A classic analog application is the precision active full-wave rectifier. Many different implementations exist of this theme, each with its own supposed advantages. However, one circuit element needed ...

Current-mode full-wave rectifiers and precision rectification techniques represent vital advancements in signal processing, enabling the conversion of alternating current (AC) signals into a stable ...

And here it is, modelled using LTSpice. It is the same circuit as the classic simple precision rectifier (set to pass the negative half-sine), but with the non-inverting input of the op-amp connected ...