On Analysis of Harmonic Distortion in Op Amps Based Circuits via Volterra Series

A. Borys (Gdynia Maritime Univ., Poland)

This paper was inspired by an article entitled “An approach to model high-frequency distortion in negative-feedback amplifiers” by S. O. Cannizzaro, G. Palumbo, and S. Pennisi. The objective of this presentation is to point out that some results presented therein are not so novel as argued. First, we point out here that an idea of partition of a nonlinear circuit into interconnected smaller basic blocks, used in the above paper under a name of an analytical approach, is not new. For the first time, it has been used in the literature by S. Narayanan, pioneer of the Volterra series usage in calculations of nonlinear distortion in electronic circuits, and afterwards by many others. Second, we show that descriptions of the basic blocks mentioned above follow from their more general representations by the Volterra series, specialized for harmonic inputs. Third, we recall references in which the joint and complementary elements as well as some invariants occurring in modelling of op amp inverting and non-inverting configurations for the purpose of nonlinear distortion evaluation have been reported before publication of some similar results by S. O. Cannizzaro, G. Palumbo, and S. Pennisi. Finally, we show that an operator o that was introduced by the above authors in their paper leads to calculation errors. Alternative approach to this point is presented.