Comments on “A Note on Spectral Conditions for Positive Realness of Single-Input-Single-Output Systems With Strictly Proper Transfer Functions”.

The necessary and sufficient conditions for (strict) positive realness of strictly proper transfer functions are derived in the above-mentioned paper refid="ref1"/. Presenting a counter-example, we show that there are inconsistencies between definitions stated in refid="sec2"Section II and main results proved in section III of refid="ref1"/. Also, the required corrections in the main results of refid="ref1"/ are presented. Note however that the results in refid="ref1"/ are correct for the definition of SPR in the Circuit Theory sense. [ABSTRACT FROM AUTHOR]