An Estimation Technique for Accurately Modelling the Magnetic Recording Channel Including Nonlinearities

Nonlinear distortion in the recording process of the magnetic recording channel causes severe degradation and leads to detected bit errors at higher densities and data rates. Identification and quantification of the nonlinear write effects are important to a reliable magnetic recording system. Identification or rough quantification of the nonlinearities has been described by Palmer et al.¹,² The technique they used involves the recording of a pseudorandom binary sequence and the processing of the readback complex waveform. Based on their method, we will describe a channel model (which may be called a modified superposition model) and an estimation technique which can accurately estimate the nonlinearities of the magnetic recording channel.