Scaled time-constant true integrator-differentiator building block

Operational amplifier-based circuits to produce both true integrators and differentiators in the same scheme are presented. Instead of resorting to a complementary scheme of an integrator for the realization of a differentiator or vice versa, one of a pair of resistors is either disconnected or connected to a specific point in the circuit to produce the desired integrator or the differentiator. The disconnection or connection change can be provided through an appropriate switching scheme. Both the integrator and the differentiator so derived have their time constants scaled with either a resistance ratio scale factor (RRSF) or a difference term divisor scale factor (DTDSF), allowing very large time constants to be realized in the schemes. All the schemes use two operational amplifiers (ΟA), but the performance limitations encountered in conventional integrators-differentiators are eliminated.