# FIR filter design with flat passband but equi-ripple stop-band

I am looking for a lowpass FIR filter with flat passband but equi-ripple stopband. In other words, it likes Chebyshev_filter Type II except that it is FIR instead of IIR. Linear-phase is preferred.

Thanks

I suggest you the Parks-McClellan method. In Matlab you can use $\tt{firpm}$.

Matlab's (now obsolete function) $\tt{remez}$ also uses this scheme.

The FIR filter is optimally designed to approximate e.g. a Chebyshev filter such that the maximum error between the filter's response and the desired response is minimized.