

[Martin Holters]

Butterworth yields an IIR filter, but FIRFilter is for FIR filters, as the name suggests. You can use remez to design an FIR filter. E.g.:

h = remez(100, [(0, 0.45) => 1, (0.55, 1) => 0]; Hz=2)
H = FIRFilter(h)
y = filt(H, x) # for whatever input x

Better documentation would obviously be welcome.