This paper shows that the capacitor value spread of the third-order single amplifier lowpass filter can be significantly reduced at the price of a slightly larger resistor value spread. It is found that the sensitivity performance is also improved over that of the conventional equal-resistor design.

A unified approach to the derivation of canonical single amplifier circuits capable of realizing second-order filters with finite transmission zeros is proposed. Application of the proposed approach leads to the known circuits, as well as some new ones. Design formulae for the new circuits are presented, and their salient features are pointed out. Finally, design examples are also presented.

In this paper, a generalized voltage-current simulation (GVCS) of doubly resistively terminated LC bandpass filters, with minimum capacitors that can be equal-valued and minimum opamps is proposed. With the proposed GVCS, some new minimum capacitor minimum opamp topologies for the realization of bandpass filters are derived. The improved sensitivity performance of the derived circuits over that of the cascade design is demonstrated through practical design examples. Furthermore, it is also shown that all of the derived circuits can always be designed to have good dynamic range.

A new class of circuits for the realization of second-order filters with finite transmission zeros is proposed. The proposed circuits have their pole frequency to be independent of the amplifier gain. Design formulae with all the capacitors to be arbitrarily chosen are presented. Additionally, a new single amplifier third-order low-pass notch filter circuit is also proposed. The design formulae with all the capacitors arbitrarily chosen are explicit and extremely simple.

Optimum topologies for the realization of symmetrical bandpass filters with minimum capacitors and minimum opamps are proposed. The derivation of them is largely based on some important results of the GVCS synthesis proposed previously by the author. Design equations for the realization of fourth, sixth and eighth order elliptic bandpass filters are presented in detail and generalized to high order synthesis. Finally the low sensitivity property of the proposed topologies is demonstrated through design examples. Furthermore, some suboptimum topologies, which design equations are much simpler than that for the corresponding optimum topologies, are also presented.