Selectivity of elliptic filters

The problem of determining the band-edge selectivity of elliptic filters is addressed. First, the band-edge selectivity is derived with respect to the nth order elliptic function. The sensitivity of the selectivity to the various design parameters such as passband and stopband requirements is studied next. The maximisation of the band-edge selectivity of elliptic filters without increasing their order is finally considered. Examples are submitted and reviewed in support of the proposed methods.