Design of equiripple minimum phase FIR-filters

The numerical robustness and applicability of a recent approach to the design of minimum phase FIR filters by cascading a passband and a stopband filter [Go 80] is improved by the following measures: i) Spectral factorization (root finding) is avoided by exploiting the Hilbert relations between attenuation and phase ii) Unbounded gain in don't care regions is restricted by prescription of appropriate desired values. As a result, highly selective minimum phase FIR filters requiring a considerably reduced number of multiplications are obtained.