# FIR butterworth also possible or just IIR?

can we use butterworth and other such filters like chebyshev,elliptic etc with FIR

or they can be only used with IIR?

• There's a lot of beginners asking how to build Butterworth filters, without actually needing them. Why do you want to use a Butterworth FIR (which can't exist, sadly)? – Marcus Müller Dec 19 '18 at 20:19

• also, abt, you can actually implement your FIR filter that approximates some IIR filter as a Truncated IIR (TIIR) filter. it might not be what you want, but it's a method to get some FIR properties (such as linear phase) with the lower computational cost of an IIR. it turns out, that to get linear phase with a TIIR, you have to do this filtfilt() thing in blocks. – robert bristow-johnson Dec 19 '18 at 19:20