Dual input summing/differentialdifferentiators: applications as a high frequency tunable selective filter

Abstract

A two-amplifier single grounded-capacitor active-RC network is proposed. Analysis of the network in the low and high frequency regions has been carried out assuming respectively high-gain ideal amplifiers and single-pole frequency-dependent-gain amplifiers. The network realises a dual-input tunable differentiator, both summing and differential, in the low-frequency bands with appropriate design. In the high-frequency regions, the circuit can be conveniently designed to yield a second-order bandpass type filter function with single-resistor tunability of ω o and Q. This design utilises the amplifier gain-bandwidth parameter. All the design equations along with some recommendations on the choice of the amplifier types suitable for the dual-input summing/differetial circuit capabilities at low and high frequency ranges have been included. The network parameters have been shown to exhibit low active/passive sensitivities.