磁気記録における非線形磁化遷移点シフトの測定法に関する検討

Abstract

In magnetic recording it is known that nonlinear distortion occurs in the recording process. Nonlinear distortion is separated into phase distortion and amplitude distortion; phase distortion is a shift in position and amplitude distortion is variability in the magnetization magnitude of magnetic transition in relation to the recording signal pattern. As nonlinear distortion increases the probability of errors in digital recording, it is important to be able to measure and analyse distortion. In this paper, we propose a new measuring method to estimate the nonlinear magnetic transition shift precisely from the dipulse response of the recording/reproduction system. Using this method, the nonlinear magnetic transition shift is measured by varying the amplitude, codebit reversal interval and the degree of low-frequency suppression of recording current using MP tape and Co-amorphous heads. As a result, nonlinear transition shift occurs and increases at a range exceeding 50% of the optimum recording current. It also increases at a range less than 0.5 μm of the distance between current and preceding magnetic transitions, and reaches a minimum value at a certain degree of low-frequency suppression of recording current.