Write process study utilizing non-linear distortion (NLD) harmonic ratio measurements and modeling

Harmonic ratio based measurements such as non-linear transition shift (NLTS) and partial erasure (PE) were critical to the characterization of written transition quality of inductive heads. However, with the transition to magneto-resistive based reader elements, such critical measurements have lost their ability to accurately characterize written signal quality due to the non-linearity in the readback response. In this paper, we examine in detail why and how non-linear distortion of the reader effects of NLTS, and NLTS pre-comp method via measurements and modeling to give further insight on the interpretation of these classical write process measurement techniques.