On linear integrators and differentiators using instantaneous companding

The principle of instantaneous companding, previously proposed for circuits using linear capacitors, is expanded on and extended in four ways: a) necessary conditions for input-output linearity of integrators are derived, b) differentiator circuits are proposed, c) implementations with inductors instead of capacitors are examined, and d) it is shown that, in principle, nonlinear capacitors or inductors can be used while maintaining input-output linearity