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 var
ious design parameters such as passband and stopband requirements is studie
d next. The maximisation of the band-edge selectivity of elliptic filters w
ithout increasing their order is finally considered. Examples are submitted
and reviewed in support of the proposed methods.