On the realization of an all-pass or a notch filter
It is shown that it is possible to realize either a second-order all-pass or a notch filter by a structure consisting of a grounded operational amplifier and two RC one-ports, Y 1 =G 1 +sC 1 and Y 2 =[R 2 +(1/sC 2 )]-1. It is also shown that these filters may be realized by the same structure with Y 1 and Y 2 interchanged. These realizations possess minimum sensitivity with respect to the amplifier gain.