Nonlinear distortion in long wavelength AC bias recording

Nonlinear distortion due to tape magnetization nonlinearity is analyzed for long wavelength ac bias recording. A normal distribution of particle switching fields is assumed in order to derive a transfer function. Harmonic components are computed by Fourier expansion, not only for idealized uniform magnetization but also for practical nonuniform magnetization throughout tape coating thickness. To calculate harmonics for nonuniform magnetization, the tape coating thickness is divided into thin layers. Even though the vertical magnetization component and the demagnetizing field effect are neglected, the computed results for nonuniform magnetization exhibit excellent quantitative agreement with experimental data.